Wheat Grinding Process with Low Moisture Content: A New Approach for Wholemeal Flour Production

Waleed H. Hassoon,Beata Biernacka,Antoni Miś,Dariusz Dziki

doi:10.3390/pr9010032

Waleed H. Hassoon, Beata Biernacka + Show 2 more

Open Access

https://doi.org/10.3390/pr9010032

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Abstract

The objective of this study was to determine the grinding characteristics of wheat with a low moisture content. Two kinds of wheat—soft spelt wheat and hard Khorasan wheat—were dried at 45 °C to reduce the moisture content from 12% to 5% (wet basis). Air drying at 45 °C and storage in a climatic chamber (45 °C, 10% relative humidity) were the methods used for grain dehydration. The grinding process was carried out using a knife mill. After grinding, the particle size distribution, average particle size and grinding energy indices were determined. In addition, the dough mixing properties of wholemeal flour dough were studied using a farinograph. It was observed that decreasing the moisture content in wheat grains from 12% to 5% made the grinding process more effective. As a result, the average particle size of the ground material was decreased. This effect was found in both soft and hard wheat. Importantly, lowering the grain moisture led to about a twofold decrease in the required grinding energy. Moreover, the flour obtained from the dried grains showed higher water absorption and higher dough stability during mixing. However, the method of grain dehydration had little or no effect on the results of the grinding process or dough properties.

Highlights

Wheat is one of the most important staple food crops and is used to produce a wide variety of cereal products [1]
The highest hardness was observed for the Khorasan kernels, whereas significantly lower hardness index (HI) values were observed for the spelt kernels (HI = 24.9)
In the case of Khorasan wheat, the mass fraction of the coarse particles decreased from 41.9% to 28.87% (ADI) and 31.46% (wheat stored in the climatic chamber (CM)), whereas for spelt this fraction decreased from 30.05% to 18.25% (ADI) and 19.2% (CM)

Summary

Introduction

Wheat is one of the most important staple food crops and is used to produce a wide variety of cereal products [1]. WF is rich in nutritive compounds in comparison with refined flour, which mainly contains carbohydrates and protein [3], and is made only with whole grains (100%). It contains minerals, fiber, B vitamins and bioactive compounds having high health-promoting properties [1]. During the production of WF, mill feeds (bran and germ) are first separated from endosperm using roller mills and recombined together after the mill feeds. This method of WF production is widely commercialized in the milling industry. It is economically unjustified, as the final product often has widely different particle sizes, and all the grain components may not be included in the WF [3,8]

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