| Summary: | 碩士 === 大葉大學 === 生物產業科技學系 === 96 === The bovine colostrums collected on the third day postpartum were used to prepare skimmed milk, caseins and whey that were also hydrolyzed by flavourzyme under optimal enzyme/substrate (casein, whey and skimmed milk were 2.26, 1.35 and 1 % respectively). The antioxidant properties of these samples were analyzed. The ultrafiltration and gel filtration chromatography were used to isolate the high antioxidant properties of peptide.
The results were as follows:
1. The chelating abilities of ferrous ion and the Trolox equivalent antioxidant capacities (TEAC) had the same descending order of caseins, skimmed milk and whey.
2. The hydrolysis of bovine colostrum casein, whey and skimmed milk were 29.11, 31.62 and 30.28 %, respectively.
3. The chelating abilities of ferrous ion of hydrolysates (10 mg/mL) from caseins, whey and skimmed milk were descended as caseins, skimmed milk and whey. The Trolox equivalent antioxidant capacities (TEAC) were decreased as the order of caseins, whey and skimmed milk. The antioxidant properties of the hydrolysates from caseins, whey and skimmed milk were higher than unhydrolyzed samples. The casein hydrolysates had the highest antioxidant properties.
4. The chelating abilities of ferrous ion of hydrolysates (with molecular weight greater than 10 kDa) from caseins, whey and skimmed milk were descended as caseins, skimmed milk and whey. The Trolox equivalent antioxidant capacities (TEAC) of hydrolysates (with molecular weight greater than 10 kDa) were decreased as the order of caseins, whey and skimmed milk. The chelating abilities of ferrous ion of hydrolysates (with molecular weight less than 10 kDa) from caseins, whey and skimmed milk were descended as caseins, skimmed milk and whey. The Trolox equivalent antioxidant capacities (TEAC) of hydrolysates (with molecular weight less than 10 kDa) were decreased as the order of caseins, whey and skimmed milk. The Trolox equivalent antioxidant capacities (TEAC) of hydrolysates (with molecular weight greater than 10 kDa) were higher than those of hydrolysates (with molecular weight less than 10 kDa). Casein hydrolysates with molecular weight greater than 10 kDa had the highest antioxidant properties.
5. The casein hydrolysates, with molecular weight greater than 10 kDa, were analyzed by gel filtration chromatography that had four peaks, Peak 1 (tube no. 20-31), Peak 2 (tube no. 32-47), Peak 3 (tube no. 48-55) and Peak 4 (tube no. 56-62). The ferrous ion chelating abilities of four samples were descended as Peak 3, Peak 2, Peak 1 and Peak 4. The Trolox equivalent antioxidant capacities (TEAC) were decreased as the order of Peak 3, Peak 2, Peak 4 and Peak 1. The Peak 3 had the highest antioxidant properties that had the molecular weight of 50-70 kDa.
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