The effect of various acidic solutions on the concentration of genistein in tempeh

by Garlock, Lori A.

Garlock, Lori A. The Effect of Various Acidic Solutions on the Concentration of Genistein in Tempeh MS Food Science and Nutrition December 2000 58 pages Research Advisor: Dr. A. M. Q. Vande Linde, PhD., Department of Chemistry The ACS Style Guide A Manual for Authors and Editors Tempeh is a fermented soyfood that contains a higher level of genistein in comparison to nonfermented soyfoods, such as tofu and soymilk. Control tempehs prepared in this research contained concentrations of genistein seven times greater (49.70 mg/g dry sample) than that of unprocessed soy grits (7.08 mg/g dry sample). The isoflavone genistein is of interest because of its potential anticarcinogenic effect. The main objective of this project was to investigate the effects that various acid solutions had on the concentration of genistein in tempeh. Lactic acid, citric acid, and acetic acid (0.1% solutions) were used in the soaking and/or cooking periods. The concentration of genistein in tempeh samples was measured by HPLC. Genistein concentrations in the tempehs made by methods involving acidic soaking and/or cooking solutions ranged from 24.83 ± 7.69 to 46.33 ± 7.47 mg/g dry sample. Control tempehs, prepared from soy grits soaked in water forl hour and cooked in water, had genistein concentrations of 49.70 ± 3.64 mg/g dry sample. Based on the data collected in this project, the use of an acidic solution in the soaking period and/or the cooking period did not enhance the genistein concentration in tempeh. Continuing research in our laboratory is being conducted to explore the use of a B- glucosidase enzyme that when added to the soaking solution has the potential to hydrolyze the glucose molecule attached to genistin, thus forming genistein.