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

Authors: VEGA-GALVEZ, ANTONIO - Universidad De Chile; POBLETE, JACQUELINE - Universidad De Chile; QUISPE-FUENTES, ISSIS - Universidad De Chile; URIBE, ELSA - Universidad De Chile; Bilbao-Sainz, Cristina; PASTEN, ALEXIS - Universidad De Chile

Submitted to: Journal of Food Measurement and Characterization
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/25/2019
Publication Date: 3/27/2019
Citation: Vega-Galvez, A., Poblete, J., Quispe-Fuentes, I., Uribe, E., Bilbao-Sainz, C., Pasten, A. 2019. Chemical and bioactive characterization of papaya (vasconcellea pubescens) under different drying technologies: evaluation of antioxidant andantidiabetic potential. Journal of Food Measurement and Characterization. 13:1980-1990. https://doi.org/10.1007/s11694-019-00117-4.
DOI: https://doi.org/10.1007/s11694-019-00117-4

Interpretive Summary: Ripened papaya is a perishable product due to high moisture content and easily prone to microbial spoilage. It can be maintained intact only up to 3 weeks under storage conditions (10 °C at 90–95% RH). This fact imposes a major hindrance considering the export market demands worldwide. Dehydration is a suitable preservation method to extend the storability of papaya. Therefore we evaluated the drying kinetics, chemical properties and bioactive components of papaya submitted to different drying technologies (freeze drying, vacuum drying, solar drying, convective drying and infrared drying) as well as the influence of these technologies on the antioxidant capacity and a-glucosidase inhibition of the dried fruit. We found out that papaya slices dried in a vacuum drier retained the highest amount of ascorbic acid (75%) and antioxidant activity (43%) due to the absence of oxygen in the environment. The samples also retained 39% of flavonoids and 57% of ß-carotene. In addition, this sample showed an increase in TPC and high amounts of individual phenolic acids. On the other hand, solar drying caused the largest loss in phenolic compounds (8%), individual phenolic acids, antioxidant activity (68%), ascorbic acid (71%) and ß-carotene (73%) due to the extended drying times and high-water content. In this study the a-glucosidase activity was totally suppressed when dried papaya concentration was about 0.5 mg/ml, regardless of the drying technology.

Technical Abstract: 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, ß-carotene, vitamin C, and antioxidant and a-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 ß-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 a-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.