Soy allergens reduced by fermentation

Consumption of soy has many health benefits: it is a good source of high-quality protein, B vitamins, fiber, essential fatty acids and phytochemicals that may help prevent chronic diseases, including heart disease, some cancers, osteoporosis and diabetes. However, about 0.5 percent of the population suffer from soy allergy and increase the number of amino acids and this figure can even rise because more people consume soy products. Food allergy affects about 3 percent of the adult population and up to 8 percent of infants. Food allergy is a reaction of the immune system toward food proteins. It is as an immunological based adverse reaction in response to dietary allergens. Small regions in the allergenic proteins provoke an allergenic response in IgE antibodies in mast cells and basophiles, followed by the release of inflammatory mediators such as histamine. According to a research by scientist from the University of Illinois and the Instituto de Fermentaciones Industriales in Madrid fermentation can reduce the risk of soy allergy and increase the number of amino acids in soy products. When fermenting soybeans or flour by certain microorganisms, immunoreactivity can be reduced by up to 99 percent! The scientist obtained the results from persons allergic to soy, who were exposed to protein extracts from both fermented and unfermented soy products. During the fermentation process, proteins are broken down into very small pieces, which can no longer produce the allergic reaction. Furthermore, the fermentation process improved the essential amino acid composition in the soy products and produced new peptides that may be beneficial. Previous studies have demonstrated that fermentation during soy sauce production hydrolyzes soy protein, including major soybean allergen, into smaller peptides.

Fermentation was carried out on cracked soybeans inoculated with Aspergillus oryzae, Rhizopus oryzae and Bacillus subtilis or in a soybean flour suspension fermented with bacteria naturally present in soybeans or by inoculation with Lactobacillus plantarum. Of all the microorganisms tested, Lactobacillus plantarum showed the highest reduction in immunoreactivity: 96 to 99 percent. Molds grown on cracked soybeans showed a reduced the immunoreactivity by about 67 percent. Fermentation by molds showed weaker efficacy to eliminate immunoreactive proteins than bacterial proteolysis, probably because of the slower growth rate of the molds during the fermentation process.

The scientist hope that the fermentation conditions can be further optimized to produce zero-tolerance allergens.

Source: Frias J, Song YS, Martínez-Villaluenga C, González de Mejia E, Vidal-Valverde C. "Immunoreactivity and Amino Acid Content of Fermented Soybean Products". J Agric Food Chem. 2008 Jan 9.