The Impact of Pyropheophytin a (PPP) and 1,2-Diacylglycerols (DAGs) on Extra Virgin Olive Oil Quality and Shelf Life

The quality and shelf life of extra virgin olive oil (EVOO) are pivotal to its marketability and consumer satisfaction. This study evaluated how pyropheophytin a (PPP) and 1,2-diacylglycerols (DAGs) changed for different varieties of EVOO over a 24-month storage period under varying temperature conditions (16°C, 18°C, and 20°C). PPP values were primarily influenced by storage temperature, while DAGs evolution was driven by a combination of storage time, temperature, and initial free fatty acid levels. Both DAGs and PPP had weak correlations with quality and oxidative parameters like peroxide values (PV) and UV absorbances. Applying the current California olive oil standard thresholds (PPP ≤ 17% and DAGs ≥ 35%) ensured 100% specificity (i.e., no non-rancid oils were misclassified as rancid). While alternative thresholds (e.g., PPP ≤ 12% and DAGs ≥ 47%) improved sensitivity (the ability to correctly identify rancid oils) from 21% to 42%, their practical significance is limited due to compromised specificity (97%). Our findings demonstrated PPP and DAGs can accurately classify EVOO quality. Shelf-life prediction models incorporating these chemical parameters help better determine use-by dates, enhance consumer trust, and promote greater transparency and consistency in the global olive oil industry.