Effects of riboflavin photosensitization on the changes of isoflavones in soymilk.
Effects of riboflavin photosensitization on the distribution of isoflavones in commercially available soymilk were analyzed using high-performance liquid chromatography (HPLC). Total isoflavones (TI) in soymilk with riboflavin (1000 ppm, w/v) under light were significantly different from those stored in the dark for 24 h (P < 0.05), while TI in samples with 0 and 1000 ppm added riboflavin were not significant from each other in dark conditions (P > 0.05). To test the effects of the concentration of riboflavin on TI, soymilk was mixed with riboflavin to make 0, 100, 250, and 500 ppm (w/v) and stored under light at 25 degrees C for 24 h. TI in soymilk with 100 ppm riboflavin under light significantly decreased by 13.5% for 24 h (P < 0.05) compared to control samples and were not significantly different from those with 250 or 500 ppm samples (P > 0.05). Daidzin and genistin were predominant isoflavones in soymilk, and the rate of photo degradation of genistin was higher than that of daidzin for 24 h in soymilk under riboflavin photosensitization.
Lee
S W
SW
Dept of Food Science and Technology, Seoul National Univ of Technology.
Chang
P-S
PS
Lee
J H
JH
D002851:Chromatography, High Pressure Liquid; D005511:Food Handling; D007529:Isoflavones / Q000032:analysis*; D008027:Light; D012256:Riboflavin / Q000378:metabolism*; D041942:Soy Milk / Q000737:chemistry*
D007529:Isoflavones; C040641:genistin; C013908:daidzin; D012256:Riboflavin