Assessment of the Effect of Different Preservation Techniques on the Level of Antioxidant Vitamins and Total Antioxidant Capacity in Tomato (Solanum Lycopersicon)

This study compared the effects of different preservation methods on the nutritional value of tomatoes. Five methods were evaluated: freezing, shade drying, microwave drying, hot air drying and sun drying. The levels of vitamin A, C, E, beta-carotene and lycopene were determined in all the samples using HPLC. Total antioxidant capacity was determined in all the samples using the Trolox equivalent antioxidant capacity (TEAC) method. The fresh sample serves as control. The amount of vitamin A, C, E, beta-carotene and lycopene in the fresh tomato samples were found to be 2.60 ± 0.04, 30.23 ± 2.51, 1.52 ± 0.19, 9.94 ± 0.92 and 21.09 ± 1.12 mg/100g respectively. The total antioxidant capacity in the fresh sample was found to be 20.72 mmol Trolox/g DW. A significant decrease in the amount of vitamin A, C and E in frozen, shade dried, microwave dried, hot air dried and sun-dried samples were seen when compared with control (p<0.05). A significant decrease in the content of beta-carotene and lycopene was also seen in shade dried, microwave dried, hot air dried and sun-dried samples when compared with control (p<0.05). A reduction in total antioxidant capacity was seen in all the samples when compared with control and the percentage reduction was found to be 7.77, 25.05, 39.82, 48.89 and 56.71 % in frozen, shade dried, microwave dried, hot air dried and sun-dried samples of tomato respectively when compared with control. The results showed that freezing was the most effective method for retaining the nutritional value of tomatoes, followed by shade drying with the order of retention being: fresh > frozen > shade drying > microwave drying > hot air drying > sun drying. The findings suggest that freezing can be useful method for preserving the nutritional value of tomatoes and provide insights into the optimal preservation strategies for maintaining tomato quality.