Effect of Maturity Stage of Papaya Maradol on Physiological and Biochemical Parameters

Problem statement: Nowadays, the worldwide increase in diseases has motivated consumers to increase the intake of fruits and vegetables, in response to various research reports indicating that fruits and vegetables can help prevent certain types of illnesses, due to their potentially high antioxidant properties. We evaluated the effect of the stage of ripeness of papaya fruit (Carica papaya L.) on the contents of bioactive components and their relation with antioxidant capacity. Approach: Whole papaya fruit were selected based on their visual ripeness, classifying them in four stages of ripeness (R1, R2, R3 and R4). Physiological and physical-chemical analysis performed included respiration, production of ethylene, firmness, pH, titratable acidity and total soluble solids, color (L*, a*, b*, °Hue, C); Polygalacturonase (PG) and Pectin Methyl Esterase (PME) activity, total phenolic content and antioxidant capacity (measured using DPPH, TEAC and ORAC assays). Results: The antioxidant capacity decreased approximately 27% in the RS4 when using DPPH and TEAC and increased when using ORAC (60.9%). PG activity increased from 8.14 (in RS1)-22.48 U gFW^-1 (in RS4) as the stage of ripeness of papaya fruit increased. PME was affected in a similar manner with an activity of 0.5562 U gFW^-1, at the end of the ripening storage. A high correlation between PG activity and softening of ripen papayas was observed. Conclusion/Recommendations: It was observed that papaya fruit experienced changes in firmness, which is correlated with activity from two of the main enzymes: PG and PME and with the increase of respiration and production of ethylene. The various stages of ripeness showed very good antioxidant capacity, being higher in RS1, which is correlated with the higher content of phenolic contents found in this ripening stage.