The alluring aroma of jasmine is adored by people worldwide.Benzyl acetate, a key component of the scent of jasmine, is a valuable aromatic ester compound and extensively used as flavor and fragrance in food, cosmetics, and pharmaceutical industries.However, its current production heavily relies on chemical synthesis.In this study, a de novo synthesis pathway of benzyl acetate was established in Escherichia coli strains, and benzyl acetate was successfully synthesized by microbial fermentation.Firstly, to construct the synthesis pathway of benzyl acetate, nine functional enzymes were co-expressed in BL21 (DE3) using a modular strategy.The resulting strain BZ04 produced (85.55±10.85) mg/L benzyl acetate by two-phase in situ extractive fermentation.Subsequently, the production of benzyl acetate was enhanced through the optimal screening of key acyltransferase derived from various sources and optimization of various flask culture conditions including the screen of carbon sources, the addition of solubilizer, and the increase of oxygen supply.Under optimal fermentation conditions, the final strain of BZ05 produced (592.22±36.95) mg/L benzyl acetate from glycerol in shake flasks, which was seven times compared to original production of benzyl acetate.This study provides an eco-friendly and sustainable approach for benzyl acetate production.

During the fermentation process of starchy foods, the low pH environment poses a severe challenge to the stability of maltogenic amylase.At present, most maltogenic amylase is sensitive to acidic conditions and rapidly inactivates in low pH environments, which limits its application in bread making.This research studied the maltogenic amylase derived from Lactobacillus paralimentarius and designed mutation sites for acid-resistant modification from both the pKa value of the catalytic center and surface charge.Through single-point mutation and combined mutation, the best forward acid-resistant mutant K322D/K361D was successfully screened.Its optimal pH dropped from 5.0 to 4.5, and the hydrolysis activity at pH 4.5 increased to 433.23 U/mg, which was 2.27 times higher than that of the wild type.Its stability was greater than 68% in the pH range of 4.0-5.0.Structural and electrostatic potential energy analysis showed that the change in the net charge on the surface of the mutant helped to improve the conformational state of the enzyme, enhanced the ability to adjust the flexible structure, and thereby improving pH stability.This study provides a theoretical basis for improving the anti-aging effect of maltogenic amylase in flour products and shows good application prospects.

This study established a rapid and efficient method for separating and purifying lactase using elastin-like polypeptides (ELP) tags and molecular adhesive "SpyTag/SpyCatcher", and investigated the enzymatic properties of the obtained recombinant lactase (Lac-ELP) and its application in the synthesis of GOS.The lactase gene lac was cloned from Lactobacillus kefieranofaciens ZW3 and linked to the "Spytag".The lactase containing Spytag was expressed in E.coli DH5α.The gene fragment elp encoding ELP was obtained through gene synthesis and connected downstream of the Spycatcher encoding gene.The ELP tag containing SpyCatcher was expressed in E.coli DH5α.Subsequently, by spontaneously connecting of SpyTag and SpyCatcher, Lac-SpyTag and SpyCatcher-ELP were fused to obtain recombinant lactase Lac-SpyTag-SpyCatcher-ELP (Lac-ELP).The Lac-ELP was separated and purified by using the inverse transition cycling (ITC) technology, and a molecular weight of 115 KDa was successfully obtained, with a recovery efficiency of 73.8%.Subsequently, the influence of ELP tag on activity of Lac was compared.The optimal temperature for both Lac-ELP and Lac is 50 ℃, and the optimal pH is 7.0.However, Lac-ELP exhibits better thermal and pH stability than Lac.Finally, the application of Lac-ELP in the preparation of GOS was studied using lactose as a substrate.The results showed that Lac-ELP exhibited good transglycoside activity, with a substrate concentration of 400 mg/mL and a Lac-ELP addition of 10 U/g lactose.After 24 hours of reaction at 35 ℃, the yield of GOS reached 33.23%.In summary, the ELP based lactase purification technology established in this study is convenient and can quickly obtain highly active recombinant lactase, providing a reference for the industrial synthesis of GOS.

Dihydrocarvone, a natural terpene compound, has widespread applications in the fields of medicine, food, cosmetics, and chemical industries.It can be produced through the reduction of carvone catalyzed by ene reductase.However, the coenzyme NAD(P)H required for the reaction is expensive, serving as a restrictive factor for large-scale production.In this study, the glucose dehydrogenase (GDH) from Bacillus subtilis 9902 was cloned and expressed.Based on the previously obtained ene reductase KlebER1A303N from Klebsiella sp.O852, the co-expression system of KlebER1A303N and GDH in Escherichia coli was constructed using co-expression and fusion expression strategies.The differences in the expression of target proteins and the catalytic synthesis of dihydrocarvone among different strategies were compared and analyzed.The results showed that both co-expression and fusion expression could successfully express the desired target proteins and catalyze the conversion of carvone to dihydrocarvone.Nevertheless, the effects of fusion expression were superior to that of co-expression, with a conversion rate reaching 50% after 3 h of reaction.Additionally, the order of genes in fusion expression exerted a certain influence on the catalytic synthesis of dihydrocarvone.This study offers a foundation for establishing an efficient and low-cost industrial production method for dihydrocarvone.

Penicillin acylase is mainly used in the semi-synthetic industrial production of β-lactam antibiotics.This thesis, the pga gene was obtained from Providencia rettgeri, heterologously expressed in Komagataella pastoris GS115, and the enzyme production conditions were optimized for the recombinant enzyme PA.The results of the heterologous expression constructs showed that the enzyme activity of reorganization K. pastoris fermentation supernatant was 2 155.59 U/L, and the precipitated enzyme activity was 1 375.75 U/L. The optimal conditions for induction of enzyme production of recombinant enzyme were 29 ℃, 72 h, and methanol concentration of 1.5%, and the activity of recombinant enzyme PA was (5 003.72±50.623) U/L, which was 1.57-fold higher than the pre-optimization enzyme activity, and the purified The protein size was 72 kDa, the protein concentration was 1.58 mg/mL, the optimum reaction temperature of the purified recombinant enzyme was 60 ℃, the optimum pH was 7, and it was strongly inhibited by Mn²⁺ and activated by Al³⁺.The results of this study can provide guidance for the heterologous expression of penicillin acylase and further industrial applications.

This study screened a strain of laccase-producing bacteria with high-efficiency lignin degradation ability from the natural environment by using enzyme activity as an evaluation index and the phenol blue decolorization method.Physiological and biochemical indicators and 16S rDNA molecular biology identification results showed that this strain was Bacillus subtilis, named Bacillus subtilis HB-011.Through the annotation of the Bacillus subtilis HB-011 whole gene analysis in the GO, COG, KEGG, and CAZY databases, the related pathways for its degradation of lignin were preliminarily speculated.The enzymology property research experiment showed that the fermented laccase had good stability under the conditions of pH 2-6 and temperature 20-55 ℃.The strain Bacillus subtilis HB-011 had good application potential in the degradation of lignin.This study provides strain reserves and theoretical basis for the research of high-efficiency degradation of lignin laccase.

The Lactococcus garvieae is a functionally significant microorganism widely present in the Baijiu brewing ecosystem.It not only produces diverse flavor compounds during fermentation but also plays a pivotal role in maintaining the ecological balance of the brewing system. The study annotated the functional genes of four strains of L.garvieae isolated from pit mud environments, conducted a pan-genome analysis in combination with other ecological niches of L.garvieae to explore their population characteristics in phylogenetic development and individual specificities in the Baijiu environment.The results revealed an open state of the L.garvieae pan-genome, with the core genome primarily involved in basic metabolic functions of the bacteria.The KEGG annotation of the core genome demonstrates that the L.garvieae genome possesses the ability to produce cellulases, glycosidases, and esterases, enzymes that facilitate microbial growth.Additionally, it generated precursor substances, including lactic acid, acetic acid, and ethanol.These precursors were catalyzed by esterase activity, resulting in the formation of lactic ethyl ester and acetic ethyl ester.Virulence factor analysis indicated that the four strains of L.garvieae isolated from pit mud environment possess safety at the genomic level, but may be potentially influenced by external regulatory factors.Substantial horizontal gene transfer was observed in L.garvieae.The findings of this study reveal the genetic diversity and evolutionary characteristics of L.garvieae, providing a theoretical basis for its application in the Baijiu industry.

