Hydrocolloid materials of fish bone-derived in edible films: can hydroxyapatite be an alternative approach to improving fillet shelf life?

The valorization of industrial fish waste has gained significant scientific interest due to its integrated benefits such as waste management and resource recovery. The aim of this study is to evaluate the effectiveness of fish bones, which is one of the wastes of aquaculture processing and constitutes approximately 9–15% of the waste generated as a result of the process, as a preservative in the food industry within the scope of green chemistry applications, sustainability and green product targets. In line with this objective, in the first stage, hydroxyapatite (HAP) was obtained from the fish bones, in the second stage, chitosan (Ch)-based coating solutions were enriched with HAP at different levels (0.02, 0.04 and 0.08 g / L) and in the last stage, fillets were coated with this solution and fillet quality parameters were monitored by microbiological, chemical and sensory analyses at certain intervals (0, 3, 6, 9 and 12 days) during 12 days of storage (at + 4 °C). Based on the data obtained during the storage period, the shelf life of control (Chitosan, Ch). chitosan + low HAP (Ch + L-HAP) and chitosan + medium HAP (Ch + M-HAP) fillet groups increased by 50%, 26% and 20%, respectively, compared to chitosan + high HAP (Ch + H-HAP). In the findings obtained, it was determined that the high concentration application (Ch + H-HAP) had a negative effect on all the parameters studied in fillets, and when the data on the last day of storage, especially the microbiological results were taken into consideration, it was determined that the shelf life decreased by 20–50% on average compared to the other concentrations (Ch + L-HAP and Ch + M-HAP) and Ch group and caused serious negativities in sensory parameters. Based on this result, it would be useful to try low and medium levels of this compound in different combinations. These findings indicate that HAP-enriched chitosan coatings have potential as a promising delivery system for the effective and controlled transport of bioactive ingredients in the food industry.