Valorization of tamarind (Tamarindus indica Linn) seed flour through optimization of phenolic compound extraction using response surface methodology

Seeds of Tamarindus indica Linn. represent substantial agro-industrial waste volumes that are discarded despite their high phenolic compound concentrations. However, traditional extraction methods fail to maximize bioactive yields, making optimization essential for efficient biomass valorization. We hypothesized that altering particle size and solvent volume using response surface methodology could significantly improve mass transfer. This study aimed to characterize tamarind seed flour (TSF), optimize total phenolic compound (TPC) extraction, and validate the predictive capacity of the generated model. TSF exhibited a moisture content of 9.24% and a mean particle diameter of 4.95 × 10 −4 m. Optimization was performed using a Rotational Central Composite Design with absolute ethanol, evaluating the synergistic effects of particle size and solvent volume in a 7-day kinetic study. The resulting mathematical model displayed a coefficient of determination of 0.78. Maceration proved to be the most efficient extraction approach; the optimal condition ( X 1 = 1.65 ×10 −4 m; X 2 = 500 mL) yielded 309.98 mg GAE/g TSF (dry basis) within 2 days. This represents a 205.61% increase compared to unoptimized 5-day maceration (101.43 mg GAE/g TSF), demonstrating that smaller particle sizes expand the contact surface area and accelerate solute diffusion. Model validation confirmed high predictive accuracy, yielding a low relative error of 8.20% between predicted and experimental values. Antioxidant assays indicated robust radical scavenging activity (139.05 µ mol Trolox/g). Although limited to a laboratory scale, this study advances sustainable tamarind seed valorization using a green solvent. Future work will focus on phenolic profiling, pilot-scale extraction scaling, and in vivo antioxidant assays.