Strains producing β-glucosidase were isolated by solid medium containing esculin and ferric.Then six strains having high β-glucosidase activity were selected with p-nitropheny l-β-D-glucopyranoside as substrate.Strain having high ginsenoside bioconversion was finally chosen with Rbl as substrate and converted products were determined by TLC and HPLC.β-glucosidase activity of this strain was 0.803 U/mL and ginsenoside Rd conversation rate was 97.234 2％.The selected strain was identified as Saccharomycopsisfibuligera based on the morphology and nucleotide sequence analysis of the 18S rDNA.Fermentation medium was optimized to contain lactose as carbon source and corn flour as nitrogen source,and Ca2+ as metal ion.Finally inducer was optimized to promote the ginsenoside bioconversion.Results indicated that inducer had little impact on the bioconversion but rutin,a kind of inducer,could promote the bioconversion of Rd to CK.The selected strain with high ginsenoside bioconversion had good potential application.

Single-factor experiment and response surface methodology were used to optimize the ultrasonic-assisted aqueous two-phase extraction of polysaccharides from Potentilla anserina L. Four key factors including ethanol concentration, ammonium sulfate concentration, solid-liquid ratio and ultrasonic power were selected by one-factor-at-a-time experiments. The optimum conditions of ultrasonic-assisted aqueous two-phase extraction of polysaccharides from Potentilla anserina L. were as follows: Ultrasonic power at 240 W with 31% ethanol volume and 19% ammonium sulfate, the extraction yield of polysaccharides from Potentilla anserina L. reached (9.035±0.119)%. Infrared spectrum analysis confirmed that the extracts were polysaccharides. Potentilla anserina polysaccharide was composed of rhamnose, mannose, glucose and galactose, with the molar ratio of 1.00∶1.69∶10.61∶2.66. The in vitro activity results showed that the antioxidant activity of polysaccharides extracted by ultrasonic-assisted two-phase extraction was better than that of traditional water extraction. Ultrasonic assisted aqueous two-phase technology was a reliable and efficient method for polysaccharide extraction.

研究了分别用HCl和乳酸调节培养基初始pH以及在发酵过程中加入不同的酸中和剂对乳酸菌生长和乳酸产量的影响.结果表明,终产物乳酸的积累是抑制乳酸菌生长和导致乳酸产量下降的直接原因,该情况随发酵液中H+浓度的升高(即pH的降低)而增强,H+的积累对菌体生长和产酸的影响是间接的;用CaCO3调节发酵液pH优于用NaOH和NH4OH.

Microbial food cultures are important resources of the traditional fermented food industry.In this review,the references related to functional strains from Chinese traditional fermented foods such as dairy,baijiu,tea,soy sauce,vinegar,sufu and pickle were gathered and analyzed.The scientific criteria for evaluation of microbial food cultures were summarized.The first inventory of microbial species used in Chinese traditional fermented foods was proposed,which contained 30 genera and 75 species,including 42 bacteria,12 yeasts,and 21 filamentous fungi.After analyzing the functions of microbial food cultures during the key fermentation processes,the main functions of microbial food cultures were producing flavor substances and functional enzymes,improving the nutritional value,inhibiting competitive microbes,and improving the food texture,which aimed to provide scientific basis for improving the management of microbial food cultures in China.

Microbial food cultures are important germplasm resources of the traditional fermented food industry.Based on the research of the first edition of the inventory,this study reviewed,analyzed and updated the microbial food cultures isolated from Chinese traditional fermented foods such as baijiu,dairy,condiments and tea et al.It is proposed the second inventory of microbial food cultures used in Chinese traditional fermented foods,which contained 56 genera and 124 species,including 74 bacteria,22 yeasts,and 28 filamentous fungi.Compared with the first inventory,49 new species have been added,such as the genus of Acetobacter spp., Bacillus spp., Companilactobacillus spp., Lactococcus spp., Weissella spp., Clostridium spp., Candida spp., Debaryomyces spp., Pichia spp., Aspergillus spp.,Eurotium spp. and Rhizopus spp., et al.Furthermore,the taxonomy of 41 species have been updated.This research provides references and scientific basis for application and management of microbial food cultures used in traditional fermented foods and it also aims to promote the healthy development of Chinese fermented food industry.

研究了不同种类人参中皂苷含量,以及人参不同部位中的皂苷成分及比例.总皂苷含量测定结果为,三七参根中含14.2%,西洋参须中含10.1%,人参根中含4.4%,人参头中含8.6%,人参皮中含6.7%,人参叶中含7.7%,人参须中含9.9%.对西洋参须、三七参根及吉林产的人参头、人参皮、人参叶、人参根、人参须中的总皂苷作TLC检测及薄层扫描表明,三七参根中Rg1含量最高,西洋参须中Rb1含量最高,人参根中Rd的含量可以忽略,人参叶中含有特征皂苷F2;它们的Rb1/Rg1值分别为,西洋参须中22.2,三七参根中0.6,人参头中4.3,人参皮中6.7,人参叶中0.2,人参根中2.4,人参须中11.9.

木糖广泛存在于林业及农业废弃物中,木糖发酵生产乙醇是再生资源的有效利用.文中报道了近几年来在利用基因工程菌发酵木糖生产乙醇方面的研究进展.重点介绍了大肠杆菌、酿酒酵母、树干毕赤酵母及运动发酵单胞菌的基因改造情况.

