The synergistic effect of heat treatment on alcalase-assisted hydrolysis of wheat gluten proteins: Functional and antioxidant properties

Abstract

In order to confirm the gluten potential for inclusion into functional foods, the synergistic effect of the heat treatment and controlled enzymatic hydrolysis on the functional and the antioxidant properties of alcalase-assisted wheat gluten hydrolysates (AWGHs) will be discussed. For this purpose, wheat gluten was heat-treated during 30 min at 75 °C and intensively hydrolyzed with alcalase at degree of hydrolysis (DH) 16.1%, 22.9%, and 30.2%. All the hydrolysates had excellent solubility over a pH range of 2–12. Emulsifying activity and stability were also improved, while proteolysis was deleterious to foam capacity and stability, water-holding capacity, fat-binding capacity and did not show improvement at higher DH (22.9% and 30.2%). As well, controlled hydrolysis of heat-treated gluten resulted in a remarkable improvement in antioxidant activities. The results show that the heat-treated AWGHs were superior to the untreated hydrolysate in the functional and antioxidant properties tested. Practical applications This report examines existing evidence regarding the wheat gluten proteins (WGP), which is a byproduct from wheat starch processing. It is known that enzymatic hydrolysis is frequently used to improve functional properties of protein hydrolysates and largely dependent on the degree of hydrolysis (DH), which needs to be controlled to elude redundant proteolysis that can deteriorate functionality and cause unfavorable effects. The DH is a substantial factor which affect the hydrolysates' performances and an appropriate selection of protease for WGP hydrolysis will result in maximum biological activity and improved functionalities. Heat treatment is often used to facilitate the proteolysis of proteins. Thus, functional and antioxidant properties of WGP hydrolysates, as a function of heat treatment and the DH were adequately examined in this study and results showed that by combining heat prehydrolysis treatment under controlled conditions, hydrolysates with improved properties can be produced enhancing utilization of WGP in food products.