Work

The Effect of Mineral and Organic Acid Addition on the Ethanol Organosolv Treatment of Waste Orange Peels for Producing Hesperidin-Enriched Extracts

Year: 2025

Type: article

Abstract: Waste orange peels (WOP) are a major orange processing residue, and they may be a rich source of precious bioactive polyphenols. Amongst the various WOP constituents, hesperidin holds a prominent position as the most abundant polyphenolic metabolite, with proven biological properties. The current work was performed to provide detailed information on the effect of various acid catalysts to assist hesperidin recovery, using an ethanol organosolv treatment. The treatment developed was first examined by comparing inorganic (HCl) and natural organic (oxalic, citric) acids for their influence on process performance, extraction kinetics, and severity. Following this, optimization was accomplished through response surface methodology, and the extracts produced were investigated with respect to their polyphenolic composition and antioxidant characteristics. The HCl-catalyzed treatment, carried out with 70% ethanol/2% HCl, was proven the most efficacious, giving a total polyphenol yield of 30.7 mg gallic acid equivalents per g of dry mass, and it was shown that the treatment yield was related to severity, obeying a power model. Liquid chromatography–tandem mass spectrometry analysis of the extract generated under optimized conditions (170 min, 80 °C) revealed that hesperidin was extensively hydrolyzed into hesperetin 7-O-glucoside and aglycone (hesperetin). Such an effect was very limited with the oxalic acid-catalyzed treatment, whereas citric acid did not affect the original polyphenolic composition. Overall, the HCl-catalyzed treatment was of significantly higher performance, providing a total flavanone yield of 21.22 mg per g dry mass. The results of this investigation may be of value in adjusting treatment settings for (i) increased flavonoid recovery from WOP and (ii) producing extracts enriched in hesperidin and/or its hydrolysis derivatives. Such practical recommendations may assist the establishment of WOP valorization processes in an integrated biorefinery prospect.

Source: Analytica—A Journal of Analytical Chemistry and Chemical Analysis

DOI: 10.3390/analytica6040056

Authors: Hiba Agnaou, Hela Refai, Spyros Grigorakis, Dimitris P. Makris

Institutions: Mediterranean Agronomic Institute of Chania, International Centre for Advanced Mediterranean Agronomic Studies, University of Thessaly

Language: English

Topic: Phytochemicals and Antioxidant Activities

Subfield: Biochemistry

Field: Medicine

Domain: Health Sciences

SDG: Responsible consumption and production

Open Access status: gold

Estimated APC paid: $1,207