Sensory, chemical and sensometric studies of hydrolyzed vegetable protein produced by various processes

Nine protein hydrolysates were made from untoasted defatted soygrits by acid hydrolysis, enzymatic hydrolysis for 4 h (EVP4) or 10 h (EVP10) followed by addition of monosodiumglutamate (MSG) or heating with xylose (EVP4xyl, EVP10xyl), xylose and cysteine (EVP10xylcys) or undissolved matters (EVP10un). The hydrolysates were evaluated for taste-donor and taste-enhancer effects. The taste-donor effect was mostly due to the volatile compounds while the taste-enhancing effect was more influenced by the amino acids. The acid hydrolysis product was different from the enzymatic hydrolysis products, even those that underwent MSG addition and heating. Heating of the hydrolysates resulted in bitter and malty tastes, which seemed to be due to pyrazines. Heating with undissolved matters resulted in the least bitter hydrolysate. MSG addition had the most influence on the taste-donor effect of the hydrolysates. Hydrolysis for 4 h seemed to be sufficient for taste-enhancing and for reaction by heating, but not enough to provide a specific taste-donor effect.