Effects of pre-processing cooling treatments of harvested olives on oil volatilome and quality parameters

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. Climate emergency, with prolonged summers and warmer temperatures at harvest, is threatening the quality of the production. High temperatures during the latest developmental stages and at harvest may activate oxidative reactions and induce negative effects on aroma, fatty acid, and polyphenol profiles of the resulting oil, with also a risk of reduced commercial life. To conceivably mitigate the risks and secure the olive oil quality, we herein report the results of trials regarding postharvest/pre-processing rapid cooling by means of cold-water treatments (hydrocooler) in olives of the local cultivar 'Leccio del Corno' grown in southern Tuscany (Italy). The analyses on olive oil quality and composition were performed on freshly extracted samples and after one year from the production. Non-targeted volatile organic compounds (VOCs) analyses were performed in addition to fatty acids and polyphenol content. The volatilome profiling indicates that the postharvest/pre-processing cooling of olives induces an increase of specific VOC changes concerning C6 aldehydes, which are known to be related to herbal/green flavor. Additionally, significant changes were observed in the fatty acid profile in the fresh oil after the treatment, while the treatment seems to have some effects on the oil analysed after one year of storage, possibly related to different oxidation reactions on specific VOCs, fatty acids, and polyphenols.