Effects of alkaline hydrolysis and storage conditions on the biological activity of ostrich egg white

Abstract

This study aimed to improve the biological activity of ostrich egg white (OEW) using alkaline hydrolysis (0.25 M NaOH at 40°C for 8 hr), and studied the effects of packing materials and temperature on biological and physical properties of OEW hydrolysate (hOEW). The results show that alkaline hydrolysis clearly enhanced several biological activities, including ABTS radical scavenging (61.35%), anti‐microbial (51.66% against Bacillus subtilis and 38.58% against Escherichia coli) and anti‐angiotensin converting enzyme activity (39.19%). The hydrolysate maintained biological activities after gastrointestinal digestion and showed non‐toxicity toward human red blood cells. In storage study, the best storage conditions were packing hOEW powder in an Al‐foil‐laminated bag at 4°C, resulting in slightly decreased biological activity after 6 months storage and significantly lower moisture content than plastic zipper bag. Additionally, SEM revealed smooth surfaces of hOEW powder for the best condition, while air pores and bridges were found in the worst conditions. Practical applications The alkaline hydrolysis method (incubation in 0.25 M NaOH at 40°C for 8 hr) used in this study can be used to enhance the antioxidant, antimicrobial, and anti‐ACE inhibition activity of egg white protein. This study also reports the optimal packaging and storage conditions for egg white hydrolysate powder, which are beneficial for maintaining the antioxidant, antimicrobial, and anti‐angiotensin converting enzyme activity as well as the texture of the egg white hydrolysate powder.

Effect of refrigeration storage on functional properties and structure of egg white after defrosting treatments

“…The EW morphology of the Control is flat, dense and structurally spongy intact with a smooth surface, whereas the EW of other groups, following refrigeration storage after defrosting treatments, developed irregular shapes with higher surface roughness, more and larger surface aggregates. Our results agreed well with those reported by other researchers (Khueychai et al ., 2019). This alteration in EW structure, following refrigeration storage after defrosting treatments, may be attributed to protein partial rearrangement, denaturation, aggregation and oxidation, owing to enhanced protein cross‐linking between proteins and more complex network.…”

Review on preparation methods, mechanisms and applications for antioxidant peptides in oil

“…Some researchers hydrolyzed ostrich egg white protein with 0.25 mol/L NaOH at 40 ºC for eight hours. They proved that the antioxidant activity of the protein was significantly enhanced after hydrolysis (Khueychai et al, 2019). This method is cheap and time-saving.…”