Streptococcus salivarius subsp. thermophilus is widely used in industrial fermentation due to its excellent fermentation and aroma production characteristics.Although there are unique and diverse resources of Streptococcus thermophilus in China, few studies have been conducted on the growth and fermentation characteristics of strains isolated from Chinese traditionally fermented dairy products.This study analyzed the growth and fermentation characteristics of four Streptococcus salivarius subsp. thermophilus strains isolated from China which are located in different branches of the evolutionary tree.It was found that only CCFM1095 and CCFM1308 could metabolize and utilize galactose in carbon source utilization.There were significant differences among different strains in terms of nitrogen source utilization, only CCFM1015 could utilize casein and CCFM1095 with 8 amino acid nutritional deficiencies.The composition of nitrogen sources in the milk system limited the growth and fermentation of all strains except CCFM1015.Therefore, strain CCFM1015 had the potential as a starter culture, CCFM1095 had fast lactose utilization ability and CCFM1038 was efficient in utilization of amino acids, which could provide a basis for the improvement of fermentation conditions and application of subsequent strains.

This study investigated the interactions between a high-exopolysaccharide-producing Lactobacillus kefiri (L63) isolated from kefir and two different yeasts derived from kefir.Using qPCR to amplify characteristic sequences of L63, the growth status during monoculture and coculture was determined.Results revealed that Kluyveromyces marxianus Y4 initially promoted the growth of L63, while both yeasts inhibited its growth in the later stages of fermentation.The phenol-sulfuric acid method was employed to measure differences in exopolysaccharide (EPS) production during monoculture and coculture.It was observed that coculturing with either yeast significantly increased EPS production (P<0.01).During the co-fermentation of skim milk, it was found that coculturing with both yeasts significantly increased acidity in the early fermentation stage, while in the later stage, results tended to align with a monoculture of L63.Metabolomic analysis revealed differential metabolite distribution during coculture, primarily associated with cell growth, energy metabolism, and respiratory processes, closely linked to the growth status of the cells, thereby partially elucidating the reasons for the observed changes in growth status during coculture of L63.

The bacterium Paenibacillus polymyxa HL11 was identified through morphological, physiological, biochemical experiments, and molecular biology techniques (16S rDNA).The antibacterial activity of HL11 against pathogenic Phytophthora infesfans and the Spongospora subterranea was evaluated using the plate confrontation method.The effects of volatile substances produced by HL11 on the mycelial morphology of these fungi were observed using optical microscopy and scanning electron microscopy.The volatiles were analyzed using headspace solid-phase microextraction and gas chromatography-tandem mass spectrometry.The in vitro control efficacy of these volatiles against potato late blight and potato powdery scab was also assessed.Results indicated that the average inhibition rates of HL11's volatiles against the pathogenic P. infestans and S. subterranea were (77.75±1.78)% and (54.37±1.39)%, respectively.Scanning electron microscopy revealed that exposure to HL11 volatiles caused mycelial tip swelling, surface indentation, and protrusions in the fungi.GC-MS identified 12 components with similarity over 80%, among which the antibacterial agents were primarily 3-hydroxy-2-butanone and 2-phenylethanol, accounting for 17.34% and 1.86% of the volatiles, respectively.The volatiles produced by HL11 demonstrated a protective effect against potato late blight and potato powdery scab, with control efficacies of (50±0.68)% and (41.67±0.55)%, respectively.These findings are significant for the development and utilization of HL11.

The purpose of this study was to investigate the effects of different concentrations of sodium chloride on the mixed biofilm formation of Listeria monocytogenes and Vibrio parahaemolyticus.The biomasses and metabolic activities of single species and mixed biofilm, the cell composition of biofilm and plankton at different NaCl concentrations were determined, and the interaction between the two bacteria was analyzed.The results showed that the mixed biofilm exhibited stronger biofilm formation and metabolic activity compared to the single biofilm.The dominant strain in the mixed culture system was L.monocytogenes in the TSB medium with 0.5 g/100 mL NaCl, while V.parahaemolyticus dominated in the mixed culture system at 1-5 g/100mL NaCl.L.monocytogenes showed promotion effects on the formation of V.parahaemolyticus biofilm, and V.parahaemolyticus inhibited that of L.monocytogenes.The interaction between the two bacteria was strongest at 1.5 g/100 mL NaCl concentration.In general, V.parahaemolyticus was the dominant strain in the mixed biofilm.This study provides scientific data for the control of mixed biofilm contamination of L.monocytogenes and V.parahaemolyticus.

Orthodontic treatment represents an effective modality for the amelioration of dental alignment and occlusal relationships.However, this process is frequently accompanied by excessive resorption of the alveolar bone in orthodontic patients.Prevotella intermedia has been identified as a pivotal microorganism influencing alveolar bone resorption.Consequently, the prevention of P.intermedia colonization in the oral cavity of orthodontic patients may serve to forestall the onset of alveolar bone resorption.This study initially validated the inhibitory effects of Lactiplantibacillus plantarum CCFM8724 on P.intermedia biofilms in vitro.Subsequently, the modulatory effects of L.plantarum CCFM8724 were investigated in orthodontic model rats.The interventions were assessed by monitoring bone metabolism indicators, histopathology of the alveolar bone, colonization levels of P.intermedia in the rat oral cavity, and the expression levels of gingival tissue inflammatory factors.The results showed that L.plantarum CCFM8724 significantly increased the bone volume/tissue volume (BV/TV) ratio at root apex of the first molar in rats (P<0.01), suppressed the expression of TNF-α and IL-6 in periodontal tissue, and upregulated osteoprotegerin (OPG) expression in serum (P<0.01).Furthermore, compared to the model group, P.intermedia colonization was significantly reduced following administration of L.plantarum CCFM8724 (P<0.05).These findings suggested that L.plantarum CCFM8724 can mitigate orthodontic-induced alveolar bone resorption in rats by inhibiting P.intermedia colonization in the oral cavity, downregulating orthodontic and pathogenic microbe-induced periodontal inflammation, and increasing the ratio of OPG to receptor activator of nuclear factor-kappa B ligand (RANKL) in the OPG/RANKL/RANK pathway.The study provides novel insights into the clinical management of orthodontically induced alveolar bone resorption.

To investigate the effects of Zhenjiang aromatic vinegar (VAR) on gut microbiota and its metabolites of normal C57BL/6J mice, we used 16S rRNA gene sequencing and metabolomics techniques.After continuous oral administration of VAR in mice for four weeks, we found that compared with the control group, the weight and serum high-density lipoprotein (HDL) content of mice in the VAR group were significantly increased.VAR significantly increased the α diversity of gut microbiota, and promoted the abundance of potentially beneficial bacteria such as Akkermansia and Lachnospiraceae_NK4A136, while inhibiting Desulfovibrio.Linear discriminant analysis (LEfSe) revealed that the VAR group's biomarkers were Lachnospiraceae, Bacteroidales, Muribaculaceae, Oscillospiraceae, and Ruminococcaceae.Functional prediction analysis with PICRUSt2 (Phylogenetic Investigation of Communities by Reconstruction of Unobserved States 2) revealed that the bacterial community of VAR promoted citric acid cycle, tyrosine, and glutathione metabolism, and inhibited cell apoptosis.Extensive metabolomic analysis of stool showed that the content of metabolites such as ascorbic acid and adrenergic substances, isoleucine and urobilin, which are conducive to maintaining normal life activities, increased significantly in the VAR group.The results demonstrated that VAR could significantly modulate gut microbiota and metabolites, which laid a theoretical foundation for its functional food development.

