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Effects of the storage of Turkish Gemlik olives under CO2 and N2 on the phenolic compounds and fatty acid compositions of olive oils

Bozdogan, Adnan, Eker, Tulin, Konuskan, Dilsad, Oz, Ayse Tulin, Kafkas, Ebru
Journal of food measurement & characterization 2019 v.13 no.1 pp. 187-195
acidity, air, ambient temperature, antioxidant activity, bioactive compounds, carbon dioxide, cinnamic acid, fruit quality, fruits, linoleic acid, linolenic acid, luteolin, nitrogen, oleic acid, oleuropein, olive oil, olives, oxidation, p-coumaric acid, palmitic acid, peroxide value, plant tissues, polyphenols, stearic acid, storage temperature, syringic acid
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 CO₂ atmosphere, 20 kPa N₂ 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, K₂₇₀ and K₂₃₂) 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 CO₂ and N₂ 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 N₂ than other storage conditions.