Studies on the Antigenicity and Antioxidant Activity of Milk and Soy Proteins

• Main Authors: Tsai, Yi-Ting, 蔡宜婷
• Other Authors: Wang, Cheng-Hsin
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/68012173267195147131

碩士 === 靜宜大學 === 食品營養學系 === 103 === Milk and soy proteins possessed good functionalities but some are also general allergenic. This study aimed to investigate the structure, antigenicity and antioxidant activity of the allergens in milk and soy proteins which were treated using sugars, heat treatment and enzymatic hydrolysis. The changes of protein structure and antigenicity on milk and soybean proteins were investigated using electrophoresis, competitive ELISA and Western blot analysis. The ABTS radical scavenging ability and lipid peroxidation assay were used to determine the antioxidant activity of milk and soybean proteins. The results showed that the antigenicity of casein was decreased and the antioxidant activity of casein was elevated after trypsin-hydrolysis. In the casein combined with lactose model system, (1) Maillard reaction did not have significant effect on the antigenicity. Maillard reaction and enzymatic hydrolysis treatments could decrease of antigenicity, but had no effect on the antioxidant activity; (2) Treatment with 20% lactose at 90℃ significantly increase the antigenicity. These results suggested that Maillard reaction products might contribute to the formation of glycation. In the casein combined with xylooligosaccharide model system, Maillard reaction did not have significant effect on the antigenicity; the antigenicity was decreased after enzymatic hydrolysis; the antigenicity of casein combined with 20% xylooligosaccharide was significantly increased by the heating temperature. SPI antibodies prepared in this laboratory,show great specificity and might have potential in determination of the effects of different processing conditions on the antigenicity of soybean proteins. Bovine serum albumin (BSA), BSA combined with xylooligosaccharide, casein and whey protein had no significant effect on the antioxidant activity and oxidative stability of the ground meat system using TBARS method. In conclusion, the treatments such as adding sugar, heating and enzymatic hydrolysis on the protein samples might induce the changes of protein structure, formation of polymers and Maillard reaction products. These treatments further induced protein denaturation, changes of the antigen and antibody interaction and destruction of epitopes, and thus reduced the antigenicity.