Author: Herr Dr. Amoneit
Last saved by: Saritas, Sevim

Influence of Harvest on Quality and Oxidative Stability of Virgin olive Oils
Turkan Mutlu Keceli, Buket Erdinc, Berra Nil Mercankaya, Merve Değirmen, 
Muge Akmanlar, Onur Ozdemir and Sebnem Guler
The University of Cukurova, Faculty of Agriculture., 
Department of Food Engineering 01330 Saricam-Adana, Turkey

Olives and olive oil containing minor components are Mediterranean foods and they are very important in diet. Harvest time plays a key role in the quality and oxidative stability of olive oils. Olive oils were collected from different olive oil mills in Adana, Turkey in september, october and november at 2013. Some quality criteria (acidity, peroxide value, specific absorbance at 232 and 270nm) of virgin olive oils as well as colour (L,a,b), total chlorophyll, carotenoid phenolic and tocopherol content and radical scavenging activity by DPPH were determined. The oxidative and thermal stability were also tested by using Schal-oven test for olive oils. The quality criteria of olive oils were in the limit established by Turkish Food Codex, Regulations for Olive and Olive Pomace oil (Communication No: 2010/35) for virgin olive oils. Oxidative stability was significantly reduced depending on harvest times (p≤0.05). It was found that maturation decreased the chlorophyl, carotenoid, L, a, b and tocopherol contens of virgin olive oils (p<0.05). The results showed that as the fruit matured, the oil became less stable due to decreasing total polyphenol content, increasing polyunsaturated (mainly linoleic acid), and decreasing chlorophyll, carotenoid contents and antioxidant activity. There was a strong interaction between total polyphenol content and DPPH radical scavenging activity olive oils. It was concluded that harvest time has significant effect on chemical properties and oxidative stability of virgin olive oils.

Acknowledgement: This research has been financed by the project ZF2013YL45 (2013-2014) from the University of Cukurova (Adana,Turkey)