Microwave and ultrasound-assisted natural deep eutectic solvents-based extraction of pectin from onion peel wastes

ABSTRACT

Pectin was extracted from onion peels using microwave and ultrasound-assisted natural deep eutectic solvents (NADES) and compared with conventional acid-extracted pectin. The primary screening trials indicated that the suitable combination of hydrogen bond acceptor and donor was choline chloride and tartaric acid, respectively. The Box-Behnken design was further used to optimize processing conditions like microwave intensity (26.903 W/g), microwave processing duration (2.99 min), and sonication duration (10.18 min) for maximizing the pectin yield from onion peel powder. The moisture, ash, and equivalent weight of extracted pectin were in the range specified by the International Pectin Producers Association. The higher anhydrouronic acid content of the NADES-extracted pectin indicated the higher purity of pectin compared to the conventional acid-extracted pectin. The NADES-based extraction was found to be a promising system for extracting pectin with a higher degree of esterification from onion peels.

KEYWORDS:

• Pectin
• natural deep eutectic solvents
• onion peels
• response surface methodology

Acknowledgments

The authors thank the Vellore Institute of Technology, Vellore for providing the ‘VIT SEED Grant – RGEMS Fund (SG20220041)’ for carrying out this research work’.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The datasets generated during and/or analyzed during the current study are available within this article.

Additional information

Funding

This research work was funded by the ‘VIT SEED Grant – RGEMS Fund [SG20220041]’.