Effect of Moisture Content Variation on some Engineering Properties of Almond (Terminalia catappa) Seed.

Abstract

The physical and mechanical properties of Almond seed at different moisture content levels of 6.78%, 12.39%, 17.11% and 21.97% were investigated in this study. The physical and mechanical properties determined using standard procedures were length, width, thickness, arithmetic and geometric diameter, surface area, sphericity, specific gravity, bulk density, angle of repose and coefficient of static friction (on wood, glass and steel surfaces); rupture force, compressive strength and tensile strength were also determined on the seeds. A total of one Hundred and twenty seeds were used for the study. This comprises of thirty seeds (randomly taken) per moisture content level. These thirty seeds were then replicated into three groups of ten Seeds for the experiment (three groups of ten seeds for each of the moisture content level).The length, width and thickness obtained for the samples of the almond seeds were in the range of 25.42-28.63mm, 23.69-26.63mm, and 7.51-9.18mm respectively. The calculated values of the geometric mean diameter and sphericity ranged from 16.48-19.07mm and 64.66- 66.63% respectively. The results of the surface area varied from 853.6-1143.04mm2. A high variation in the surface area of the seeds was observed with respect to the different moisture content levels. The mechanical properties showed that the fracture force and compressive strength decreased from 2689N to 2499N, 410N/mm2 to 398 N/mm2 respectively with an increase in moisture content (6.78%-21.9%). The tensile strength obtained for moisture levels of 6.78%, 12.39%, 16.11% and 21.9% were 3.20Mpa, 3.90Mpa, 4.20Mpa and 4.60Mpa respectively. From the study, it was observed that the physical properties of the seed determined as function of moisture content varied significantly with increase in moisture content as the average length, width, thickness, surface area of the seed, specific gravity and coefficient of static friction (on all three surfaces) increased; while the sphericity and weight were minimally affected. However, true and bulk density decreased as moisture content of the seed was increased. The tensile strength of Terminalia catappa increased with increase in moisture content while the fracture force and compressive strength reduced with increase in moisture content. These parameters are important in designing equipments and systems for harvesting, handling, storage and processing operations of the seed.