Optimization of Polyphenol Extraction from Apricot Kernel Shells: Comparative Study Between Box-Behnken and Central Composite Designs

Background: Prunus armeniaca L. is widely cultivated around the world. High consumption of its fruit produces a large number of apricot kernel shells. The valorization of this byproduct in terms of polyphenol compounds seems to be important. Objective: This study aimed to optimize the extraction of phenolic compounds from apricot kernel shells by different extraction techniques by studying the effects of different parameters on the extraction efficiency, and the comparison between the Box-Behnken Design and the Central Composite Design of the response surface methodology is done in order to have good extraction estimation. Methods: In this study, response surface methodology; Box-Behnken and Central Composite Designs, was used to contrast the efficacy and investigate the principal interactions of three operating parameters (ethanol concentration, microwave power, and extraction time), in the optimization of phenolic compounds extraction from apricot kernel shells by microwave-assisted extraction, ultrasonic-assisted extraction, and maceration techniques. Results: The results indicated that the optimal total phenolic compounds obtained with microwave assisted extraction techniques by Box-Behnken Design was 9.30 ± 0.22 mg/g, where the ethanol concentration, microwave power, and extraction time, were 45.85%, 370.5 W, and 11 min, respectively. However, the optimal total phenolic compounds revealed by Central Composite Design were 8.86 ± 0.05mg/g under ethanol concentration, microwave power, and extraction time of 51.99%, 394.37W, and 9.68min, respectively. Conclusion: This work proposes the best mathematical model to optimize the extraction of polyphenols from this by-product which seems to be a possible source of phenolic compounds that can be used in the food, cosmetic, and pharmaceutical industries.