【作者】 冯学武；

【导师】 邓勇；

【作者基本信息】 中国农业大学 ， 食品科学， 2001， 硕士

【摘要】 本课题以大豆分离蛋白为原料，采用碱性蛋白酶Alcalase水解制备大豆多肽，并采用葡聚糖凝胶Sephadex G-25对大豆多肽进行了分离和分子量分布的测定。研究了水解度与大豆多肽分子量分布范围以及与苦味之间的关系。结果表明，随着水解度增加，大豆多肽混合物分子量逐渐向小分子量方向靠近，当水解度为25％左右时，多肽混合物分子量绝大多数在500-1000D，而苦味较强的多肽分子量也集中在500-1000D的范围内。本文研究了遮蔽脱苦法。有机酸、酸性氨基酸、甜味剂、β-环糊精对苦味有较好的遮蔽效果，糖酸配合使用，脱苦效果更佳。本文系统研究了pH值、温度、吸附材料用量对粉末活性炭及聚苯乙烯吸附树脂吸附脱苦的影响。粉末活性炭脱苦的最适条件为：温度55℃，pH=5.0，用量3.5％，按此条件基本可以脱除水解液的苦味。聚苯乙烯吸附树脂有一定的脱苦效果，如与1％β-环糊精联合使用，则能够彻底脱除苦味。使用2—丁醇萃取脱苦，当加入的体积与原大豆蛋白水解液的体积之比为1:1时，能够完全脱除苦味，但其安全性需要进一步的研究。 本文还研究了大豆蛋白水解前后溶液的等电点沉淀情况及去除沉淀后对苦味的影响。大豆蛋白水解液的等电点沉淀约为14％，仅为原大豆蛋白溶液的1/7。水解液去除等电点沉淀后，苦味值略有降低。研究了大豆蛋白水解度与苦味值的关系。苦味值随水解度增加至最大后，再逐渐下降。研究了使用风味酶Flavourzyme的脱苦效果。Flavourzyme复合风味酶可快速降低水解液苦味值，直至苦味消失。更多还原

【Abstract】 Soybean Peptides (SP) were prepared from soybean protein isolates by using Alcalase. The relations between Degree of Hydrolysis (DH) and distribution of Molecular Weight (MW), as well as the bitterness of peptides, were studied. The peptides were separated by gel filter chromatography according to the size of MW, and then the bitterness of the separated peptides was determined by sensory evaluation. The result showed that the MW of Soybean Protein Hydrolysates (SPH) decreased with an increase in DH. When DH reached about 25%, the MW of most SPH ranged from 500 to 1000 daltons. The bitter peptides had the same range of MW as the above. The masking method was applied to debitter SPH. Organic acids, acidic amino acids, sweet agents, and I~3 梒lcyodextrin showed a great effect on masking the bitterness, and sugar with acids had a better debittering effect. Effects of pH valve, temperature and dosage of adsorbents(active carbon and polystarene adsorptive resin) on debittering of SPH were investigated systematically. The PH value 5.0, 55拁C and 3.5% of powder active carbon was the best combination of parameters, under which, the bitterness of SPH could be removed mostly. The polystarene adsorptive resin had some effect on debittering, but subsequently application of ?cyclodextrin could remove the bitterness completely after use of polystarene absoptive resin. 2梑utanol showed a very good debittering effect. The bitterness of SPH could be eliminated with 50% (v/v) of 2梑utanol. However, special attention should be paid to security of 2梑utanol. The precipitation at isoelectrie point for SPH and soybean protein solution was studied. The precipitation amount of the soybean protein solution was seven times as high as that of SPH. After removal of the precipitation, the bitterness of SPH decreased slightly. The relation between DH & the bitterness of SPH was studied. With the increase in DH, the bitterness increased rapidly to a maximum, and subsequently dropped gradually. Flavorzyme, a exopeptidase, had a significant effect on debittering, and could drop the bitterness value rapidly & dramatically.更多还原