Comparative Analysis on the Nutrient Quality of Undried, Freeze-Dried and Oven-Dried Fruits of Lycopersicon Esculentum Mill (Tomato)

Abstract

Tomato (Lycopersicon esculentum mill) is a popular vegetable across the world. However, high volumes of tomato go waste every year, due to its high seasonality and perishability, especially in sub-Saharan African countries such as Ghana.  This research focused on the impact of oven and freeze drying technologies on the proximate, physicochemical and antioxidant composition of freshly harvested tomatoes. Results from all samples (oven dried, freeze dried and fresh tomatoes) were analyzed by one-way ANOVA using Graph Pad prism version 5 software. There was a significant difference between the sample treatments (oven dried, fresh tomatoes and freeze dried) with respect to the pH ranging 3.92±0.02, 4.20±0.02 and 4.54±0.02. The Total Soluble Solids (T.S.S) varied significantly from each other (p <0.05) with the highest being 2.31±0.01 ^o brix for oven dried sample (O) and lowest for the control sample (C) with 1.20±0.00 °brix respectively. For the crude fat, there was a significant (p≤0.05) difference between the two dried samples and the control. The study also revealed that there was a significant difference in ash content between the freeze-dried sample (1.50±0.01) and the other two (control 0.50±0.01 %, oven dried (0.52±0.02 %) samples. For the crude fiber, there was no significant difference (p>0.05) between the samples. There was a significant difference (p≤0.05) between all samples with respect to the crude protein content with values ranging from 2.40±0.01, 2.71±0.01 % and 4.07±0.06 % for oven-dried, control and the freeze- dried treatment respectively. There was a significant difference among the various samples for vitamin C content. The vitamin C content for the control, oven dried and freeze-dried samples were 28.00±0.01 mg/100g; 19.40±0.01 mg/100g; 22.80±0.05 mg/100g respectively. This shows that, though both oven and freeze-drying methods lower the vitamin C content of tomatoes, they are also able to preserve and add value to tomato by improving other quality parameters. It is recommended that governments invest into scientific researches of producing tomato products, which have longer shelf –life to reduce the cost of importations of tomato and tomato postharvest losses.

Keywords: Tomato, Freeze-drying, Vitamin C, Proximate analysis, Oven drying

DOI: 10.7176/FSQM/111-04

Publication date:October 31^st 2021