Production of Antioxidant Egg White Hydrolysates in a Continuous Stirred Tank Enzyme Reactor Coupled with Membrane Separation Unit

Abstract

The objective of this research was to design an efficient continuously operated membrane reactor with a separation unit for egg white protein (EWP) hydrolysis and production of hydrolysates with improved antioxidant properties. For this purpose, a mechanically stirred tank reactor coupled with the polyethersulfone ultrafiltration module with a molecular weight cutoff of 10 kDa was employed. Several proteolytic enzymes have been tested in order to obtain the best quality of peptide-based formulations intended for human consumption. Among protease from Bacillus licheniformis (Alcalase), protease from Bacillus amyloliquefaciens (Neutrase), and protease from papaya latex (papain), the highest degree of hydrolysis (DH), as well as the best antioxidant properties of obtained hydrolysates, was achieved with Alcalase. The effects of operating variables such as enzyme/ substrate ([E]/[S]) ratio, impeller speed, and permeate flow rate were further studied using response surface methodology (RSM) and Box-Behnken experimental design. Results obtained in RSM analysis confirmed that over the studied range [E]/[S] ratio, impeller speed and permeate flow rate had the significant effect on the DH and reactor capacity. The effects of different impeller geometries were also studied and fourbladed propeller stirrer enabled the highest DH. Antioxidant properties were analyzed by the 2,2-diphenyl-1-picrylhydrazyl (DPPH), by the 2,2′-azino-bis-(3-ethylbenzothiazoline)-6-sulfonic acid (ABTS) radical scavenging activity, and by the linear voltammetry methods. Results show that the use of Alcalase in the membrane reactor system is of potential interest for the EWP hydrolysis and obtaining value-added egg products.

Bioactivity of Hydrolysates Obtained from Chicken Egg Ovalbumin Using Artichoke (Cynara scolymus L.) Proteases

“…The activity of the hydrolysates against the DPPH radical was substantially lower than that shown in the inhibition of the ABTS radical, with TEAC values of µM of Trolox/mg vs. mM of Trolox/mg, respectively. These results are similar to those obtained in other works with enzymatic hydrolysates of egg white protein [ 37 , 42 , 60 ]. This difference is probably due to the distinct solubility and diffusion of the radicals used [ 62 ].…”

“…Our results are consistent with several studies on egg white protein hydrolysates, where the degree of hydrolysis increased with hydrolysis time, using both enzymes of plant origin, such as papain [ 34 , 35 ], as well as digestive enzymes of animal origin [ 25 , 34 , 36 ], microbial origin (such as alcalase, neutrase, and thermolysin) [ 34 , 37 , 38 ], or fungal origin (Flavourzyme) [ 34 ].…”

Separation and Identification of Highly Efficient Antioxidant Peptides from Eggshell Membrane

“…The reducing power was also positively correlated with the amounts of enzymes added but reached a maximal value of 0.66 at 12 U/mg. As the dose of the enzyme increased to 15 U, however, it showed an insignificant decrease because of the saturation of binding sites in the substrate [39]. ESM-EH exhibited higher Fe 2+ -chelating activity at low concentration of alkaline protease (3 U/mg), which is due to the reduction of disulfide bonds in the eggshell membrane to sulfhydryl groups.…”

Production of Hydrolysate of Okara Protein Concentrate with High Antioxidant Capacity and Aglycone Isoflavone Content

“…Furthermore, in the results found by our research group (Sbroggio et al [8]), it was verified that the ABTS and DPPH free radicals scavenging ability and ferric reduction antioxidant power (FRAP assay) of protein hydrolysates of okara obtained by Alcalase increased significantly when the DH varied from 0 to 33.6%. Other authors also reported a positive effect of DH on antioxidant capacity [9,10] by increasing exposition of bioactive peptides. In addition, Lu et al [11] reported a gradual decrease in isoflavone glycosides, accompanied by an increase in aglycones, in the course of protein hydrolysis time.…”