Fat-reduced soybean protein material and soybean emulsion composition, and processes for production thereof

A process for producing a reduced-fat soybean protein material, comprising the steps of:

• (1) adding water to
• a modified fat-containing soybean, which comprises, as a raw material, a fat at a content of 15 wt % or more in terms of dry basis and has a Nitrogen Solubility Index (NSI) value in the range from 20 to 65, wherein “modified” means that protein in the fat-containing soybean is denatured to 20 to 65 of NSI,
• to prepare a suspension liquid;
• (2) subjecting the suspension liquid of the modified fat-containing soybean to a solid-liquid separation to transfer a neutral lipid, a polar lipid and a protein comprising a lipophilic protein as a major component to an insoluble fraction comprising fiber, and
• (3) then removing the insoluble fraction and recovering a soluble fraction comprising sugar and protein comprising glycinin and β-conglycinin as major components,
• wherein the fat content is calculated as a total amount extracted with a mixed solvent of chloroform and methanol at a volume ratio of 2:1 at an atmospheric boiling point for 30 minutes, and
• wherein the NSI value is determined by the following procedure:
• (a) adding 100 ml of water to 2.0 g of a sample to obtain a first mixture,
• (b) stirring the first mixture at 40° C. for 60 minutes, and then subjecting the first mixture to centrifugation at 1400×g for 10 minutes to obtain a supernatant 1,
• (c) adding 100 ml of water to a residual precipitate to obtain a second mixture,
• (d) stirring the second mixture obtained in step (c) at 40° C. for 60 minutes, and then subjecting the second mixture to centrifugation at 1400×g for 10 minutes to obtain a supernatant 2,
• (e) combining supernatant 1 and supernatant 2, and adding water to 250 ml to obtain a third mixture,
• (f) filtering the third mixture with No. 5A filter paper to obtain a filtrate,
• (g) determining a nitrogen content in the filtrate by the Kjeldahl method,
• (h) determining a nitrogen content in the sample by the Kjeldahl method, and
• (i) calculating the NSI value as wt % by dividing the nitrogen content in the filtrate by the nitrogen content in the sample.