Chemical and bioactive characterization of papaya (Vasconcellea pubescens) under different drying technologies: evaluation of antioxidant and antidiabetic potential

Chilean papaya slices were dried using different technologies to evaluate the effect of the different technologies on drying kinetics, bioactive compounds and biological activities. Five techniques were used: freeze drying (FD), vacuum drying (VD), solar drying (SD), convective drying (CD) and infrared drying (IRD). Fresh and dried samples were evaluated in terms of proximate composition, phenolic profiles, total phenolic and flavonoid contents, β-carotene, vitamin C, and antioxidant and α-glucosidase activities. CD-papaya showed lower processing time, requiring 270 min to reach the dynamic equilibrium condition, while SD-papaya required 870 min. The five drying technologies were found to have variable effects on proximate composition. VD-samples showed the lowest loss of individual phenolic compounds, total phenolic content and vitamin C while IRD- and CD-samples showed lower total flavonoids (42%) and β-carotene (32%) loss after processing, respectively. With respect to biological activities, all samples possessed enzymatic activity in a dose-dependent manner (0–2.0 mg ml−1), being IRD-sample the most effective in inhibiting α-glucosidase (IC50 = 13 mg ml−1). Also, the highest antioxidant capacity measured by DPPH and ORAC was obtained for the papaya samples dried using a vacuum drier.