2010年河南省仓储小麦品质状况研究

通过对河南省仓库存储的2010年收获的27份小麦样品进行检测,分析其籽粒品质及面团流变学特性.结果表明,2010年仓储小麦中,100％的小麦样品容重达到三等及以上,81.48％的小麦样品籽粒粗蛋白质质量分数在14.0％以上,22.22％的小麦样品湿面筋质量分数在32.0％以上,44.44％的小麦样品稳定时间在7.0 min以上,59.26％小麦样品的降落数值在300 s以上,达到《优质小麦强筋小麦》(GB/T 17892-1999)品质标准的规定.     

2012年河南省仓储小麦品质状况研究

通过对河南省仓储的2012年新收获的27份小麦样品进行检测,分析了其籽粒品质及面团流变学特性。结果表明,2012年河南省仓储小麦体积质量平均为（764.04±17.47）g/L,蛋白质质量分数平均为(15.53±0.98）%,湿面筋质量分数平均为(34.79±3.20)%,沉淀指数平均为(48.67±6.77) ml,降落数值平均为(359.89±25.09) s,面团稳定时间平均为(14.93±11.26) min;其中,92.59%的小麦样品籽粒蛋白质质量分数在14.0%以上,77.78%小麦样品湿面筋质量分数在32.0%以上,74.07%小麦样品的面团稳定时间在7.0 min以上,100%的小麦样品降落数值在300 s以上,达到《优质小麦 强筋小麦》（GB/T 17892—1999）品质标准。     

2011年河南省大田小麦品质状况研究

通过对2011年河南省三个主要种植区域收获的81份小麦样品进行检测,分析其籽粒品质性状及面团流变学特性。结果表明,小麦体积质量(容重)平均值为(781.58±21.13)g/L,籽粒蛋白质质量分数平均值为(14.27±0.91)%,湿面筋质量分数平均值为(30.78±2.77)%,面筋指数平均值为(79.99±16.41)%,降落数值平均值为(329.86±37.06)s,面团稳定时间平均值为(9.63±8.55)min,拉伸面积平均值为(81.88±33.26)cm2;其中,59.26%的小麦样品籽粒蛋白质质量分数在14.0%以上,32.10%小麦样品湿面筋质量分数在32.0%以上,41.98%小麦样品的面团稳定时间在7.0min以上,79.01%的小麦样品降落数值在300s以上,达到《优质小麦强筋小麦》(GB/T 17892—1999)品质标准的规定。     

2010年河南省大田小麦品质状况研究

通过对2010年收获的81份小麦样品进行检测,结果表明,小麦容重平均为（793.6±17.21）g/L,籽粒蛋白质平均含量为（15.06±0.83）%,湿面筋含量为（31.78±2.33）%,面筋指数为（255.4±105.26）%,降落数值为（255.4±105.26）s,面团稳定时间为（6.52±5.82）min,拉伸面积为（74.3±32.56）cm2。其中,91.35%的小麦样品籽粒蛋白质含量在14.0%以上,50.62%小麦样品湿面筋含量在32.0%以上,20.99%小麦样品的面团稳定时间在7.0 min以上,44.44%的小麦样品降落数值在300 s以上,达到优质小麦-强筋小麦品质标准（GB/T 17892—1999）的规定。     

2013年河南省大田小麦品质状况研究

通过对2013年河南省三个主要种植区域收获的81份小麦样品进行检测,结果表明,小麦容重平均为(779.23±15.67)g/L,籽粒蛋白质平均含量为(15.80±1.13)%,湿面筋平均含量为(34.11±4.00)%,面筋指数平均为(68.83±18.42)%,降落数值平均为(246.72±75.94)s,面团稳定时间平均为(5.94±3.26)min,拉伸面积平均为(72.07±24.71)cm2;其中,97.53%的小麦样品籽粒蛋白质含量在14.0%以上,80.25%小麦样品湿面筋含量在32.0%以上,23.46%小麦样品的面团稳定时间在7.0min以上,92.59%的小麦样品降落数值在300s以上,达到GB/T17892-1999《优质小麦强筋小麦》品质的规定。     

