분자량에 따라 분획된 유청단백분해물이 Bifidobacterium bifidum Bb-11의 생장에 미치는 영향

초록

This study was carried out to evaluate the effect of whey protein concentrate-80%(WPC-80) and whey protein isolate(WPI) on the growth of B. bifidum Bb-11. Whey proteins(α-lactalbumin, β-lactoglobulin) were digested with trypsin, then their hydrolyzates were separated into three fractions (>10,000Da, 3,000～10,000Da, <3,000Da) by two-step ultrafiltration process with Centriprep 10 and Centricon-30. These three fractions by molecular weight were evaluate growth-promoting effects for the B. bifidum Bb-11. The results obtained were summarized as follows; The growth rate of B. bifidum Bb-11 tended to increase by supplementation of WPC-80 to basal medium, but decreased by supplementation of WPI. Two whey proteins were hydrolyzed by trypsin at 40℃ for 6 hrs, and three fractions were collected by UF treatment and concentrated by Centricon-30. Collected concentrations of protein of F-I and F-II and F-III from α-lactalbumin were 11.53mg, 7.79mg, and 5.21mg and those of protein from β-lactoglobulin were 4.13mg, 5.30mg, and 9.351mg, respectively. Three fractions of α-lactalbumin hydrolyzates promoted the growth rate of B. bifidum Bb-11. Growth promoting activities of hydrolyzates(F-I and F-II) with molecular weight below 10,000Da were stronger than that of hydrolyzate(F-III) above 10,000Da. However, there was no significant difference between the hydrolyzate F-I and F-II. Three fractions of β-lactoglobulin hydrolyzates improved the growth rate of B. bifidum Bb-11. The growth of B. bifidum Bb-11 was decreased after 24 hr incubation by supplementation of either F-II or F-III fraction compared to basal Whey medium, but maintained the enhancement by supplementation of F-I.

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