Effect of Moisture Content on the Mechanical Properties of Watermelon Seed Varieties

The effect of moisture content on the mechanical properties of agricultural material is essential during design and adjustment of machines used during harvest, cleaning, separation, handling and storage. This study determined some mechanical properties of Black and Brown colored of watermelon seed grown in Nigeria under different moisture contents range of 6.5 to 27.8% (d.b). The results for the mechanical properties obtained ranged from 15.68-29.54 N for compressive force; 1.95-3.40 mm for compressive extension; 0.13-0.33 N mm-2 for compressive strength; and 0.17-1.93 kJ for deformation energy at vertical loading position while at horizontal loading position, results obtained ranged from 14.71-38.36 N for compressive force; 1.94-4.20 mm for compressive extension; 0.16-0.32 N mm-2 for compressive strength; and 1.47-76.39 kJ for deformation energy for Black colored watermelon seed. The compressive force, compressive extension, compressive strength, deformation energy ranged from 14.18-36.49 N, 1.85-5.20 mm, 0.19 0.76 N mm-2, 26.23-189.75 kJ at vertical loading position and 16.47-41.82 N, 1.68-11.08 mm, 0.34- 0.57 N mm-2, 27.67-319.99 kJ at horizontal loading position for Brown colored watermelon seed. The correlation between the mechanical properties and moisture content was statistically significant at (p≤0.05) level. It is also economical to load Black colored in vertical loading position at 27.8% moisture content and Brown colored in vertical loading position at 27.8% moisture content to reduce energy demand when necessary to crack or compress the seed. This research has generated data that are efficiently enough to design and fabricate processing and storage structures for Black and Brown water melon seeds.