Blends of fresh olive oil and old olive oil: Characterization and quantification through chemical and sensory assessment

Study on the Effect of Climate Changes on the Composition and Quality Parameters of Virgin Olive Oil "Zalmati" Harvested at Three Consecutive Crop Seasons: Chemometric Discrimination

Trees of the olive (Olea europaea L.) cultivar Zalmati grown in Zarzis (Mednine) with different main climate traits (temperature, precipitation, humidity, and wind) were studied for 3 years to evaluate the impact of climate on the quality of olive oil. The effect on quality indices, free fatty acids, peroxide value, UV spectrophotometry, pigment content, and phenol and O-diphenol concentrations, of the three harvesting periods was considered. Linking to the purity parameters (fatty acid, triacylglycerol, total phenols, and tocopherols composition), our results showed a trivial reduction in fatty acid composition and polyphenols content caused by the high temperature. In fact, precipitation strongly affects the pigment content, which showed a significant decrease during rainy seasons. Nevertheless, principal component analysis allowed us to highlight the correlation between parameters and indicates that 57.8% of the variation of monounsaturated fatty acids (MUFAs), polyunsaturated fatty acids (PUFAs), MUFA/PUFA, α-tocopherol, C 18:1, and C 18:2 amounts was explained by the mean temperature.