大豆分离蛋白-大米粉复合凝胶特性及形成机理研究

Research on gelation characteristics and formation mechanism of soy protein isolate-rice flour composite gel

将大豆分离蛋白(soy protein isolate, SPI)和大米粉(rice flour, RF)按比例混合后水浴加热制备复合凝胶,以SPI 100%为对照,考查RF的添加量对SPI与RF形成的复合凝胶特性的影响及复合凝胶形成机制。结果表明,添加RF制备的SPI-RF复合凝胶的持水性和黏度系数均高于对照样品(P<0.05);随着RF添加量的增加,SPI-RF复合凝胶的硬度、弹性、胶黏性、咀嚼性皆呈先升后降的趋势(P<0.05);RF添加量为40%时,复合凝胶的持水性、硬度、弹性、胶黏性和咀嚼性均达最大值,依次为87.33%、1 739.491 g、0.230、1 104.656和1 084.008。分子对接结果显示,SPI中蛋白质与RF中的淀粉分子主要通过氢键和疏水作用形成复合凝胶,用原子力显微镜(atomic force microscope, AFM)观察微观结构,可见来自SPI和RF中蛋白质、淀粉分子的单条链、多条链及聚集体的存在。RF的添加能显著提高SPI的凝胶特性,在植物基产品加工中有应用潜力。

Soy protein isolate(SPI)and rice flour(RF)were mixed in an appropriate proportion and then heated in the water bath to prepare SPI-RF composite gel.SPI 100%was used as the control to investigate the effects of different concentrations of RF on the gel properties,the gelatinization mechanisms of SPI-RF composite gel was revealed.Results showed that the water holding capacity and viscosity coefficient of the composite gel were higher than those of the control sample(P<0.05).The hardness,elasticity,viscosity,and chewiness of the gel raised initially and then reduced(P<0.05)as the amount of RF increased.The water holding capacity,hardness,elasticity,adhesiveness,and chewiness of SPI-RF 40%gel reached the maximum values,which were 87.33%,1739.491 g,0.230,1104.656,and 1084.008,respectively.Molecular docking indicated that the main interaction force of protein-starch in the gel were the hydrogen bond and hydrophobic interaction.The microstructure was examined by atomic force microscopy(AFM),the single chain,multiple chains,and chain aggregates were showed.Obviously,the addition of RF improved significantly the gel properties of SPI,that would be potential for application in plant-based products.