Evaluation of Alginate-Gum Arabic Coating and Pomegranate (Punica granatum L.) Peel Extract Impact on Microbial and Physicochemical Properties of Shrimp (Litopenaeus vannamei) During Refrigerated Storage

Abstract

This study evaluated the impact of alginate-gum Arabic coating and pomegranate (Punica granatum L.) peel extract (PPE) on the microbial and physicochemical properties of shrimp (Litopenaeus vannamei) during refrigerated storage. The treatments included T1 (0.5% encapsulated PPE), T2 (1% encapsulated PPE), T3 (1% free-form PPE), T4 (2% free-form PPE), T5 (1% alginate-gum Arabic coating), and T6 (control). Results indicated that the peroxide value ranged from 0.42 meq/kg (T2, day 3) to 2.15 meq/kg (T6, day 15); TBARS was lowest at 0.18 mg MDA/kg (T2, day 3) and highest at 1.02 mg MDA/kg (T5, day 9); free fatty acid (FFA) varied from 0.35% (T1, day 3) to 1.85% (T6, day 15); pH ranged from 7.34 (T1, day 3) to 8.30 (T5, day 9). Firmness peaked at 4.5 N (T2, day 3) and was lowest at 2.1 N (T6, day 15); resilience was highest at 0.85 (T1, day 3) and lowest at 0.45 (T6, day 15); cohesiveness and adhesiveness showed no significant differences (p > 0.05), with values slightly higher on day 15 (cohesiveness: 0.75–0.82; adhesiveness: −1.2 to −0.9 g/s). Sensory scores for taste, texture, color, odor, and overall acceptance were highest in T1 and T2 (4.5–4.8 on day 3, declining to 3.2–3.5 on day 15). Total bacterial count (TBC) was lowest at 2.5 log CFU/g (T2, day 3) and highest at 6.8 log CFU/g (T6, day 15). The highest saturated fatty acid (SFA), monounsaturated fatty acid (MUFA), and polyunsaturated fatty acid (PUFA) were palmitic acid (20.91%), elaidic acid (26.91%), and linoleic acid (7.53%), respectively, on day 3, with better preservation in T1 and T2. Overall, 0.5% (T1) and 1% (T2) encapsulated PPE incorporation provided the best physicochemical and sensory properties compared to other treatments. PPE is a viable natural preservative for maintaining the quality of shrimp and other seafood products during refrigerated storage.