Collagen peptides(CPs) emerging as a new functional protein ingredients,were developing rapidly at home and abroad in recent years.In order to scientifically guide the industry crowd engaged and concerned about the CPs and promote the healthy and sustainable development of the CPs industry,the CPs definition,properties,preparation technology as well as current situation of domestic and foreign CPs industry were reviewed in this paper.And the three questions which concerned about by the downstream production enterprises and consumers during the promotion process of CPs,including the relationship between raw material sources and CPs product quality,the relationship between CPs efficacy and molecular weight,and the applied laws and regulations of CPs,were clarified.Finally,the research and development trends of CPs were prospected.

植物油是食用油的主要来源,植物油氧化对食品安全和人体健康有重要影响.因受到环境及其组成因素的影响,植物油脂氧化过程有别于脂肪酸简单氧化过程,全面了解其氧化过程及机理对于开展抗氧化研究具有重要意义.该文归纳了植物油氧化过程以及宏观氧化机理,并对各阶段氧化产物检测技术的发展进行了总结,最后系统综述了植物油脂氧化的影响因素,以期为相关工作的深入研究提供借鉴.

综述了抗氧化剂抑制脂质氧化、清除自由基、抑制自由基对底物的氧化降解以及还原能力4类测定抗氧化活性的方法,并讨论了评价或表征测定结果的方法和参数以及对测定方法的要求.

对低甲氧基果胶的胶凝机理及影响胶凝的主要因素--pH值、可溶性固形物含量、钙离子浓度进行了探讨,并针对低甲氧基果胶应用中产生的降低产品质量的预凝胶问题进行了讨论,为分析低甲氧基果胶应用中的问题提供了依据,并提出了一些防止预凝胶形成的措施.

简要介绍了我国果蔬贮藏保鲜的现状,指出了当前果蔬贮藏的主要问题.论述了国内外有关果蔬贮藏保鲜的新技术及研究进展情况,包括:天然果蔬保鲜剂的研究、利用调压技术贮藏、臭氧及负氧离子保鲜、利用生物技术保鲜、静电场处理贮藏、低剂量辐射处理和紫外线处理保鲜以及细胞水结构化气调保鲜等国内外近几年发展起来的现代果蔬贮藏保鲜技术.并阐述了科技对我国果蔬贮藏保鲜产业的支撑作用.

生物类黄酮具有多种生物活性,可用于延缓衰老,治疗和预防癌症、心血管病等退变性疾病,具有很大的开发应用价值.论文就生物类黄酮的生物活性、药理作用、提取分离方法及应用进行了详细阐述,旨在为生物类黄酮的研究、开发、应用提供参考.

花青素是一种存在于自然界的水溶性多酚类化合物,现巴发现其具有多种功能.有关花青素的提取、分离和纯化研究报道很多,文中就近年来国内外相关方面的研究进展进行了分析.

蛋白质乳浊液体系是食品中最重要的体系之一.如何提高蛋白质乳浊液体系的稳定性的问题一直是食品科学家关心的热点,文中主要介绍了蛋白质乳浊液体系稳定性的破坏,有关乳浊液体系稳定的理论以及影响乳浊液体系稳定性的因素,如蛋白质的功能性质,乳化剂以及pH值和盐等.同时,文中还介绍了多糖与蛋白质相互作用对蛋白质乳浊液体系稳定性的影响.

乳酸菌是革兰氏阳性菌,广泛用于食品、医药、轻工业及饲料工业等行业.对乳酸菌进行遗传操作是调节、优化其代谢途径的基础.通过基因敲除技术改造乳酸菌基因组,可以判断基因组中未知基因所编码产物的功能,有目的、有选择地使乳酸菌生产有益的异源基因产物.基因敲除技术已成为当前乳酸菌分子生物学研究的热点.文中对几种乳酸菌基因敲除策略研究进展及影响敲除效率的因素进行了综述,分析存在的问题并初步探讨展望了乳酸菌敲除技术的未来发展趋势.

综述了鱼肉制品腥味物质的形成机理、检测方法和脱除方法的国内外研究进展.重点介绍了物理法、化学法、生物法、感官屏蔽法祛腥的特点及应用,旨在为鱼内制品加工过程中的脱腥研究提供参考和借鉴.

介绍了利用可见分光光度法测定还原糖的几种新方法,如MBTH、甲胺法,以及一些经典方法如DNS法、铁氰化物法、BCA法的改进情况.分析了各方法的优劣和适用范围,为多糖水解酶的活力测定提供指导.

对近几年来国内外将二氧化氯(ClO2)应用于食品保鲜的研究概况进行了综述,其中包括在果蔬、畜禽制品、奶制品、水产品和饮料保鲜中的最新研究进展.ClO2是一种高效安全的杀菌剂、食品保鲜剂,能够有效杀死微生物、无气味残留,可以阻止蛋氨酸生成乙烯,破坏已生成的乙烯,并对动植物机体不产生毒效,在食品保鲜中具有独特的性能优势.文中还对其应用前景进行了展望.

微生物酵素食品是以乳酸菌、酵母菌等益生菌发酵果品、蔬菜而成的一种富含脂肪酶、淀粉酶、蛋白酶和超氧化物歧化酶及乳酸、醋酸和少量乙醇等代谢产物的一种功能性液体或固体食品.文章综述了微生物酵素食品的营养和保健功效、主要含有的微生物和酶以及生产发酵工艺和应用等方面的研究进展,并展望了我国酵素食品应用的广阔前景.