Development of multi-functional collagen films for maintaining and visually monitoring shrimp freshness

• Published in: Food hydrocolloids 2025-03, Vol.160, p.110734, Article 110734
• Main Authors: Ran, Ruimin, He, YeQing, Zhang, Xiaoxia, Zeng, Xingling, Guo, Xin, Luo, Xiaoyun, Li, Guoying
• Format: Article
• Language: English
• Subjects: Collagen; Freshness maintaining; Freshness monitoring; Laccase-catalyzed anthocyanins; Pickering emulsion
• ISSN: 0268-005X
• DOI: 10.1016/j.foodhyd.2024.110734

Anthocyanin-rich films enable real-time monitoring of food freshness without opening the packaging. However, the easy migration of hydrophilic anthocyanins and poor antimicrobial activity of films are problems that need to be addressed. Here, laccase was used for tightly immobilizing black wolfberry extract (BWE), black rice extract (BRE), and bilberry extract (BE), characterized by containing mainly cyanidin (two phenolic hydroxyls and one methoxyl on the B-ring), petunidin (two phenolic hydroxyls on the B-ring), and delphinidin (three phenolic hydroxyls on the B-ring), respectively, in the film matrix, and a cinnamon essential oil-based Pickering emulsion was used to enhance film bacteriostatic activity. The results showed that laccase catalyzed the conversion of anthocyanin (BWE, BRE, BE) to anthocyanin o-quinone (OBWE, OBRE, OBE) without destroying the anthocyanin pH sensitivity. Collagen film modified with anthocyanin o-quinones and Pickering emulsion showed enhanced resistance to anthocyanin migration compared with non-laccase-catalyzed anthocyanin/Pckering emulsion-based films via the formation of strong cross-links with the collagen film matrix mediated by Schiff-base and hydrogen bonds. The degree of anti-anthocyanin migration was ranked as COL-OBE (from 33.76 to 10.74%) > COL-OBRE (from 39.29 to 19.44%) > COL-OBWE (from 41.06 to 26.67%). Furthermore, the COL-OBE film demonstrated improved pH sensitivity, antimicrobial activity (from 0 to 95.99%), antioxidant activity (from 6.56 to 91.78%), water absorption resistance (from 581.88 to 151.03%), and light-blocking properties compared with collagen film. When COL-OBE film was used for preserving shrimp, it was found that the film not only extended shrimp shelf life (about three days) but also allowed real-time monitoring of changes in shrimp freshness. [Display omitted] •Oxidized anthocyanins (OBWE, OBRE, OBE) were prepared by laccase catalysis.•Collagen film (COL) was modified by oxidized anthocyanins and a Pickering emulsion.•Modified films had enhanced pH response/anti-anthocyanin migration/bacteriostasis.•The high quinone content in OBE led to superior performance of the COL-OBE film.•The COL-OBE film prolonged shrimp shelf life and monitored freshness in real time.