Shelf-life Determination of Dried Onion (Allium cepa) and Tomato (Lycopersicon esculentum) Products

The role of nutrient-rich vegetables in promoting good health has resulted in an increase in their demand over the past decade, but they are highly seasonal, causing lower prices and heavy losses at peak season. The objective of the study was to determine the shelf life of dried onion and tomato products. The study was conducted in Mekelle University’s food science and post-harvest technology laboratory. Four treatments (sun, shade, solar, and oven drying methods) were used to dry onion and tomato products, and shelf life was determined using CRD at a 5% level of significance. Data such as microbial counts, time and temperature of drying, moisture content, rehydration ratio, and sensory characteristics were recorded and analyzed using analysis of variance. The highest microbial load obtained was for shade-dried onion (6.06 log10cfu/g) and sun-dried tomato (5.83 log10 cfu/g). For dried onion, significant differences were observed among the driers on the microbial population of coliform (p<0.05) and total bacterial count (p<0.01) but not on yeast and mold count. The maximum rehydration was achieved in the oven-dried products (3.64) followed by solar drying (3.28). Dried onion and tomato remained organoleptically acceptable, except for sun-dried tomatoes for color and appearance (4.75) and aroma (4.75) in the first month of storage. The oven-drying method was the best method of dehydration of freshly dried onions and tomatoes. Further research should be carried out to determine the effect of drying on the extended storage time of the dried products.