Flatulence-free soybeans pass the prototype test
The levels of flatulence-causing stachyose and raffinose were reduced by 92 and 80 per cent, respectively, by germinating the soybeans under in the presence of the food grade R. oligosporus fungus, according to findings published in the Journal of Agricultural and Food Chemistry.
Despite possessing several advantages to dairy yogurt, soy yoghurt only has a 1.9 per cent market share of the global yoghurt market, according to Euromonitor.
“The indigestibility of oligosaccharides, mainly raffinose and stachyose, is blamed as the causative factor for flatulence associated with the human consumption of soy products,” wrote lead author Shengbao Feng from the National University of Singapore.
“Thus, it would be desirable to remove the flatulence-causing raffinose and stachyose from the soy yogurt to improve the consumers’ preferences.”
Feng and co-workers formulated soy yoghurt with lactic acid bacteria and found that, although the concentrations of isoflavones such as genistein and daidzein, and their derivatives remained largely unchanged, generation of compounds unique to soybeans, such as oxylipins and glyceollinssa type of phytoalexins, occurred.
“We have demonstrated for the first time that germinated black soybeans under fungal stress can be fermented into a soy yogurt which features a low amount of flatulence-causing oligosaccharides but with a significant level of isoflavones including glyceollins,” wrote Feng.
Moreover, they report that the characteristics of the soy milk from germinated soybeans under fungal stress were suitable for yogurt-making.
However, “the resulting soy yogurt had significantly altered micronutrient profiles with significantly reduced oligosaccharides and enriched glyceollins,” wrote Feng.
A long way to go before the trumpet fanfare
The researchers noted that yoghurt formulated in the new study was only a prototype, and stress that significant additional research is needed for “scaling up the production processes and optimizing flavour attributes”.
No artificial additives were used in the soy yogurt, as they may have affected the potential health benefits of the final product, they said..
“In a broader perspective regarding the health benefits, we have a long way to go in terms of garnering scientific evidence on the chronic disease prevention properties of the soy yogurt described herein.”
Source: Journal of Agricultural and Food Chemistry Published online ahead of print, November 2008, doi: 10.1021/jf801905y“Novel Process of Fermenting Black Soybean [Glycine max (L.) Merrill] Yogurt with Dramatically Reduced Flatulence-Causing Oligosaccharides but Enriched Soy Phytoalexins”Authors: S. Feng, C.L. Saw, Y.K. Lee, D. Huang
