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

作者：Xiao Chao Wu^*; Wood Carla M; Robertson Patrick; Gilani G Sarwar

来源：Journal of Food Composition and Analysis, 2012, 25(2): 130-136.

DOI：10.1016/j.jfca.2011.10.001

• Food analysis
• Food composition
• Trypsin inhibitor
• Chymotrypsin inhibitor
• Isoflavones
• Soymilk
• Soy infant formula

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 +/- 0.18 to 55.3 +/- 3.48 mu g/g wet weight in liquid formulas or 137.5 +/- 3.0 to 229.1 +/- 2.3 mu g/g dry weight in powdered formulas and 49.8 +/- 0.5 to 279.9 +/- 3.4 mu g/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.

• 出版日期2012-3