This study was conducted to investigate the effect of temperatures (4, 25 and 37 ℃) on the color, physicochemical characteristics and antioxidant activities of ovalbumin-glucose system during the Maillard reaction induced by alkali. The results showed that with increasing either incubation time or temperature, the color of ovalbumin-glucose system was deepened, and the contents of brown products and fluorescent compounds increased gradually; the content of intermediate products increased at 4 and 25 ℃, but increased at first and then decreased at 37 ℃ with increasing reaction time. Likewise, the pH increased at first then decreased. Fourier transform infrared (FTIR) spectroscopic analysis showed that ovalbumin was conjugated with glucose. Amino acid analysis suggested that the serine, histidine and cysteine residues in ovalbumin had relatively high reactivity, and the cysteine residue had the highest reactivity among them. The antioxidant activity of the reaction product from ovalbumin-glucose system was significantly improved compared with their physical mixture, but it slightly decreased with incubation time.

Inflammation underlies many chronic diseases, and inflammatory bowel disease (IBD) is a condition characterized by long-term inflammation of the gut. Egg whites have been shown to contain many beneficial active substances. Therefore, we obtained 2 peptides from salted egg white: Val-Val-His-Phe (VF-4) and Asp-Thr-Gln-Ala-Met-Pro-Phe-Arg (DR-8). The sodium dextran sulfate (DSS)-induced mice colitis model was used to evaluate its regulatory effect on colitis in vivo. The results showed that VF-4 and DR-8 improved the clinical symptoms of DSS-induced colitis, attenuated colon tissue damage, inhibited the activation of nuclear factor kappa-B (NF-‍κB)/mitogen-activated protein kinase (MAPK)/phosphoinositide 3-kinase-Akt (PI3K-AKT) signaling pathways, and inhibited the expression of inflammatory cytokines. 16S rRNA gene sequencing showed that VF-4 and DR-8 administration increased the relative abundance of intestinal beneficial bacteria including Lactobacillus, Blautia, and down-regulated the relative abundance of inflammation-related bacteria including Acinetobacter, Lachnospiraceae_NK4A136_group, Klebsiella. Moreover, the degree of correlation between pro-inflammatory cytokines and microbiota was as follows: interleukin-6 (IL-6) > tumor necrosis factor-α (TNF-α) > interleukin-1β (IL-1β) > interferon-γ (IFN-γ). In conclusion, this study suggests that salted egg white peptides VF-4 and DR-8 have a significant anti-inflammatory effect in vivo. It also provides a strategy for the treatment of IBD and a new way for the high-value utilization of salted egg white.

As a kind of food rich in high-quality protein, poultry eggs not only play the most basic nutritional role in national life, but also widely used in bread, pastry, baking and other food industry because of its excellent processing characteristics such as foaming, emulsification and gel properties, besides its active ingredients can also develop new egg products and functional foods. China, a large country producing and consuming of poultry eggs, has ranked first in the annual production of poultry eggs since 1985. However, the consumer market is dominated by fresh eggs, whose processing conversion rate is only about 12%, and it is mainly based on traditional egg products such as salted eggs and preserved eggs. Compared with Western countries, the market share of egg powder, egg liquid, dry egg products, egg drinks, convenient egg products and other new egg products is small in China. In recent years, China’s egg industry has entered the mature stage of development, which takes a favorable trend. In 2022, the output value of China’s egg processing industry has exceeded 400 billion RMB. This paper mainly updates and interprets the history, present situation and prospect of egg processing industry in China.