为探究茄替胶(gum ghatti,GG)发挥乳化作用的关键结构特征,利用部分酸水解获得5种不同结构的GG组分,采用离子色谱、傅里叶变换红外光谱和气质联用等方法进行结构表征;通过美拉德反应与大豆分离蛋白(soy protein isolate,SPI)形成共价复合物,并制备水包油乳液;利用傅里叶变换红外光谱、十二烷基硫酸钠-聚丙烯酰胺凝胶电泳、粒度分析和zeta电位等技术探究复合物的理化性质及乳化特性。结果表明,随着酸水解的进行,GG的糖醛酸和蛋白质含量逐渐升高,分子质量逐渐减小,支化度逐渐降低;酸水解后的GG与SPI能形成稳定的共价复合物,支链度较低的GG与SPI共价复合后可以显著提高SPI的溶解度(36.60%>22.31%),且支链度最低的GGA5-SPI共价复合物绝对电位值显著高于GG-SPI(53.63 mV>46.99 mV),乳液体系更加稳定。综上,美拉德反应可显著提升GG-SPI复合物的功能特性与乳化特性,且GG的支链度越低,形成的复合物乳化能力越好,稳定性越高。该研究结果有望为糖-蛋白类乳化剂的研发和应用提供理论依据。
In order to explore the key structural characteristics of gum ghatti (GG) for emulsification, five GG components with different structures were obtained by partial acid hydrolysis, and their structures were characterized by ion chromatography, Fourier transform infrared spectroscopy and gas chromatography-mass spectrometry.The conjugate was formed with soy protein isolate (SPI) by Maillard reaction, and the oil-in-water emulsion was prepared.The physicochemical properties and emulsifying properties of the conjugates were investigated by infrared, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, particle size analysis and zeta potential.The results showed that with the progress of acid hydrolysis, the uronic acid and protein content of GG gradually increased, the molecular weight gradually decreased, and the degree of branching gradually decreased.The GG after acid hydrolysis could form a stable conjugate with SPI.The solubility of SPI could be significantly improved by covalently combining GG with lower branching degree with SPI (36.60%>22.31%), and the absolute potential value of GGA5-SPI conjugate with the lowest branching degree was significantly higher than that of GG-SPI (53.63 mV>46.99 mV), and the emulsion system was more stable.In summary, Maillard reaction could significantly improve the functional properties and emulsifying properties of GG-SPI conjugates, and the lower the branching degree of GG, the better the emulsifying ability and the higher the stability of the conjugates.The results are expected to provide a theoretical basis for the development and application of sugar-protein emulsifiers.
[1] TAO X, CAI Y J, LIU T X, et al.Effects of pretreatments on the structure and functional properties of okara protein[J].Food Hydrocolloids, 2019, 90:394-402.
[2] CAI Y J, DENG X L, LIU T X, et al.Effect of xanthan gum on walnut protein/xanthan gum mixtures, interfacial adsorption, and emulsion properties[J].Food Hydrocolloids, 2018, 79:391-398.
[3] HUANG L H, CAI Y J, LIU T X, et al.Stability of emulsion stabilized by low-concentration soybean protein isolate:Effects of insoluble soybean fiber[J].Food Hydrocolloids, 2019, 97:105232.
[4] LI Q Y, ZHENG J B, GE G, et al.Impact of heating treatments on physical stability and lipid-protein co-oxidation in oil-in-water emulsion prepared with soy protein isolates[J].Food Hydrocolloids, 2020, 100:105167.
[5] AL-ASSAF S, PHILLIPS G O, AMAR V.Gum ghatti[M].Handbook of Hydrocolloids.Amsterdam:Elsevier, 2009:477-494.
[6] AL-ASSAF S, AMAR V, PHILLIPS G O.Characterisation of gum ghatti and comparison with gum Arabic[M].Gums and Stabilisers for the Food Industry 14.The Royal Society of Chemistry, 2008:280-290.
[7] GUO Q B, CUI S W, WANG Q, et al.Extraction, fractionation and physicochemical characterization of water-soluble polysaccharides from Artemisia sphaerocephala Krasch seed[J].Carbohydrate Polymers, 2011, 86(2):831-836.
