Process Optimization for Foam Mat-Tray Drying of Passiflora edulis Flavicarpa Pulp and Characterization of the Dried Powder

Passion fruit ( Passiflora edulis flavicarpa) is a seasonal, tropical, pulpy fruit, known for a rich source of Vitamin C, antioxidants, and delicate flavor. Presently, freezing technique has been used to preserve the pulp. This article reports alternate method of preservation by foam mat convective air drying of fruit pulp under moderate temperatures. The optimization of process parameters, particularly air temperature, was done with subsequent mathematical modeling of the process and assessment of quality parameters by retention of physicochemical properties and antioxidant capacity of the fruit powder. Sixty degree Celsius was found to be the optimum temperature, and Henderson and Pabis model showed best fit to the drying characteristics data (R 2 = 0.99). Diffusivity characteristics of moisture during drying were also studied. As drying temperature was increased, total color difference and rehydration ratio decreased, whereas non-enzymatic browning index, total phenolic content, and total antioxidant activity showed increase that was attributed to inhibition of oxidative enzymes and biochemical changes. Dried passion fruit powder showed overall acceptability in terms of organoleptic properties and total antioxidant activity.