Pheophytin α degradation products as useful indices in the quality control of virgin olive oil

Abstract

In previous studies we reported the presence of compounds with spectral characteristics similar to pheophytin α (Pheo α), which often accompany the Pheo α peak in the chromatographic profile of virgin olive oils (VOO) at 410 nm under normal-phase HPLC conditions. The occurrence and levels of these compounds were found to be affected by storage conditions of the oil samples. In the present study we investigated whether the major Pheo a degradation products, identified as pyropheophytin α (coeluting with the respective epimer) and 13 2 -OHpheophytin α, could be used as estimates of VOO history. The content of Pheo α and its degradation products was determined for a great number of authentic olive oil samples of unknown history. Results are discussed in comparison with other quality indices (e.g., antioxidant content) when necessary. High amounts of the pyro form (20-30% of total pheophytins) were related to thermal abuse or lengthy storage. The presence of allomers indicated oxygen availability. The levels of these products, 0-20% of the total pheophytin content for 62% of the samples, seemed to be influenced by the presence of pro-and antioxidants. When low levels of Pheo α are not accompanied by other degradation products, light exposure for a certain period of storage can be assumed.

Evaluation of the Effect of Packaging Materials and Storage Temperatures on Quality Degradation of Extra Virgin Olive Oil from Olives Grown in Palestine

“…In accordance with our results, other investigators [5,30,37] found that PV of oils bottled in glass and PET stored at room temperature fluctuated during storage time and did not exceed the official limit during six months of storage. In the other hand, a linear increase in PV with storage time at room temperature in oil stored in glass bottles [9,10] and in tin plates [38] was reported. In the same line with our results in oil stored in glass, PET, and cans at room temperature and elevated temperature, PV decreased significantly with increasing storage time [7].…”

“…Some reporters [30] found that total phenols of oils bottled in glass and PET container didn't show significant decrease during storage, while others reported an increase in phenolic compounds contents with increasing time of storage [10,28], a situation found in our findings when oil was stored in glass and cans after 180 days of storage compared to the previous sampling date (135 days), which could be due to hydrolysis of secoiridoid derivatives in oil. As phenolic compounds act as natural antioxidants in oil and inhibit autoxidation of lipids (RH) by trapping intermediate peroxyl radicals [48], their reduction during storage is a result of oil oxidation [38].…”

Comparison of flavour fingerprint, electronic nose and multivariate analysis for discrimination of extra virgin olive oils

“…EVOO's definition originates from its first-class qualities. In the last few years, several techniques have been used for the quality control of EVOO, such as near-, mid- and Fourier-transform infrared spectroscopy [4,5], nuclear magnetic resonance spectroscopy [6], high-performance liquid chromatography–mass spectrometry [7], electro- and sonic-spray ionization mass spectrometry [8], capillary electrophoresis or electrochromatography [9], UV–visible spectroscopy [10] and high-resolution mass spectrometry [11,12].…”

High-performance liquid chromatography with fluorescence detection for the rapid analysis of pheophytins and pyropheophytins in virgin olive oil

“…One particular class of compounds are those derived from the degradation of chlorophyll pigments, pheophytins (PP) and pyropheophytin (PPP) (Fig. ) .…”

“…Its level increases over time depending on the storage condition and if the oil is exposed to heat treatments during the refining process, such as deodorization . Therefore, this conversion is used as a sensitive indicator of stress during the manufacturing and storage of the oil .…”