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.

Effects of enzymatic hydrolysis treatments on the physicochemical properties of beef bone extract using endo‐ and exoproteases

“…This could be due to the manufacturing process of bone extract, whereby the bones are pressure cooked in water for at least 2 h at 121 °C. Similar hydrolysis due to heat treatment had been reported for wheat gluten proteins (Elmalimadi et al ., ). Bone extract hydrolysed by Flavourzyme ® showed the highest DH compared to Protamex ® and bromelain at E/S ratio of 0.5–4% w/w.…”

Hydrolytic enzymes and their directly and indirectly effects on gluten and dough properties: An extensive review

“…On the other hand, foam stability was reduced in more extensive hydrolysis due to the increased polypeptide chains unable to make foam air cells stable Wouters et al, 2016;. Gluten treated with alcalase was further reported to increase solubility, emulsifying capacity, foaming stability, and foaming capacity owing to produce lower molecular size hydrolysates (Elmalimadi et al, 2017;He et al, 2019;Kong et al, 2007b). Deng et al, (2016) revealed that enzymatic hydrolysis is capable of breaking some SS bonds to unfold the globular structure of gluten and new SS bonds are generated between both newly generated SH and original free SH groups to stabilize the structure of smaller peptides.…”

“…On the other hand, foam stability was reduced in more extensive hydrolysis due to the increased polypeptide chains unable to make foam air cells stable (Wouters, Fierens, et al., 2017; Wouters et al., 2016; Wouters, Rombouts, et al., 2017). Gluten treated with alcalase was further reported to increase solubility, emulsifying capacity, foaming stability, and foaming capacity owing to produce lower molecular size hydrolysates (Elmalimadi et al., 2017; He et al., 2019; Kong et al., 2007b).…”

“…Wheat gluten hydrolysis to smaller peptides and free amino acids with more hydrophilic polypeptide (Wang et al, 2016; Zhou et al., 2017; Hwang et al, 2016) normally is carried out via peptidase and protease (reaction 1). Hydrolyzing treatment: 1) enhance functional features (solubility, foaming, and emulsifying capacity) (Wang et al, 2016; Wouters et al., 2016; Wouters, Fierens, et al, 2017; Kammoun et al, 2003); 2) improve the safety and nutritional values of gluten protein by reducing the allergenic potential of wheat gluten which cause celiac disease (Elmalimadi et al., 2017; Henggeler et al., 2017; Merz et al., 2015; Merz, Appel, et al, 2016); 3) improve dough handling through managing the viscoelasticity of gluten network and modifying dough rheology; 4) improve the antioxidant activity of hydrolyzed gluten (Abedi & Pourmohammadi, 2020a; Pourmohammadi & Abedi, 2021). The antioxidant properties are the ability to hinder linoleic acid peroxidation inhibition or put out the DPPH (2,2‐diphenyl‐1‐picrylhydrazyl), ABTS (2,2‐azino‐bis (3‐ethylbenzothiazoline‐6‐sulfonic acid)), or other radicals (Elmalimadi et al., 2017; Elmalimadi, 2018; Jin et al., 2016; Wang et al, 2016).…”

Immunomodulatory and Antioxidant Properties of Wheat Gluten Protein Hydrolysates in Human Peripheral Blood Mononuclear Cells

“…Therefore, the GSH/GSSG ratio is the major cellular redox buffer and the maintenance of GSH levels is an essential biological process [ 41 ]. Previous studies have shown the antioxidant properties of Alcalase 2.4 L-digested wheat gluten hydrolysates in cell-free in vitro systems [ 42 , 43 , 44 ]. Furthermore, in vitro treatment of the PC12 rat adrenal medulla cell line with WGPHs (0.25–1 mg/mL) protects against H 2 O 2 -induced oxidative stress [ 45 ].…”