# Effects of Enzymatic Pretreatment on Yield and Volatile Composition of Citrus Peel Essential Oils

## TL;DR

This study shows how enzyme pretreatment can change the chemical makeup of citrus peel essential oils, though it only slightly increases their yield.

## Contribution

The novelty lies in systematically evaluating how different enzymes and buffers affect the volatile composition of citrus essential oils.

## Key findings

- Enzymatic pretreatment increased essential oil yield slightly for orange and mandarin peels but not for clementine.
- Mandarin oils showed increased sesquiterpenes and aldehydes after pretreatment, while clementine oils had higher oxygenated monoterpenes.
- Limonene remained the dominant compound in all oils, with no significant shift in its proportion.

## Abstract

Enzymatic pretreatment is a promising method for modulating essential oil isolation. This study evaluated the effects of pectinase, cellulase, xylanase, and their mixture, applied in purified water or citrate buffer before Clevenger hydrodistillation, on the yield and volatile composition of essential oils from orange, mandarin, and clementine peels. Essential oil yield increased slightly for orange and mandarin peels (up to approximately 2%) compared to non-enzymatic controls, while clementine yield was unaffected. Limonene remained the dominant compound in all oils, reaching 81.16% in orange, 77.50% in mandarin, and 75.29% in clementine. Enzyme pretreatment particularly affected the secondary components: mandarin peel showed increased sesquiterpenes (up to 60.52%) and aldehydes (up to 4.86%), while clementine oils exhibited higher oxygenated monoterpenes after buffer-based enzymatic treatments. These results indicate that enzyme-assisted pretreatment can modulate the volatile profile of citrus essential oils, although overall yield gains are modest. The inclusion of no-enzyme and no-pretreatment controls is crucial for the reliable assessment of enzymatic effects under laboratory conditions. This systematic approach provides insight into enzyme-assisted extraction, highlighting its potential to influence essential oil quality and composition rather than dramatically increase yield, and offers a foundation for further optimization research.