[8] SUN H Q, SONG W W, ZHANG L J, et al.Structural characterization and inhibition on α-glucosidase of a novel oligosaccharide from barley malt[J].Journal of Cereal Science, 2018, 82:82-93.
[9] CORTÉS-RíOS J, ZÁRATE A M, FIGUEROA J D, et al.Protein quantification by bicinchoninic acid (BCA) assay follows complex kinetics and can be performed at short incubation times[J].Analytical Biochemistry, 2020, 608:113904.
[10] GUO Q B, CUI S W, KANG J, et al.Non-starch polysaccharides from American ginseng:Physicochemical investigation and structural characterization[J].Food Hydrocolloids, 2015, 44:320-327.
[11] QIAN K Y, CUI S W, NIKIFORUK J, et al.Structural elucidation of rhamnogalacturonans from flaxseed hulls[J].Carbohydrate Research, 2012, 362:47-55.
[12] ZHANG R J, CHENG L R, LUO L, et al.Formation and characterisation of high-internal-phase emulsions stabilised by high-pressure homogenised quinoa protein isolate[J].Colloids and Surfaces A:Physicochemical and Engineering Aspects, 2021, 631:127688.
[13] LIU Y, ZHAO G L, ZHAO M M, et al.Improvement of functional properties of peanut protein isolate by conjugation with dextran through Maillard reaction[J].Food Chemistry, 2012, 131(3):901-906.
[14] 张宏媛, 钱佳俊, 李哲远, 等.部分酸水解对桃胶多糖结构和乳化功能的影响[J].食品科学, 2023, 44(4):99-106.
ZHANG H Y, QIAN J J, LI Z Y, et al.Effect of partial acid hydrolysis on the structure and emulsifying function of peach gum polysaccharide[J].Food Science, 2023, 44(4):99-106.
[15] WANG L, LIU H M, QIN G Y.Structure characterization and antioxidant activity of polysaccharides from Chinese quince seed meal[J].Food Chemistry, 2017, 234:314-322.
[16] GUO R, CAO N N, WU Y, et al.Optimized extraction and molecular characterization of polysaccharides from Sophora alopecuroides L.seeds[J].International Journal of Biological Macromolecules, 2016, 82:231-242.
[17] 冯卫生, 吴锦忠.天然药物化学[M].2版.北京:中国医药科技出版社, 2018.
[18] QU P, HUANG H Y, WU G F, et al.Effects of hydrolysis degree of soy protein isolate on the structure and performance of hydrolyzed soy protein isolate/urea/formaldehyde copolymer resin[J].Journal of Applied Polymer Science, 2015, 132(7):e41469.
[19] LI R, CUI Q, WANG G R, et al.Relationship between surface functional properties and flexibility of soy protein isolate-glucose conjugates[J].Food Hydrocolloids, 2019, 95:349-357.
[20] MA X B, HOU F R, ZHAO H H, et al.Conjugation of soy protein isolate (SPI) with pectin by ultrasound treatment[J].Food Hydrocolloids, 2020, 108:106056.
[21] CHEN L, CHEN J S, WU K G, et al.Improved low pH emulsification properties of glycated peanut protein isolate by ultrasound Maillard reaction[J].Journal of Agricultural and Food Chemistry, 2016, 64(27):5531-5538.
[22] TANG C H.Emulsifying properties of soy proteins:A critical review with emphasis on the role of conformational flexibility[J].Critical Reviews in Food Science and Nutrition, 2017, 57(12):2636-2679.
[23] ZHENG J C, XIAO N, LI Y, et al.Free radical grafting of whey protein isolate with tea polyphenol:Synthesis and changes in structural and functional properties[J].LWT, 2022, 153:112438.
[24] DAI T T, LI T, LI R Y, et al.Utilization of plant-based protein-polyphenol complexes to form and stabilize emulsions:Pea proteins and grape seed proanthocyanidins[J].Food Chemistry, 2020, 329:127219.
[25] DAI S C, LIAO P L, WANG Y L, et al.Soy protein isolate-catechin non-covalent and covalent complexes:Focus on structure, aggregation, stability and in vitro digestion characteristics[J].Food Hydrocolloids, 2023, 135:108108.