To investigate the anti-inflammatory mechanisms of monascinol (MC), monascin (MS), and ankaflavin (AK), the Monascus yellow pigment MC was extracted and separated from the red yeast rice obtained by the solid-state fermentation of Monascus CP-1 and then its purity was analyzed using thin-layer chromatography (TLC) and HPLC. Inflammatory models of human THP-1 macrophages and mouse RAW264.7 macrophages were established using 2 μg/mL lipopolysaccharide (LPS), and morphological observations were conducted. Cell viability was determined using the methylthiazolyldiphenyl-tetrazolium bromide (MTT) method. The effect of Monascus yellow pigment MC on the expression of IL-6 and TNF-α in LPS-induced THP-1 and RAW264.7 cells was measured using quantitative real-time polymerase chain reaction (RT-qPCR) and enzyme linked immunosorbent assay (ELISA), with MS and AK as references. The results indicated that the purity of MC reached over 98%, making it suitable for cellular experiments. After 24 hours of treatment with 6 μg/mL of MC, MS, and AK, the cell viability of THP-1 cells exceeded 90%, meeting the experimental requirements. After treating THP-1 cells and RAW264.7 cells with 6 μg/mL of MC, MS, and AK for 24 hours, the expression of interleukin-6 (IL-6) was significantly suppressed at both the transcriptional and translational levels (P<0.01). MC inhibited the expression of tumor necrosis factor-α (TNF-α) in THP-1 and RAW264.7 cells at both the transcriptional and translational levels significantly (P<0.01), whereas MS and AK only suppressed the secretion of TNF-α in RAW264.7 cells at the translational level significantly (P<0.01).

Achyranthes bidentata polysaccharide (AP) is a functional compound in A. bidentata with diverse pharmacological effects, including antitumor and immunomodulatory properties.However, the impact of AP on the intestinal health of lung cancer patients remains unclear.To investigate the gastrointestinal digestive properties of AP and its influence on the gut microbiota in lung cancer patients by utilizing an in vitro simulation of the gastrointestinal digestive system and the fecal fermentation model tailored to lung cancer patients.These findings showed that the molecular weight of AP remained relatively unchanged following simulated digestion by oral, gastric, and small intestinal fluids in vitro, reflecting it could transit to the colon in a more intact form.After fermented by fecal flora of patients with lung cancer, it regulated the structures and compositions of gut microbiota in the fermentation fluid, promoting the growth of beneficial bacterial genera such as Prevotella, Phascolarctobacterium, Akkermansia, and others while inhibiting the proliferation of Ruminococcus and Sutterella.Meanwhile, AP promoted the production of acetic acid, propionic acid, and butyric acid.In addition, functional predictions indicated that AP improved microbial metabolic function, promoted amino acid biosynthesis, pantothenic acid and coenzyme A metabolism, and had the potential to inhibit the development of lung cancer.In conclusion, the ability of AP to modulate the gut microbiota and promote the production of short-chain fatty acids in lung cancer patients may provide new ideas for the prevention and mitigation of lung cancer.

As one of the efficient and safe selenium-enriched foods, selenium-enriched green tea has gained an increasing interest.This study investigated the effects of ultrafine grinding and conventional grinding on the proximate compositions, selenium species, and powder properties of selenium-enriched green tea.This study further explored the release profile of selenoamino acids from ultra-fine selenium-enriched green tea and its in vitro probiotic characteristics.Results indicated that ultrafine grinding could significantly increase the release of free amino acids, chlorophyll, and total extractables from the tea as well as enhance its expansion behavior and solubility.However, it did not affect the content and species of selenium.The in vitro simulated gastrointestinal digestion revealed that the release rates of selenomethionine and methyl-selenocysteine within ultra-fine selenium-enriched green tea gradually increased during the digestion process, while selenocysteine was reduced to selenomethionine during the intestinal digestion phase.Subsequently, the residue of ultra-fine selenium-enriched green tea powder obtained after gastrointestinal digestion was used for the in vitro human fecal fermentation.Compared with the control group without green tea, the addition of ultra-fine selenium-enriched green tea increased the DPPH and ABTS radical scavenging activities, along with iron-reducing capacity in the fecal slurry supernatant after 24 h fermentation.Besides, the addition of ultra-fine selenium-enriched green tea increased the enzymatic activities of superoxide dismutase and glutathione peroxidase within the intestinal flora and the production of total short-chain fatty acids by at least 300% and 105%, respectively.Microbial diversity analysis indicated that ultra-fine selenium-enriched green tea powder significantly improved the intestinal flora structure by decreasing the Firmicutes/Bacteroidota ratio and the relative abundance of Bilophila and Fusobacterium, highlighting its potential in mitigating obesity, intestinal inflammation, and related diseases.This study provided a theoretical perspective for the development and advancement of ultra-fine selenium-enriched tea products.

To determine the impact of Lactiplantibacillus plantarun N1 fermentation on Auricularia auricula-judae polysaccharides, the polysaccharides were extracted using ethanol precipitation, deproteinized via the Sevag method, and further purified using DEAE-Sepharose Fast Flow and Sephacryl S-300 columns, resulting in the refined polysaccharide designated as fermented Auricularia auricula-judae polysaccharide-2-1 (FAAP-2-1). The hypoglycemic activities of FAAP-2-1 were evaluated using insulin-resistant HepG2(IR-HepG2) cell models and diabetic zebrafish models.Real-time qPCR was utilized to investigate the mechanisms underlying glucose reduction.Results showed that FAAP-2-1, with a molecular weight of 1.48×10⁶ Da, primarily comprises eight monosaccharides:galactose, mannose, xylose, fucose, glucose, arabinose, galacturonic acid, and glucuronic acid, at ratios of 4.27∶55.27∶0.36∶1.90∶16.34∶1.54∶2.51∶17.81.Experiments indicated that FAAP-2-1 restores glucose consumption in IR-HepG2 cells and decreases blood glucose in diabetic zebrafish by 73.52%.Furthermore, FAAP-2-1 upregulates the expression of genes related to diabetes, including AKT, PI3K, IRS, and GLUT2, thereby ameliorating glucose metabolism abnormalities in diabetic zebrafish and improving insulin sensitivity via the PI3K/AKT pathway.

To evaluate the effect of fermentation on the in vitro hypoglycemic and antioxidant activities of goji berry juice, the most suitable strains for fermentation of goji berry juice were preferably selected through the fermentation performance and in vitro hypoglycemic activities of Lacticaseibacillus rhamnosus, Lactobacillus acidophilus, Lactiplantibacillus plantarum, and Lacticaseibacillus paracasei on goji berry juice.The fermentation process of goji berry juice was optimized by using response surface methodology.Results showed that L. paracasei showed better acid resistance, bile salt resistance, fermentation performance, and higher α-amylase and α-glucosidase inhibition.The optimal fermentation process was 9 h of fermentation time, 5% inoculum, and a fermentation temperature of 37 ℃.Compared with unfermented wolfberry juice, the polyphenol content increased by 5.66%, the total flavonoid content increased significantly by 31.81%, the scavenging rate of DPPH free radicals and hydroxyl radicals could reach up to 92.3% and 95.84%, and the scavenging rate of ABTS cationic radicals was significantly increased by 42.74%, as well as the inhibition rate of α-glucosidase was also significantly increased by 30.23%.Probiotic fermentation enhanced the in vitro antioxidant and hypoglycemic activities of goji berry juice to a certain extent, which provided a theoretical basis for the subsequent study of fermented goji berry food with hypoglycemic function.

