Effect of measurement method and moisture content on wheat kernel density measurement
Effect of measurement method and moisture content on wheat kernel density measurement
复制标题
测量方法和水分含量对小麦籽粒密度测量的影响
DOI：
10.1205/09603080051065278
复制
发表时间：
2000
影响因子：
4.6
通讯作者：
G. Campbell
中科院分区：
文献类型：
--
作者：
C. Fang;G. Campbell
小麦籽粒破碎是制粉过程中的一个关键因素，受籽粒密度的影响。不进行常规的籽粒密度测量，这取决于所使用的测量技术和谷物的水分含量。本研究比较了现有的基于气体置换和液体置换(使用水、水-乙醇混合物和二甲苯)的湿法和干法测定不同大小和水分含量的Hereward(硬)和Consort(软)小麦籽粒的密度。用气体比重瓶测量小麦籽粒样品的平均密度，用双杯系统称空气中和浸泡在液体中的籽粒来测量单个籽粒的密度。硬质小麦品种Hereward的籽粒平均密度略高于软质品种康索特，分布范围较窄。籽粒密度与籽粒大小无关，而水分含量的增加会降低所测得的籽粒密度。气瓶干燥技术的籽粒密度最高，其次是二甲苯浸泡，水浸的密度最低，分别比干燥技术低6.2%和9.9%。这归因于表面张力的影响，有效地提高了湿法测得的籽粒体积。对不同表面张力的水-乙醇混合物的进一步研究支持这一点。目前谷物品质检测的趋势是测量单粒理化参数的分布。湿法可以测量单粒密度的分布，但由于表面张力的原因，测量精度较差；需要一种干法单粒密度法。
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.