ศูนย์นวัตกรรมเทคโนโลยีหลังการเก็บเกี่ยว

Grain Physico-mechanical Properties Affect Occurrence of Stress Cracks in Maize Grains

Kim TH, Opara LU, Hampton JG, Hardacre AK, MacKay BR

Institute of Technology and Engineering, Massey University, Palmerston North bNZ Seed Technology Institute, Lincoln University, Lincoln cCrop & Food Research Institute, Palmerston North d Institute of Natural Resources, Massey University

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บทคัดย่อ

The effects of grain hardness and morphological factors (grain size and shape) on the development of stress cracking in maize grain were investigated. Hybrid and grain size/shape significantly affected stress cracking, such that removing small and rounded grains could reduce checking by up to 40 to 50% in some dent maize hybrids. The results also showed that stress cracking in maize grains developed over time during cooling after drying, and not during drying or immediately after the finish of drying. The extent and rate of development of stress cracking differed significantly among the hybrids and grain size/shape categories. Very few stress-cracked grains were found immediately after drying and some grains became single or double fissured during the first 30 to 60 minutes after drying. Single and double stress cracks progressed into multiple or checked stress cracking, and these were in the majority at the end by 72-hour after drying irrespective of hybrids and grain size/shape categories. This result also indicated significant variation in physico-mechanical properties (e.g., grain moisture content and hardness ratio) of maize grains within the same grain size/shape category.