The effect of drying temperature on physicochemical properties of kilka and carp fish powder

Producing of fish powder is a good way for increasing the shelf life of these valuable protein sources, easy accessing and increasing of food variety.In this study, the effect of drying temperature on physicochemical properties of kilka and carp fish powder was investigated. For this purpose, temperatures of 45, 55, 65 and 75 °C were used to dry the fish. The results of this study showed that moisture, fat, protein and TVN for carp powder was 7.02%, 4.92%, 83.80%, and 150 mg/g, while moisture, fat, protein and TVN of kilka fish powder was 8.12, 8.8%, 5.09%, 82.18% and 140 mg/g, respectively. The highest water binding capacity was related to dried carp samples at 45 °C and dried kilka at 55 °C. The lowest and highest fat reabsorption was in dried carp samples at 45 °C and dried kilka at 55 °C, respectively. The results of density test showed that with decreasing drying temperature, the density of the final powder decreased. The highest densities of carp and kilka powders were 0.511 g/cm3 and 0.408 g/cm3, respectively, which were dried at 45 °C. The study also represented that with increasing temperature from 45 to 75 °C, L* factor of the powders decreased. Besides, scanning electron microscopy (SEM) results indicated that the proteins were more denatured at higher temperature and the particle sizes were reduced.