Use of nanoliposome loaded with chitosan‐epigallocatechin gallate conjugate for shelf‐life extension of refrigerated Asian sea bass (Lates calcarifer) slices

Abstract

Treatments of chitosan-epigallocatechin gallate (CE) conjugate nanoliposome (CELP) and unencapsulated CE conjugate (UNCE) at different concentrations (0.025 and 0.05 g 100 g À1 ) on quality and shelf-life of Asian sea bass slices (ASB-S) kept at 4°C were studied. Total viable count of ASB-S treated with 0.05 g 100 g À1 CELP (SB-CELP-0.05) was less than permissible limit (6 log CFUg À1 sample) within 15 days. Moreover, SB-CELP-0.05 sample had the lowest pathogenic and spoilage bacterial count than remaining samples during the storage (P < 0.05). Lower thiobarbituric acid reactive substances and peroxide values were obtained for SB-CELP-0.05 sample than those treated with 0.05 g 100 g À1 UNCE (SB-UNCE-0.05) at the end of storage (P < 0.05). The result was also advocated by higher polyunsaturated fatty acid content of SB-CELP-0.05 than SB-UNCE-0.05 (P < 0.05). Therefore, CELP efficiently extended ASB-S shelf-life with high consumer acceptability at 4°C for minimum 12 days, whereas control had the shelf-life less than 6 days.

The impact of chitosan film or chitosan/chitosan–epigallocatechin gallate conjugate composite film on the quality changes of Asian sea bass (Lates calcarifer) slices stored in air or under vacuum packaging

“…NaCl solution (0.85%, w/v) was used for serial dilutions of homogenate. Standard plate count agar (HiMedia, Mumbai, India) was used for enumeration of total viable count (TVC) and psychrophilic bacterial count (PBC) of ASBS, in which the plates were incubated at 35 °C for 48 AE 2 h (AOAC, 2002) and 4 °C for 7 days (Mittal et al, 2021b), respectively. Lactic acid bacteria count (LABC) was enumerated on a double-layered plates of deMann-Rogosa Sharpe medium (MRS) agar (HiMedia, Mumbai, India) after 72 h of incubation at 37 °C.…”

“…Lactic acid bacteria count (LABC) was enumerated on a double-layered plates of deMann-Rogosa Sharpe medium (MRS) agar (HiMedia, Mumbai, India) after 72 h of incubation at 37 °C. H 2 S-producing bacteria (HSPBC) and Pseudomonas count (PC) were evaluated using triple sugar iron agar (Difco Laboratories, BD, Sparks, MD, USA) and Pseudomonas isolation agar (HiMedia, Mumbai, India) plates, respectively, after being incubated for 3 days at 25 °C (Mittal et al, 2021b). Eosin methylene blue agar (HiMedia, Mumbai, India) plates were used for EC when incubated for 24 h at 37 °C (Mittal et al, 2021b).…”

“…H 2 S-producing bacteria (HSPBC) and Pseudomonas count (PC) were evaluated using triple sugar iron agar (Difco Laboratories, BD, Sparks, MD, USA) and Pseudomonas isolation agar (HiMedia, Mumbai, India) plates, respectively, after being incubated for 3 days at 25 °C (Mittal et al, 2021b). Eosin methylene blue agar (HiMedia, Mumbai, India) plates were used for EC when incubated for 24 h at 37 °C (Mittal et al, 2021b). Perfringens agar base was used for the enumeration of Clostridium perfringens, incubated anaerobically at 35 °C for 20-24 h (FDA BAM, 1998).…”

“…The global production of Asian sea bass (ASB) has been reached 0.74 million metric tonnes for 2018, in which the contribution of Thailand was about 12% (FAO-FIGIS, 2021). Among all the fish, ASB is intensively reared and considered an economically important fish in many Southeast Asian countries, particularly in Thailand since 1970s (Mittal et al, 2021b). ASB is generally sold or exported in the form of fillets or whole fish.…”

“…However, various factors including enzymatic and biochemical reaction, lipid oxidation and microbial contamination are considered as the principal contributors to quality deterioration and limited shelf-life of ASB during post-harvest handling and storage (Chaijan et al, 2006). To enhance shelf-life of seafood and impede the rate of biochemical and microbial activities, use of natural additives including chitosan (CS) with or without non-thermal processing techniques have been gaining attention instead of synthetic preservatives, which cause adverse effect or risk to human health (Singh et al, 2021a, Mittal et al, 2021b.…”