Mixing design for optimizing ultrasound-assisted extraction of phenolic components and anthocyanins from blue berries and grape marc

Waste from fruit processing can be used for obtaining additives as colorants and antioxidant compounds by extraction processes. Despite there are many works optimizing parameters as temperature and solvent concentration during this process, the mixture of solvents has not been optimized yet. Therefore, the present work aimed to find the optimum solvent mixture among water, ethanol, and acetone to obtain the maximum yields of phenolic compounds and monomeric anthocyanins from blue berry and grape marc by ultrasound-assisted extraction. For that, the Reticular Simplex Mixtures Design was used to obtain the models that can predict the optimum values of extraction yields. As a result, the quadratic model successfully fit the experimental data, demonstrating the best mixture solvents were the ones that presented a high percentage of water. This result was obtained not only for phenolic compound, but also for monomeric anthocyanin extraction from blue berry and grape marc. Further, using the optimum mixture, values of 502.2 GAE/100 g of phenolic compound and 1349.1 mg/100 g of monomeric anthocyanins from blue berry and 2642.4 GAE/100 g of phenolic compounds and 31.5 mg/100 of monomeric anthocyanins from grape marc were obtained. In conclusion, the optimum solvent demonstrated to be efficient extracting both components increasing the extraction yields and reducing the cost of extraction. Finally, by overlapping the optimization plot, a unique solvent mixture for obtaining a high yield of phenolic compound and anthocyanins at the same time from blue berry and grape marc was obtained.