In this study, an effective protocol for the preparation of water-soluble yeast β-D-glucan (WSYG) was established.By means of dimethyl sulfoxide(DMSO) extraction and ethanol precipitation, WSYG was prepared from brewer's yeast cell wall.The optimal process conditions were determined by response surface analysis.Besides, the physicochemical properties of WSYG were investigated using HPLC, GC, FT-IR, and Congo red test.And its antioxidant and hypoglycemic activities were evaluated through in vitro experiments.The results indicated that the maximum yield of WSYG was (16.38±0.17)% and the polysaccharide content was (96.02±1.37)%, using the DMSO-dissolved ethanol precipitation method with the conditions of 90% (v/v) DMSO concentration, 91% (v/v) ethanol concentration, and a 4.4∶1 volume ratio of ethanol to DMSO solution.The relative molecular mass of the polysaccharide was 602.56 kDa, and monosaccharide composition analysis showed that it consisted solely of D-glucose, and the infrared spectrogram displayed characteristic absorption peaks of polysaccharides with a β-configuration.Furthermore, the atomic force microscopy and the Congo red test demonstrated that it existed in a chain form and did not possess a triple helix structure in aqueous solution, which might contribute to the increased water-solubility of yeast β-glucan.The in vitro activity assays revealed that WSYG had excellent superoxide anion scavenging ability and inhibitory effects on α-amylase and α-glucosidase, exhibiting certain hypoglycemic activity.This approach is facile and practical, and the resulting WSYG demonstrates high purity and good activity.The findings of this study can provide a theoretical basis for the further development and utilization of yeast β-glucan.

In the manufacturing process of Jiang-flavor high-temperature Daqu, affected by the environment and operation, three colors of high-temperature Daqu will inevitably form, including yellow Daqu, white Daqu, and black Daqu.To clarify the quality differences between the three colors of Daqu and their impact on the entire production cycle of Jiang-flavor liquor, this study first measured the physicochemical indicators and enzymatic properties of different colors of Daqu and analyzed the physicochemical properties of the three colors of Daqu.Secondly, using the finished Daqu as a control group, the three colors of Daqu were used in in-situ fermentation experiments to explore the effects of different colors of Daqu on the fermentation parameters of different rounds of fermented grains of Jiang-flavor liquor and the flavors of different rounds of fermented liquor samples.Results showed that black Daqu had higher total acidity and reducing sugar content than yellow and white Daqu, while white Daqu exhibited significantly superior enzymatic activity compared to yellow and black Daqu.At the same time, Daqu of different colors was used to drive the fermentation of Jiang-flavor liquor, and it was found that the impact of rounds on the flavor of the liquor samples was far greater than the effect of Daqu of different colors on the flavor of the liquor samples.In addition, it found that in the first round, the content of higher alcohols in the liquor samples fermented with black Daqu was significantly higher than that of other liquor samples.In the fifth round, the content of ester substances in the liquor samples fermented with white Daqu was significantly higher than that of other liquor samples.In the seventh round, the content of various flavor substances in the liquor samples fermented with white Daqu was higher than that of other liquor samples.This study provides theoretical support for the full and reasonable utilization of Daqu of different colors at different stages of rounds.

The 7 kinds of medium-temperature Daqu (EEDS, HB, HT, LT, MGW, ST, YHD) in Inner Mongolia were used as the research objects, and their physicochemical and microbial diversity were analyzed.The results showed that there were differences in moisture, acidity, saccharifying power and liquefying power and fermentation power among them.Saccharifying and liquefying power of EEDS were significantly higher than the other 6 kinds of Daqu (P<0.05).There were differences in the types and abundances of the dominant bacterial genera of these 7 kinds of Daqu.Pseudomonas was dominant in EEDS, Streptomyces was dominant in HB, LT and ST, Staphylococcus was dominant in HT and MGW, Weissella was dominant in YHD;there are differences in the types and abundance of their dominant fungal genera, Aspergillus was dominant in EEDS, MGW, ST and YHD, Monascus was dominant in HB;Rhizopus was dominant in LT;Thermomyces was dominant in HT.Beta diversity analyses (PCoA) were performed to assess the divergence in the structure of the microbial community in the 7 kinds of Daqu, they were divided into 2 groups in terms of bacterial(group a:EEDS, HB, LT, ST and YHD, group b:MGW and HT) and fungal (group c:EEDS, ST, LT, HB, MGW and YHD, group d:HT) community composition.In the bacterial community, Staphylococcus in group b was the main differential microorganism;in the fungal community, Aspergillus and Thermomyces were the main differential microorganisms in group c and d.The correlation analysis has revealed that physicochemical properties (P<0.05) are significantly correlated with 16 dominant bacterial genera and 9 dominant fungal genera.Staphylococcus was the main differential microorganism in group b, which had significant positive correlation with acidity (P<0.05).

This study conducted an intensive fermentation with aroma-producing yeast-Wickerhamomyces, during the fermentation process, monitored the key physicochemical factors such as temperature, moisture, and total acid of the grains, analyzed the structure of the vinegar flora by Illumina Miseq high-throughput sequencing, analyzed the volatile components of the vinegar by headspace solid phase microextraction gas chromatography-mass spectrometry, and combined with the sensory evaluation, to determine the effect of the enhanced fermentation.The effect of fermentation was determined.Results showed that the key physicochemical indexes of the control group and the aroma-producing yeast group differed to a certain extent during the fermentation process without adding aroma-producing yeast as the control, among which the total acid content of the vinegar spirits in the aroma-producing yeast group increased by 4.7%, and the utilization rate of starch increased by 4.80%, the aroma-producing yeast group increased aroma significantly, and the relative content of alcohols in the vinegar increased by 187.34%, the relative content of volatile acids increased by 45.75%, and the relative content of esters increased by 128.99%, especially phenylethanol, 2,3-butanediol, acetic acid, ethyl acetate, ethyl lactate, and other contents increased significantly.Lactobacillus, Acetobacter, Bacillus, Pichia, Aspergillus, Saccharomyces, Issatchenkia, and Wickerhamomyces were the main dominant genera in the fermentation process.Compared with the control group, the introduction of aroma-producing yeast increased the relative abundance of Wickerhamomyces in the pre-fermentation and mid-fermentation periods, and disturbed the Lactobacillus, Acetobacter, Picrytus, Saccharomyces, and Trichoderma in the grains of vinegar, which resulted in differential changes in the bacterial flora structure.The results of this study indicate that the aroma-producing yeast can significantly improve the flavor quality of bran vinegar, and provide a reference for the improvement of flavor quality of bran vinegar.

The raw materials and degree of fermentation affect the growth and metabolism of fermented Pu-erh tea microbiota, which ultimately affects the quality of fermentation.This study used 16S rRNA and ITS amplicon sequencing to study the effect of the raw materials and degree of fermentation on the fermented Pu-erh tea's microbiota differences and quality.Results showed that the abundance and diversity of the prokaryotic microbiota of high-fermented Pu-erh tea were significantly higher, but the abundance of eukaryotic flora decreased significantly.Compared to light-fermented teas, the high degree of fermentation was more conducive to increasing the content of soluble polysaccharides, lignin, total flavonoids, proteins, and theabrownin in Pu-erh tea.The fermentation of tea stems significantly increased Pseudomonas (86.78%) abundance and decreased protein content.Adding honey significantly increased Aspergillus (87.47%) abundance and increased the content of theabrownin.Fermentation of yellow tea-leaf comprehensively increased the abundance of Aspergillus (31.90%), Thermomyces (41.91%), Rhizomucor (20.09%), Pseudomonas (40.46%), and Bacillus (21.44%), and increased the content of soluble polysaccharides.The predictions of PICRUSt2 function revealed that the degree of fermentation had a greater effect on the microbiota of fermented Pu-erh tea than the fermented raw material.Redundancy analysis revealed that free amino acids, lignin, cellulose, and theabrownin were significantly associated with eukaryotic microbiota, while proteins and soluble polysaccharides were significantly associated with prokaryotic microbiota.This study provides a theoretical basis for the strain improvement of the fermentation process of Pu-erh tea.

