Quality and Physiological Changes During Pre- and Postharvest Development and Ripening of Soursop Annona muricata L. Fruit

Soursop fruit of Annona muricata L. is a delicious tropical fruit with several medicinal properties. Previous research focused mainly on postharvest fruit development. This study aims to study the changes during preharvest development and ripening of soursop fruit. Flowers were tagged, and fruit samples were collected at different developmental stages based on days after take-off (DAT). The weight changes, flesh firmness, ethylene production, respiration rate, pH, total acidity (TA), total soluble solids (TSS), and cuticle thickness were measured. An increase in respiration rate from 7 to 41 mL CO2 kg−1 h−1, a weight increase from 20 to 600 g, a pH decrease from 6.5 to 3.8, a firmness reduction from 20 to 0.8 N, and a cuticle thickness change from 6 to 4 μm were recorded. During preharvest, two different growth periods were recorded: a continuous increase in respiration rate and TSS, a slow decrease in TA, and a constant pH. Further, an increase in firmness was observed until 75 DAT and a decrease after 90 DAT. Cuticle thickness did not show significant changes. During postharvest, soursop fruit showed a sharp increase in TSS, TA, and a notable decrease in pH and firmness. A climacteric peak was recorded six days after harvest with a short postharvest shelf life. It was concluded that the fruit showed the typical behavior of a climacteric fruit. Also, future investigations should focus on the period between 105 and 120 DAT to identify the optimal harvest periods due to the relatively short postharvest shelf life.