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Olive oil is the product obtained from the olive fruit. Several grades can be obtained, extra virgin olive oil being the top category. The balanced fatty acid composition of olive oil, particularly its high content of oleic acid, makes this product nutritionally important. In addition, virgin olive oil contains bioactive compounds such as unsaponifiable constituents and phenolic compounds. Polar phenols and volatile compounds are two of the most interesting classes of compounds in olive oil. The scientifically proven beneficial health effects related to VOO consumption and the unique sensory properties of this product make it versatile for several culinary uses. This chapter reviews olive oil composition, focusing on the flavour-active compounds and their changes due to the variety, environmental conditions, processing and technological factors. The culinary uses of olive oils are then presented, with emphasis on traditional uses, possible food pairing and innovative applications including substitution of other fats and molecular gastronomy.

Accumulated epidemiological, clinical and experimental evidence has indicated the beneficial health effects of the Mediterranean diet, which is typified by the consumption of virgin olive oil (VOO) as a main source of dietary fat. At the cellular level, compounds derived from various olive (Olea europaea), matrices, have demonstrated potent antioxidant and anti-inflammatory effects, which are thought to account, at least in part, for their biological effects. Research efforts are expanding into the characterization of compounds derived from Olea europaea, however, the considerable diversity and complexity of the vast array of chemical compounds have made their precise identification and quantification challenging. As such, only a relatively small subset of olive-derived compounds has been explored for their biological activity and potential health effects to date. Although there is adequate information describing the identification or isolation of olive-derived compounds, these are not easily searchable, especially when attempting to acquire chemical or biological properties. Therefore, we have created the OliveNet™ database containing a comprehensive catalogue of compounds identified from matrices of the olive, including the fruit, leaf and VOO, as well as in the wastewater and pomace accrued during oil production. From a total of 752 compounds, chemical analysis was sufficient for 676 individual compounds, which have been included in the database. The database is curated and comprehensively referenced containing information for the 676 compounds, which are divided into 13 main classes and 47 subclasses. Importantly, with respect to current research trends, the database includes 222 olive phenolics, which are divided into 13 subclasses. To our knowledge, OliveNet™ is currently the only curated open access database with a comprehensive collection of compounds associated with Olea europaea. Database URL: https://www.mccordresearch.com.au

Virgin olive oil is a high quality natural product obtained only by physical means. In addition to triacylglycerols it contains nutritionally important polar and non-polar antioxidant phenols and other bioactive ingredients. The polar fraction is a complex mixture of phenolic acids, simple phenols, derivatives of the glycosides oleuropein and ligstroside, lignans, and flavonoids. These compounds contribute significantly to the stability, flavor, and biological value of virgin olive. In the various stages of production, during storage and in the culinary uses, polar phenols and other valuable bioactive ingredients may be damaged. Oxidation, photo-oxidation, enzymic hydrolysis and heating at frying temperatures have a serious adverse effect. Due to the biological importance of the oil and its unique character, analytical methods have been developed to evaluate antioxidant activity or analyse complex phenol mixtures. These are based on radical scavenging assays and chromatographic techniques. Hyphenated methods are also used including liquid chromatography-mass spectrometry and liquid chromatography-nuclear magnetic resonance spectroscopy.

Publisher Summary Table olives have more or less the same health properties as olive oil, but this has been overlooked because, with the exception of Mediterranean countries, this product was seen as a piece of decoration for pizzas and breads. They are a highly functional food with a balanced content of fats made up mainly of monounsaturated oleic acid. They contain fiber, vitamins, minerals, phytosterols, triterpenic acids, and squalene and contribute to the daily intake of nutritional antioxidants, mainly phenols, such as verbascoside, hydroxytyrosol, tyrosol, luteolin, and apigenin 7-O-glycosides, as well as phenolic acids. Raw olives are bitter and not fit for consumption due to the high levels of bitter secoiridoids, mainly oleuropein. Oleuropein can be removed by natural methods, alkali treatment, drying, or salt curing. Profiles of phenolic compounds in the end products and, consequently, the nutritional value are influenced by the olive cultivar, the pre- and postharvest factors, the debittering methods, and the processing style. Olives' ripening stage strongly influences changes in phenolic content and the profile of bioactive phenols. During olive ripening, the concentration of total phenols usually increases progressively to a maximum level at the green-skin stage, decreasing sharply as ripening progresses. The harvesting method is also important for table olive quality. Numerous table olive processing methods are available. Each process is suitable for a particular olive variety and degree of ripeness and the processes may vary according to tradition and other cultural factors. Whatever the method used, a significant loss in phenols occurs during the various processing steps. The potential use of enzymes instead of traditional lye treatment can result in products richer in polyphenols.

Publisher Summary Phenolic compounds are important for the sensory and nutritional qualities of Virgin Olive Oil (VOO). During the extraction process, phenolic substances undergo chemical and biochemical changes that modify their structure and influence their presence in the final product. High-quality virgin olive oil can be produced only from healthy, fresh fruits at the right ripening grade. The final quality of virgin olive oil and the level of bioactive compounds arise inside the orchard. The phenolic content depends both quantitatively and qualitatively on its genetic makeup. After choosing the best harvesting time for each cultivar in each particular geographical area, the other two main factors that are crucial for establishing the final quality should be considered: the harvesting methods and the post-harvesting storage. A deeper knowledge of the working parameters is necessary to diversify the oil quality. Malaxing conditions can modify the phenol contents in virgin olive oil and, as a consequence, its nutritional and sensory properties. It is important to develop innovative solutions to increase oil yields and improve quality, reducing at the same time the environmental impact of the process. Emerging technologies, such as pulsed electric fields, microwaves and ultrasound are promising techniques suitable for plant improvement and optimization. Innovations are also being developed in the sector of pomace olive oil, aiming at obtaining a final product richer in functional minor components.