Effects of the storage of Turkish Gemlik olives under CO 2 and N 2 on the phenolic compounds and fatty acid compositions of olive oils

Because of the limited number and size of the oil extraction opportunities, olives are generally piled and stored at ambient temperatures for weeks before processing. Under these conditions biochemical changes could result a negative affect on the olive quality. The changes in the olive result poor stability in olive oil because of the oxidation and decomposition of bioactive compounds such as phenolic substances. Indeed, it is known that polyphenols are a large family of compounds found in plant tissues, which show strong antioxidant activity. The healthy characteristic of the phenolic compounds is associated to their radical scavenging activities. In this study, Gemlik olives cultivated from Osmaniye area were stored for 25 days at 5 °C under three different conditions (20 kPa CO 2 atmosphere, 20 kPa N 2 atmosphere and air). Olive oil was extracted following of 0, 5, 15 and 25 days of olive fruits storage. Qualtiy markers (free fatty acidity, peroxide value, K 270 and K 232 ) together with the phenolic compounds and fatty acid compositions of oils were determined. The physical properties of olives (flesh/pit ratio, average weight and fruit firmness) were well-preserved under CO 2 and N 2 atmospheres. The phenolics (tyrosol, syringic acid, vanilin, p-coumaric acid, oleuropein, cinnamic acid and luteolin) and fatty acids (palmitic, palmiteloic, heptadecanoic, heptadecenoic, stearic, oleic, linoleic, linolenic, arachidic, behenic, docosadienoic and lignoceric acids) composition were generally unchanged during storage. Oleuropein, the bitter principle of olives disapperead faster in the oils obtained through storage under N 2 than other storage conditions. © 2018, Springer Science+Business Media, LLC, part of Springer Nature.OKÜBAP-2015-PT3-011?Each data point represents mean of three replicates ± SD aSmall letters indicate significance for olive storage duration within each treatment (p < 0.05) ACapital letters indicate significance at a given storage time between treatments (p < 0.05) Acknowledgements Many thanks to Osmaniye Korkut Ata University Research Council for funding this research (OKÜBAP-2015-PT3-011). Many thanks also go to Prof. Ziya Günata for proofreading the manuscript