Pyropheophytin a in Soft Deodorized Olive Oils

Area of Science:

• Food Chemistry
• Analytical Chemistry
• Olive Oil Quality

Background:

• Blending mild refined olive oil with extra virgin olive oil (EVOO) is difficult to detect.
• Chlorophyll derivatives, specifically pheophytins and pyropheophytins, are proposed markers for detecting refining processes.

Purpose of the Study:

• To investigate changes in pheophytins and pyropheophytins in EVOO after controlled mild refining processes.
• To establish reliable parameters for detecting adulteration of EVOO with refined olive oil.

Main Methods:

• Controlled mild refining processes applied to EVOO.
• Quantification of pheophytins a+a' and pyropheophytin a.
• Analysis of pigment changes under varying temperatures, stripping gases, and acidity levels.

Main Results:

• At temperatures below 100 °C, pheophytin a+a' decrease is more significant than pyropheophytin a formation.
• The ratios R_a+a' and R_a are linked to pheophytin decrease, not pyropheophytin formation.
• Acidity and nitrogen gas enhance pigment ratio changes; initial pheophytin content influences the increase in these ratios.

Conclusions:

• Pheophytin and pyropheophytin ratios are effective indicators for detecting mild refining processes in olive oil.
• Refining temperature, acidity, and initial oil composition significantly impact chlorophyll derivative transformations.