Effects of salt and storage temperature on pysico-chemical and sensory properties of salt fermented herring (Amblygaster sirm)

Abstract

Herring (Amblygaster sirm) is a high fat abundant fatty fish and has a good potential to develop new fish products. Salt fermentation is a traditional preservation technique, which is practiced to develop different fish products. This study was carried out to identify the effect of salt and storage temperature on pysico-chemical and sensory properties of salt fermented herring. Initially, herrings were salted at three fish: salt ratios (3:1, 4:1 and 5:1) and stored at two different temperatures, 4±1 oC and ambient temperature for a period of 24 and 48 hours under light proof conditions. The salted samples were analysed for sensory attributes (colour, odour, texture, taste and overall preference) after 24 and 48 hours, by 30 untrained panellists and using a hedonic scale. Herrings treated with 4:1 ratio shown significantly (p<0.05) high acceptable sensory attributes, than other two treatments. Moreover, salted herrings (4:1) stored for 48 hours, at both temperatures had significantly (p<0.05) favourable sensory attributes. Herrings salted at 4:1 ratio were selected for further processing and analysed for physico-chemical properties. The samples were immersed in 75% and saturated salt solution at 4±1 oC and ambient temperature for further fermentation process. Samples were tested for Total Volatile Base Nitrogen (TVB-N) content and sensory attributes, at weekly intervals. The level of TVB-N was found to increase gradually in the salted herrings stored in 75% salt solution and sensory attributes became gradually unacceptable, by the sixth week at both storage temperatures. Even though, the above parameters of salted herrings (4:1) stored in saturated brine solution, had gradually varied they remained within the acceptable limit. Therefore, salt fermentation of herrings at 4:1 ratio for 48 hours, followed by storage in saturated brine preserves herring (A. sirm) at least up to three months without affecting their sensory qualities.