【作者】 张桂英；

【导师】 张国权；

【作者基本信息】 西北农林科技大学 ， 粮食、油脂及植物蛋白工程， 2010， 硕士

【摘要】 为掌握陕西关中地区大田生产小麦的品质状况,改进馒头品质分析与评价技术,以2008年陕西关中大田生产的92个小麦样品为材料,在系统分析小麦的籽粒物理品质、磨粉品质、蛋白质品质、淀粉品质、面团流变学特性及馒头食用品质性状的基础上,确定了影响小麦品质的关键指标及陕西关中优质小麦生产区域,并将馒头品质的感官评价指标与质构仪、色彩色差仪测试指标相结合,明确了馒头品质评价的关键指标,构建了馒头品质评价体系。主要试验结果如下:(1)陕西关中地区大田生产小麦的容重、籽粒硬度、蛋白质含量均较高,但沉淀值较低,蛋白质质量较差,面团流变学特性表现一般。其中15%的大田生产小麦样品达到了优质小麦-强筋小麦国家标准的要求,9%达到了优质小麦-弱筋小麦国家标准的要求,其余76%为中筋小麦。(2)在陕西关中的三个地区中,渭南地区小麦的出粉率较高,面粉色度较好,籽粒蛋白质含量较低,但面筋蛋白质量较好,面团粉质参数和拉伸参数表现优良。咸阳地区小麦的千粒重、容重和籽粒色度较为均衡,出粉率相对较低,面粉灰分含量较高,蛋白质含量、沉淀值较低,湿面筋含量、面筋指数较高,粉质参数优良,面团延伸性小、弹性较强。宝鸡地区小麦的容重和籽粒硬度较低,籽粒蛋白质含量较高,面筋蛋白质量较差,粉质参数和拉伸参数表现一般。(3)评价小麦品质性状的29个指标经因子分析可压缩为7个公共因子,即蛋白质质量因子、加工品质因子、淀粉糊化特性因子、面筋数量因子、籽粒物理品质因子、淀粉热糊稳定因子、淀粉回升因子,累计贡献率超过82.14%。以面粉L*、灰分含量、籽粒蛋白含量、吸水率、弱化度、评价值、最大拉伸阻力、拉伸能量、峰值黏度(B)、起始恒温糊化阻力(C)、起始降温糊化阻力(D)、降温结束糊化阻力(E)和破损值(B-D)13个指标进行聚类分析,92个大田生产小麦样品可以分成3大类(地区),即三原县、泾阳县和武功县北部地区的大田生产小麦为一类,该区较干旱,小麦粉的粉质参数较好、拉伸参数和淀粉糊化特性优;渭南地区的临渭区和蒲城县的大田生产小麦样品为一类,该区小麦粉的粉质参数好、拉伸参数较好,淀粉糊化特性一般;从蒲城县沿省道经富平县、三原县、泾阳县、武功县、扶风县、岐山县和凤翔县的8个县(区)大田生产小麦为第三类,该区小麦种植的水肥条件较好、产量高,其加工品质好,但粉质参数、拉伸参数和淀粉糊化特性表现较差。(4)小麦子粒品质性状中的籽粒物理品质与磨粉品质对馒头表面色泽和外观性状有一定影响,其优劣直接影响馒头的外观和结构的形成,进而影响馒头的总评分。蛋白质含量和面筋强度有利于馒头表面色泽,可增加馒头的比容,改善其内部结构,明显提高馒头的总评分,优质馒头要求其面团的延展性和弹性比较适中。峰值黏度(B)、起始恒温糊化阻力(C)、起始降温糊化阻力(D)、降温结束糊化阻力(E)和50℃恒温糊化阻力(F)主要通过提高馒头的表面色泽和韧性来提高馒头的总评分。比容是评价馒头品质的关键指标之一,湿面筋含量、拉伸能量、降落数值、最大拉伸阻力、容重、破损值、籽粒硬度、吸水率对馒头比容均有影响,其影响程度依次减弱,对馒头比容直接影响效应最大的是拉伸能量,且拉伸能量与馒头比容呈显著正相关。用拉伸能量对馒头比容即馒头品质进行预测的效果较好。(5)在馒头品质评价体系中,比容与质构仪TPA测试指标硬度、胶着性、弹性、回复性、咀嚼度呈极显著正相关,L*与表面色泽呈极显著正相关,延展率与高度呈极显著负相关,质地特性(硬度*胶着性*咀嚼度)与外观性状和内部结构呈显著正相关,气味与压缩张弛性(弹性*凝聚性*回复性)呈显著正相关,比容、L*、延展率、质地特性、压缩张弛性、弹性、黏着性为馒头品质评价的关键指标。根据对7个关键指标的权重分配结果,并借鉴小麦品种品质鉴评原理与方法构建的馒头品质评价体系为,比容25分、L*为15分、质地特性10分、黏着性15分、压缩张驰性15分、弹性15分、延展率5分,总分采用100分制。以2009年的22个大田生产小麦样品为验证材料,利用GB/T17320-1998标准中的感官评分及馒头品质评价体系对馒头的分类结果基本一致。所构建的馒头品质评价体系能够比较客观地反映面粉的品质特性,其评价结果将更为可靠。更多还原

