Optimization of an Enzyme-Assisted Extraction Method for the Anthocyanins Present in Açai (Euterpe oleracea Mart.)

Abstract

Several investigations have proven the presence of anthocyanins in different parts of açai plants. These compounds are responsible for the notable therapeutic properties of açai such as antioxidant, antimicrobial, anti-inflammatory, anticancer, and anticonvulsant. We have therefore optimized an enzyme-assisted extraction method for the anthocyanins found in açai, to be subsequently applied in many fields such as agrifood, medicine, or cosmetics. A Plackett–Burman design with seven variables (time of extraction, pH, temperature, agitation, percentage of ethanol in the solvent, amount of sample, and units of enzyme) was employed to determine the predominant extraction variables, of which four were categorized as influential. Subsequently, a Box–Behnken design–response surface methodology made it possible to determine the degree of influence from these variables and their optimal values. The optimal conditions were established as 0.1 g of açai heated up to 60 °C and extracted using 15 mL of solvent with pH 4 and 40% ethanol, 500 units of enzyme per gram of sample, and agitation at 150 rpm for 15 min. The repeatability and intermediate precision of the developed method were confirmed by variation coefficients below 5%. Finally, the developed method was compared against the extensively used maceration and ultrasound-assisted extraction methods.