Biological activity of egg-yolk protein by-product hydrolysates obtained with the use of non-commercial plant protease

Main Article Content

A. Zambrowicz
E. Eckert
M. Pokora
A. Dąbrowska
M. Szołtysik
Ł. Bobak
T. Trziszka
J. Chrzanowska

Keywords

egg yolk proteins, Cucurbita ficifolia protease, hydrolysis, antioxidant, ACE-inhibitory activity, immunostimulating activity

Abstract

Enzymatic hydrolysis leads to improved functional and biological properties of protein by-products, which can be further used as nutraceuticals and protein ingredients for food applications.
The present study evaluated ACE-inhibitory, antioxidant and immunostimulating activities in hydrolysates of egg-yolk protein by-product (YP), generated during industrial process of delipidation of yolk. The protein substrate was hydrolyzed using non-commercial protease from Asian pumpkin (Cucurbita ficifolia). The reaction was conducted in 0.1 M Tris-HCl buffer (pH 8.0) at temperature of 37°C for 4 hours using different enzyme doses (100-1000 U/mg of substrate). The protein degradation was monitored by the determination of the degree of hydrolysis (DH), release of free amino groups (FAG) and by RP-HPLC. In the obtained hydrolysates we also evaluated biological activities. It was shown that the highest DH of substrate (46.6%) was obtained after 4h of reaction at the highest amount of enzyme. This hydrolysate exhibited antioxidant activity, including ferricion reducing (FRAP) (56.41 ?g Fe2+/mg), ferric ion chelating (695.76 ?g Fe2+/mg) and DPPH free radical scavenging (0.89 ?mol troloxeq/mg) as well as ACE-inhibitory (IC50=837.75 ?g/mL) activities.
The research showed improved biological properties of enzymatically modified YP by-product.
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