Quality and Shelf Life Evaluation of Chitosan-coated Dried Bombay Duck (Harpodon nehereus)

Abstract

Background: Bombay duck (Harpodon nehereus) is one of the most abundant and preferable marine species in the Maharastra and Gujrat region. Bombay duck is mostly consumed in dried form. The major problem associated with traditionally sun-dried Bombay duck is contamination by insects or pest, uneven drying which leads to spoilage and poor quality of end product. Chitosan and its derivatives are used as edible coating food applications due to its antioxidants and antimicrobial action. In the present study was aimed to improve the quality of dried Bombay duck by applying chitosan coating and drying under controlled temperature Methods:The five different lots of samples were prepared viz. (i) control (without any treatment) (ii) dip treated in1% acetic acid (AA) (iii) dip treated in 0.5% chitosan dissolved in 1% acetic acid (CAA) (iv) dip treated in 1% malic acid (MA) (v) dip treated in 0.5% chitosan dissolved in 1% malic acid (CMA). All the samples were dried at 50°C. Biochemical, microbiological and sensory analyses were assessed out up to 4 months.

Results: The study revealed that sample coated with chitosan which was pre dissolved in either acetic acid or malic acid had lower TVB-N (86.5-115.25 mg/100g), TPC (5.3-5.5 log cfug/g) than control (TVB-163mg/100g; TPC-7.4 log cfu/g). Similar trend also observed for TBA values. Microbial analysis revealed that TPC crossed the limit of acceptability (5.2 log cfu/g) on 2nd month in control. However, AA, CAA, MA, and CMA had acceptable level up to three months. Sensory analysis showed that overall acceptability score was higher for fish coated with chitosan. Results suggested that chitosan coating and drying could improve the quality of dried Bombay duck.