Assessment of physico- chemical properties of processed and unprocessed tomato (Lycopersco esculentum) vars manica and power

Thumbnail Image
Journal Title
Journal ISSN
Volume Title
Tomato is an important vegetable that is consumed in various forms by most households across Africa. However, tomatoes are seasonal and very perishable. Consequently, these and other factors have increase the industrial processing of tomatoes into various forms, such as, tomato sauce, ketchup and powder. This study thus was carried out to assess the processing quality of two tomato varieties (power and manica) in Ghana. Fruits of the two varieties were stored under ambient condition and physico-chemical characteristics such as total soluble solids, total titratable acid, vitamin C, pH, moisture content, firmness, mesocarp thickness, colour, and diameter analyzed at the six stages of ripening (matured green, breaker, turning, pink, light red and red-ripe stages). Daily weight loss was also taken for twenty three days and the average weight loss determined. Fully ripe tomatoes of the two varieties were processed into ketchup and stored for three months and biological studies and chemical characteristics such as the pH, Total Soluble Solids, Total Titratable Acidity were determined. A completely Randomized Design was used as experimental design for the study. All treatments were replicated three times. From the results, there was no significant variation (p>0.01) among power and manica for physical characteristics of unprocessed tomato, firmness, mesocarp thickness, diameter and colour. Power had 5.40, 3.32, 54.31, while Manica tomato variety had 6.26, 4.13, 49.70 and respectively. For chemical characteristics, PH,,moisture content, vitamin C content, weight loss and total soluble solids did not differ significantly (p>0.01) between the two varieties. Power recorded 4.00, 93.29, 38.90 and 5.94 while manica variety had 4.00, 95.21, 42.95 and 3.88 respectively. However, Power variety recorded significantly (p>0.01) higher (0.44) total titratable acidity than Manica variety which had the least value (0.29). Results from the processed tomato showed there was no significant difference (p>0.01) between the two tomato varieties for pH and total titratable acidity. Both Power and Manica varieties had pH of 4.00 and TTA of 0.57 and 0.49 respectively. However, total soluble solids of Power variety varied significantly (p>0.01) from Manica variety. Power variety recorded appreciable amount of TSS (24.40) than manica variety (18.58). Microbial analysis showed that growth of total viable count of ketchup from the two tomato varieties did not vary significantly (p>0.01) for the three months of storage. Comparing the two varieties, it was revealed that although both varieties could be processed into ketchup, using the power variety could produce sweeter ketchup than manica variety.
A thesis submitted to The School of Research and Graduate Studies, Kwame Nkrumah University of Science and Technology, Kumasi in partial fulfillment of the requirement for the award of the degree of Master of Philosophy (M.Phil.) in Postharvest Technology,