S23 - Session O3 - Effects of rapid postharvest cooling treatments of olives on oil quality parameter

Authors: Mario Vendrell Calatayud *, Stefano Brizzolara, Pietro Tonutti

The olive ( Olea europaea L.) crop is at the roots of the Mediterranean culture and became part of its heritage. Olive fruit quality strongly depends on environmental conditions and climate emergency, with prolonged summers and warmer temperatures at harvest, is threatening the quality of the production. The possible effects of the rising temperature in the fruit is to trigger oxidative reactions coupled with increased respiration rate leading to possible negative effects on aroma, fatty acids, and polyphenol profiles. To possibly mitigate the risks and secure the olive oil quality, we herein report the results of trials regarding post-harvest/pre-processing rapid cooling by means of rapid (few seconds) cold-water treatments (hydrocooler) of olives from different genotypes cultivated in Southern Tuscany (Italy). Volatilomics (GC/MS) and untargeted metabolomics (NMR) analyses were carried out on the resulting oil samples. The cooling treatment induced different responses in the tested cultivars, suggesting the presence of genotype-dependent responses, as well as ripening-related effects. After cooling treatment specific cultivars (e.g. cv. Frantoio and cv. Moraiolo) produced oil characterized by higher levels of C6 aldehydes, which are known to be related to herbal/green flavor. On the contrary, other cultivars (e.g. cv. Leccino) were less pronounced regarding volatiles, showing a decrease in several desirable aromas. Our results also indicate that cooling harvested olives right before processing could help reducing VOCs related to off-flavors while potentially boosting green and fresh attributes which may improve the olive oil quality. Additionally, several changes depending on the treatment were observed in the fatty acids profile, while, regarding polyphenols, no significant relation between the treatment and the modification of these compounds was detected. A marked effect of the genotype has been observed in relation to the treatment and further investigation is necessary to better elucidate this cultivar-specific behavior.