Influence of the Ripening Stage and Extraction Conditions on the Phenolic Fingerprint of ‘Corbella’ Extra-Virgin Olive Oil

Abstract

The ancient ‘Corbella’ olive variety from the center-north of Catalonia is being recovered to obtain quality extra-virgin olive oil (EVOO) with unique organoleptic properties. The aim of this work was to determine the effect of agronomic and technical factors on the phenolic fingerprint of EVOO and to establish the optimum harvesting time and crushing and malaxation conditions for ‘Corbella’ olives. Therefore, three different ripening indices (0.3, 1.2, and 3.2) and three crushing temperatures (10, 18, and 25 OC) were studied. Additionally, a factorial design to optimize the phenolic concentration of the EVOO was developed, applying a range of sieve diameters (4 and 6 mm), and malaxation time (30 and 60 min) and temperature (27, 32, and 37 °C). The phenolic profile was analyzed by ultra-high performance liquid chromatography coupled to mass spectrometry in a tandem detector. The level of secoiridoids, the major phenolic compounds in the oil, was higher when using olives harvested earlier. Oleuropein aglycone and ligstroside aglycone were degraded during crushing at high temperatures, resulting in the formation of oleacein and oleocanthal. The best processing conditions in terms of total phenolic content were found to be 30 min of malaxation at 37 OC, the crushing size not having any affect.

Optimizing the Malaxation Conditions to Produce an Arbequina EVOO with High Content of Bioactive Compounds

“…A principal component analysis (PCA) was performed using SIMCA 13.0.3 to assess the impact of the different variables on our EVOO samples and see how they were distributed. The PCA indicated that the RI had a considerable impact on the phenolic profile of the olive oil, confirming previous reports [ 7 , 13 , 21 ]. The values of the RI were different depending on the olive tree from which the olives were collected ( Table A1 ).…”

“…An increase in phenolic alcohols with temperature and time has been attributed to the hydrolysis of secoiridoids [ 7 , 25 , 36 ] and was more visible at temperature ranges above those tested here (>30 °C). Likewise, an increase in flavones could be attributed to the transformation of its glycosylated forms into the aglycones, increasing its solubility in the oil [ 13 ]. Contrary, phenolic acids showed a negative correlation with higher temperatures (20−60 °C) [ 36 ].…”

“…The values ranged from 1.16 to 2.26. Therefore, in order to eliminate the effect of this variable and focus only on the temperature and time of malaxation, results were adjusted taking into account the RI of the olive samples, which was performed in three groups (1.16–1.20, 1.44–1.54, and 2.20–2.26), as we have previously classified [ 13 ]. Afterwards, the statistical analyses to see the effect of temperature and time of malaxation were performed.…”

“…The ripening index (RI) also influences the content of the bioactive compounds [ 13 ]. Numerous studies have demonstrated that the phenolic content of the olive fruit decreases during ripening [ 3 , 14 ], as does the chlorophyll level [ 7 ].…”

Therapeutic Properties and Use of Extra Virgin Olive Oil in Clinical Nutrition: A Narrative Review and Literature Update

“…Smaller amounts of simpler phenolic compounds—such as caffeic, vanillic, and ferulic acids—have the role of protecting and enhancing the bioavailability of α-tocopherol [ 6 , 7 , 8 , 9 , 12 , 13 , 14 , 33 , 34 ]. See Table S2 for further information regarding antioxidants in the unsaponifiable fraction of EVOO from the main cultivars in the Mediterranean Area [ 17 , 19 , 20 , 21 , 22 , 23 , 25 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 ]. Chlorophyllic and carotenoid pigments.…”