Multiomics Approach To Decipher the Origin of Chlorophyll Content in Virgin Olive Oil

Area of Science:

• Agricultural Science
• Plant Biochemistry
• Food Chemistry

Background:

• Olive oil color is a key consumer choice and quality indicator, determined by chlorophyll content.
• Chlorophyll levels in olives are influenced by fruit composition and ripeness.
• Understanding chlorophyll metabolism is crucial for olive oil quality.

Purpose of the Study:

• To investigate the biochemical and molecular basis of chlorophyll content variations in olive fruits.
• To identify enzymes and pathways responsible for chlorophyll biosynthesis and degradation during olive ripening.
• To elucidate the role of specific enzymes in the accumulation of dephytylated chlorophyll in certain olive varieties.

Main Methods:

• High-performance liquid chromatography with high-resolution mass spectrometry (HPLC-hrMS) for chlorophyll analysis.
• Biochemical assays to measure enzymatic activity related to chlorophyll metabolism.
• Quantitative reverse transcription polymerase chain reaction (qRT-PCR) to analyze gene expression.

Main Results:

• Identified protochlorophyllide reductase as the primary enzyme for chlorophyll biosynthesis in olive fruits.
• Characterized chlorophyll degradation via the stay-green and pheophytinase pathways.
• Demonstrated the novel role of chlorophyll dephytylase in accumulating dephytylated chlorophyll in 'Arbequina' olives.
• Ruled out the in vivo function of chlorophyllase in olive fruit chlorophyll degradation through multiomics analysis.

Conclusions:

• Enzyme activity and specific metabolic pathways significantly determine chlorophyll content and thus olive oil color.
• Chlorophyll dephytylase plays a critical role in the unique chlorophyll profile of 'Arbequina' olive oil.
• This research provides molecular insights into factors affecting virgin olive oil quality.