The comparison of the olive oils by different production techniques

In this research, 8 different samples of olive oils produced in different production systems in Çanakkale in 2008 season were collected immediately after the production from the factories, and some quality analyses were conducted to compare with international standards and by themselves. In addition, the sensorial description analysis and consumer tests were completed.When the physical properties of the 8 olive oils were analyzed, the specific absorbance at K232 of 1,602-3,140 and K272 of 0,116-0,898; refractive index of 1,4635-1,4700; viscosity of 66,60-77,35 cP; total volatiles of 0,09-0,25% values were measured. The instrumental color values of the samples were as follows: L values of 48,14-71,77; a* values of ? 4,58-2,86 and b* values of 1,165-31,115. When the measured chemical properties are examined, the free acidity value was 0,20-3,365 (as oleic acid%), peroxide value was 5,00-18,00 meqO2/kg, total phenolics content was 7,61-168,29 mg gallic acid/kg and antioxidant capacity was 0,08-2,484 mmol TE/kg.In this thesis, the sensorial properties of the 8 olive oil samples were determined by the Quantitative Descriptive Analysis (QDA), and the panel were determined olive oils appearance by `yellowness?, `greenness? and `clarity? terms; aroma properties by `olive?, `grassy?, `rancid? and `musty/muddy? terms; flavor properties by `acid?, `astringent?, `bitter?, `soap? and `metallic? terms; and mouthfeeling properties by `throatcatching? and `thickness? terms. The appearance properties of the 2. Extraction oil was very different (much lesser yellowness, much more greenness) from the other samples, while there were little differences among the others. In the aroma descriptors of `olive? and `grassy? refined samples (riviera, refined pomace and mixed pomace) were found lower than others, while in the `rancid? and `muddy/musty? characters were somewhat higher than the others. Interestingly, the negative descriptors were also higher in the Antique sample. The highest scores were also in the Antique sample in the `acid?, `bitter?, `soap? and `metallic? descriptors. While the mouthfeeling property of `throatcatching? was the lowest in refined and highest in Antique samples, in the `thickness? property only the 2. Ekstraction sample was higher than the others.The results of consumer Hedonic test have shown that the lowest value in the appearance, smell and flavor properties were seen with the 2. Ekstraction oil sample. The highest consumer buying decision were with the Riviera, Stone pressed, Virgin and Organic samples. It was interesting that the riviera sample had higher buying decision scores than the other virgin class samples. The explanation for this may be the less profound characteristics of appearance, smell and flavor of that sample. On the other hand, it was very obvious that consumers have seperated and have not preferred the 2. Ekstraction oil which has previously determined as negative in the most of the measured properties.In this research the Multidimensional Scaling (MDS) analysis has been applied to all data to see the relationship among the measured properties and the samples alltogether. In general, there was a group forming tendency among the measured physico-chemical and sensorial properties by the characters named as positive or negative property. When the distribution of all 8 samples by all characters are examined, it has observed that refined samples are one group, virgin samples (Antique sample is a little seperated) are another group and 2. Ekstraction sample was seperated from all others. Practically it can be concluded from these results that even the 2. Ekstraction sample can be produced with good practices, it is ususally a wrong practice to mix this oil with the virgin samples, since the analytical indices distray significantly. This practice is also not concominant with the laws. But further research to find reasonable consumption forms for this oil should be aimed. In addition, another important finding was that, the consumer preference of the Antique oil, which is produced in a very time taking costly system as a special product, was lower than the virgin samples. This general result was also evidended in the sensory and analytical measures.In conclusion, the most apropciate products for most of the consumers were the high quality virgin olive oils produced in the common technology and the riviera samples.Key word: Production systems, Olive oil, Quality, Sensory, Consumer, Standard.