Drying Kinetics of Olive Leaves (Olea europaea L.) (Turkish with English Abstract)

Abstract

Recently, interest on olive leaves (Oleaeuropaea L.) has been increased because the leaves are a rich source of phenolic compounds. Although olive leaves can be used in food, medicine and drug industries, their use and research on this matter is limited. The critical process in olive leaf treatment is drying and the drying behaviors of olive leaves are not known. In this study, olive leaves were dried in a tray drier to determine the dying behaviors of olive leaves. Eleven of semi-theoretical thin layer drying curve models were used to model the drying behaviors of olive leaves and non-linear regression analysis were performed to obtain the model that gives the best fit to the experimental data. After calculating the coefficients of the models, the effect of air velocity to the coefficients of models were determined at 50 oC with non-linear regression analysis. The primary criterion for selecting the best equation to describe the drying curve equation is correlation coefficient (r). In addition to r, the reduced chi-square (χ2) was used to determine the best fit. According to regression analysis, the best model describing the thin layer drying characteristics of olive leaves at 50 oC and air velocity interval of 0.5 and 1.5 m/s was Modified Henderson and Pabis model with r = 0.99960 and χ2 = 6.81 x 10-5.

Keywords

• Olive leaves, oleuropein, drying, thin layer, mathematical modelling, non-linear regression 

Zeytin Yaprağının (Olea europaea L.)Kuruma Kinetiğinin İncelenmesi

Abstract

Zeytin yaprakları (Olea europaea L.), içeriğinde bol miktarda bulunan fenolik maddeler sayesinde son yıllarda önemi artan bir üründür. Zeytin yaprakları, gıda, ilaç, kozmetik gibi farklı sanayilerde kullanılabilen bir ürün olmasına ve ülkemizde bol bulunmasına karşın değerlendirilememekte ve konu ile ilgili araştırmalar ise sınırlı kalmaktadır. Zeytin yapraklarının işlenmesinde kritik işlem kurutmadır, ancak zeytin yapraklarının kuruma kinetiği bilinmemektedir. Bu çalışmada, zeytin yapraklarının kuruma davranışlarının deneysel olarak tanımlanması amacıyla yapraklar tepsili kurutucuda kurutulmuştur. İnce tabaka prensibine dayanan 11 ayrı yarı-teorik modelle, kurutmada elde edilen deneysel sonuçların uygunluğu doğrusal olmayan regresyon analizi uygulanarak karşılaştırılmış, modellerin katsayıları hesaplanmıştır. Daha sonra ise deneysel sonuçlarla en iyi uyum gösteren modelin katsayıları hava hızını değişken alacak şekilde doğrusal olmayan regresyon analizi uygulanarak yeniden düzenlenmiştir. Buna göre 50 oC sıcaklık ve 0,5-1,5 m/s hava hızı aralığında zeytin yaprağının kuruma davranışlarıyla, Modifiye Henderson ve Pabis modelinin r = 0,99960 ve χ2 = 6,81 x 10-5 değerlerinde iyi uyum gösterdiği tespit edilmiştir. 

Keywords

• Zeytin yaprağı, oleuropein, kurutma, ince tabaka, matematiksel modelleme, doğrusal olmayan regresyon

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