Olive fruit (Olea europaea L.) contain high levels of phenolic compounds, which contribute to the antioxidant protection of plant tissues and determine the sensory and nutritional properties of olive products. In this doctoral thesis, we studied the changes in the phenolic content of olive fruits during ripening, storage, processing and after damage. In the first experiment, we studied gene expression and phenolic content in the skin and pulp of cultivars 'Leccino' and 'Istrska belica' during ripening and found that the expression and content were higher in the skin. We also observed cultivar-specific differences in the content of anthocyanins and the expression of genes involved in their synthesis. In the second experiment, we monitored the effect of the brown marmorated stink bug's (Halyomorpha halys STÅL.) attack and found statistically significant differences in the content of 38 individual phenolics, with a more pronounced response in damaged tissues. We also found that the response to damage was cultivar-specific. The third experiment showed that storage at higher temperatures accelerated the degradation of phenolics, loss of firmness and spread of damage, while cold storage preserved quality better. Riper fruits at harvest were less suitable for storage as they showed more damage compared to less ripe fruits. In the fourth experiment, we found that the duration of fruit processing is cultivar-specific. The phenolic content of the final product is mainly influenced by the initial phenolic content. The research results demonstrate the important role of phenolic compounds in the metabolic changes of olives and provide guidelines for optimising technological processes in olive growing, where maintaining both quality and quantity is key.
|
