中国农业科学 ›› 2014, Vol. 47 ›› Issue (8): 1567-1576.doi: 10.3864/j.issn.0578-1752.2014.08.013

• 贮藏·保鲜·加工 • 上一篇    下一篇

糙米粉对小麦面团流变学及饼干品质特性的影响

 汤晓智, 扈战强, 周剑敏, 方勇, 沈新春, 胡秋辉   

  1. 南京财经大学食品科学与工程学院,南京 210046
  • 收稿日期:2013-09-13 出版日期:2014-04-15 发布日期:2013-10-12
  • 作者简介:汤晓智,Tel:025-85870277;E-mail:warmtxz@njue.edu.cn
  • 基金资助:

    国家科技支撑计划项目(2012BAD34B08)

Influence of Brown Rice Flour on Wheat Dough Rheological Properties and Cookie Quality Characteristics

 TANG  Xiao-Zhi, HU  Zhan-Qiang, ZHOU  Jian-Min, FANG  Yong, SHEN  Xin-Chun, HU  Qiu-Hui   

  1. College of Food Science and Engineering, Nanjing University of Finance and Economics, Nanjing 210046
  • Received:2013-09-13 Online:2014-04-15 Published:2013-10-12

摘要: 【目的】研究糙米粉对小麦面团热机械学和动态流变学特性及对饼干品质感官特性的影响,为进一步应用糙米开发食品新产品提供依据。【方法】利用混合实验仪、动态流变仪和扫描电子显微镜分析糙米粉替代对于小麦面团热机械学、动态流变学特性和面团微观结构的影响,并结合饼干的烘焙制作分析糙米粉替代对饼干物理特性及感官品质的影响。【结果】混合实验仪结果表明糙米粉的添加造成了面团吸水率的提高;面团的形成时间、稳定时间则随着糙米粉的添加呈下降趋势,并且蛋白质弱化度不断提高。糙米粉的加入稀释了面粉中的面筋蛋白,破坏了面团的连续性,不易形成稳定的网状结构,从而导致面团形成时间和稳定时间下降,并且面团在机械力和加热的双重作用下蛋白质的弱化度不断增加。随着糙米粉替代比的升高,淀粉糊化温度降低,糊化后的峰值扭力、谷值扭力均下降,且淀粉回生的回生扭力(MSB)同样随着糙米粉替代比的增加而降低,主要由于淀粉分解程度增加而导致老化速度变慢;动态流变研究结果显示,添加糙米粉后,面团体系仍然为黏弹性体系;储能模量(G’)和损耗模量(G”)随糙米粉替代量的升高而升高,损耗角正切值tanδ则随着糙米粉的添加而呈降低的趋势,表明了混合体系中分子交联的程度有所增加,弹性比例增大;扫描电镜观察结果显示,添加10%的糙米粉的面团表面变得松散,且开始出现小的裂缝,淀粉球分布变得不均匀,可以观察到不规则形状的米淀粉颗粒,淀粉颗粒与面团表面的附着性明显降低;随着糙米粉替代比继续增加,面团表面裂纹褶皱明显增多加深,并且可以观察到大量的纤维素暴露在其表面,淀粉颗粒分布在其间。烘焙饼干的物理及感官特性研究结果显示,随着糙米粉的添加,饼干的宽度和膨胀比增加,厚度和硬度降低。饼干的硬度、口感、色泽、风味、质构及综合评分等指标均呈降低的趋势,尤其是色泽和风味降低的趋势更加明显,表明由于糠皮部分的存在,糙米糠层中高含量的纤维素及其复合物使糙米加工食品的口感依然较差,此外糠的不愉快气味及其较暗的色泽也使得糙米加工食品的色泽风味难以被接受。【结论】糙米粉的添加使面团更赋有弹性,但不利于面团的稳定性,糙米中糠层的不愉快气味及其较暗的色泽仍然是影响糙米加工食品接受度的关键因素。

关键词: 糙米粉 , 小麦面团 , 流变特性 , 饼干 , 品质特性

Abstract: 【Objective】Effects of brown rice flour on the thermomechanical and dynamic rheological properties of wheat flour dough as well as physical and sensory characteristics of the cookies were investigated. The aim of the research is to provide a basis for further utilization of brown rice in developing new food products.【Method】 Mixolab and dynamic rheometer were employed to study the effects of brown rice flour replacement on rheological properties of wheat flour dough. The dough microstructure was observed by scanning electron microscope (SEM). Cookies were prepared and tested to investigate the effects of brown rice flour replacement on cookie quality characteristics. 【Result】 With the addition of brown rice flour, the water absorption of the flour dough and the degree of protein weakening increased, while dough development time and stability time decreased. The addition of brown rice flour diluted the concentration of gluten and destroyed the continuous state of the flour dough, which resulted in being difficult to form the stable gluten network structure, and subsequently leading to higher degree of protein weakening under double effects of mechanical force and heating. The increase of replacement ratio of brown rice flour decreased the temperature of starch gelatinization, peak and break down viscosity of the mixed flour, and setback value of the starch due to the higher degree of starch hydrolysis. It was shown from dynamic rheological studies that with the addition of brown rice flour, the dough remained viscoelastic system and storage modulus and loss modulus increased, while tan δ of the dough decreased, indicating higher degree of molecular cross-linking and elastic proportion in the mixed system. From SEM, with the addition of 10% brown rice flour, the dough microstructure became loose with small cracks and starch granules distributed unevenly. Irregular shape of rice starch granules could be observed and their adhesion force to dough surface significantly decreased. With further increase of replacement ratio, more and more big cracks could be observed and fibres were exposed to the dough surface. With the addition of brown rice flour, the width and expansion ratio of the cookies increased, whereas the thickness, hardness, score of taste, color, flavor and overall acceptability all decreased, especially score of color and flavor, indicating that existence of rice bran made the processed food hard to be acceptable due to high content of fibres, and especially its unpleasant smell and dark color. 【Conclusion】 The addition of brown rice flour made the wheat flour dough more elastic, but not beneficial to the stability of the dough. The rice bran, especially its unpleasant odor and dark color, is still the key factor affecting the acceptability of processed foods.

Key words: brown rice flour , wheat flour dough , rheological properties , cookie , quality characteristics