Investigation of physicochemical attributes of olive pastes dried with different drying methods

In this study, olive pastes were dried using different drying techniques and the effects of the techniques used on the dried olive pastes were investigated. The drying process was carried out in 3 different ways, namely, conventional drying (in the oven), infrared drying and microwave drying. In this research, Sarı Ulak olive variety obtained from Mersin province in Turkey was used. The pulped olives were dried using; oven at 105°C, two different infrared lamps at 150W and 250W power in infrared drying, and in a microwave oven at 140W, 364W and 511W power. Moisture loss (%), water activity, pH, free acidity, total phenolic content and color analyzes were performed in the dried olive pastes. Analysis of variance of the results obtained from the analysis was performed. The average moisture loss and water activity values of the fresh olive fruit used in our research were found to be 47.31% and 0.97, respectively. In the dried olive pastes, the lowest water activity value was found to be 0.15 at 105°C in the oven and the lowest moisture loss was found to be 13.57% at 364W in the microwave drying at the shortest time. The pH values of the samples varied between 5.16-6.29 and the total acidity values between 1.30-2.78. The average L*, a* and b* values of the olive pastes dried with infrared were found to be 29.16, 6.2 and 9.77, respectively, and the average L*, a* and b* values of the olive pastes dried with the microwave were found to be 35.29, 7.25 and 18.54, respectively. The drying method which is the most similar to the color of fresh olive paste was found microwave drying with a ΔE* value of 5.14 in 1 minute at 364W power. The total amount of phenolic content was found to be 6.02-13.65 mg GAE (gallic acid equivalent)/g dry matter. At the end of the study, it was observed that the olive pastes dried using microwave and infrared energies dried much faster and more effectively than the samples dried using the traditional method, and it was revealed that these two innovative technologies can be used as an alternative to traditional drying methods.