Development and characterization of a functional pea-based energy drink enriched with hibiscus and caffeine

This study aimed to develop a functional pea milk-based energy drink enriched with varying caffeine concentrations (0.00%, 0.05%, and 0.10%) and Hibiscus sabdariffa extract. The formulations were evaluated in terms of physicochemical, structural, and sensory attributes to assess the effects of plant-based bioactive enrichment on product stability and consumer acceptance. pH and titratable acidity analyses revealed that H. sabdariffa extract lowered pH and increased acidity due to its intrinsic organic acids, while caffeine addition had minimal impact on pH but slightly enhanced acidity at lower concentrations. Physical stability was assessed through phase separation, where the control pea milk (PM) exhibited the highest stability, while the 100C-HPM sample (with hibiscus + 0.10% caffeine) showed pronounced serum separation, indicating reduced homogeneity. Color measurements demonstrated significant changes in Lab* values due to hibiscus pigments, particularly in caffeine-enriched formulations. Particle size distribution and zeta potential analyses revealed that the 50C-HPM (with hibiscus + 0.05% caffeine) sample had the smallest particles and lowest surface charge, implying enhanced dispersion but reduced electrostatic stability. Total soluble solids increased with H. sabdariffa and low-dose caffeine but decreased at higher caffeine levels, likely due to protein–polyphenol interactions. Microscopic observations confirmed emulsion destabilization at high caffeine concentrations. Sensory evaluation highlighted that 50C-HPM was the most preferred sample in terms of flavor, mouthfeel, and overall acceptance, whereas 100C-HPM received the lowest scores due to its astringency and turbidity. Overall, the findings suggest that the addition of H. sabdariffa and moderate caffeine can enhance the nutritional and functional profile of pea milk without compromising consumer appeal.