Protease inhibitor activities and isoflavone content in commercial soymilks and soy-based infant formulas sold in Ottawa, Canada

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• 作者：Chao Wu Xiao^a ; ^b ; ^{chaowu.xiao@hc-sc.gc.ca} ; Carla M. Wood^a ; Patrick Robertson^a ; G. Sarwar Gilani^a
• 关键词：BAPNA ; N-benzoyl-dl-arginine-p-nitroanilide ; BBI ; Bowman-Birk inhibitor ; HPLC ; high performance liquid chromatography ; KTI ; Kunitz trypsin inhibitor ; PDA ; Photo Diode Array ; SBCI ; soybean chymotrypsin inhibitor ; SBTI ; soybean trypsin inhibitor ; TIA ; tryps
• 刊名：Journal of Food Composition and Analysis
• 出版年：2012
• 出版时间：March, 2012
• 年：2012
• 卷：25
• 期：2
• 页码：130-136
• 全文大小：424 K

文摘

The content of isoflavones and residual activities of soybean trypsin (SBTI) and chymotrypsin (SBCI) inhibitors in the major soymilks and soy-based infant formulas sold in Ottawa, Canada were examined. The residual SBTI activities ( % whole soybean) measured as the ability to inhibit the release of p-nitroaniline from N-benzoyl-dl-arginine-p-nitroanilide by trypsin were from 6.4 % to 55.6 % in soymilks (8 brands), 4.2 % to 8.8 % in liquid formulas (4 brands) and 1.9 % to 5.1 % in powdered formulas (8 brands). SBCI activities ( % whole soybean) measured as the ability to inhibit the degradation of casein by chymotrypsin in soymilks were from 3.5 % to 33.7 % . Total isoflavones measured as aglycones were from 26.4 ¡À 0.18 to 55.3 ¡À 3.48 ¦Ìg/g wet weight in liquid formulas or 137.5 ¡À 3.0 to 229.1 ¡À 2.3 ¦Ìg/g dry weight in powdered formulas and 49.8 ¡À 0.5 to 279.9 ¡À 3.4 ¦Ìg/g wet weight in soymilks. Compared to soymilks, the residual SBTI activities and total isoflavones in infant formulas were lower. The residual SBTI activities in 6 out of the 8 soymilks measured were higher than the level (10 % ) considered being safe.