Kim Y-R, Cornillon P, Campanella O H, Stroshine R L, Lee S, Shim J-Y
Center for Agricultural Biomaterials and Department of Biosystems & Biomaterials Science and Engineering, Seoul National University, Seoul, 151-742, Korea.
J Food Sci. 2008 Jan;73(1):E1-8. doi: 10.1111/j.1750-3841.2007.00599.x.
The effects of mixing and resting on the physicochemical properties of doughs prepared with strong and weak hard wheat flours were investigated, specifically concerning aspects related to their rheological behavior and molecular mobility. Small deformation dynamic tests showed that, during the initial resting period, the complex modulus G* decreased and phase angle decreased for undermixed dough, whereas overmixed dough showed opposite trends. G* values for optimally mixed dough did not vary during the resting period investigated. This was more obvious for the strong dough. Large deformation tests more clearly showed differences among optimal, under-, and overmixed dough, and also between doughs prepared with strong and weak flour. Optimally mixed dough exhibited the highest peak stress and strain for both samples. In addition, the peak stress of dough prepared with the strong flour was higher than that of dough prepared with weak flour. Inconsistent results between small and large deformation tests implied that small and large deformation tests reflected different structural aspects of dough. NMR measurements were performed to estimate the relaxation properties of the sample upon resting. Decreased water mobility during resting, indicated by decreasing T(1) relaxation time, was possibly attributed to increasing molecular interactions caused by continued hydration. Evidence of additional molecular interactions created by mixing was also observed.
研究了搅拌和醒发对用强筋和弱筋硬质小麦粉制备的面团物理化学性质的影响，具体涉及与它们的流变行为和分子流动性相关的方面。小变形动态试验表明，在初始醒发期，搅拌不足的面团复数模量G降低，相角减小，而搅拌过度的面团则呈现相反趋势。在所研究的醒发期内，搅拌适度的面团G值没有变化。对于强筋面团，这种情况更为明显。大变形试验更清楚地显示了搅拌适度、不足和过度的面团之间的差异，以及用强筋和弱筋面粉制备的面团之间的差异。对于两个样品，搅拌适度的面团都表现出最高的峰值应力和应变。此外，用强筋面粉制备的面团的峰值应力高于用弱筋面粉制备的面团。小变形和大变形试验结果不一致，这表明小变形和大变形试验反映了面团不同的结构方面。进行了核磁共振测量以估计样品醒发时的弛豫特性。醒发期间水流动性降低，表现为T(1)弛豫时间缩短，这可能归因于持续水合作用导致分子间相互作用增加。还观察到了搅拌产生额外分子间相互作用的证据。
