Evaluation of the antioxidant activity and total phenolic compounds of lychee pulp by different dehydration methods

Abstract

Fruits and vegetables are major sources of bioactive compounds included in human diet. The objective of the study was to evaluate the antioxidant activity and total phenolic compound content of lychee pulp. Hydroalcoholic extracts were obtained from the pulp (fresh, dried and freeze-dried), and analyzed by in vitro Folin-Ciocalteu, Fast Blue, ABTS+, Beta Carotene and Phosphomolybdenum Complex assays. The color and water activity of the pulp submitted to each dehydration treatment were also evaluated. The results obtained in the determination of total phenolic content did not differ statistically (p>0.05) between dried and freeze-dried pulp. The values obtained for the antioxidant activity by the ABTS+ method and by the phosphomolybdenum complex had a statistically significant difference. The data regarding the percentage of protection by the ?-Carotene/Linoleic Acid method showed that the dried pulp did not differ statistically from the fresh and freeze-dried pulp. However, the freeze-dried pulp presented higher antioxidant activity by the ABTS+ and Phosphomolybdenum Complex assays when compared to the other treatments (fresh and dried pulps).