Wheat endosperm compressive strength properties as affected by moisture.
Wheat endosperm compressive strength properties as affected by moisture.
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小麦胚乳抗压强度特性受水分的影响。
DOI：
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发表时间：
2000
期刊：
影响因子：
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通讯作者：
S. Delwiche
中科院分区：
文献类型：
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作者：
S. Delwiche
回火，在碾磨之前向小麦中加入水，常规地进行以使小麦的果皮变韧。
从而提高出粉效率。为了更好地理解回火如何影响
小麦籽粒内部结构、水分对小麦籽粒胚乳物理强度特性的影响
原位基础研究。五个软小麦和五个硬小麦样品，可从美国国家标准研究所获得，
技术的标准参考物质计划，目的是标准化小麦硬度仪器，
考察小麦胚乳的几何精确圆柱体（1 mm直径×3 mm高）在以下条件下进行处理：
五种相对湿度之一（约0至93% RH，产生3至28%的水分含量，干基），然后测试
以下抗压强度性能：最大压缩应力（S max）、弹性模量（E）、
最大应力[W（S max）]和最大应力下的应变[e（S max）]。强度特性出现较大变化
在相同的样品和湿度下，如通过高达56%的变异系数所看到的。S max的平均值，
E、W（S max）和e（S max）基于每个样品8至13个胚乳圆柱体×湿度设置，标准化为
参考含水量为13% d.b.前三个性质的归一化值与水分线性拟合
内容和统计测试，以确定样品之间的响应相似性。S max与
水分含量当合并硬度等级内的样品时，标准化S max回归的斜率
硬麦和软麦的回归方程差异极显著（P < 0.01）。一个类似的池化过程，
显示软质和硬质类之间的斜率存在中度显著性差异（P < 0.05）。对于W（S max），大多数
样品没有表现出对水分的敏感性;然而，当合并成软类和硬类时，
各组间差异有高度显著性（P < 0.01）。除最大值外，e（Smax）对水分的响应是恒定的
水分含量（24 - 28% d.b.），其中值大约是两倍大。
Tempering, the addition of water to wheat before milling, is routinely performed to toughen the pericarp of the
kernel and thus improve the efficiency of flour extraction. In an effort to better understand how tempering affects the
kernel’s internal structure, the effect of moisture on the physical strength properties of wheat kernel endosperm on an in
situ basis was studied. Five soft and five hard wheat samples, available from the U.S. National Institute of Standards and
Technology’s Standard Reference Materials Program for the purpose of standardizing wheat hardness instruments, were
examined. Geometrically precise cylinders of wheat endosperm (1 mm diameter ×3 mm height) were conditioned under
one of five relative humidities (~0 to 93% RH, producing moisture contents of 3 to 28%, dry basis), then tested for the
following compressive strength properties: maximum compressive stress (S max ), modulus of elasticity (E), work to
maximum stress [W(S max )], and strain at maximum stress [e(S max )]. Large variations in strength properties occurred
within the same sample and humidity, as seen by coefficients of variation reaching as high as 56%. Mean values of S max ,
E, W(S max ), and e(S max ), based on 8 to 13 endosperm cylinders per sample ×humidity setting, were normalized to a
reference moisture content of 13% d.b. Normalized values of the first three properties were linearly fitted to moisture
content and statistically tested to determine the similarity in response among samples. S max was most linearly related to
moisture content. When samples within a hardness class were pooled, the slopes of the normalized S max regression
equations were significantly different (P < 0.01) for hard and soft wheats. A similar pooling procedure for normalized E
revealed a moderately significant (P < 0.05) difference between slopes of soft and hard classes. For W(S max ), most
samples did not exhibit a sensitivity to moisture; however, when pooled into soft and hard classes, the difference between
these classes was highly significant (P < 0.01). The response of e(S max ) to moisture was constant except at the highest
moisture content (24 to 28% d.b.), where the values were approximately twice as large.