调质过程小麦水分变化及迁移的研究

调质的目的是改变小麦中水分的含量,提高粮食的加工品质。以三种具有代表性的国产小麦(软、中、硬)为实验材料,设置梯度温度,采用低场核磁共振技术研究不同条件下水分状态变化;用核磁共振成像技术(NMRI)研究不同条件下的水分迁移规律。结果表明:在不同调质温度条件下,各样品T_(21)、A_(21)均呈显著上升趋势;T_(22)、A_(22)呈先下降后上升趋势;T_(23)与温度为正相关性,A_(23)调质初期达到峰值之后逐渐下降。NMRI表明水分在小麦籽粒内传导有两个主要路径和一个辅助路径,一是水分通过珠心层进入胚部向茸毛端扩散,二是透过糊粉层细胞壁由外向内渗透;辅助路径为水分从茸毛端逐步向胚乳中心扩散。

Study onmoisture variation and migration during tempering

The purpose of tempering is to change the moisture content of wheat and improve the processing quality of grain. Three kinds of representative domestic wheat (soft, medium and hard) were used as experimental materials, and the temperature gradient was set, and the water state change under different conditions was studied by using low-field nuclear magnetic resonance (NMR) technology; the water migration patterns under different conditions were studied by nuclear magnetic resonance imaging (NMRI).The results showed that: T21 and A21 of the samples showed a significant upward trend under different tempering temperature; T22, A22 first decreased and then increased; T23 was positively correlated with temperature, and A23 reached the peak at the preliminary stage of tempering then decreased gradually. NMRI showed that there were two major pathways of moisture and one ancillary path in wheat kernel. One was moisture diffused through the nucellar layer into the germ line, the other was moisture infiltrated through the cell wall of the aleurone layer; the auxiliary path was moisture diffused from the fuzzy end to the endosperm center.