酶水解法制备大豆肽的研究

Studies on Preparation of Soybean Peptide by Enzymatic Hydrolysis

采用酶水解法，由大豆分离蛋白制备大豆肽。对五种蛋白酶水解大豆分离蛋白的特性进行了比较。筛选出水解能力最强的碱性蛋白酶，其最佳水解条件为：温度５５℃、ｐＨ１０．５、酶用量５％（Ｖ／Ｗ，相对于底物蛋白）、底物浓度５％（Ｗ／Ｖ）、反应时间６ｈ。水解度可达到３０％～４０％，产物平均肽链长度２．５～４．０。水解产物经超滤膜分离后的混合物溶解性良好，ＮＳＩ值达９８％以上。水解产物有很强烈地的苦味，用２０％的活性炭粉可以有效地吸附脱苦。脱苦的最佳条件是：温度５０℃～５５℃、ｐＨ４．０～４．５、活性炭／蛋白质＝０．１～０．２／１（Ｗ／Ｖ），慢速搅拌２ｈ。

The enzymatic hydrolysis method was utilized to make soybean peptides from Soybean Protein isolates (SPI).Five kinds of protases from diffirent sources (Alcalase 2709,Neutrase ASI.398,Papain,Frypsin and Pepsin)were estimated based on degree of hydrolysis (DH) and average peptide link length (APLL).Through this screening,Alcalase 2709(liquid)was selected because of the most effient hydrolysised ability.And then,proteolytic characteristics of this enzyme was investigated.The optimum conditions for enzyrnatic hydrolysis were temperature=55℃,pH=105,enzyme concentration=5%(V/W,rilative substrate protein),substrate concentration=5%(W/V),reaction time=6 h.DH can achieve 30%～40% and APLL=25～40.The bitterness of hydrolysates was very intense.The hydrolysates were seperated by ultrafilter Membrane of hollow fibers (MWCO=6000D).The NSI of product=98%.The bitter peptides were absorbed seleetively by activated carbon.The optimum conditions of Debittering were temperature=50 ℃-55 ℃,pH=40～45,ratio of activated carbon to protein=01～02(W/V),and slowly stirring 2 h.