Effects of different drying methods and packaging materials on the physical and sensory qualities of tomato (Lycopersicon lycopersicum L.)

Fresh tomato fruits have a very limited shelf life partly due to their high moisture content and respiration rate. A possible way of storing tomato fruits is to dry and process them into powder or paste. Therefore, this research was conducted to determine the effects of drying methods and packaging materials on physical and sensory qualities of powdered tomato in Yola, Adamawa State, Nigeria. Harvested fruits of tomato variety, “Rio de grande” were subjected to blanching and subsequent drying methods and packaging materials. The experiment was laid out in a Completely Randomized Design (CRD); with the drying methods placed in main plot while the packaging materials in sub-plot and repeated three times before storage for twelve weeks. At four weeks of storage, oven drying method was found to be statistically different (p≤0.05) in terms of water absorption capacity value of 3.19 (mg/100g). The glass jars performed better than polythene bags in color retention, taste and consistency at four weeks of storage. The study shows that tomato fruits can be successfully dried using oven, sun and shade drying methods but preferably oven drying method. The processed powder could be successfully stored for 12 weeks or above using either glass jars or plastic container without affecting the consumer appeal and this will also reduce the postharvest losses of tomato fruits.

Effect of Supplementation of Dried Bioflocs Produced by Freeze-Drying and Oven-Drying Methods on Water Quality, Growth Performance and Proximate Composition of Red Hybrid Tilapia

Supplementation of dried bioflocs for red hybrid tilapia (Oreochromis sp.) was examined during 57 days of feeding trials. Five experimental treatments; T1 (the control; without bioflocs), T2 (4% freeze-dried bioflocs), T3 (16% freeze-dried bioflocs), T4 (4% oven-dried bioflocs), and T5 (16% oven-dried bioflocs) were prepared to examine the water quality, growth performance and body composition of red hybrid tilapia. T2 and T4 treatments resulted in a higher growth rate and survival similar to the control, while T3 and T5 treatments showed the lowest values of growth performance among all treatments. T1 treatment showed the best quality of culture water followed by T2 and T4 treatments, while T3 treatment resulted in poor water quality followed by T5 treatment. Based on these results, the ratios of bioflocs (4% and 16%) had more effect on fish growth and water quality than the drying methods (freeze-drying and oven-drying). The ratio of 4% freeze-dried or oven-dried bioflocs provided higher growth rates and better water quality parameters similar to the control, while the ratio of 16% showed the worst growth performance and water quality in the present study. In addition, body compositions of tilapia fed 4% dried bioflocs showed better nutritional value than tilapia fed 16% dried bioflocs. Protein and energy levels showed an increasing trend with decreasing supplement levels of bioflocs. Moisture content was significantly higher when supplementation of 16% bioflocs was used. Overall, supplementation of 4% freeze-dried or oven-dried bioflocs can be successively included in red hybrid tilapia diets without any effects on growth or body composition and can result in a good quality of culture water for red hybrid tilapia.