Table Olives as Sources of Bioactive Compounds

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.