Four vitamins were analyzed in several fruit and vegetable commodities to evaluate the differences between fresh and frozen produce. Ascorbic acid, riboflavin, α-tocopherol, and β-carotene were evaluated in corn, carrots, broccoli, spinach, peas, green beans, strawberries, and blueberries. Samples of each commodity were harvested, processed, and analyzed for nutrient content at three storage times per treatment. Ascorbic acid showed no significant difference for five of the eight commodities and was higher in frozen samples than fresh for the remaining three commodities. Apart from broccoli and peas, which were higher and lower in frozen vs fresh samples, respectively, none of the commodities showed significant differences with respect to riboflavin content. Three commodities had higher levels of α-tocopherol in the frozen samples, while the remaining commodities showed no significant difference between fresh and frozen. β-Carotene was not found in significant amounts in blueberries, strawberries, and corn. Peas, carrots, and spinach were lower in β-carotene in the frozen samples, while green beans and spinach showed no significant difference between the two storage methods. Overall, the vitamin content of the frozen commodities was comparable to and occasionally higher than that of their fresh counterparts. β-Carotene, however, was found to decrease drastically in some commodities.
Keywords: frozen storage; fruits; hplc; nutrients; refrigerated storage; vegetables; vitamins.