Physical, chemical, and physiological characterization of chilling injury in soursop fruit (Anonna muricata L.)

Abstract

Soursop fruit (Anonna muricata L.) can be marketed fresh or processed due to its excellent sensory characteristics and pulp yields; it is, however, highly perishable and suffers from chilling injury (CI) when stored below 15 °C. In this study, symptoms of CI were evaluated in soursops ripened at 25 °C after a period of storage at 9 or 14 °C for 4 or 8 d (control fruit was stored at 25 ± 2 °C and 60 % RH for 8 d). While soursops stored at 14 °C behaved similarly to controls in all variables measured, color and firmness did not develop normally in those refrigerated at 9 °C, and the activity of polyphenol oxidase (PPO, an enzyme involved in the browning of damaged tissues) declined; however, the activities of superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD, another enzyme involved in tissue browning) all increased. In addition, soursops stored for 8 d at 9 °C suffered from substantial decreases in respiration, ethylene production, electrolyte leakage (EL), and the content of flavonoids, whereas total phenolics rose considerably. CI was therefore induced at 9 °C, and several of the aforementioned physical and chemical alterations are good indicators of this physiopathy in fruit of A. muricata L.