INVESTIGATING PHYSICAL PROPERTIES OF KERNEL AND BULK OF LEMON AND THE EFFECT OF MOISTURE CONTENT ON THEM

Abstract

Lemon is one of the most important citrus fruit and is consumed as fresh and dry. In this study the effect of fruit moisture content on the size, sphericity, geometric mean diameters and kernel density were studied. The bulk density and porosity were also evaluated in three different arrangements. Airflow resistance is a fundamental parameter for designing an efficient drying and aeration systems for lemon fruit bed. Using a laboratory test rig, two sets of experiments were carried out: thick and thin layers. In the thick layer experiments 4 bed depths, 11 air flow rates and 4 air temperatures were adopted as independent variables. In the thin layer the effect of filling arrangements in three patterns: A, B and random, at 5 moisture contents and 11 flow rates on pressure drop were envisaged. Results showed that all the physical parameters listed decreased by reducing moisture content. Results indicated that resistance to airflow through a column of lemon fruit increased with increasing bed depth and airflow rate. In the latter experiment pressure drop decreased with a decrease in moisture content. Airflow rate was the most significant factor affecting the pressure drop of lemon fruit in the both experiment. Also the filling arrangement B has a higher affect on pressure drop comparing with other arrangements. Three applicable models (Shedd, Hukill & Ives, and Ergun) were used to evaluate the pressure drop data. The Ergun model, with higher values for coefficient of determination and lower values for root mean square error, is the best model for predicting pressure drop across lemon fruit bed for the conditions studied.