Effect of Carbon Dioxide and Nitrogen Ratios on Shelf-life of Fish Balls Packed under Modified Atmosphere Condition

Abstract

The extension of shelf-life of fish balls by modified atmosphere packaging (MAP) was investigatedby packing fish balls in nylon/PE bags with various gas concentrations (100%CO₂, 80%CO₂+ 20%N₂,60%CO₂+ 40%N₂ and 40%CO₂+ 60%N₂). All samples were kept at 4±2°C and taken for determiningmicrobiological, chemical, physical and sensory qualities during storage. The results showed that storagetime had significant effects on total bacteria, pH, Aw, drip loss and firmness (p≤0.05). As storage timeincreased, total bacteria, drip loss and firmness of fish balls packed under all modified atmosphere conditionsincreased while pH and Aw of those fish balls decreased. The various packing conditions had significanteffects on qualities of fish balls as well. Total bacteria number of the fish balls packed under 100%CO₂was lower than that of any other modified atmosphere conditions. In addition, the decrease of pH of fishballs packed under 100%CO₂ was the lowest following by 80%CO₂+20%N₂, 60%CO₂+40%N₂ and40%CO₂+60%N₂, respectively. The increment of CO₂ concentration resulted in significant decrease in Awbut increase in drip loss and firmness (p≤0.05). However, the results from sensory evaluation indicated thatfish balls packed under 60%CO₂+ 40%N₂ obtained the highest score and were accepted by the panelistsuntil 12 days of storage.

Keywords : Fish balls / Shelf life / Modified Atmosphere