Application of Chitosan in Extending the Shelf-Life of A Popular Indigenous Food Item – Nga-Pi

Abstract:

Biogenic active chitosan has a wide range of commercial aspects due to its high nitrogen content when compared to synthetic cellulose substitutes. Among various additives, chitosan has been considered as a powerful antimicrobial agent, preservative, binder agent and texturizer in food industry. Synthetic preservatives are not suitable for developing food preservation due to their harmful health effects and less consumer preference. Therefore, the present study was conducted to increase the shelf-life and retaining quality of indigenous semi-fermented shrimp product Nga-pi using chitosan as a natural preservative. Hydrogel was prepared by adding chitosan powder with required amount of water containing acetic acid. Different concentrations of chitosan gel were considered as treatment (CT0-0%, CT1 0.125%, CT2-0.25%, CT3-0.50% and CT4-01%) were incorporated with Nga-pi and its effects on functional, microbiological and oxidation parameters were examined for 45 days’ storage period in ambient temperature. The organoleptic characteristic of Nga-pi was evaluated for preference of color, odor, texture, appearance and overall acceptability. Analyses of moisture content showed significant difference between control samples and treatment groups (p < 0.05). The pH value of control samples was found 7.49± 0.01 and chitosan treated sample CT1:7.11±0.14, CT2:7.21±0.01, CT3:7.24±0.06 and CT4:6.93±0.09 respectively. Thiobarbituric acid reactive substances (TBARS) of the chitosan treated samples were significantly lower than control samples (p< 0.05) at the end of observation period. The Total plate count (TPC) analysis showed drastic reduction of bacterial count in chitosan treated sample after inclusion. Whether the control sample recorded TPC value of 5.8×107 ± 1.6 CFU/g which were over the acceptable limit. Evaluation of sensory score preference of color, odor, texture, appearance and overall acceptability, results showed better sensory quality in chitosan treated groups. Treated with 1% chitosan content uphold the best necessary qualities of indigenous semi- fermented food products Nga-pi.