Process optimization for ultrasound and microwave-assisted phytonutrients extractions from Averrhoa carambola fruit

The purpose of the current study was to improve the phenolic and flavonoid extraction process variables from the powder of freeze-dried Averrhoa carambola fruit. Since extraction of phytonutrients by using conventional methods takes a prolonged period, which causes the heat destruction of phytocompounds, therefore ultrasound-assisted and microwave-assisted extraction techniques were applied to overcome the above problem. The effect of process variables such as solvent proportion, duration (in minutes for ultrasonic-assisted extraction and in seconds for microwave-assisted extraction), and microwave power on the TPC and TFC yield was investigated and optimized using the response surface methodology. The verification of the model was established by analyzing the extract, separated according to the optimal conditions of each extraction technique. Additionally, the outcomes of each technique were compared to the conventional approach. TPC 75.57 +/- 0.37 mgGAE/g and TFC 66.53 +/- 0.35 mgQE/g, as well as maximum antioxidant capacity (95.2 +/- 0.21%) and radical scavenging activity (92.43 +/- 0.32%) in microwave-assisted ethanolic extracts, were higher than other two extracts. According to the comparative investigation with the traditional solvent extraction which was 35.90 +/- 0.20 mgGAE/g for TPC, 33.52 +/- 0.24 mgQE/g for TFC along with antioxidant capacity of 86.66 +/- 0.28%, and radical scavenging activity of 81.04 +/- 0.08%. Additionally, for all three extractions, ethanolic extracts had better TPC, TFC, DPPH, and ABTS values than that of with acetone. These findings thus show that the microwave-assisted extraction method was the most economical method for extracting the phytochemical components from the carambola fruit since it involves less time and temperature in extraction, thus lowering the chances of thermal degradation of the sensitive phytonutrients.

Automated summary

The purpose of this study was to improve the extraction process variables for phenolic and flavonoid compounds from freeze-dried Averrhoa carambola fruit powder. The conventional extraction methods were not ideal due to the heat destruction of the compounds, so ultrasound-assisted and microwave-assisted extraction techniques were used. The effects of solvent proportion, duration, and microwave power on the yield of phenolics and flavonoids were investigated and optimized.