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    Effect of ozone treatment on the physical, microbiological and sensorial properties of Spanish-style table olives
    (Consejo Superior Investigaciones Cientificas-Csic, 2020) Gungor, F. Ozturk; Ocak, O. Ozdestan; Unal, M. K.
    Ozone has been widely used in the food industry as an effective antimicrobial agent. in this study the possibilities of using ozone in table olive preservation was investigated for the first time. For this purpose, the Domat variety of table olives was processed according to the Spanish style and treated with aqueous ozone for 5, 10, and 20 minutes at 0.5, 1, 2 and 4 ppm. the effects of ozonation on the microbiological, physical and sensory characteristics of the table olives were evaluated during the storage period (up to 180 days). the pH, color and firmness of the ozone treated table olives showed higher stability. Statistically significant reductions in the total bacteria and yeast/mould counts were obtained (p < 0.05). Enterobacteriaceae and Escherichia coli were not found in the samples. After 60 days of storage the control samples (ozone untreated olives) obtained low values for sensory analysis, and did not meet market requirements. the results indicate that treating green table olive with ozon (1 ppm concentration) for 10 min in aqueous form reduces the microbial population without any negative effects on the firmness, color (L*, a* b*) or sensory attributes of the table olives.
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    The effect of phenolic compounds on the quality and stability of virgin olive oil
    (Int Soc Horticultural Science, 2008) Koseoglu, O.; Unal, M. K.; Ozkaya, MT; Lavee, S; Ferguson, L
    Virgin olive oil possesses a characteristic aroma, taste and colour that distinguishes it from other vegetable oils. Consumption is currently increasing thanks to its excellent organoleptic and nutritive qualities and to growing consumer preference for minimally processed foods. Phenolic substances are widely distributed amongst the plant world and are found in large quantities in olives, mostly in the form of glycosides which are water-soluble compounds having a characteristics bitter taste. Depending on the phenol content, the intensity of the bitterness of olive oils can be higher or lower. Bitterness is a desirable characteristic of olive oil; however, a bitterness of high intensity could also present a problem for consumers. They are important factors to be considered when evaluating the quality of virgin olive oil, since they are partly responsible for its oxidative stability and sensory characteristics. Phenolic compounds, moreover, being powerful antioxidants, protect the oil to oxidation which can take place during conservation. The phenolic composition and content depends on different factors such as olive variety, climatic conditions, fruit ripeness, storage conditions of olive fruit, technological process of oil extraction and also storage conditions of olive oil. The fraction of phenolic substances varies as a result of the processing method used for the olives. In this paper, influence of extraction systems, cultivar of olives and fruit ripeness of phenolic compounds of virgin olive oil and effect on the olive oil quality and stability was discussed.