Effects of different drying methods and ascorbic acid pretreatment on carotenoids and polyphenols of papaya fruit in Ethiopia

Frequent consumption of fruits can prevent nutrient deficiencies and promote health. However, the perishability and unaffordability of fruits had led to very low levels of fruit consumption in low- and middle-income countries (LMICs). The objective of this study was to evaluate the retention of nutrients and bioactive compounds of papaya fruit (Carica papaya L) with/without ascorbic acid pretreatment and drying under different techniques, to then estimate the vitamin A intakes for vulnerable population. Yellow pulp ripped papaya fruits (i.e., >75% level of skin color/stage level 4) (n = 14), with and without ascorbic acid pretreatment were dried using (a) solar drying: open-air, tray driers, and glasshouse; (b) refractance window drying; (c) oven drying; and (d) freeze-drying (control). The fresh fruit had high moisture content (87%) and an acidic pH. The dried papaya had a water activity of 0.5–0.6. The highest TPC, TFC, total carotenoids, and ß-carotene were found in freeze-dried papaya samples, followed by refractance window, and solar glass house (p <.05). The highest retention in total carotenoids (81.5%) and ß-carotene (61.9%) relative to freeze-drying was for the refractance-window; 25 g of dried papaya could contribute to 38% of the retinol equivalents’ requirement for young children. Ascorbic acid pretreatment increased the retention of total carotenoids, ß-carotene, TPC, and TFC (p <.05) by (6–11)%, (8–34)%, (7–58)%, and (6–30)%, respectively, for all the drying methods. Refractance window and solar glass house drying can improve diets and constitute a promising food systems’ intervention that can increase year-round availability, accessibility, and affordability of vitamin A-rich fruits like papaya.