Damage resistance and compressive properties of bulk maize kernels at varying pressing factors: Experiments and modeling

The physical and mechanical properties of two maize cultivars, ZD 958 and SR 999, were determined. Compression testing of bulk corn kernels was performed using a universal compression testing machine and a transparent device with a plunger. The purpose of the research was to describe damage resistance and compression properties of bulk maize kernels by measuring the broken rate, deformation, deformation energy, volume energy, and hardness for different varying pressing factors. Moisture content levels of 12, 14, 17, 21, 25, and 31% were assayed for two corn varieties. The tested compression forces were 1,000, 1,500, 2,000, 2,500, 3,000, and 3,500 N. Three pressing vessels, 60, 80, and 100 mm in diameter, were used. The results showed that moisture content, pressing force, and vessel diameters created a significant effect on the values of broken rate, deformation, deformation energy, volume energy, and hardness (p < .01). The broken rate, deformation, and deformation energy increased with increases in moisture content and pressing force. The hardness increased with pressing force and vessel diameter, whereas decreased with the increase of moisture content. Linear regression models were described for bulk maize kernels deformation energy, volume energy, and hardness depending on moisture content, force, and vessel diameter. Practical applications Maize is one of the most versatile cereal crops of the word but has a wide application in food industries, pharmaceutical industry, and forage industries. The determination of the damage resistance and compressive properties such as deformation energy, volume energy, and hardness will help researchers and industrial process designers to design the process handling equipment, postharvest machinery, storage structures, processing equipment, and so forth, in the processing and manufacturing industries.