Effects of drying on total polyphenols content and antioxidant properties of Carica papaya leaves

BACKGROUND Papaya is widely grown in Malaysia and normally only the fruits are consumed. Other parts of the plant such as leaves, roots, bark, peel, seeds and pulp are also known to have medicinal properties and have been used to treat various diseases. Papaya leaves also contain flavonoids, alkaloids phenolic compounds and cynogenetic compounds, and are also reported to be able to treat dengue fever. RESULTS Studies were carried out on drying of papaya leaves using hot air (60, 70 and 80 °C), shade and freeze drying. Effective diffusivities were estimated ranging from 2.09 × 10−12 to 2.18 × 10−12 m2 s−1 from hot air drying, which are within the order of magnitudes reported for most agricultural and food products. The activation energy to initiate drying showed a relatively low value (2.11 kJ mol−1) as a result of the thin leave layer that eased moisture diffusion. In terms of total polyphenols content and antioxidant activities, freeze‐dried sample showed a significantly higher (P