Antioxidant Activity and Total Phenolic Content of Hot and Cold Water Extracts of Bitter Melon Fruit (Momordica charantia)

The method of beverage preparation, whether using hot or room temperature water, significantly affects the extraction of bioactive compounds and the resulting antioxidant activity. However, limited information is available on the antioxidant properties of Momordica charantia (bitter melon) fruit when extracted using hot and cold water. In this study, bitter melon fruit was subjected to both hot and cold water extraction methods. Antioxidant activity and total phenolic content were evaluated using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay and the Folin–Ciocalteu reagent (FCR) method, respectively. Fourier-transform infrared (FTIR) spectroscopy was employed to identify functional groups present in the samples. Results indicated no significant difference in total phenolic content between the two extraction methods. A weak negative correlation (R² = 0.1261) was observed between antioxidant activity and phenolic content, suggesting that higher phenolic content did not correspond to increased antioxidant capacity. The highest FTIR absorption peak was observed at 2905.87 cm⁻¹, corresponding to the C–H stretching vibration. Overall, hot water extraction appeared to yield higher antioxidant activity and phenolic content, making it the preferred method for extracting bioactive compounds from bitter melon.