67B-12 |
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C.-Y. CHANG and S.-H. Chiang. Department of Bioindustry Technology, Da-Yeh University, 112 Shan-Jiao Rd., Dah-Tsuen, Chang-Hwa, 515, Taiwan Bovine colostrum is the milk secreted during the first seven days by cow after birth. It is thought that colostrum can strengthen human immune system. Up to present, the researches concerning the antioxidant properties of colostrum caseins are so many, however, the relationship between the protein composition and the antioxidant properties of colostrum is seldom reported. The objective of this study is to investigate the antioxidant properties of colostrum caseins and whey proteins and the relationships between the protein composition and the antioxidant properties. The colostrum was precipitated using 1.0N HCl to obtain caseins and whey proteins. The caseins and the whey proteins were freeze-dried and then dissolved in a phosphate buffer (pH7.0) for the evaluation of antioxidant properties. The compositions of caseins and whey proteins were analyzed using electrophoresis and Sephacryl S-200 chromatography. According to the results of protein composition analysis, we divided each of caseins and whey proteins into four groups. The molecular weight of four protein groups of caseins were I: 225.0-75.0, II: 75.0-25.0, III: 25.0-20.0, and IV: below 20.0kDa, and those of whey proteins were I: 225.0-75.0, II: 75.0-50.0, III: 50.0-20.0, and IV: below 20.0kDa. Caseins had lower reducing power (RP), ferrous ion chelating power (FICP), and DPPH radical scavenging activity (DRSA) than whey proteins. The RP and DRSA of caseins were significantly and positively correlated to the amount of Group I-proteins. The FICP and DRSA of whey proteins were significantly and positively correlated to the amounts of all four-group proteins and Group IV-proteins, respectively. The antioxidant properties of whey proteins investigated in this study were apparently higher than those of caseins. This is supposed that whey proteins have more proteins of 225.0-75.0kDa than caseins. The results of this study also revealed that whey proteins have higher potential of use as antioxidants than caseins.
Session 67B, Food Chemistry: Antioxidants and bioactive agents
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