Microwave-assisted extraction and ultrasound-assisted extraction for recovering carotenoids from Gac peel and their effects on antioxidant capacity of the extracts.

Hoang V Chuyen,Minh H Nguyen,Paul D Roach,Sophie E Parks,John B Golding

doi:10.1002/fsn3.546

Abstract

The peel of Gac fruit (Momordica cochinchinensis Spreng.) contains high levels of bioactive compounds, especially carotenoids which possess significant antioxidant capacities. However, the peel of Gac is regarded as a waste from the production of carotenoid‐rich oil from Gac fruit. In this study, carotenoids of Gac peel were extracted by microwave‐assisted extraction (MAE) and ultrasound‐assisted extraction (UAE) using ethyl acetate as extraction solvent. The effect of extraction time and different levels of microwave and ultrasonic powers on the yield of total carotenoid and antioxidant capacity of the extracts were investigated. The results showed that an extraction at 120 W for 25 min and an extraction at 200 W for 80 min were the most effective for MAE and UAE of the Gac peel samples, respectively. The maximum carotenoid and antioxidant capacity yields of UAE were significantly higher than those of the MAE. The antioxidant capacity of extract obtained by the UAE was also significantly higher that of the conventional extraction using the same ratio of solvent to material. The results showed that both MAE and UAE could be used to reduce the extraction time significantly in comparison with conventional extraction of Gac peel while still obtained good extraction efficiencies. Thus, MAE and UAE are recommended for the improvement of carotenoid and antioxidant capacity extraction from Gac peel.

Highlights

Gac fruit (Momordica cochinchinensis Spreng.) contains very high levels of carotenoids which includes lycopene and β-carotene (Ishida, Turner, Chapman, & Mckeon, 2004; Vuong, Franke, Custer, & Murphy, 2006)
microwave-assisted extraction (MAE) and ultrasound-assisted extraction (UAE) at different power levels were investigated for the extraction of carotenoids and antioxidant capacity from Gac peel
The applied microwave and ultrasonic powers significantly increased the recovery of carotenoids from the peel and antioxidant capacity of the extracts

Summary

| INTRODUCTION

Gac fruit (Momordica cochinchinensis Spreng.) contains very high levels of carotenoids which includes lycopene and β-carotene (Ishida, Turner, Chapman, & Mckeon, 2004; Vuong, Franke, Custer, & Murphy, 2006). The UAE of lycopene from tomato waste has shown to occur with shorter extraction times, lower temperatures and smaller solvent volumes with higher extraction yields compared to the conventional extractions (Kumcuoglu, Yilmaz, & Tavman, 2014) These studies suggest that extraction of carotenoids from Gac peel may be improved with the assistance of microwave and ultrasound. Different power levels of microwave radiation and ultrasound and extraction times were investigated for enhancing the extractability of carotenoids from Gac peel. The effects of these parameters on antioxidant capacity of the extracts from the peel were determined. After 60 min, no significant improvement in the antioxidant capacity was observed

Findings

| DISCUSSION

| CONCLUSION