Ultrasound-Assisted Extraction of GAC Peel: An Optimization of Extraction Conditions for Recovering Carotenoids and Antioxidant Capacity

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

doi:10.3390/pr8010008

Hoang V Chuyen, Minh H Nguyen + Show 3 more

Open Access

https://doi.org/10.3390/pr8010008

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Abstract

The peel of Gac fruit (Momordica cochinchinensis Spreng.), which is considered as waste of Gac processing, has been found to possess high levels of carotenoids and other antioxidants. This study aimed at determining the optimal conditions of an ultrasound-assisted extraction for recovering carotenoids and antioxidant capacity from Gac peel. A response surface methodology using the Box–Behnken design was employed to investigate the impact of extraction time, temperature and ultrasonic power on the recovery of total carotenoid and antioxidant capacity. The results showed that an extraction time of 76 min, temperature of 50 °C and ultrasonic power of 250 W were the optimal conditions for the extraction. The experimental carotenoid yield and antioxidant capacity obtained under the optimal extraction conditions were validated as 269 mg/100 g DW (dry weight) and 822 µM TE (Trolox equivalent)/100 g DW, respectively. These values were not significantly different from the values predicted by the models. The HPLC analysis for carotenoid composition showed that β-carotene, lycopene and lutein were the principal carotenoids of the extract, which constitute 86% of the total carotenoid content. Based on the obtained results, the ultrasound-assisted extraction using ethyl acetate under the above optimal conditions is suggested for the simultaneous recovery of carotenoids and antioxidant capacity from Gac peel.

Highlights

Gac (Momordica cochinchinensis Spreng.) is a tropical vine popularly grown in Southeast Asia, China and India
0.005 yield and antioxidant the optimal conditions to obtain the maximum values of total carotenoid
The response surface methodology using the Box–Behnken design was successfully applied for optimizing extraction time, extraction temperature and ultrasound power of an ultrasound-assisted extraction to recover carotenoids and antioxidant activity from Gac peel

Summary

Introduction

Gac (Momordica cochinchinensis Spreng.) is a tropical vine popularly grown in Southeast Asia, China and India. Gac fruit has been reported as one of the richest natural sources of carotenoids [1,2]. In the processing of Gac fruit, only the aril (seed membrane) is used to produce commercial products like Gac oil and Gac powder while other parts of the fruit such as seeds, pulp and peel are discarded as wastes [3]. The pulp (yellow fruit meat) and the peel (spiny red skin) of Gac fruit have been found to contain a significant amount of bioactive compounds and have significant antioxidant ability [5,6]. The peel of Gac fruit has been reported to have a comparable carotenoid content as the well-known carotenoid-rich sources like tomatoes and carrots [7,8,9]. If carotenoids from Gac peel can be Processes 2020, 8, 8; doi:10.3390/pr8010008 www.mdpi.com/journal/processes

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