Mathematical Modeling and Optimization of the Microwave Assisted Extraction of the Solid Waste of the Pomegranate Juice Industry

Pomegranate pomace is the solid waste of the pomegranate juice industry which accounts for approximately 50% of the quantity of the fruits, which is processed into juice and is a good raw material for production of high added value products with diverse uses. Pomegranate pomace is rich in polyphenols and flavonoids which could substitute the potentially hazardous synthetic antioxidants/antimicrobials used in agro-food and cosmetics sectors. In this work, eco-friendly aqueous microwave assisted extraction of pomegranate pomace was investigated and optimized in order to produce effectively novel natural antioxidant/antimicrobial extracts. A three-factorial response surface optimization methodology with centered Box & Behnken experimental design was used to obtain the predictive models and the maximum values of total polyphenols, total flavonoids and total antioxidant capacity (TAC). The three optimization factors involved were: (a) water/solid ratio; (b) extraction temperature; (c) extraction time and the effectiveness and robustness of the three models were statistically verified by ANOVA.