Isoflavones in Retail and Institutional Soy Foods

TLDR

A national sampling plan selected the most widely used isoflavone‑containing foods in the U.S., sampling them in five geographic areas covering seven metros, analyzing composite raw and cooked samples by brand, and evaluating quality control throughout. Isoflavone concentrations varied from 1 µg/g in soy sauces to 540 µg/g in tempeh, with soymilk and tofu comprising the majority of soy foods examined. The data will appear in the electronic version of USDA Handbook No.

Abstract

A national sampling plan was developed to select the most widely used isoflavone-containing foods in the United States. Foods were selected based on their retail volume and sampled in five geographical areas representing seven metropolitan areas. Isoflavones were analyzed from composite samples, raw and cooked, and reported by brand. Quality control measures were evaluated throughout the study. Isoflavone levels ranged from 1 μg/g in soy sauces to 540 μg/g in tempeh. Soymilk and tofu represented the major portion of soy foods evaluated. These data will appear in the electronic version of USDA Handbook No. 8 of Food Composition Data in 1999. Keywords: Phytoestrogens; genistein; glycitein; daidzein; biochanin A; formononetin