Caracterização físico-química e avaliação da atividade antioxidante de polpas de pitaias (Hylocereus undatus e Hylocereus costaricensis) in natura e congeladas

Abstract

The pitaia, a cactaceous, and its fruit is known for its high nutritional power and has been sold in ready-made drinks, jellies and wine. What draws attention in this fruit, considered exotic, are the pigments, phenolic compounds and antioxidant activity that can assist in the defense mechanism, in controlling the damage caused to cells by free radicals. The objective of this study was to compare the physical-chemical characteristics and to evaluate the antioxidant activity of the red and white pulps of pitaia (Hylocereus undatus and Hylocereus costaricensis) in the fresh and frozen form and to obtain physical-chemical parameters of the commercial pitaia cream in order to compare the results with the of pure pulps for nutritional assessment. For the antioxidant analysis three methods were used: DPPH, ABTS, FRAP and the FolinCiocalteau colorimetric method for the quantification of phenolic compounds, the other analyzes followed the Analytical Standards of the Adolfo Lutz Institute. The results obtained from white pitaia pulp showed higher values for white pulp frozen in ash (0.74 ± 0.01%), titratable acidity (1.09 ± 0.04%) and for white pulp fresh in moisture ( 86.90 ± 0.09%), pH (5.00 ± 0.04), soluble solids (15.27 ± 0.06 ° BRIX), lipids (0.51 ± 0.02%), proteins (0 , 72 ± 0.04%), carbohydrates (11.21 ± 0.09%) and vitamin C (33.59 ± 0.73 mg / 100mL). For the red pulps, higher results were obtained for pulp frozen in ash (0.81 ± 0.03%), titratable acidity (1.18 ± 0.01%), soluble solids (10.33 ± 0.12 ° BRIX) and for fresh pulp in moisture (84.99 ± 0.01%), pH (4.82 ± 0.02), lipids (0.66 ± 0.01%), proteins (0.78 ± 0, 04%), carbohydrates (12.83 ± 0.09%) and vitamin C (50.89 ± 0.34 mg/100 mL). In the analysis of DPPH, ABTS, FRAP and phenolic compounds, greater results were obtained for fresh white pulp (0.234 ± 0.01 mg DPPH / g fruit, 42.74 ± 0.06 μM Trolox / g fruit, 21.54 ± 0.91 μM Trolox / g fruit, 51.03 ± 0.37 μM ferrous sulfate / g fruit and 73.5 mg AG / 100 g fruit) and fresh red pulp (0.140 ± 0.01 mg DPPH / g fruit, 53.68 ± 0.02 μM Trolox / g fruit, 32.47 ± 0.68 μM Trolox / g fruit, 107.44 ± 0.55 μM ferrous sulfate / g fruit and 110.83 mg AG / 100 g of fruit). The comparison of the pulp data with the physical-chemical parameters of the industrialized pitaia cream showed greater antioxidant activity in the cream and a much higher vitamin C value. In most of the analyzes, the red pulp showed better results than the white, with a relationship between vitamin C and phenolic compounds. In the comparison between the DPPH and ABTS methods, ABTS was considered better for its speed, reproducible results and consistent with the literature. It is expected that the results found to favor the increase in the consumption of pitaias and other tropical and exotic fruits, as they have high vitamin content when compared to common fruits that are consumed daily.