Fabrication of black wolfberry anthocyanin-based hydrogels for monitoring freshness and extending shelf-life of Dolang lamb

Abstract

In this study, a black wolfberry anthocyanin-based indication label (BWIL) was developed using black wolfberry pigment (BWP) in combination with polyvinyl alcohol (PVA) and carboxymethyl cellulose (CMC) (PVA:CMC = 4:3). The potential use of BWIL for monitoring the freshness of Dorang lamb was further investigated. As revealed, physical cross-linking occurred between PVA, CMC and BWP during the preparation of BWIL. The addition of BWP promoted the internal cross-linking, porosity, and thermal stability of BWIL significantly (p < 0.05). Specifically, BWIL showed a distinct color change when exposed to the refrigerated conditions of Dorang lamb. After 6 days, 12 days and 16 days of lamb refrigeration, the ΔE of BWIL was 26.3, 28.6 and 30.7, respectively, which far exceeded the human eyes' color threshold discernible (ΔE = 3.5). Besides, the ΔE of BWIL was significantly correlated with pH, fat oxidation, and TVB-N content of Dorang lamb (p < 0.05). This result indicated that BWIL could be used for identifying the freshness of lamb accurately. Importantly, the shelf-life of lamb with BWIL was extended from 6 days to 16 days, which suggests that BWIL would be an effective tool for real-time freshness monitoring and shelf-life extending of Dorang lamb.