A Multienzyme Technique for Estimating Protein Digestibility

Abstract

An in vitro method using a multienzyme system for the estimation of protein digestibility has been developed. The multienzyme system consists of trypsin, chymotrypsin and peptidase. It was found that the pH of a protein suspension immediately after 10 min digestion with the multienzyme solution was highly correlated with the in vivo apparent digestibility of rats. Regression analyses of 23 samples tested showed that the correlation coefficient between pH at 10 min and in vivo apparent digestibility was 0.90 with a standard error of estimate of 2.23. The regression equation was Y = 210.464 -18.103, where "X" was the pH of protein suspension immediately after the 10 min digestion with the multienzyme solution. The most significant advantage of this in vitro method for predicting apparent protein digestibility was that it can be completed within 1 hr and with a high degree sensitivity. The method can detect the effects of trypsin inhibitor, chlorogenic acid, and heat treatment on protein digestibility. Strong buffer salts may affect the measurement of protein digestibility, but the buffering effects found in general food proteins and products tested did not create any problem with the procedure.

Chemical and nutritional evaluation of kernels of bocaiuva, Acrocomia aculeata (Jacq.) Lodd.

“…The pH of the solution was recorded 10 min after adding the enzyme solution. The in vitro digestibility was calculated using the HSU et al equation [15].…”

Emprego de fubá de melhor qualidade protéica em farinhas mistas para produção de biscoito

“…Os escores químicos foram multiplicados pelas digestibilidades in vitro da proteína -80% para os de farinha de trigo e 78% para os contendo as FM -determinadas para biscoitos assados e semelhantes aos aqui estudados [19]; b -C-PER (calculated protein efficiency ratio) [6]: foi calculado tomando-se por base a composição em aminoácidos essenciais (g/16g N) obtida no item 2.2.3 para os diversos biscoitos [18]. Empregaramse para os biscoitos os mesmos valores de digestibilidade [19].…”

“…Avaliar o valor nutritivo em potencial da proteína contida nestes biscoitos por métodos in vitro tem a vantagem de ser mais rápido e com custos reduzidos [2,21]. Com base nos teores de aminoácidos essenciais e nas digestibilidades reais estabelecidas por ensaios biológi-co ou in vitro, constantes na literatura [17,19,26,29] foi possível calcular os índices: PDCAAS e C-PER -que já incluem a correção pela digestibilidade -dos biscoitos contendo as FM e compará-los aos do controle, contendo apenas farinha de trigo. Os resultados são apresentados na Tabela 7.…”

Critical Evaluation of in Vitro Methods for Estimating Digestibility in Simple-Stomach Animals

“…A solution of trypsin, chymotrypsin and peptidase (1 ml) is added to the protein suspension, and after exactly 10 min of incubation, pH is recorded (Hsu et al 1977). A modified method incubating additionally with a proteinase from Streptomyces griseus has been described by Satterlee et al (1981).…”