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The effect of diet on skin aging has become an interesting research topic. Previous studies have mostly focused on the beneficial effects of collagen peptides derived from marine organisms on the aging skin when administered orally, while the beneficial effects of collagen peptides derived from poultry on aging skin have been rarely reported. In this study, collagen peptides were prepared from chicken bone by enzymatic hydrolysis, and the effect and mechanism of action of orally administered collagen peptides on alleviating skin aging induced by UV combined with D-galactose were investigated. The results showed that the chicken bone collagen had typical characteristics of collagen, and the chicken bone collagen peptides (CPs) were mainly small molecular peptides with a molecular weight of <3000 Da. In vivo experiments showed that CPs had a significant relieving effect on aging skin, indicated by the changes in the compostion and structure of the aging skin, improvement of skin antioxidant level, and inhibition of inflammation; the relieving effect was positively correlated with the dose of CPs. Further investigation showed that CPs first reduce the level of skin oxidation, inhibit the expression of the key transcription factor AP-1 (c-Jun and c-Fos), then activate the TGF-β/Smad signaling pathway to promote collagen synthesis, inhibit the expression of MMP-1/3 to inhibit collagen degradation, and inhibit skin inflammation to alleviate skin aging in mice. Moreover, the skin transcriptome found that lysosomes activated after oral administration of CPs may be an important pathway for CPs in anti-skin aging, and is worthy of further research. These results suggested that CPs might be used as a functional anti-aging nutritional component.

Summary The effects of ultrasound‐assisted phosphate curing (UPC), phosphate curing (PC), and deionised water curing (DC) on the quality of chicken breast meat were investigated. The analysis of tissue sections, low‐field nuclear magnetic resonance (LF‐NMR), and headspace solid‐phase microextraction gas‐phase mass spectrometry (HS‐SPME‐GC‐MS) of water distribution, myofibrillary structure, and volatile components of the meat samples were performed to reveal the mechanism. Also, the curing rate, water holding capacity (WHC), and shear force of meat were assessed. The results revealed that ultrasonic‐assisted salting improved the meat salting rate, WHC, and tenderness by mechanically destroying the muscle fibre structure, increasing the space between the muscle fibre bundles, promoting water migration and uniform distribution, and reducing water freedom in the treated samples. In addition, HS‐SPME‐GC‐MS analysis revealed that PC significantly reduced the content of volatile flavour components in the chicken breast meat compared with DC (P < 0.05); however, the combination treatment with PC and ultrasonic curing could reconstruct the flavour loss caused by phosphate. Thus, our cumulative results suggest that the ultrasonic technology may effectively assist the processing technology in improving the quality of meat and reconstructing the flavour loss in meat products.

The present study used acetic acid, sodium hydroxide, and pepsin extract acid-soluble collagen (ASC), alkali-soluble collagen (ALSC), and pepsin-soluble collagen (PSC) from the bones of spent-hens, and the effects of three extraction methods on the characteristics, processing properties, antioxidant properties and acceptability of chicken bone collagen were compared. The results showed that the extraction rates of ASC, ALSC and PSC extracted from bones of spent-hens were 3.39%, 2.42% and 9.63%, respectively. The analysis of the amino acid composition, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), Fourier transform infrared spectroscopy (FTIR), and ultraviolet full spectrum showed that the collagen extracted by the three methods had typical collagen characteristics and stable triple-helix structure, but the triple helical structure of PSC is more stable, and acid and alkaline extraction seems to have adverse effects on the secondary structure of chicken bone collagen. Differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) scanning showed that PSC had higher thermal stability and more regular, loose, and porous microstructure. In addition, PSC has good processing properties, in vitro antioxidant activity, and organoleptic acceptability. Therefore, enzymatic hydrolysis was still one of the best methods to prepare collagen from bones of spent-hens, and enzyme-soluble collagen has wider application prospects in functional food and medicine and also provides an effective way for the high-value comprehensive utilization of waste chicken bone by-products.

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