B. R. CHAVAN, A. YAKUPITIYAGE, S. KUMAR AND V. B. SUTAR
Abstract
Drying trials were conducted for drying mackerel using solar biomass hybrid tunnel dryer (SBHTD) and open sun drying (OSD) at air temperatures 32.4-57.7oC, relative humidity 23.9-85.8% and air flow rate 0.20-0.6 ms-1. Solar radiation ranged between 287- 898 Wm-2 during the experimentation. At night time, drying was carried out by combusting biomass. The fresh mackerel dried in experimental dryer and in open sun drying to achieve the final moisture content <17% (w.b.). The drying time required in S-BHTD 21 h. The overall drying efficiency of the solar-biomass hybrid tunnel dryer is estimated to be about 5.42 during fish drying. S-BHTD was significantly influencing the biochemical properties of dried mackerel. Mackerel dried by using S-BHTD showed very high corresponding coefficients of determination, where all R2 were greater than 0.85, except histamine value. In experimental dryer microbial growth were not found except TPC which was <30 cfu/g. Contour plots of dried mackerel in S-BHTD dryers also showed that for all sensory attributes examined, panelists preferred fish dried with S-BHTD than OSD. The optimum points for all sensory attributes of dried mackerel evaluated were at temperatures ranged from 45-55 oC for 20-30 h. Biochemical, microbial analysis and sensory evaluation showed that the dried mackerel remains in prime acceptable form after 120 days of storage at ambient temperature. The analyzed data showed that the SBHTD was found positive result for production of high quality dried mackerel. However, by improving the design (large size) of biomass stove will help to utilize the complete biomass energy and will enhance drying efficiencies. Therefore, the study suggests that the current experimental dryers design could be used to produce high quality dry fish products and thus, may help the fisher in achieving high quality dry fish products.