POSTHARVEST QUALITY OF PITAHAYA (Hylocereus undatus Haw.) FRUITS HARVESTED IN THREE MATURITY STAGES

Abstract

In this study we evaluated the postharvest quality of pitahaya fruits (Hylocereus undatus Haw.) in three maturity stages: initial, medium, and complete, which corresponded to 25-50, 50-75, and 75-100 % of red peel color, respectively. The fruits were stored under marketing conditions (20 ± 2 °C). Physical and chemical characteristics were evaluated during 12 d and the physiological characteristics during 8 d. By the end of the storage period, weight loss was higher (P ≤ 0.05) in fruits harvested at initial maturity (7.8 %), than in fruits of medium (6.1 %) and complete (5.6 %) maturities. Peel color was different (P ≤ 0.05) between maturities and storage times. At day 12, fruits harvested at medium and complete maturities showed hue angle (°Hue) values of 15.6 (red) and 8.6 (red-dwelled), respectively, whereas fruits harvested at initial maturity ended with 31.7 (red-orange). Firmness, titratable acidity (TA), total soluble solids (TSS) and vitamin C decreased (P ≤ 0.05) during storage. Firmness remained higher (P ≤ 0.05) in fruits harvested initial maturity. TA decreased 80 % (P ≤ 0.05) in fruits of the three maturity stages, but it remained higher in fruit of the initial maturity stage. TSS had significant reduction (P ≤ 0.05) during storage, and °Brix values were higher (P ≤ 0.05) in fruits harvested in medium and complete maturity stages, as compared with fruits harvested at initial maturity. The Brix/acidity ratio (BAR) was similar in the first 4 d of storage, but the fruits in initial maturity showed longer (10 d; P ≤ 0.05) optimal values of BAR (<40). Decrease in vitamin C was higher (P ≤ 0.05) in fruit harvested in complete maturity. Respiration rate was higher (P ≤ 0.05) in fruits with complete maturity than in fruits with initial maturity and medium maturity, and a non-climacteric behavior was observed. Shelf life for fruits with medium and complete maturity was between 6 and 8 d, whereas for initial maturity was 10 d, but in the last ones the less intense red color affected fruit quality.