Performance Evaluation of Solar Greenhouse Type Dryer for Fish Drying

The solar tunnel/greenhouse dryer can successfully used for drying of most types of agricultural produce including fruits, vegetables, spices, medicinal plants and marine products. The single span arc type G.I pipe framed greenhouse tunnel dryer of size 21.3 m X 4.6 m X 2.2 m covered with single layer 200m thick UVS polyethylene sheet was developed and installed at Jose and Bros. Fish Industry Veraval (Gujarat). Inlet air vents were provided on west and south side of the dryer. For exhaust purpose and to enhance the air movement inside the dryer, five zero energy turbine air ventilators were provided. Freshly available fish of the variety Croaker, Anchovy and Ribbon fish were taken for drying. The drying was carried out by loading the fish on the wire net or jute net inside the dryer. The drying was started at 9: 00 a.m. and ended at 17: 00 p.m. The fish were dried up to safe moisture content for storage and marketing. Treatments for the experiment were considered as: S-Pretreatment (S₀: salt treated and S₁: unsalted); T-Drying temperature range (T₁: 40–45°C and T₂: 45–49°C) and V-variety (V₁: Croaker, V₂: Anchovy and V₃: Ribbon). The Drying experiment was conducted according to CRD statistical design. Data obtained for each treatment were analyzed for the drying rate, moisture ratio and bio-chemical analysis like fat, protein and ash content. From the study, it was observed that in salt treated fish, moisture content was reduced up to 42.85% to 66.66% (d.b.) in 1 or 2 days of drying for different treatments as compared to 17.64% to 25% (d.b.) in 3 or 4 days of drying in unsalted fish. There was no significant effect of variety was found however, effect of drying air temperature showed significant difference in final moisture content. The minimum drying time was observed for T₂ for both salted and unsalted fish. For all treatments dryingrateremained higher in solar drying than that of sun drying. The biochemical analysis revealed that V*S interaction was significant for protein content. The highest protein content was found for the combination of V₃S₀ (60.39%). The decrement in fat content of different selected varieties was found in order of V₂ (7.08%), V₁(6.54%) and V₃ (4.63%) respectively. The effect of temperature and salting were also found significant at 5% level of significance. Highest fat content was observed at T₂ (6.25%) and without salting (7.34%). Treatment V₁T₂S_{0 gave} the highest colour score (7.5). Dried fish obtained through treatment V₁T₁S₁, and V₂T₂were highly accepted by judges. ^V2^T1^S1^S0 The Good quality Salt treated fish were obtained in T₁ range (40–45°C) whereas T₂ range (45–49°C) was found best for unsalted fish. The solar dried fish were liked more than sun dried fish.