Effect of measurement method and moisture content on wheat kernel density measurement

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

Wheat kernel breakage is a critical factor in the flour milling process, and is affected by kernel density. Kernel density measurement is not routinely performed, and depends on the measurement technique used and the moisture content of the grains. This study compared currently available wet and dry methods based on gas displacement and liquid displacement (using water, water-ethanol mixtures and xylene) to determine the density of Hereward (hard) and Consort (soft) wheat kernels of different sizes and moisture contents. A gas pycnometer was used to measure the average density of a sample of wheat kernels, while a double cup system was used to measure individual kernel density by weighing kernels in air and immersed in liquid. The hard wheat variety, Hereward, had kernels of slightly higher average density, with a narrower distribution, than the soft variety, Consort. Kernel density was independent of kernel size, while increasing moisture content decreased the measured kernel density. The dry technique using the gas pycnometer gave the highest kernel densities, followed by xylene immersion, with water immersion giving the lowest density values, lower than the dry technique by 6.2% for Hereward and 9.9% for Consort. This was attributed to the effect of surface tension effectively increasing the kernel volume measured by the wet method. Further investigations with water-ethanol mixtures of varying surface tension supported this. The current trend in cereal quality testing is to measure distributions of single kernel physico-chemical parameters. The wet method allowed the measurement of the distribution of single kernel densities, but with poor accuracy due to surface tension; what is needed is a dry single kernel density method.

Original languageEnglish
Pages (from-to)179-186
Number of pages8
JournalFood and Bioproducts Processing
Volume78
Issue number4
DOIs
Publication statusPublished - Dec 2000
Externally publishedYes

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Triticum
Surface Tension
Moisture
Surface tension
water content
Xylenes
wheat
Water
Gases
Immersion
Xylene
seeds
Ethanol
Liquids
Flour
Weighing
methodology
surface tension
pycnometers
Air

Cite this

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title = "Effect of measurement method and moisture content on wheat kernel density measurement",
abstract = "Wheat kernel breakage is a critical factor in the flour milling process, and is affected by kernel density. Kernel density measurement is not routinely performed, and depends on the measurement technique used and the moisture content of the grains. This study compared currently available wet and dry methods based on gas displacement and liquid displacement (using water, water-ethanol mixtures and xylene) to determine the density of Hereward (hard) and Consort (soft) wheat kernels of different sizes and moisture contents. A gas pycnometer was used to measure the average density of a sample of wheat kernels, while a double cup system was used to measure individual kernel density by weighing kernels in air and immersed in liquid. The hard wheat variety, Hereward, had kernels of slightly higher average density, with a narrower distribution, than the soft variety, Consort. Kernel density was independent of kernel size, while increasing moisture content decreased the measured kernel density. The dry technique using the gas pycnometer gave the highest kernel densities, followed by xylene immersion, with water immersion giving the lowest density values, lower than the dry technique by 6.2{\%} for Hereward and 9.9{\%} for Consort. This was attributed to the effect of surface tension effectively increasing the kernel volume measured by the wet method. Further investigations with water-ethanol mixtures of varying surface tension supported this. The current trend in cereal quality testing is to measure distributions of single kernel physico-chemical parameters. The wet method allowed the measurement of the distribution of single kernel densities, but with poor accuracy due to surface tension; what is needed is a dry single kernel density method.",
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Effect of measurement method and moisture content on wheat kernel density measurement. / Fang, C.; Campbell, G. M.

In: Food and Bioproducts Processing, Vol. 78, No. 4, 12.2000, p. 179-186.

Research output: Contribution to journalArticle

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