In order to investigate the effect of aromatic amino acids on the colour stability of anthocyanin, the present experiments investigated the co-pigmentation of three amino acids (L-phenylalanine, L-tryptophan, and L-tyrosine) with malvidin-3-O-glucoside in a model solution of red wine, screened for the optimal co-pigment by using co-pigmentation and thermodynamic parameters of the reaction as the indexes, and analyzed the interaction using Fourier transform infrared (FT-IR) spectroscopy, molecular docking, and molecular simulation.The results showed that the best tryptophan co-pigment was achieved at the highest molar ratio of 1∶100 (λ_max increased by 46.19%) and ΔG°<0, a spontaneous exothermic reaction.FT-IR.Molecular docking and molecular dynamics simulations showed that L-tryptophan can interact with malvidin-3-O-glucoside through hydrogen bonding and van der Waals forces, and is the main driving force to improve the stability of amino acid-malvidin-3-O-glucoside complexes.Therefore, the stability of malvidin-3-O-glucoside can be improved by adding L-tryptophan as a co-pigment in practical applications.

Caffic acid phenethyl ester (CAPE) was known as the characteristics that are difficult to dissolve in water, unstable and easily oxidized.To address this issue, in this study, according to the characteristics of the gastrointestinal environment, CAPE was loaded into porous starch (CAPE-HD/PS) in the form of CAPE-hordein nanoparticles (CAPE-HD), which was then coated with pectin-alginate to form the pH- and α-amylase-responsive dual-responsive drug controlled-release system (CAPE-hordein nanoparticles/porous starch-pectin-alginate, CAPE-HD/PS-PA), for the oral drug delivery of CAPE.CAPE-HD/PS and CAPE-HD/PS-PA were examined for their structure, morphology, and encapsulation effect on CAPE, and were evaluated for their swelling behavior and release behavior.Results showed that CAPE and hordein were combined and loaded as nanoparticles on the surface and inside the pores of porous starch, and uniformly dispersed in a three-dimensional hydrogel network cross-linked by pectin and alginate.Moreover, after loading onto the complex hydrogel, the state of existence of CAPE changed.Instead of simple physical mixing between the components in the complex, new conjugates were formed by non-covalent forces such as hydrogen bonding.The hydrogel spheres showed swelling characteristics of “contraction” in simulated gastric fluid and “swelling” in simulated intestinal fluid.The results of the release behavior study showed that CAPE-HD/PS-PA had the dual-responsive release characteristics of pH and α-amylase, which effectively realized the protection of CAPE in gastric fluid and the controlled release effect in the intestine, and was conducive to the improvement of CAPE dispersion and bioavailability.The development of the CAPE-HD/PS-PA complex hydrogel system provides a new development direction for the clinical use of difficult-to-soluble active ingredients, such as CAPE, and provides a basis and reference for edible polysaccharides, such as porous starch and pectin, in the field of oral delivery of drugs or active ingredients.

(-)-Epigallocatechin-3-gallate (EGCG) exhibits physiological functions such as antioxidation, anti-inflammation, anti-tumor properties, and cardiac protection.However, its application is limited due to poor stability and rapid degradation during the early stages of digestion.This study utilized a water-in-oil (W/O) emulsion template to prepare microcapsules in the internal aqueous phase, creating a microcapsule-shell structured W/O high internal phase emulsions (MS-W/O HIPEs).The structure of W/O HIPEs, the digestion characteristics of the loaded EGCG, and their effects on mouse colitis were characterized using Cryo-scanning electron microscopy, rheometry, simulated in vitro digestion, and animal experiments.Compared to W/O HIPEs and BW-W/O HIPEs, MS-W/O HIPEs exhibited higher gel strength.The encapsulated EGCG in MS-W/O HIPEs retained about 14 times more EGCG post-intestinal digestion than the EGCG solution, significantly slowing down the degradation of EGCG during digestion.Compared to the EGCG solution, the MS-W/O HIPEs loaded with EGCG significantly improved symptoms in mice such as weight loss, colon redness, and shortening, effectively reducing the expression of pro-inflammatory factors TNF-α, IL-1β, and IL-6, and promoted the production of the anti-inflammatory factor IL-10.In summary, using a W/O emulsion template to prepare microcapsules in the internal aqueous phase to construct MS-W/O HIPEs is a reliable technique for colonic delivery of EGCG, laying a theoretical foundation for the development of EGCG-related products.

To solve the problem of moisture loss and sensory quality degradation of deacetylated konjac gel food due to freezing, composite gels were prepared by mixing gelatin (GEL) and deacetylation konjac glucomannan (DKGM).The effects of GEL additions (10%, 20%, and 30% on weight basis) on the water-holding capability, texture, rheology, and thermal stability of the DKGM gels were investigated under freeze-thaw cycles (0, 1, 3, and 5 cycles), and the mechanism to improvement the freeze-thaw stability of the composite gels was also explored.Results showed that GEL significantly improved the water-holding capability (P<0.05), textural properties, and freezing resistance of DKGM gels and suppressed the deterioration of rheological properties.In addition, GEL reduced the amount of freezable water inside the gel.GEL maintained the crystallinity, the microstructural integrity, and compactness of DKGM gels during freeze-thaw.In conclusion, GEL provided protection for DKGM gels during the freeze-thaw process and improved their freeze-thaw stability.

The phosvitin phosphopeptide (PPP) was obtained through enzymatic hydrolysis of phosvitin (PV) and subsequently chelated with zinc to produce the phosvitin phosphopeptide-zinc chelate (PPP-Zn), aiming to develop safe and highly bioavailable zinc supplements.PV was initially subjected to a two-step enzymatic hydrolysis using alkaline protease and trypsin, followed by a third step involving α-chymotrypsin.The conditions for enzymatic hydrolysis were optimized based on the degree of hydrolysis to prepare PPP effectively.The preparation process of PPP-Zn was further optimized using response surface methodology, with the zinc chelation rate as an index parameter.The structure of PPP-Zn was characterized using Zeta potential analysis, fluorescence spectroscopy, Fourier transform infrared spectroscopy, and scanning electron microscopy.Results showed that the optimal conditions for preparing PPP were pH 7.50 and enzymolysis at 50 ℃ for 4 h with an addition of 8% α-chymotrypsin, resulting in a hydrolysis degree of (26.62±0.39)%.For PPP-Zn preparation, the optimum conditions included a mass ratio of zinc to peptide at 1∶90(g∶mmol), pH 5.20, and temperature at 60 ℃ for 60 min, achieving a zinc chelation rate of (94.18±0.38)%.Upon zinc chelation, both Zeta potential and fluorescence intensity decreased while FTIR spectra indicated that carboxyl oxygen atoms, amino nitrogen atoms, and phosphate groups within PPP served as primary sites for binding with zinc ions.The high content of zinc in PPP-Zn indicated its promising potential as a novel type of effective zinc supplement.

To investigate the effect of cellulase pretreatment on the flavor proteinase hydrolysis of Lanmaoa asiatica, this study focused on L. asiatica, using reducing sugar content as the evaluation index, optimized the cellulase pretreatment process through single-factor and orthogonal experiments.Peptide content and amino nitrogen content were used as indicators to further evaluate the impact of cellulase-assisted flavor proteinase hydrolysis.Subsequently, intelligent sensory evaluation techniques (electronic nose, electronic tongue) were used to analyze the flavor of the hydrolysate.The results showed that the optimal cellulase pretreatment process was cellulase addition of 0.3%, initial pH of 4.0, at 45 ℃ for 4 hours, with a released reducing sugar content of (5.002±0.02) μg/mL under these conditions.Compared to direct hydrolysis, cellulase pretreatment followed by flavor proteinase hydrolysis significantly increased the peptide content and amino nitrogen content of the hydrolysate.The intelligent sensory evaluation results indicated that the aroma profile of the hydrolysate changed after cellulase pretreatment, with noticeable differences in aroma and taste.In conclusion, cellulase pretreatment followed by flavor proteinase hydrolysis can effectively enhance the release of flavor substances in L. asiatica.

