Extension of shelflife of the fermented fish product, shidal by packaging in glass bottle and low temperature storage

Abstract

Shidal is a very popular, salt free, semi-fermented traditional fish product of north-east India prepared using minor carps (Puntius spp.) in specially designed earthen pots (mutka). The prime quality of shidal is given by its characteristic aroma and flavor which is lost very fast, once it is taken out of mutka. A study was conducted to preserve the quality of shidal outside mutka, by packing in glass bottles and storing under refrigerated temperature. Microbiological, biochemical and sensory changes during storage period of 120 days were analysed at 15 days interval. The total plate count (TPC) did not change significantly (p>0.05) and remained near 7 log CFU g-1 during storage. The total fungal count (TFC) was negligible., The pH of shidal was initially acidic (4.42 ± 0.25) which increased significantly (p<0.05) towards the end of storage period. The non-protein nitrogen (NPN), free α-amino nitrogen (AAN) and total volatile base nitrogen (TVB-N) increased significantly (p<0.05) during storage indicating hydrolysis and degradation of protein. Similarly, showing high hydrolytic rancidity, the peroxide value (PV), free fatty acid (FFA) and thiobarbituric acid (TBA) number significantly increased throughout the storage period (p<0.05). The sensory scores showed significant differences (p<0.05) during the storage period. Shidal retained good quality up to 60 days at room temperature whereas 90 days at refrigerated temperature showing significantly high sensory scores in the treatment.