Evaluation of physicochemical, functional, and antimicrobial properties of a functional energy drink produced from agricultural wastes of melon seed powder and tea stalk caffeine

A functional energy drink (FED) was prepared based on the agricultural wastes of melon seed powder (MSP) (1% and 3%) and tea stalk caffeine (TSC) (160 and 320 ppm). The beverages' physicochemical, functional, sensory, antimicrobial, and nutritional properties were measured. Results showed that increasing MSP levels increased beverage calories by 23% and beverage fiber by 53.3%. Combinations of 320 ppm of TSC with both MSP levels could show better antimicrobial properties against undesirable gram-positive bacteria. Comparison of the best FED produced in this study with two popular brands in the market showed the superiority of functional, nutritional, and safety characteristics of FEDs. The total phenolic compounds (TPC) and antioxidant capacity in the best drink produced were 1.56 mg gallic acid/mg and 48.72%, respectively. The sensory properties increased by increasing MSP and TSC, indicating good overall acceptance. In general, by MSP and TSC addition, a desirable FED can be achieved. Practical applications The food processing industry, along with increased awareness of nutrition among consumers, is completing a cheaper source of nutrients to finally become functional foods. Our results showed that the appropriate combination of agricultural waste to produce a FED has better quality and activity compared to those on the market.