Work

Enzymatic browning in fresh extra virgin olive oil (EVOO): Detection of polyphenol oxidase, assessing moisture impact, and revealing the anti-browning capacity of EVOO

Year: 2024

Type: article

Abstract: This study investigates the presence of active olive polyphenol oxidase ( Oe PPO) in freshly extracted extra virgin olive oil (EVOO) and its role in triggering enzymatic browning during EVOO storage. Oe PPO's presence in EVOO was validated through its distinct molecular weights observed in SDS-PAGE gels. The generation of quinones in EVOO was tracked spectrophotometrically over a storage period of one month, revealing browning reactions, particularly in the early days of storage, followed by a decline concurrent with water sedimentation. Introducing various water percentages into EVOO revealed the critical and proportional impact of moisture content on enzymatic browning. Microscopic examination showed the formation of colloidal matter around water microdroplets suspected to accommodate browning reactions. The reduction of EVOO moisture content to < 0.15 % coincided with a progressive decrease in browning across all samples, hinting at a potential anti-browning capacity of EVOO. A novel analytical method is proposed to evaluate EVOO's anti-browning capacity, utilizing chemically oxidized 4-tert-butylcatechol (TBC) quinones. After one month of storage, a significant decrease in total phenols and antioxidant activity proportional to the moisture content and enzymatic browning was noted in EVOO samples. To prevent such losses, the EVOO extraction process should effectively minimize moisture content to less than 0.15 %. • Olive polyphenol oxidase was identified in EVOO through gel electrophoresis. • Enzymatic browning in fresh EVOO is directly proportional to its moisture content. • Browning reactions reduce EVOO's phenolics and antioxidant activity, lowering its quality. • Reducing moisture in fresh EVOO effectively reduces quinones and prevents enzymatic browning. • A new method is proposed, enabling easy detection of EVOO's anti-browning capacity.

Source: Food Chemistry

DOI: 10.1016/j.foodchem.2024.142582

Authors: Ala eddine Derardja, Matthias Pretzler, Malika Barkat, Saliha Dassamiour, Annette Rompel

Institutions: University Frères Mentouri Constantine 1, University of Vienna, University of Batna 2

Language: English

Topic: Edible Oils Quality and Analysis

Subfield: Organic Chemistry

Field: Chemistry

Domain: Physical Sciences

SDG: Zero hunger

Open Access status: hybrid

Estimated APC paid: $4,620