Scilight Press

Watermelon rind is generally considered agricultural waste and has wide application due to the presence of polyphenolic compounds and citrulline which have many health benefits. This investigation was aimed at the valorisation of watermelon rind by converting it into freeze-dried powder. The powder was examined for its physico-chemical, dielectric, structural, functional, thermal and flow characteristics. Watermelon rind powder had 10.22% moisture, 12.93% ash, 11.16% protein, 1.30% fat and 0.40% water activity, with a slight green tint in colour. It had good solubility, flowability and foaming. Semi-crystalline profile was demonstrated by X-ray diffraction. Scanning electron properties microscopy revealed aggregated particles with a comparatively smooth surface. Different functional groups were identified by Fourier transformer Infrared spectroscopy including carboxylic groups, N-H, O-H, C-C, C-O-C and C-O-H bonds. Thermo-gravimetric analysis revealed three major regions of weight loss in the powder sample. The dielectric analysis showed that the powder had a dielectric constant of 171 at 95°C and a loss factor of 2.8. Overall, the study provided insightful data about the properties of freeze-dried watermelon rind powder, which could be useful for its application in the food industry.