To assess the effectiveness of ultra-fine mango powder with peel in ice cream, the effects of dried ultra-fine mango powder retained mango peel on the physicochemical, functional, and sensory properties of ice cream were investigated in the present study.Results showed that, comparing the ice cream prepared with mango flavorings to commercially available freeze-dried mango powder (IC1 and IC2), the L^*, pH, and total soluble solid content of ice cream made by using ultra-fine mango powder with peel (IC3) decreased.Furthermore, particle size, viscosity, a^*, b^*, ΔE^*, expansion, adhesiveness, springiness, and chewiness increased.There was no significant change in density, gumminess, cohesiveness, resilience, and thermal properties.During the melting process, the first dropping time of IC3 was 17.27 min, which was 8.75 and 0.68 min longer than the IC1 and IC2 of ice creams respectively.Moreover, the melting rate was reduced by 19.41% and 6.24%, respectively.The total phenol content of IC3 was 56.38 μg GAE/g, which was 1.52 times higher than that of the IC2 ice creams.In addition, the total flavonoid content, β-carotene content, and antioxidant capacity were also significantly improved.In flavor, it was indistinguishable from freeze-dried mango powder and differed significantly from mango flavorings.High acceptability was also obtained in the sensory evaluation.Overall, ultra-fine mango powder with peel improved the nutritional and functional value of the ice cream, providing a replacement for the traditional freeze-dried mango powder and mango flavor in mango ice cream production.

The microbial community succession of raw camel milk during cold storage is a complex and significant process, which has an important impact on the quality of camel milk.In this paper, the physical and chemical properties and microscopic characteristics of raw milk during cold storage were studied.The differences in microstructure and protein structure of raw milk stored at 4 ℃ for 6 days were compared, and the deterioration law of raw milk during cold storage was discussed.Results showed that with the extension of cold storage time, the main physical and chemical properties (fat, protein, lactose) in raw milk showed dynamic changes, and the pH generally showed a downward trend.The main microorganisms (total number of colonies, number of psychrophilic bacteria, number of Escherichia coli, number of lactic acid bacteria) increased significantly.After 3 days of cold storage, the activity of key enzymes (lipase and protease) decreased.In addition, based on Fourier transform infrared spectroscopy, the results of raw milk with different cold storage treatments showed that with the extension of cold storage time, the peaks of fat, protein and lactose in raw camel milk shifted after 3 days.Therefore, the third day of cold storage is the key stage of quality control of raw camel milk.

To obtain a drying method with high retention of 6′-O-caffioylarbutin (CA), 3′-O-caffeoylquinic acid (CGA) and Arbutin (Arb) in ‘Quezui Tea', nine drying methods of hot air drying (HAD), freeze vacuum drying (FVD), vacuum drying (VD), sun drying (SD), microware drying (MD), natural air drying (NAD), boiling and natural air drying (B-NAD), steaming and natural air drying (S-NAD), and quick-boiling and natural air drying (QB-NAD) were used to dry the leaf buds of Vaccinium dunalianum.HPLC was used to establish the content analysis method of three main components.Furthermore, six different pretreatment times were set to optimize the innovative methods S-NAD, QB-NAD, and B-NAD.Results showed that the contents of the three main components obtained by 9 drying methods were CA>CGA>Arb.S-NAD was the drying method with the highest retention of CA and CGA content, up to 428.726 mg/g and 13.213 mg/g respectively.VD was the drying method with the highest retention of Arb content, up to 16.054 mg/g, and S-NAD method could also obtain a higher Arb content (11.815 mg/g).The optimal pretreatment time of the three innovative drying methods was S-NAD steaming for 5 min, QB-NAD scalding for 1 min, and B-NAD boiling for 1 min, respectively.Therefore, the drying method significantly affected the retention content of the three main active components, but the order of the content of the three main active components was not affected by the drying method in ‘Quezui Tea'.To achieve high retention of the three main components of in ‘Quezui Tea' at the same time, S-NAD was the most suitable drying method, and steaming pretreatment for 5 min is the best.

This study aimed to investigate the effects of microbial solid-state fermentation technology on the quality characteristics of instant porridge made from sea red rice.Using sea red rice as the research subject, instant porridge was prepared using extrusion puffing technology, followed by solid-state fermentation with Saccharomyces cerevisiae and Bacillus subtilis.The study explored the impact of solid-state fermentation on the nutritional and quality characteristics of sea red rice instant porridge.The results indicated that after microbial solid-state fermentation, the amylose content in sea red rice instant porridge decreased by 50.89%, while the amylopectin/amylose ratio and soluble dietary fiber content increased by 14.92% and 16.59%, respectively.Additionally, the organic selenium content and selenium bioavailability increased by 60.51% and 2.54 times, respectively.The color of the porridge remained essentially unchanged, the rehydration time decreased by 17.30%, and its pasting properties and sensory qualities were significantly improved.Differential scanning calorimetry analysis showed that solid-state fermentation reduced the onset temperature, peak temperature, and end temperature of gelatinization, with an enthalpy value reduction of 16%.The microstructure of the instant porridge was altered post-fermentation, exhibiting a rough surface with cracks and micropores.In summary, microbial solid-state fermentation significantly enhanced the physicochemical and quality characteristics of sea red rice instant porridge, providing a theoretical foundation for the high-value utilization and intensive processing of sea red rice.

Aligned with the growing emphasis on whole food nutrition and its health benefits, this study aimed to provide theoretical insights for the development of functional staple foods and to foster advancements in the miscellaneous pasta products industry.The research investigated the quality attributes, gluten protein structure, and antioxidant properties of noodles produced by substituting wheat flour with varying proportions of quinoa whole flour in Chinese dried noodles.The experimental results indicated that incorporating quinoa whole flour augmented the content of free thiol groups (—SH) while reducing the content of glutenin macropolymer.This dual effect potentially decreases the formation of gluten polymers and impairs the viscoelastic properties of the noodles.Scanning electron microscopy results revealed disruptions in the continuity of the gluten network structure.Furthermore, as the proportion of quinoa whole flour increased, the L^* value of the noodles decreased significantly, while both a^* and b^* values exhibited progressive increments.The noodles exhibited an overall light brown color, indicating improved antioxidant properties.However, excessive incorporation of quinoa flour adversely affected the cooking quality and texture of the noodles.The study concluded that adding quinoa flour at levels up to 20% holds promise for developing noodles with antioxidant activity while maintaining desirable cooking and textural characteristics.

Toughness biscuits are popular among consumers because of their crispy taste and distinct layers.And many factors such as ingredients and processing technology can affect their toughness, among which dough modulation is the key to obtaining suitable tough dough.The stirring time (5, 15, 25, 35, 45 min) was used as a variable to explore the effect of stirring intensity on the characteristics of ductile dough and its baking quality.The results show that with the increase of mixing time, the tensile properties of the dough first increase and then decrease.Elastic modulus G′ of the dough increases first and then decreases by a rheometer, and viscous modulus G″ continues to increase.The low-field NMR shows that the content of strongly bound water decreases significantly at 35 min, and some free water is precipitated.Fourier infrared spectrometer show that the proportions of α-helix and β-sheets decrease at 35 min, which was consistent with the results of disulfide bond and free sulfhydryl content.The results of scanning electron microscopy show that stirring time affect the binding degree of starch and gluten protein in the dough.And the baking characteristics of biscuits are also different under different stirring times, and the taste of biscuits is the best under 35 min conditions, which is consistent with the results of their texture characteristics, namely moderate hardness, crisp and delicious.Therefore, considering the characteristics of the tough dough and the quality of the biscuits under various conditions, the final mixing time of the dough is 35 min.

