USE OF PHYTASE IN THE PREPARATION OF A FERMENTED SOY BASED PRODUCT

摘要

The present invention relates to a method of preparing a fermented soy-based product, said method comprising: a. providing an aqueous liquid containing 0.5-10 wt. % of soy protein; b. pasteurizing or sterilizing the aqueous liquid; c. inoculating the pasteurised or sterilised liquid with a lactic acid bacterium containing starter culture; d. fermenting the inoculated aqueous liquid by incubation at a temperature in the range of 15-48° C. for 0.5-24 hours to obtain a fermented product; wherein phytase is incorporated in the aqueous liquid followed by pasteurization of said aqueous liquid in step b. or wherein phytase is added to the pasteurized or sterilized liquid no later than 10 minutes before termination of fermentation step d, said phytase being incorporated in the pasteurized or sterilized liquid in an amount of not more than 11 FTU per gram of soy protein; and wherein fermentation step d. is terminated by pasteurization, cooling or pH-adjustment. It was found that by conducting phytase treatment and fermentation in a concurrent fashion, a substantial increase in bioavailability of minerals such as iron and magnesium can be achieved whilst at the same time minimizing the negative effect of phytic acid degradation on lipid oxidation. The invention also provides a fermented soy-based product containing soy protein, polyunsaturated fatty acids, iron and/or magnesium and inositol phosphates, wherein the average number of phosphate residues of the inositol phosphates contained in the fermented product is within the range of 1.5-4.0.