【摘要】 通过大豆分离蛋白(soybean protein isolate,SPI)冷冻前后功能性的变化,研究低温冷冻条件(料液比、冷冻温度、冷冻时间)对SPI功能性(保水保油性、乳化特性及质构特性)的影响。结果表明:在经过冷冻实验的样品中,随着SPI添加量的减小,其保水保油性、乳化性先增加后减小,当SPI料液比为1∶12时,其保水性、保油性、乳化稳定性、硬度和弹性均达到相对最大;冷冻温度为-18℃时,其保水保油性、乳化性、硬度和弹性相对最大,-20℃时,其乳化稳定性相对最好;随着冷冻时间延长,其乳化稳定性减小,冷冻3 d时,SPI的乳化稳定性相对最好,冷冻2 d时其保水性相对最大。和未经冷冻处理的原样品相比,经过冷冻处理的SPI,功能性明显减弱,其中保水保油性、乳化性、质构特性都小于未冷冻处理的SPI。更多还原

【Abstract】 The changes in functional properties of soybean protein isolates(SPI) before and after freezing were investigated to reveal the effect of cryopreservation conditions, namely sample concentration, freezing temperature, freezing time on functional properties of SPI including water-holding capacity, oil-holding capacity, emulsifying property and texture property. The results showed that reduced SPI concentration could lead to an initial increase and then a final decrease in water-holding capacity, oil-holding capacity and emulsifying property. When SPI concentration was 1:12, the waterholding capacity, oil-holding capacity, emulsion stability, hardness and elasticity achieved maximum levels. When freezing temperature was-18 ℃, the water-holding capacity, oil-holding capacity, emulsion stability, hardness and elasticity reached maximum levels; however, when freezing temperature was-20 ℃, the best emulsion stability was observed. With the prolongation of freezing time, the emulsion stability of SPI gradually decreased, reaching the highest level when freezing time was 3 days; after 2 days of freezing, the highest water-holding capacity was achieved. Compared with unfrozen samples, the functional properties of frozen SPI were obviously weakened, indicating poorer water-holding capacity, oilholding capacity, emulsifying property and texture property.更多还原