Consumers prefer cured fish due to its distinctive flavor and convenient preservation methods.Color is a crucial attribute for assessing product quality, however, the current cured fish products exhibit varying degrees of redness due to disparities in raw materials and processing techniques.To investigate the key factors influencing the formation of red color in cured fish, this study focused on two types of cured fish samples exhibiting distinct colors (dark red and yellow white).The analysis compared the variations in color-presenting substances between these different colored cured fish products, while also examining the impact of different degrees of bleeding on both color-presenting substances and coloration by varying slaughter methods.Results showed that myoglobin content in dark red and yellow white fish was 7.32 mg/g and 13.00 mg/g, nitroso-heme content was 69.21 mg/kg and 5.41 mg/kg, total pigment content was 83.64 mg/kg and 13.15 mg/kg, and heme iron content was 7.23 mg/kg and 0.75 mg/kg, indicating that heme content played a crucial role in influencing the formation of red color in cured fish.The hemoglobin residues in the fish obtained through two slaughter methods with and without bloodletting were 132.60 mg/kg and 26.16 mg/kg, respectively.The redness of the sample without bloodletting exhibited a significantly higher level compared to that of the sample with bloodletting following nitrite addition for curing, and the contents of nitroso heme were measured to be 13.05 mg/kg and 5.03 mg/kg, respectively, indicating that slaughter methods can influence the residual hemoglobin levels in fish to enhance the color rendering effect of cured fish.

In this study, the combined technique of freeze drying (FD) and hot air drying (HAD) was used to dry Xinjiang quince pulp.The effects of combined drying on the physical indices (colour difference, microstructure, hardness, and volumetric shrinkage) and active substances (total phenolics, total flavonoids, triterpenoids, sterols, vitamin C, and reducing sugars) of Xinjiang quince pulp were assessed.Low-field nuclear magnetic resonance (LF-NMR) technique was used to analyze the moisture state and moisture distribution during FD to help select a suitable moisture transition point.Results showed that when the FD time was 36 h, only 8.47% of free water remained, preserving the original tissue structure of the samples.Moreover, the samples treated with HAD for another 2 h (FD36-HAD2) were similar in appearance to the FD.Under FD 12 h followed by HAD treatment for 5 h, FD12-HAD5 caused severe loss of active substances, while FD36-HAD2 pulp exhibited the highest total phenolics and total flavonoids content, triterpenes, and sterols content.Furthermore, for the same group, it did not show significant differences compared to the FD pulp, vitamin C content was 3.2 times higher than that of FD12-HAD5 pulp, and reducing sugar content was (573.37±0.16) mg/g DW.

In order to investigate the changes of quality of Phyllostachys praecox shoots under ice temperature storage, the color, microstructure, weight loss rate, hardness, soluble protein content, malondialdehyde content, lignin content, total phenol content, phenylalanine ammonolyase (PAL) and peroxidase (POD) activities of the shoots under ice temperature (-1 ℃) and control group (4 ℃) storage were analyzed, on the basis of clarifying the freezing point temperature of P. praecox shoots (-1.1 to -1.5 ℃).The correlation between the indicators was also demonstrated using Pearson heat map and principal component analysis (PCA).The results indicated that as compared with the control group, the ice temperature group not only maintained better color, but also had uniform cell arrangement and complete cell wall structure, while the cell wall structure of the control group collapsed and ruptured at 12 d.At the end of the storage period, the soluble protein content of the ice temperature group was 76.78% higher than the control group, while the lignin content and the activity of enzymes (PAL and POD) that regulated the lignification were lower than control group by 31.76%, 32.65%, and 25.60%, respectively.The results of PCA showed that the confidence circle formed in ice temperature group was smaller than control group, which mean the changes in the quality of P. praecox shoots under ice temperature were small.This study could effectively extend the shelf-life of P. praecox shoots and provide a theoretical basis for their preservation and storage.

Pullulan based films cooperated with waxy starch/thymol nanoemulsion (S-T-NE) were prepared to prolong the freshness of strawberry.The changes in structural properties of the films before and after S-T-NE addition and the impact on strawberry flavors were investigated by scanning electron microscope, fourier transform infrared reflection, X-ray diffraction, thermogravimetric analyzer, and taste sensing system.When S-T-NE was added into the matrix, the roughness of fracture surface of pullulan based film increased, and the transmittance of vibration absorption peak of hydroxyl group was enhanced and shifted to a lower wavenumber, yet the film still maintained amorphous structures as the control one.In the meantime, the addition of S-T-NE brought about the increment of water vapor permeability(WVP) value of pullulan based film from 3.37×10^-10 g/(m·s·Pa) to 6.39×10^-10 g/(m·s·Pa), and the peak temperatures of heat dissipation and pyrolysis behavior within the film both increased.When strawberries were sprayed with the film-forming solution with S-T-NE and stored at 4 ℃, the samples showed more favorable appearances and smoother surfaces through out the entire storage period.Furthermore, when strawberries were stored at 25 ℃, the sourness and bitterness values of the samples treated with S-T-NE were lower than the control group, whereas it showed higher value of umami in the group of strawberries with S-T-NE.The findings provided technical references for the potential application of bio-active nanostarch based emulsion in prolonging the freshness of perishable food.

This study aimed to investigate the antimicrobial resistance phenotype and resistance gene carrying of Vibrio alginolyticus in aquatic products in Hangzhou and to provide a reference for the prevention and control of V. alginolyticus pollution in aquatic products and improve the safety of aquatic products.The drug resistance of 14 strains of V. alginolyticus isolated from commercially available aquatic productswas detected by drug-sensitive paper diffusion method, and the multiple antimicrobial resistance index (MARI) was calculated.PCR amplification was used to detect 8 classes of 21 drug resistance genes and 1 class of integron gene, and the correlation between antimicrobial resistance phenotype and genotype of V. alginolyticus was analyzed.Results showed that fourteen strains of V. alginolyticus showed 14 antimicrobial resistance phenotypes, and all isolates were resistant to penicillin and amoxicillin, followed by cefazolin and ampicillin, which were resistant to 13 isolates respectively.A total of 13 isolates were sensitive to chloramphenicol and flufenicol, and all strains were sensitive to meropenem.The MARI of 11 isolates exceeded 0.2, accounting for 78.57% of the total.All isolates were detected to carry 3 or more antimicrobial resistance genes at the same time, sulfamide resistance gene sul1 and aminoglycoside resistance gene strB had the highest detection rates, respectively, detected in 13 isolates (92.86%), followed by tetracycline drug resistance gene tetA (85.71%), and the antimicrobial resistance genotypes were not completely consistent with the antimicrobial resistance phenotypes.This study showed that the detection rate of V. alginolyticus in aquatic products collected in Hangzhou was 13.3%.Most of the isolated strains had multiple antimicrobial resistance, and all isolates carried resistance genes of class 2 or above antibiotics, which was related to the pollution of the growth environment by antibiotics.Therefore, it is necessary to pay more attention to and standardize the rational use of antibiotics to prevent or reduce the occurrence of food safety incidents.

To elucidate the effects of temperature on the taste and aroma of light-flavor Baijiu, electronic tongue, headspace-solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS), and gas chromatography with hydrogen flame ionization detection (GC-FID) techniques were applied.The results showed the light-flavor Baijiu could maintain relatively stable taste qualities during 49 d at 25 ℃ and 35 ℃.Compared to 25 ℃, the samples stored at 35 ℃ had a slightly higher saltiness, a slightly lower umami and fresh aftertaste, and an extremely low bitterness and astringency.The taste of the samples stored at 50 ℃ for 7-21 d was similar to that at 35 ℃ for 7-49 d, and the taste at 50 ℃ for 28-49 d was similar to that at 25 ℃ for 7-49 d.Eight key aroma compounds were screened by multivariate statistical analysis with odor activity value.The clustering results indicated that the light-flavor Baijiu was able to maintain a relatively stable flavor profile in the late stage of 25 ℃ and within 49 d at 35 ℃.The excessively high temperature could cause huge changes in the aroma stability of light-flavor Baijiu.From the correlation analysis, it was hypothesized that there were aldehydes and phenols similar to each other and opposite to alcohols and esters in terms of their effect on taste, which deserved further investigation.Based on the results, the long-term stability study of the sensory reference material of Baijiu could be carried out in the middle and high-temperature range of room 25-35 ℃, and 35-50 ℃ could be used as the accelerated temperature conditions.This study provides data support for the parameter setting and auxiliary indicators screening in the stability study and provides ideas for the accelerated stability experiments of sensory reference material of Baijiu.

