Nutritive value of fresh and salted fermented fish (Alestes dentex) Terkin

Abstract

The aim of the current study was to evaluate the nutritional value of salted-fermented fish compared to fresh ones. Kawara fish (Alestes dentex) were used in this study. The fish samples were salted in layers, preserved in a tight container for- twenty four hours and boiled once. Next the mixture was fermented under direct sun light and stirred twice a day until the product became homogenous after twenty days. The parameters used for comparison included; proximate analysis, in vitro protein digestibility, minerals, heavy metals content and amino acid composition. In addition the total bacteria and coli-form count were determined. The results obtained showed high levels of moisture (68.20%) and protein (23.30%) in fresh fish compared to the salted- fermented one (40.08% and 14.25%) respectively. However, the ash content of salted-fermented fish was higher than that in fresh ones. No significant difference was found in the in vitro protein digestibility in the salted-fermented fish and fresh one. Minerals content showed different levels of calcium, potassium, copper and iodine in both type of fish, the level of sodium was high in the salted-fermented fish. It’s worth mentioning that the levels of calcium and potassium were highest in both fresh and salted-fermented fish compared to other minerals. Generally iodine and copper were lowest in fresh and salted –fermented fish. Amino acids analysis showed that the glutamic acid was the highest among all other amino acids in both fresh and salted-fermented fish. Whereas the levels of glycine, alanine, isoleucine, phenylalanine ,lysine and proline were significantly increased in salted-fermented fish , those of tyrosine, histidine and arginine were reduced in salted compared to fresh fish. In addition the total bacterial and coli form count were evaluated before processing and then ten and twenty days post processing. Total bacterial count was (3.5×105) cfu/g in fresh fish and reached (1.5× 106) cfu/g after ten days post processing. No bacterial growth was found after twenty days of fermentation. The coli- form count in fresh fish was (6.0× 105) cfu/g and no growth was found in both ten and twenty days old Terkin. In conclusion, the nutritive value of salted and fermented fish was decreased compared to fresh fish.