Effect of ripening on physico-chemical properties and bioactive compounds in papaya pulp, skin and seeds

Byproducts generated by the food industry represent an alternative to obtain functional ingredients. Byproducts of tropical fruits, such as papaya skin and seeds, represent a source of bioactive compounds (BC), which could change during fruit ripening. Effect of ripening stage (RS) on BC content and antioxidant properties of edible pulp, skin and seeds of papaya cv. Maradol was determined. Papaya skin showed significantly higher ascorbic acid (~250 mg AAE/100 g) content than seeds (~20 mg/100 g), while pulp had the highest values (~600 mg/100 g). However, papaya skin presented higher total phenolic content (~560 mg GAE/100 g) and flavonoids (~1000 mg QE/100 g) than pulp and seeds. Also, papaya skin showed the highest values followed by pulp and seeds with TEAC, FRAP and DPPH. Papaya skin had higher carotenoids and α-tocopherol (~1500 µg/100 g and ~4000 µg/100 g, respectively) content than pulp and seeds. BC content in each byproduct varied in all RS. Therefore, among the papaya byproducts, skin represents a good source of BC with good antioxidant properties, which may be used to extract them for its incorporation in functional foods depending on RS.