Abstract: The effects of Alcalase (AT), Protamex (PT) or Flavorzyme (FT) treatment on the antigenicity and molecular mass distribution of proteins, flavor and color of skim milk were investigated by using various techniques such as indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) and Tricine-sodium dodecyl sulphate polyacrylamide gel electrophoresis (Tricine-SDS-PAGE). The results showed that the effect of AT treatment on reducing the antigenicity of the major milk allergens was significantly better than that of PT and FT treatment (P < 0.05). The antigenicity of α-lactalbumin (α-LA), β-lactoglobulin (β-LG) and casein (CN) was inhibited by 64.01%, 76.00% and 69.10% by AT treatment for 20 min at an enzyme/substrate ratio of 500 U/g, respectively. The amount of low molecular mass peptides in skim milk increased significantly after treatment with each of the three enzymes. The bitterness, astringency, aftertaste of bitterness (aftertaste-B) and aftertaste of astringency (aftertaste-A) increased with increasing enzymatic treatment time and with increasing enzyme/substrate ratio. The taste of FT-treated milk was better than that of AT- or PT-treated milk. The brightness value of milk decreased significantly, while the redness value increased significantly after enzymatic treatment (P < 0.05). The transmittance increased as well. The color of skim milk treated by AT was more similar to that of whole milk.

Key words: skim milk; enzymatic hydrolysis; antigenicity; taste; color

摘要： 以脱脂牛乳为原料，采用间接竞争酶联免疫吸附测定法和三(羟甲基)甲基-甘氨酸-聚丙烯酰胺凝胶电泳等 方法研究碱性蛋白酶（Alcalase，AT）、复合蛋白酶（Protamex，PT）和风味蛋白酶（Flavorzyme，FT）处理对脱 脂牛乳的抗原性、分子质量分布、滋味和色泽的影响。结果表明：AT对主要致敏乳蛋白的脱敏效果显著优于PT和 FT（P＜0.05），当酶底比为500 U/g、酶解时间为20 min时，其对α-乳白蛋白、β-乳球蛋白和酪蛋白的抗原抑制率 分别达到64.01%、76.00%和69.10%；AT、PT和FT处理后脱脂牛乳中低分子质量肽段明显增加，且苦味、涩味、苦 后味、涩后味随酶解时间延长、酶底比的增加而升高，FT处理脱脂牛乳的滋味优于AT和PT；酶解脱脂牛乳的亮度 值显著降低，红度值显著升高（P＜0.05），透光性增加，AT处理脱脂牛乳的色泽更接近于牛乳。

关键词: 脱脂牛乳；酶解；抗原性；滋味；色泽