Figures (2)  Tables (4)

    • Figure 1. 

      Developmental stages of S. megalanthus pitaya. S1 – Immature 1; S2 – Immature 2; S3 – Mature green; S4 – Early ripening; S5 – Ripe.

    • Figure 2. 

      Micrographs of the cell wall of S. megalanthus peel at different pitaya developmental stages. Stages: S1 - Immature 1; S2 - Immature 2; S3 - Mature green; S4 - Early ripening; S5 - Ripe.

    • Code Stage Description of maturity stage*
      S1 Immature 1 Hue = 84.48; AT = 0.83; SS = 6.34; DL = 9.36, and
      DT = 4.73
      S2 Immature 2 Hue = 113.72; AT = 0.64; SS = 10.3; DL = 10.53, and DT = 6.48
      S3 Mature green Hue = 115.44; AT = 0.51; SS = 13.29; DL = 12.40, and DT = 7.86
      S4 Early ripening Hue = 112.49; AT = 0.41; SS = 16.4; DL = 13.95, and DT = 8.61
      S5 Ripe Hue = 112.31; AT = 0.28; SS = 20.4; DL = 14.15, and DT = 8.73
      * Peel tone (hue), titratable acidity – TA (%), soluble solids SS (%), and fruit dimensions [longitudinal [DL] and transverse [DT]) in cm.

      Table 1. 

      Physicochemical characteristics of S. megalanthus fruit at five stages of development.

    • Stadium* S1 S2 S3 S4 S5 VC (%)
      pH 3.05e** 3.49d 3.70c 4.04b 4.67a 2.01
      L* (peel) 49.80a 36.82b 27.29c 29.34c 35.26b 11.09
      C* (peel) 44.87a 26.11b 21.57bc 18.61cd 16.43d 13.42
      L* (pulp) 70.97a 69.42a 68.75a 62.95ab 53.46b 11.61
      C* (pulp) 11.34a 11.25ab 11.18ab 11.09ab 8.56a 18.67
      Hue (pulp) 94.00ab 92.18b 93.01ab 95.37a 91.87b 2.98
      Mass (g) 106.82e 227.13d 303.14c 387.87b 401.57a 1.24
      Fruit yield (%) 31.16d 45.32c 47.42bc 50.17b 72.43a 3.08
      Dimension length (cm) (pulp) 2.46d 3.42c 4.54b 4.33b 5.69a 8.01
      Dimension width (cm) (pulp) 2.30c 3.44b 3.97b 4.31b 5.70a 8.70
      Diameter of the exocarp (cm) 1.16a 0.99a 0.96a 0.89a 0.68a 28.62
      Firmness (N) (peel) 89,41a 88,03a 80,11b 78.09b 54.45c 7.79
      Firmness (N) (pulp) 4.75a 4.66a 2.88b 2.54b 2.23b 14.54
      * Stadium: S1 - Immature 1; S2 – Immature 2; S3 - Mature green; S4 - Early ripening; S5 - Ripe. ** Means followed by the same letters on the same line do not differ from each other according to Tukey's test (p > 0.05), respectively. VC (%): Variance coefficient.

      Table 2. 

      Morphological and physicochemical characteristics: pH, L, C, °hue; mass (g); fruit yield (%); L, C, °hue; firmness (N); longitudinal and transverse diameters; and exocarp thickness (cm) of S. megalanthus fruits.

    • Stadium* S1 S2 S3 S4 S5 VC (%)
      TPC (peel)
      (mg GAE 100 g−1)      		 139.33e** 179.39d 211.39c 304.79b 334.80a 5.43
      TPC (pulp)
      (mg GAE 100 g−1)      		 101.07e 139.74d 178.88c 302.43b 347.63a 4.66
      PC (peel)
      (mg AA 100 g−1)      		 568.87cb 459.68c 584.07cb 590.54b 1108.41a 14.52
      PC (pulp)
      (mg AA 100 g−1)      		 345.39b 281.10c 290.83c 311.49ab 421.84a 8.41
      β-car/LA (peel)
      (% protection)      		 74.08b 77.39ab 77.20ab 80.64ab 83.15a 7.33
      β-car/AL (pulp)
      (% protection)      		 48.40d 71.92c 78.77cb 80.79ba 87.05a 7.97
      * Stadium: S1 - Immature 1; S2 – Immature 2; S3 - Mature green; S4 - Early ripening; S5 - Ripe. ** Means followed by the same letters on the same line do not differ from each other according to Tukey's test (p > 0.05), respectively. VC (%): Variance coefficient.

      Table 3. 

      Total phenolic compounds and antioxidant activity of dragon fruit S. megalanthus throughout its development.

    • Stadium S1 S2 S3 S4 S5 VC (%)
      β-gal (U·g−1 protein) 0.0015a 0.0008a 0.0011a 0.00142a 0.00085a 12.35
      Cx (U·g−1 protein) 0.0100b 0.0047b 0.0068b 0.0606ab 0.0923a 13.09
      PME (U·g−1 protein) 0.0046b 0.0096b 0.7466a 0.0300ab 0.0110b 11.46
      PG (U·g−1 protein) 0.0294c 0.0784b 0.0876b 0.1551a 0.1393a 15.92
      * Stadium: S1 - Immature 1; S2 – Immature 2; S3 - Ripe green; S4 - Beginning of ripening; S5 - Ripe. ** Means followed by the same letters on the same line do not differ from each other according to Tukey's test (p > 0.05), respectively. VC (%): Variance coefficient.

      Table 4. 

      Activity of cell wall-modifying enzymes in S. megalanthus fruit during development.