Comparative study of preservation techniques for refrigerated Atlantic bonito Fillets: Effects of modified atmosphere packaging, vacuum packaging, and alginate coating on shelf life and quality

Abstract

Effective preservation strategies are essential to extend fish shelf life, minimize waste, and ensure product quality. Owing to its high perishability, fish is prone to rapid deterioration due to physicochemical changes and microbial growth. This study evaluated the effectiveness of vacuum packaging (50 % vacuum), modified atmosphere packaging (MAP: 80 % N₂ + 20 % CO₂), and sodium alginate coating (1 %), all under refrigeration, compared to refrigeration alone as a control. Atlantic bonito (Sarda sarda) fillets were stored at 4 °C for 15 days. Physicochemical parameters (moisture, pH, lipid and protein content, chloride, ash, and fibre), oxidative stability (peroxide index and TBARs), texture, colour, microbiological load, and sensory attributes were analysed at defined intervals. Among the treatments, MAP was most effective in preserving fillet quality, exhibiting the lowest peroxide (1.10 ± 0.05 mEq/kg) and TBARs values (1.29 ± 0.06 mg MDA/kg). MAP samples also demonstrated better retention of texture and colour and maintained microbial counts within acceptable regulatory limits throughout storage. Sensory evaluation confirmed superior freshness, texture, and aroma in MAP-treated fillets, closely resembling freshly processed fish. In contrast, samples stored under vacuum or with sodium alginate coating showed moderate improvements over refrigeration alone but were less effective than MAP. These findings highlight MAP as a promising packaging solution for extending the shelf life of Atlantic bonito, offering enhanced oxidative stability, microbial safety, and sensory quality. The results support the application of MAP in the fish industry to improve product stability and consumer acceptability during refrigerated storage.