An Enzymatic Process for a Protein‐containing Beverage Based on Soybean Protein and Lemon Juice

SUMMARY —An acidic enzymatic process for a bland soybean protein hydrolysate is described. Cooked suspensions (5.0%) of isolated soybean protein are mixed with small amounts of an acid‐protease preparation from Trametes sanguinea, adjusted to pH 3.3–3.5 with concentrated lemon juice and incubated at 50°C for 8–10 hr. After stopping the proteolysis by heat treatment, the clear supernatant is separated from any insoluble residue by centrifugation. A solubilized nitrogen recovery of 88–90% is obtained. All nitrogenous substances in the hydrolysate are 5% trichloroacetic acid‐soluble, and the dehydrated hydrolysate easily reconstitutes to a clear solution with cold water. After being diluted about twice and sweetened with sugar, the hydrolysate constitutes a clear, slightly yellowish lemonade‐like flavored beverage. The data on chemical analysis, gel‐filtration and rheological behavior of the hydrolysate are also described and discussed.