Grading Factors of Wheat Kernels Based on Their Physical Properties

Abstract

Cereal grains are biological materials and as such have certain unique characteristics greatly affected by both genetics and environment. Wheat is worldwide considered as the main cereal grain in the average human diet. The aim of this chapter is to provide an overview of the most important grading factors and kernel physical parameters that are involved in the estimation of quality specifications. The determination of the physical properties of wheat kernels gives a first approximation of the structural characteristics useful for the design and selection of equipment for handling, harvesting, aeration, drying, storing and more importantly to functionality, processing and end uses. For instance, physical quality test that directly measure those properties are needed. To get a better prediction, physical evaluation of the wheat kernels offers a first and interesting quality control for their selection as raw materials in order to optimize quality of a large diversity of products. Kernel colour, shape, size, sphericity, porosity and bulk and specific densities and damages incurred due to heat, insects, molds or sprouting are relevant tests related to wheat kernel properties and quality.

Multivariate Analysis on the Properties of Intact Cereal Kernels and Their Association with Viscoelasticity at Different Moisture Contents

“…Such properties affect kernel selection by sieve separators and the estimated extraction rate during size reduction processes. The axial dimensions of kernels are essential for calculating the kernel volume for modeling drying, aeration, heating, and cooling [10]. The results of this study showed that the axial dimensions of the three cereal types corresponded to optimal values reported in other studies, which can be used to produce specific food products.…”

“…Gómez et al [4] demonstrated that the starch structure, enzyme content (amylases), and other soluble components of the pericarp have important effects on the rheological properties of rye dough during the bread-making process. In previous studies, some mechanical and viscoelastic properties of kernels showed a significant correlation with the dough performance and quality of bakery products [10,37]. The bread-making process is very complex, and it involves mixing, sheeting, fermentation, and baking in the oven.…”

“…The shape and size of kernels are closely related to their mechanical and viscoelastic properties. The viscoelasticity of kernels can be used as a practical approach to recognize and predict the potential use and industrial performance of different cereal types [9,10]. However, the mechanical properties of conditioned wheat kernels have not been investigated sufficiently, let alone those of rye and triticale kernels, despite the critical technological implications.…”