Response surface methodology for optimization of the mucilage extraction process from Pereskia aculeata Miller

In this report, a process for hydrocolloid extraction from Pereskia aculeata Miller (Barbados gooseberry), popularly known in Brazil as Ora-pró-nóbis (OPN), was developed. In the process, several operations, such as extraction, pressing, filtration, precipitation, grinding and drying, were required. The independent variables evaluated to determine the optimum extraction conditions were the ratio of water:raw material and the extraction temperature. The significant results at each stage were analyzed using the response surface method. The conditions that presented the highest precipitate yield, highest pH value, highest hue value (clear product), highest filtrate viscosity and minimum flow rate value were a water:raw material ratio of 2.46–3.70 L/kg and an extraction temperature between 54.6 and 80 °C. Using the optimized process, gums were prepared at different concentrations and the centesimal composition, mineral content, viscosity and emulsion formation capacities were analyzed. The stability of these emulsions was evaluated at room temperature and at 80 °C. The emulsion formation capacity of the product was verified as being proportional to the increase of the powder concentration. The OPN gums obtained at a solution concentration of 1 g/100 mL presented an emulsion formation capacity of 83%, and the increase in temperature reduced emulsion stability. The powdered product obtained was found to be close to yellow in color with high protein content and with functionalities that can be used in the food industry.