α-Chitosan Coating as a Bio-preservative: Mitigating Spoilage and Extending the Shelf-life of Chilled Squid Rings

Abstract

This study evaluated the effectiveness of a 0.5% α-chitosan edible coating in preserving the quality of squid (Uroteuthis duvaucelii) rings during chilled storage at 4 °C. The coated samples (Tα) and uncoated controls (C) were assessed over 8 days for physicochemical parameters (colour, pH, drip loss, lipid oxidation) and sensory attributes. Results showed that α-chitosan substantially retarded quality deterioration compared to the control. Lightness (L*) decreased sharply in the control, whereas coated samples maintained higher values. Redness (a*) and yellowness (b*) increased more gradually in coated samples, indicating reduced surface oxidation. The rise in pH was significantly suppressed in coated samples relative to the control, suggesting reduced microbial spoilage. Drip loss reached 6.5% in the control but remained significantly lower (3.8%) in coated samples, while TBA values an indicator of lipid oxidation were markedly reduced in the coated group compared to the control. Sensory evaluation further confirmed the preservative effect, with coated samples retaining acceptable odour, texture, and overall acceptability up to Day 8, whereas control samples fell below the acceptability threshold by Day 6. Overall, α-chitosan coating acted as an effective oxygen- and moisture-barrier, slowing biochemical and oxidative spoilage processes and extending the sensory shelf life of squid rings by at least two days. These findings highlight α-chitosan as a promising natural bio-preservative for enhancing the storage stability and commercial quality of cephalopod products.