Phosphoric Acid → Phytate

Beteiligte Stoffe

Reaktionsschritte

Soybeans were pressurized, and then oil therein was extracted, separated, and removed using n-hexane as an extraction solvent to obtain low denatured defatted soybeans. To 5 kg of the obtained low denatured defatted soybeans (nitrogen solubility index (NSI) 91) was added 35 kg of water, and the pH was adjusted to 7 using diluted sodium hydroxide solution. Next, it was extracted while stirring for one hour at room temperature, and then centrifuged at 4000 G to separate bean curd refuse and insolubles, to obtain defatted soybean milk. The pH of this defatted soybean milk was adjusted to 4.5 using phosphoric acid, and then centrifuged using a continuous centrifugal separator (decanter) at 2000 G, to obtain an insoluble fraction (acid precipitated curd) and a soluble fraction (whey). Water was added so that the acid precipitated curd became 10% by mass of solid content, to obtain an acid precipitated curd slurry. After the pH of this was adjusted to 4.0 using phosphoric acid, it was heated to 40° C. To this solution (phytic acid content 1.96% by mass; solid content, TCA solubilization ratio 4.6%) was added phytase (manufactured by NOVO, Inc.) of equivalent to 8 units per solid content, allowing the enzymes to act for 30 minutes. After the reaction, the pH of this enzyme-applied product (phytic acid content 0.04% by mass; solid content, TCA solubilization ratio substantially unchanged) was adjusted to 3.5, and heat treatment was performed at 120° C. for 15 seconds, using a continuous direct heat treatment sterilizer. This was then spray dried, to obtain 1.5 kg of low phytate soybean protein powder. The dissolution ratio of this protein (pH 3.5) was 95%.

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