Determination of wheat grain hardness by different kernel measurement techniques

Wednesday, December 31, 2014

Authors: Balázs, P. Szabó; Antal, Véha; Ernő, Gyimes


1. Summary


The grain hardness is one of the most important parameter of wheat. On morphological level it depends on the adhesion of the protein matrix and starch granules. The correlation between the endosperm structure, and the resultant milled grain has long been investigated. In the present experiments the grain hardness of winter wheat varieties were examined with Lloyd 1000 R Testing Machine, where an innovative, quasi-static procedure was developed. The wheat grain was examined in two positions (vertical and horizontal). The Young’s modulus, the break work and the maximum breaking force were determined. The results were compared with other well-known method (Perten SKCS 4100 device).







The method of pair correlation was applied for comparison study among the results. In case of our sample set (water content: 13,52 %), there were strong correlation among the Hardness Index and the Young’s modulus, the break work and between the maximum breaking force at vertical position. At horizontal position of the grains, the Hardness Index had robust correlation with the deformation modulus at compression, and adequate correlation with the breaking force. In the milling and baking industry the harder wheat grains expected to have higher quality. Our experiments can be helpful to distinguish the softer and harder grains.


2. Introduction

In the recent decades the classification based on the internal structure of wheat grain (hard and soft type of wheat grain) increased significantly. The endosperm (core part of the grain) structure is strongly related with the key properties of the final product. The inner part of the grain consists the major portion of the seed weight and volume, and therefore it must be known. It contains two parts, closer to the seed hull is the aleurone layer, and inside the inner, starchy endosperm can be found. The aleurone layer is one cell line width. The starchy endosperm forms the main weight. It is composed of parenchymal cells, and the insides chemically composed by starch mainly, and amorphous proteins are inserted in this structure.


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