Isoflavones in retail and institutional soy foods

A national sampling plan was developed to select the most widely used isofl avone-containing foods in the United States. Foods were selected based on t heir retail volume and sampled in five geographical areas representing seve n 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 mu g/g in soy sauces to 540 mu g/g in tempeh. Soymilk and tofu represented the major portion of soy foods evaluated. These data will appear in the electronic version of U SDA Handbook No. 8 of Food Composition Data in 1999.