Optimization of Microwave-Assisted Extraction for the Recovery of Bioactive Compounds from the Chilean Superfruit (Aristotelia chilensis (Mol.) Stuntz)

Maqui berry (Aristotelia chilensis) is being explored in the food industry, and is considered to be one of the healthiest berries due to its bioactive components and high commercial value. Microwave-assisted extraction (MAE) was developed for the determination of total phenolic compounds and anthocyanins from maqui. A Box-Behnken experimental design was employed in conjunction with a response surface methodology to optimize the conditions based on 27 different experiments. The extractions were carried out with four factors (i.e., methanol percentage, pH, temperature, and solvent volume:sample mass ratio), and two responses-total phenolics and anthocyanins. Temperature and methanol percentage were found to be the most influential parameters for total phenolic compounds and anthocyanins, respectively. The optimum MAE conditions were: 65% MeOH in water at pH 2, temperature of 100 degrees C, and a ratio of 10:0.5 for total phenolics; and 60% MeOH in water at pH 2, temperature of 50 degrees C, and a ratio of 14:0.5 for anthocyanins. Kinetics assays were carried out and an optimum time of only 2 min was identified for the extractions. Repeatability and intermediate precision were also evaluated, and coefficients of variation below 5% were obtained. The new methods were successfully applied to a foodstuff made with maqui.