Naturally evolved fermented fish products of Northeast India (<i>Seedal</i> and <i>Shidal</i>) - A comparative study

Abstract

The indigenous fermented fish products of Northeast India namely <i>seedal</i> and <i>shidal</i> were studied to record the preparation processes and general biochemical and microbiological characteristics of the products. The production centers of different states including Assam and Tripura were surveyed and the data were recorded through personal interview and on the spot observation. The most common methods have been reported for the products including <i>seedal</i><i style="mso-bidi-font-style:normal"> </i>and <i>shidal</i> from Assam and Tripura, respectively. These solid products are prepared from small fish species belonging to the carp family (Cyprinidae) by a combined process of drying and semi-fermentation which are then consumed with further elaborate cooking. <i style="mso-bidi-font-style:normal">Seedal</i> was found to contain better original organoleptic characteristics than <i style="mso-bidi-font-style: normal">shidal.</i> The proximate composition of moisture and protein showed significant changes (<i>P</i><0.05), e.g. less moisture content in <i style="mso-bidi-font-style:normal">shidal </i>(30%) than in seedal (36%); however, more protein content was evident in <i style="mso-bidi-font-style: normal">shidal</i> (39%) than in <i style="mso-bidi-font-style:normal">seedal</i> (31%). The protein breakdown products such alpha amino nitrogen, Total Volatile Bases (TVB-N) and Non-Protein-Nitrogen (NPN) showed minimal protein degradation in both the products which is a major peculiarity of these products. The indices for lipid hydrolysis including Peroxide Value (PV), Free Fatty Acid (FFA) and Thiobarbituric Acid number (TBA) showed significantly higher lipid oxidation in <i style="mso-bidi-font-style: normal">shidal </i>than in <i style="mso-bidi-font-style:normal">seedal</i>. The pH also showed significantly higher value in <i style="mso-bidi-font-style: normal">seedal</i> than in <i style="mso-bidi-font-style:normal">shidal</i>. Total Plate Count (TPC) was recorded significantly higher in shidal (7.2 log CFU/g) than in <i style="mso-bidi-font-style:normal">seedal </i>(6.4 log CFU/g) having the Total Fungal Count (TPC) almost negligible in both the products. Being produced in large scale<i style="mso-bidi-font-style:normal">, shidal</i> contained more dry fish like characters than <i style="mso-bidi-font-style: normal">seedal</i> which had higher market value than the other.