Quality of Olive Oils Obtained from Fruits Damaged by fly

CDR OxiTester, the analytical system for vegetable oils and fats, was used to perform Peroxide Value testing and Free Fatty Acids testing during the study entitled “Qualitative Changes of Olive Oils Obtained from Fruits Damaged by Bactrocera oleae (Rossi)“, made by Riccardo Gucci, Giovanni Caruso, Angelo Canale, Augusto Loni, and Alfio Raspi Department Coltivazione e Difesa delle Specie Legnose ‘‘G. Scaramuzzi,’’ University of Pisa, 56124 Pisa, Italy Stefania Urbani, Agnese Taticchi, Sonia Esposto, and Maurizio Servili Department Scienze Economico-Estimative e degli Alimenti, University of Perugia, 06126 Perugia, Italy.

Mature fruits of Olea europaea L. ‘Frantoio’ with different degrees of damage caused by the olive fruit fly (Bactrocera oleae) were sampled to quantify the effects on free acidity, peroxide value (PV), and concentrations of secoiridoids and lignans of virgin olive oil (VOO).

” […] Free acidity and PV of oils were determined using an CDR OxiTester unit (CDR OxiTester; CDR, Ginestra Fiorentina, Italy). This equipment allowed to determine both parameters rapidly (within 8 min) on small samples. An aliquot of oil sample (2.5 and 5.0 mL for free acidity and PV, respectively) was added to a pre-filled cuvette where fatty acids react with a chromogen developing a color with an optical density at 630 nm that is proportional to the fatty acid concentration. As for PV, radical peroxide value oxidize Fe2+ and the resulting Fe3+ forms a red complex, the absorbance of which, measured at 505 nm, is directly proportional to the concentration of peroxide value in the oil. Free acidity and PV determined by the CDR Oxitester method had been preliminarily checked against the official method of analysis (EU 1989/2003 modifying the ECC 2568/91) using oil samples over a wide range of values. Regression equations between the two methods were highly significant. […]”

The relationship between free acidity (A) or peroxide value (B) measured according to the Official method (EU 1989/2003 modifying the ECC 256/91) and the CDR OxiTester.

Regression equations:
(A) y=1.06x + 0.001, R2 =0.996; (B) y=1.09x – 0.21, R2 =0.995.

From HortScience 47(2):301–306. 2012 – Qualitative Changes of Olive Oils Obtained from Fruits Damaged by Bactrocera oleae (Rossi)