Preparation and Whitening Activity of Sialoglycopeptide of Chalaza from Liquid Egg Process

The liquid egg processing industry generates a significant amount of solid byproduct known as chalaza (CHA), which is rich in sialic acid and exhibits notable biological activity. In this study, the preparation process, N-glycan profile, and skin-whitening activity of CHA-derived glycopeptides (CHAH) were investigated. By comparing the hydrolysis efficiency of trypsin, alcalase, and papain, a dual-enzyme hydrolysis strategy was developed: initial hydrolysis with 1.5% trypsin for 3 h, followed by treatment with 1% papain for 2 h. The resulting CHAH exhibited both a high hydrolysis yield and strong antioxidant activity. The sialic acid content in CHAH reached 1.96% (<i>w</i>/<i>w</i>), and 14 distinct N-glycan chain structures were identified. The whitening effect of CHAH was assessed using a combined approach involving an in vitro B16 cell model and an in vivo zebrafish model. CHAH was found to inhibit tyrosinase activity and reduce melanin production in a concentration-dependent manner. Mechanistic studies revealed that CHAH acts by significantly downregulating the expression of key genes involved in melanin synthesis, including MITF, TYR, TYRP1, and TYRP2. This study establishes an efficient preparation method for CHAH, elucidates its skin-whitening efficacy and underlying mechanism, and provides experimental support for the potential industrial application of CHAH as an active ingredient in skincare products.