Optimization of the Extraction Process of Bioactive Compounds from Red Fruits of Stenocereus stellatus: Response Surface Methodology (RSM)

Stenocereus stellatus is one of the 10 species of cactus of greatest economic importance in Mexico, although its fruits contain bioactive components such betalains and phenolic compounds, which in turn cause multiple positive pharmacological effects on health, very little has been explored. This study aimed to employ a response surface methodology (RSM) approach to optimize the extraction conditions for maximizing the concentration of betalains (betacyanins and betaxanthins), total phenolic compounds (TPC), and antioxidant capacity (AC). To optimize the extraction of betalains, pH (W), extraction temperature (X), extraction time (Y), and water:ethanol solvent ratio (Z) were evaluated. For TPC and AC, the same factors were evaluated, except Z. All these factors influenced on the concentration of betalains. The optimal extraction conditions were found to be pH 4.2, extraction temperature of 10 °C, extraction time of 60 min, and a water:ethanol solvent ratio of 55%, and under these conditions, 0.51 mg per g total betalains (BT) were obtained, of which 0.25 mg per g corresponded to BC and 0.26 mg per g to BX. In TPC and AC, only pH and temperature affected these determinations. The optimal conditions for both variables were pH of 4 and extraction temperature of 60 °C, and under these conditions, 2.34 mg of gallic acid equivalents per g and 18.60 µmol of Trolox equivalents per g were obtained. The results suggest that Stenocereus stellatus could be a promising source for these compounds, which have potential applications in the food and pharmaceutical industries due to their excellent stability under these conditions.