CHANGES IN ISOFLAVONE GLUCOSIDE AND AGLYCONE CONTENTS OF CHICKPEA YOGHURT DURING FERMENTATION BYLACTOBACILLUS BULGARICUSANDSTREPTOCOCCUS THERMOPHILUS

Abstract

Lactobacillus bulgaricus and Streptococcus thermophilus fermented chickpea yoghurt with a ratio of 1:1 (v/v) for 6–7 h at 42C. All cultures reached 109 cfu/mL of chickpea yoghurt. After 8 h, pH and titratable acidity ranged from 5.74 to 4.25 and 0.16 to 0.62%, respectively. Daidzein and genistein increased to 39.92 µg/g DW (dried weight of freeze-dried chickpea yoghurt) and 50.34 µg/g DW, respectively, after a 4-h fermentation. The amount of aglycone genistein and daidzein were more than that of glucoside daidzin and genistin. Total content of the aglycone daidzein and genistein was 90.26 µg/g DW at 4 h, which was 5.7 times of the initial fermentation (15.71 µg/g DW). Chickpea yoghurt fermentation hydrolyzed the isoflavone glucosides, and L. bulgaricus and S. thermophilus converted isoflavone glucosides to aglycones. L. bulgaricus and S. Thermophilus seemed to be effective starters for chickpea milk with more aglycones and appropriate acidity. PRACTICAL APPLICATION Chickpea is one of the oldest consumed legumes in Xinjiang, and has a significant contribution to human diet treatment. Leguminosea is the plant family most abundant in isoflavones. Furthermore, researchers have credited isoflavones in soybeans for some beneficial health effects. The addition of chickpea to milk-based products could be a good alternative for increasing the intake of chickpea. In the present study, changes in the contents of isoflavone glucosides and aglycones during chickpea yoghurt fermentation were investigated. Lactic acid bacteria were expected to effectively convert isoflavone glucosides to aglycones in chickpea milk.