【Abstract】 In order to master wheat quality of field production in Guanzhong region of Shaanxi province, and improve techniques of quality analysis and evaluation of steamed bread, 92 wheat samples were taken as materials in Guanzhong region of Shaanxi province in 2008. On the basis of systematic analysis of grain physical quality, milling quality, protein quality, starch quality, dough rheological properties of wheat and edible quality of steamed bread, key indexes of wheat quality and production area of high quality wheat in Guanzhong region of Shaanxi province were determined, and this study was also to determine key indicators of steamed bread quality by combining sensory evaluation index, chroma meter index, and texture analyzer index. Evaluation system of steamed bread quality was constructed. Main test results were as follows:Test weight, grain hardness and protein content of wheat cultivars of field production in Guanzhong region of Shaanxi province were higher, but sedimentation value was lower, protein quality was poor, and general in rheological properties of dough. 15% wheat samples of field production reached the national standard of strong gluten wheat, 9% reached the national standard of weak gluten wheat, and other 76% were middle gluten strength wheat.In the three areas of Guanzhong region of Shaanxi province, wheat from Weinan area was higher in flour extraction, better in flour’s color and gluten protein quality, but lower in grain protein content, the performance of farinograms and extensographs of dough were excellent. In Xianyang area, 1000-grain weight, test weight and grain color of wheat were more balanced, flour extraction, sedimentation value and protein content of wheat was lower, flour ash content, wet gluten content and gluten index was higher, farinograph parameter was excellent, extension of dough was small but more flexible. In Baoji area, grain hardness and test weight of wheat were relatively low, grain protein content was higher, but gluten protein quality was poor, the performance of farinographs and extensographs of dough was general.29 indexes of wheat quality properties can be compressed into seven common factors, namely protein quality factor, quality processing factor, starch pasting properties factor, gluten quantity factor, wheat physical quality factor, starch hot paste stability factor and starch setback factor. The accumulative variance contribution was more than 82.14%. Cluster analysis was conducted according to 13 key quality properties, namely flour L*, ash content, protein content, water absorption, softening degree, valorimeter value, maximum resistance, extension area, peak viscosity, pasting viscosity at the beginning of constant phase at 93℃, pasting viscosity at the beginning of cooling phase, pasting viscosity at the end of cooling phase and break-down, and 92 wheat samples were clustered into three categories, namely wheat samples from the northern part of Sanyuan County, Jingyang county and Wugong county which were drought area can be attributed to one type had better farinograms, excellent extensograms and starch gelatinization viscosity properties; the wheat samples from Linwei county and Pucheng county can be attributed to a second type with excellent farinograms, better extensograms, and ordinary starch gelatinization viscosity properties; the third type was from Pucheng county, along the provincial highway to Fuping county, Sanyuan county, Jingyang county, Wugong county, Fufeng county, Qishan county, and Fengxiang county. This area include eight counties (districts) of Weinan, Xianyang and Baoji city. This area had better water-fertilizer conditions, high yield and good processing quality, but the performance of farinograms, extensograms and starch gelatinization viscosity properties was poor.Wheat grain physical quality and milling quality have effect on appearance traits and surface color of steamed bread, especially the appearance and formation of structure of steamed bread and finally affect the total score of steamed bread. Protein content and gluten quantity are beneficial to surface color of steamed bread, increase specific volume of steamed bread and improve internal structure, which affect the total score of steamed bread. Modest extensibility and flexibility meet requirements of high quality steamed bread. Peak viscosity, pasting viscosity at the beginning of constant, pasting viscosity at the beginning of cooling phase, pasting viscosity at the end of cooling phase and pasting viscosity at the end of constant phase at 50℃were closely related to color, elasticity and toughness of steamed bread. Specific volume is one of the most key index of steamed bread quality.Wet gluten content, extension energy, falling number, maximum resistance, test weight, break-down, hardness and water absorption influenced the specific volume of steamed bread, and the degree of the affect decreased in turn, extension area had the biggest influential effect for specific volume of steamed bread. There was a positive correlation between extension area and specific volume,the prediction effect of extension area for teamed bread quality was better.Based on evaluation system of steamed bread quality, the specific volume had highly positive correlation with hardness, gumminess, elasticity, resilience and chewiness of texture analyzer TPA testing, L* were highly positive correlation with surface color, extension rate had significant negative correlation with height, textural properties(hardness * gumminess * chewiness) were positively related to the appearance of characteristic and internal structure, odor was positively related to compressed relaxation properties (elastic* cohesive * reversibility). The specific volume, L*, extension rate, texture, compression relaxation, flexibility, adhesion were regarded as key indicators for quality evaluation of steamed bread. Based on the results of weight distribution of seven key indicators and using reference principle and method of appraisal of wheat cultivars and quality, evaluation system of steamed bread quality was that, specific volume is 25 points, L* is 15 points, textural properties is 10 points, adhesion is15 points, compression relaxation properties is 15 points, springis15 points, extension rate is 5 points, and total score is 100 points. 22 field production wheat samples in 2009 were used as verified materials, according to sensory score of SB/T10137-1993 standard and evaluation system of steamed bread quality, classification results are in agreement. Evaluation system of steamed bread quality objectively reflects the quality characteristics of wheat flour, and the evaluation results will be more reliable.更多还原