• Korean Journal of Poultry Science
• /
• v.49 no.4
• /
• pp.221-228
• /
• 2022

Major egg white proteins and their hydrolysates serve as functional food ingredients that have certain metal-chelating properties. Employing egg white proteins and their hydrolysates to scavenge dietary oxalates is anticipated to have beneficial effect in the prevention of kidney stones. The objective of this study was to determine the biogenic oxalate-chelating activity of ovalbumin, ovomucin, and ovotransferrin and their hydrolysates. To prepare oxalate extracts, 30 mL of 0.25 N HCl was added to separately to 0.5 g of dried spinach and starfruit powders followed by boiling for 15 min, and after cooling, the addition of a further 20 mL of 0.25 N HCl. Having prepared these extracts, ovalbumin, ovomucin, and ovotransferrin and their hydrolysates were separately mixed with oxalate extracts and incubated at 3℃ for 24 h. Following centrifugation, supernatants were analyzed by HPLC using a reverse-phase C18 column coupled with a diode array detector. We found that all assessed proteins and their hydrolysates showed biogenic oxalate-chelating activity against the oxalates of spinach. In contrast, however, only ovalbumin, ovalbumin-hydrolysate, and ovomucin showed chelating activity (57.10%±8.84%, 85.44%±5.30%, 73.20%±4.13%, respectively) against the oxalates of starfruit (P<0.05). Overall, hydrolyzed ovalbumin was identified as the most effective chelator of the oxalates both spinach and starfruit. In this study, we thus established that the assessed egg white proteins and their hydrolysates have oxalate-chelating activity in vitro, thereby indicating that these compounds have potential utility as nutraceuticals for the chelation of dietary oxalate. However, further research will be necessary to verify their oxalate-chelating activities against different fruits and vegetables and under specific in vivo conditions and against purified oxalate.

• Food Science of Animal Resources
• /
• v.44 no.4
• /
• pp.885-898
• /
• 2024

Ovomucin (OM), which has insoluble fractions is a viscous glycoprotein, found in egg albumin. Enzymatic hydrolysates of OM have water solubility and bioactive properties. This study investigated that the immunostimulatory effects of OM hydrolysates (OMHs) obtained by using various proteolytic enzymes (Alcalase^®, bromelain, α-chymotrypsin, Neutrase^®, pancreatin, papain, Protamax^®, and trypsin) in RAW 264.7 cells. The results showed that OMH prepared with pancreatin (OMPA) produced the highest levels of nitrite oxide in RAW 264.7 cells, through upregulation of inducible nitric oxide synthase mRNA expression. The production of pro-inflammatory cytokines such as tumor necrosis factor-α and interleukin-6 were increased with the cytokines mRNA expression. The effect of OMPA on mitogen-activated protein kinase signaling pathway was increased the phosphorylation of p38, c-Jun NH2-terminal kinase, and extracellular signal-regulated kinase in a concentration-dependent manner. Therefore, OMPA could be used as a potential immune-stimulating agent in the functional food industry.

• Food Science of Animal Resources
• /
• v.38 no.2
• /
• pp.291-301
• /
• 2018

To shorten the production cycle of Zaodan, this study first pickled Zaodan by a novel technology - vacuum decompression technology. Vacuum decompression technology could reduce the pickling time of Zaodan from 20 wk to about 9 wk. The protein content, moisture and pH of the Zaodan egg white gradually decreased with a concomitant increase in salt during the pickling process. The total sulfhydryl group (SH) group content of the egg white proteins was increased to $2.43{\times}10^{-3}mol/L$ after being pickled for 30 d, whereas the content of disulphide bonds (SS) was reduced to $23.35{\times}10^{-3}mol/L$. The surface hydrophobicity was lowest after pickling for 30 d. In addition, great changes occurred in the secondary structure of the egg white proteins after pickling for 20 d. The disappearance of ovomucin was noticeable based on sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis.

• Proceedings of the Korea Society of Poultry Science Conference
• /
• 2006.11a
• /
• pp.43-58
• /
• 2006

As a bioreactor, bird has proved to be most efficient system for producing useful therapeutic proteins. More than half of the egg white protein content derives from the ovalbumin gene with four other proteins(lysozyme, ovomucoid, ovomucin and conalbumin) present at levels of 50 milligrams or greater. And the naturally sterile egg also contains egg white protein at high concentration allowing for a long shelf life of recombinant protein without loss in activity. In spite of these advantages, transgenic procedures for the bird have lagged far behind because of its complex process of fertilized egg and developmental differences. Recently, a system to transplant mouse testis cells from a fertile donor male to the seminiferous tubules of an infertile recipient male has been developed. Spermatogenesis is generated from transplanted cells, and recipients are capable of transmitting the donor haplotype to progeny. After transplantation, primitive donor spermatogonia migrate to the basement membrane of recipient seminiferous tubules and begin proliferating. Eventually, these cells establish stable colonies with a characteristic appearance, which expands and produces differentiating germ cells, including mature spermatozoa. Thus, the transplanted cells self-renew and produce progeny that differentiate into fully functional spermatozoa. In this study, to develop an alternative system of germline chimera production that operates via the testes rather than through developing embryos, the spermatogonial stem cell techniques were applied. This system consisted of isolation and in vitro-culture of chicken testicular cells, transfer of in vitro-maintained cells into heterologous testes, production of germline chimeras and confirmation of germline transmission for evaluating production of heterologous, functional spermatozoa.