Quality control and storage studies of virgin olive oil: Exploiting UV spectrophotometry potential

• Published in: European journal of lipid science and technology 2006-01, Vol.108 (1), p.61-69
• Main Authors: Grigoriadou, Despina, Tsimidou, Maria Z.
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Conjugated dienes; Fat industries; Food industries; Fundamental and applied biological sciences. Psychology; General aspects; Methods of analysis, processing and quality control, regulation, standards; olive oil quality control; olive oil storage; peroxide value; UV derivative spectrophotometry
• ISSN: 1438-7697; 1438-9312
• DOI: 10.1002/ejlt.200500204

The present work was undertaken in order to examine whether K232 values and other UV absorbance characteristics could replace the determination of peroxide value (PV) in routine quality control and also in storage studies of virgin olive oil (VOO). For this reason, PV and extinction coefficients were determined for a large number of VOO samples (n = 40). The samples were then stored at 45 °C for several weeks. Changes in the lipid matrices were monitored by periodic measurements of the same quality indices. UV absorption spectra and the respective derivative ones were obtained before and during storage. Regression data showed that the PV is correlated with the K232 value not only at time zero but also during storage. Evidence derived from the first derivative spectrum is strongly related to the oxidative status of the oil. The findings may be used (a) to simplify the decision tree suggested for “the verification of consistency of a VOO sample with commercial category declared” in the EEC Regulation No 1989 (2003), which takes into account acidity measurement, PV and absorbance values (K270, ΔK, K232), and (b) to collect qualitative and quantitative information about the oxidation process during storage.