Optimization of the Ultrasound-Assisted Extraction (UAE) of antioxidant activity: a review

Optimization of extraction parameters is necessary in order to obtain a maximum amount of antioxidants from a plant. Optimizing the Ultrasound-assisted extraction (UAE) is needed recently due to the benefit of determining the optimum level of the parameters including solvent-to-material ratio, power, extraction time, solvent concentration, temperature, pH in addition to their effect and interaction. No analysis has been carried out so far on the optimization of UAE antioxidant activity parameters to guide the design of the RSM experiment. This analysis therefore focuses on the effects of each UAE parameter on the antioxidant activity and its interaction, as well as on the best method of antioxidant activity as an answer to the UAE optimization. Optimal extraction time is 15 minutes, which is higher than that which could result in the depletion of antioxidant activity. Temperature effect is important, antioxidant activity decreases by more than 45 ° C. Generally rising concentrations of solvents lead to an increase in antioxidant activity, but no substantial increase is observed above the 50 percent concentration; and higher ultrasound power creates free hydroxyl radicals that destroy the antioxidant compound. The effect of the solvent on the solid ratio was important due to a decrease in the density of the mixture, although no increase was observed with a ratio of more than 40:1 ml / g. The radical scavenging activity was found to increase dramatically with an increase in pH. However, it should be at a medium level such as pH 6, since it will affect the balance of deprotonation, which will reduce the antioxidant activity. Comparative literature has shown that optimization of the UAE not only leads to improved antioxidant activity, but also increases the conservation of energy and chemicals. A full picture of UAE optimization is provided to serve as a reference material for optimising UAE parameters for optimum results and antioxidant activity performance