To study the effect of dehydration process on the polyphenol content of celery, the content changes of seven key polyphenol compounds, including rutin, hyperoside, isorhamnetin, catechin, scopoletin, gallic acid, and chlorogenic acid, were measured by high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) in the process of dehydration, and the changes of the enzyme activities of polyphenol oxidases (PPO) and peroxidases (POD) were investigated under different blanching parameters.The study showed that ultrasonic cleaning did not cause the loss of seven polyphenol substances mentioned above, and the sterilization process had a small effect on the changes in the polyphenol content of celery.Blanching significantly reduced the enzyme activity, and the activities of both PPO and POD were negatively correlated with the blanching temperature and time.The optimal blanching parameter was 90 ℃ for 90 s. The total loss of polyphenols after hot air drying was 19.46%, while the total loss of polyphenols after rehydration was 2.25%, which indicated that hot air drying was the most important step of the dehydrated celery production process in terms of the loss of polyphenol content.It provides a reference for illustrating the changes of polyphenols and enzyme activities of dehydrated celery during processing and optimizing the parameters of the production process.

Microcapsule technology is an immobilization technology that uses natural or synthetic polymer materials to encapsulate the core material to form tiny particles, which can protect the core material from the external environment and improve stability.Yeast is one of the most commonly used food-grade industrial microorganisms.The double-layer capsule structure composed of cell wall and cell membrane can realize the effective encapsulation of hydrophilic and hydrophobic compounds.The microcapsule products prepared with yeast cells as the embedding wall material are uniform in size, good in biocompatibility, and easy to biodegrade.It is a new type of green natural encapsulation matrix.In this paper, the structure and encapsulation characteristics of yeast cells, the preparation process, and performance characterization of yeast encapsulated microcapsules were reviewed.The application progresses of yeast encapsulated microcapsules in the fields of oil, nutritional additives, antibacterial agents, storage, and preservation were discussed, providing reference for the research and development of yeast encapsulated microcapsules technology in food industry.

Peptide-metal ion chelate is a stable cyclic compound formed by chelation reaction between peptide and metal ion.Peptide-metal ion chelates have been reported to possess antimicrobial activity, which makes them show application potential in preventing food spoilage.The present review provide a comprehensive overview of the antimicrobial activity, the relationship between structure and antimicrobial activity of peptide-metal ion chelates and the antimicrobial mechanism of their action on different targets.Finally, this paper summarize the application of peptide-metal ion chelates in food preservation based on the current research.It can provide a reference for the further research and development of peptide-metal ion chelates with antimicrobial activity.

Chitin and chitosan are natural polymers with good biological and cationic properties and have been widely used in many fields.However, commercial chitosan mainly relies on crustacean extraction, and the process involves a large number of chemicals, which can easily lead to environmental pollution.In contrast, fungal chitosan extraction has many advantages, such as simple extraction and good quality, but it faces the challenges of low yield and high cost.In this review, the effects of fungal chitosan producing bacteria and fungal culture factors on the yield of chitosan and the downstream extraction methods of fungal chitosan were briefly introduced, which provided a sustainable, efficient and green new way for the large-scale commercial production of fungal chitosan, so as to promote its wider application in medicine, food and environmental engineering.

Paocai is made by dipping a variety of fresh vegetables into salt brine (4%-10%) and fermenting with lactic acid bacteria as well as other microorganisms, which features unique flavor.During fermentation, the nitrate derived from vegetables would be transformed into nitrite by miscellaneous bacteria.Nitrite is a common pollutant in Paocai and poses a threat to human health.Hence, comprehensively understanding the degradation mechanisms of nitrite in Paocai, particularly its removal by microorganisms, is of great benefit to guarantee Paocai's safety.Based on the formation and transformation mechanism of nitrite in Paocai, the profile of nitrite and factors affecting nitrite content in Paocai were systematically summarized.Then, elimination approaches towards nitrite were introduced, with emphasis on biodegradation technique.Furthermore, the pathways and mechanisms of nitrite degradation by lactic acid bacteria through enzymes and acids were reviewed, together with involved enzymes and their encoding genes, degrading microorganisms and their efficacy.The present review provides theoretical basis for the production of Paocai with low or no nitrite content.

Pectin is a kind of polysaccharide present in large quantities in plant tissues, which is widely used in the food industry because of its good thickening, stabilizing and gelling properties, which can give food a unique texture and taste, and changes in its content and structure usually affect the organoleptic properties and storage stability of food.With the improvement of the quality of life and consumer awareness of modern human beings, some new thermal and non-thermal processing technologies have been gradually applied to the food industry.High pressure processing (HPP) is an emerging food processing method with great development potential in recent years, which can effectively sterilize and passivate enzymes, and also better preserve the freshness and nutrients of food.This thesis explores the effects of HPP on pectin in recent years, from the structural characteristics of pectin, the effects of HPP on the molecular weight and esterification degree of pectin, and the effects of HPP on the enzyme modification and modification of pectin, etc., to reveal the intrinsic mechanism of the effects of HPP on the quality of food products, to expand the application of pectin in the field of food products, and to provide a theoretical guidance for the sustainable development of the food industry.

As a green biodegradable material, plant-derived edible film can not only realize the function of preservative and freshness preservation, but also has many advantages such as safety and non-toxicity, isolation and protection, and as a carrier of active substances as well as edible raw materials.In view of the fact that plant-derived edible film has become a hot research topic in the field of food packaging and freshness preservation.This paper introduces an overview of three current plant-derived edible membranes of polysaccharides, proteins, and composites, elucidates the mechanisms and modes of action, and summarizes their applications in the field of food processing.Finally, the future development direction of edible films is prospected.The purpose of this review is to provide reference for further research on plant-derived edible packaging materials in the field of food preservation.

Fruits and vegetables are important food sources for human beings because they are rich in vitamins, minerals, and other nutrients.However, the quality of fruits and vegetables is easy to deteriorate after harvesting, and diseases and rotting cause serious economic losses.Slightly acidic electrolytic water (SAEW) is an emerging green sterilization technology after acidic electrolytic water, which is safer, more efficient, low-cost, and non-toxic.The work aims to explore the main mechanism of SAEW in the preservation of fruits and vegetables and the latest progress of application research. The preparation and separate use of SAEW are introduced, and the progress of application research on the synergistic treatment of SAEW with physical, chemical, and biological technologies is described.The internal mechanisms of SAEW in fruit and vegetable preservation are mainly inhibition of enzymatic browning, antioxidants, and accelerating microbial inactivation effects.Combining SAEW with other technologies can make its freshness preservation significantly improved.SAEW treatment can extend the storage period of fruits and vegetables, which is conducive to the preservation of fruits and vegetables, and combining it with other technologies is an effective method to improve the storage period of fruits and vegetables.

Wheat is one of the important grains in China with abundant nutrients and long history, and its quality has far-reaching effects on agricultural production, food processing, nutrition and health, so it is particularly important to detect wheat quality quickly and accurately.Hyperspectral imaging technology (HSI) is a combination of digital imaging technology and spectral technology, which has been widely used in wheat quality detection and achieved good research results.Compared with other inspection methods, HSI has the characteristics of high efficiency, accuracy, rapidity, and non-destructive, which has great potential and value to satisfy the needs of wheat production and processing.This paper introduced the principle and system components of HSI and summarized the application progress and current problems of HSI in wheat quality detection.This paper also analyzed and prospected the future development of HSI to provide a theoretical basis and technical support for future non-destructive testing of wheat quality.As advancements in HSI continue, it would play a pivotal role in the production and processing of wheat.