Hydrolysates of skim milk: Peptide profiles using two proteolytic enzymes

Abstract

Purpose

The aim of this research is the evaluation of the profile of peptides isolated from skim milk hydrolysates.

Design/methodology/approach

Five hydrolysates were prepared using a protease from Aspergillus Oryzae (AO) separately or in combination with papain (PA) in different reaction times. The hydrolysates were fractionated by size‐exclusion HPLC and the rapid method of correct fraction area (CFA) was used for quantifying the peptides and free amino acids in the chromatographic fractions. The nutritional quality of hydrolysates is directly related to their di‐ and tripeptide contents, several reports show that the amino acid provided by these peptides are more quickly and completely absorbed than those from intact protein.

Findings

The results showed a nutritional similarity of the isolated action of AO and its combinations with PA, considering the peptide patterns produced, giving rise to 16 percent of di‐ and tripetides. Increasing the reaction time of the two enzymes led to poorer peptide profiles, while no change was achieved when the reaction time of only one enzyme (AO) in the combination was enlarged. Other hydrolytic conditions could be tested in order to improve the peptide profile of skim milk hydrolysates.

Practical implications

The application of this study relates to the possibility of using these hydrolysates for preparing high nutritional formulation for dietetic purposes. The use of a technique allowing the fractionation of peptides according to their size as well as the use of the skim milk as protein source, instead of casein, which is very expensive in the developing countries, represents a novel approach.

Originality/value

Provides an evaluation of the profile of peptides isolated from skim milk hydrolysates.

Citation

Cristine Fialho Lopes, D., Meneghello Delvivo, F. and Pinto Coelho Silvestre, M. (2005), "Hydrolysates of skim milk: Peptide profiles using two proteolytic enzymes", British Food Journal, Vol. 107 No. 1, pp. 42-53. https://doi.org/10.1108/00070700510573195