METHODS OF DRYING OF TOMATO SLICES AND THE EFFECT OF THE USING OF ITS POWDER ON THE PRODUCTION AND CHARACTERISTICS OF EXTRUDED SNACKS

In this study, tomato samples were subjected to different pre-treatments (0.2 % sodium meta bisulphate (Na_2S_2O_5), 1 % calcium chloride (CaCl_2)and steam blanching. Untreated samples served as control. After pretreatment, tomato slices were subjected to three different drying methods (oven air, solar and microwave / hot air) and milled in grinder to powder. Tomato powder had been packed in multilayer films consists of low density polyethylene, aluminum and Polyester. Physical properties and bioactive compounds (total phenolic compounds, total flavonoids, β- carotene, lycopene, and ascorbic acid) of tomato powder were studied. The powder produced was used in functional food (extruded snacks). Dried tomato powder was added to corn grits flour at levels of 3 and 6% and extruded in a single screw extruder to produce healthy extrudes. Sensory characteristics and physical properties of snacks were evaluated. The studied parameter (moisture, total phenolic, total flavonoids lycopene and β-carotene) were significantly (p ≤ 0.05) affected by different pretreatments processes and drying methods. The results showed that solar drying had negative effect of all characteristics of tomato slices and the color was dark. The sensory analysis findings showed that, extrudes contain 3 and 6% tomato powder (dried by oven and microwave/hot air) had significant higher color and taste scores. Adding tomato powder at level 6% led to increment in scores of crispness, flavor and overall acceptability.