Variability of Isoflavone Content in Soy Milk Products Commercially Available in Thailand

Abstract

Objective: To determine the isoflavone content in soy milk products commercially available in Thailand. Material and Methods: Two flavors of each of 4 brands of soy milk were obtained from retail outlets in Chiang Mai, Thailand. The isoflavone content in soy milk was determined using high-performance liquid chromatography. Results: Genistin and daidzin, both β-glycoside conjugates, were found to be the main isoflavone components in soy milk. The total amount of isoflavones varied considerably among different products, ranging from 25.5 to 63.5 mg per serving (250 mL) of soy milk. Marked variation in total isoflavones was also found even among different lots of the same product. Conclusion: The isoflavone content in soy milk products available in Thailand varies substantially among different products as well as among different lots of the same product. This suggests that standardizing or, at least, declaring the isoflavone content in soy milk products is needed to facilitate the optimal consumption of soy milk for health benefits.

Keywords

• isoflavones
• soy milk
• thailand