GEOMETRICAL, THERMAL AND MECHANICAL PROPERTIES OF OLIVE FRUITS

Abstract

ABSTRACT In Mediterranean countries, olive trees play a significant economical role. Knowledge of olive fruits properties is essential for the efficient handling of the product and optimizing oil yield. The lack of such knowledge at the local level triggered this study in an attempt to report the fruit's chemical composition and some major engineering properties. Established procedures were followed in conducting the measurements and calculations on fruit samples. The study examined four major varieties of olive fruits, including Spanish, Black Spanish, improved Nabali and Nabali Baladi for their chemical composition and other properties, including geometrical, thermal and frictional properties. Thermal properties, including thermal conductivity, heat capacity and thermal diffusivity, ranged from 0.41 to 0.47 W/(m·K), 2.35 to 2.39 kJ/(kg·K) and 2.88 × 10−7to 2.779 × 10−7 m2/s, respectively. The geometrical properties of the Spanish and Black Spanish were quite similar except for roundness and sphericity. Similar results were found for improved Nabali and Nabali Baladi. The properties of weight, density and packing coefficient ranged from 2.22 to 8.60 g, 890 to 1,230 kg/m3 and 0.43 to 0.52, respectively. The fruit's static friction coefficient over mild steel, aluminum and softwood surfaces ranged from 0.20 to 0.30, 0.21 to 0.29 and 0.22 to 0.33, respectively.PRACTICAL APPLICATIONSIn Jordan and other Mediterranean countries, olive fruits are produced in large quantities every season. They are very widely used as pickled fruits or are processed in mills to extract their oil. Despite the fact that fruit properties are a necessary prerequisite for the efficient handling and processing of fruits, literature search indicated the lack of a comprehensive study of scientific merit that reports on the engineering properties of olive fruits. In addition, it is established that knowledge of the fruit properties leads to optimized handling and processing and results in knowledge‐based development of all processes and equipment that deal with the fruits. The practical merit of this study stems from the fact that it reports on the key properties of a major product (olive fruits) that has social, cultural and economical significance throughout a whole region and is expanding throughout the globe.