QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Gauthier, S. F. Articles by Savoie, L. Search for Related Content PubMed PubMed Citation Articles by Gauthier, S. F. Articles by Savoie, L.

Assessment of Protein Digestibility by In Vitro Enzymatic Hydrolysis with Simultaneous Dialysis^1,2,

Centre de recherche en nutrition and Département de nutrition humaine, Université Laval, Sainte-Foy, Québec G1K 7P4, Canada

An in vitro digestion method to assess the quality of proteins based on enzymatic hydrolysis is presented. The method consists of a two-step proteolysis at 37°, a 30-minute incubation of the protein with pepsin at pH 1.9, followed by pancreatin digestion at pH 8 for 24 hours in a dialysis bag with a 1000 molecular weight cutoff for the continuous elimination of the digested products into a replaceable buffer. Three types of buffer replacement were tried. These were, in increasing order of efficiency: intermittent with either six changes (infrequent buffer replacement) or eleven changes (frequent buffer replacement) or continuously circulated at the rate of 212 ml/hour (continuous buffer replacement). By using three protein sources, i.e., casein, soybean and rapeseed proteins, it was found that the degree of digestion (dialyzed N) as well as the regularity of the process were markedly improved by increasing the frequency of buffer replacement. In spite of different pepsin digestibilities, as determined from the production of trichloroacetic acid-soluble N, the digestion of the three proteins gave equivalent results when the best procedure of buffer replacement was used (continuous buffer replacement). The deleterious effect of heat and alkali treatment on protein digestion was readily shown by this procedure and indicated casein to be a very heat-sensitive protein as compared to the others.

KEY WORDS: • protein digestibility • enzymatic hydroxlysis • dialysis • pepsin • pancreatin

¹ Supported by contract No. 0SZ79-00150 and grant No. 8053 from Agriculture Canada and by grant No. EQ-1188 (FCAC program) from Ministère de l'Education du Québec.

² Food Research Institute Publication No. 486.

³ Address reprint requests to: Sylvie F. Gauthier, Centre de recherche en nutrition, Université Laval, Sainte-Foy, Québec G1K 7P4, Canada.

⁴ Food Research Institute, Research Branch, Agriculture Canada, Ottawa, K1A OC6.

Manuscript received 20 January 1982.