2009年冀中小麦品质状况分析

小麦是我国的第二大粮食作物,河北省是我国小麦主产省和重要商品粮基地,小麦品质状况对全国商品小麦品质的影响至关重要。在河北省中部石家庄、衡水、沧州3个地区抽取81个小麦品种样品进行品质检测分析。结果表明:沧州地区小麦样品千粒重、容重和籽粒硬度显著低于衡水地区和石家庄地区;衡水地区小麦样品的出粉率和小麦粉色泽b*值显著高于沧州和石家庄地区;石家庄地区小麦样品的籽粒蛋白质含量、籽粒沉降值、湿面筋含量、面筋指数、面团的形成时间、稳定时间、粉质质量指数、拉伸长度、拉伸阻力、最大拉伸阻力、拉伸能量和拉伸比例显著高于衡水地区和沧州地区;有82.72%的小麦样品容重达到1级小麦标准1,9.75%的小麦样品的籽粒蛋白质含量在14.0%以上;96.30%的降落数值在300 s以上;16.05%的小麦样品的面团稳定时间在7 min以上。     

2008年河南省大田小麦品质状况分析

对河南省2008年收获的81份小麦样品进行检测,结果表明,小麦体积质量平均为(789.6±14.34)g/L,籽粒蛋白质平均含量为(14.18±0.82)%,湿面筋含量为(30.05±2.23)%,面筋指数为(69.51±26.27)%,降落数值为(352.8±10.77)B,面团稳定时间为(7.19±7.40)min,拉伸面积为(69.7±31.18)cm2.其中,58.02%的小麦样品籽粒蛋白质含量在14.0%以上,18.52%小麦样品湿面筋含量在32.0%以上,34.57%小麦样品的面团稳定时间在7.0 min以上,91.36%的小麦样品降落数值在300 s以上.达到GB/T 17892-1999的规定.     

发芽小麦对面粉品质特性及卫生安全研究

针对小麦在收获季节连遇降雨造成籽粒穗发芽现状,研究分析发芽小麦对原料籽粒品质特征容重、硬度指数、生芽率、降落数值等的影响,以及对制成面粉后其特征品质如灰分、粗蛋白、湿面筋、降落数值、白度等所产生的影响。本研究选择发芽小麦按照不同比例混入正常小麦中进行实验研究,探究发芽小麦对改良小麦特性品质、加工品质和食用品质的影响和变化规律,并进行了馒头、面条的蒸煮试验分析及食品质量安全检测分析。结果表明:混入不同比例发芽小麦均对小麦品质、加工品质、食用品质以及面团的流变学特性有一定的影响,其中降落数值对发芽小麦的反映比较灵敏;真菌毒素检测表明随着发芽小麦含量的增加,黄曲霉毒素增多,发芽小麦含量与黄曲霉毒素成正相关。     

2009年冀中商品小麦品质分析

在河北省中部石家庄、衡水、沧州3个地区,抽取27个粮库商品小麦样品进行品质检测分析。结果表明:在抽取27个样品中,有88.89%的小麦样品的容重达到1级小麦的要求;22.22%小麦样品的籽粒蛋白质含量在14.0%以上;15.63%的小麦样品湿面筋含量达到二级优质小麦品质标准的要求;88.89%的降落数值达到一等优质小麦品质标准的要求;3.70%的小麦样品的面团稳定时间达到二等强筋小麦品质要求;有3.70%小麦样品的面团拉伸阻力在200～300 BU之间,40.74%的在100～200 BU之间。     

2010年度陕西小麦产区品质特性分析

陕西小麦,以白麦为主,籽粒大、硬度指数高,湿面筋含量比国内其他主产省份高2%之上。对300个样品种主栽、搭配、推广和其他76个品种品质特性进行测报。数据显示：主栽品种大体稳定,品质特性指标面团稳定时间大于3 min的样品占57.6%,筋力适中。关中东部小麦有较高的湿面筋含量和面团稳定时间;中部小麦各指标表现一般;西部小麦有较高硬度指数和粗蛋白含量,小麦生芽率含量较高,表现在降落数值指标较低;渭北旱原小麦降落数值较高,而筋力较弱,表现在面团稳定时间较短,拉伸面积较小。种植区域需适当改变耕作方式,才能提高使用价值。     

A finer screening of wheat cultivars based on comparison of the baking potential of whole‐grain flour and white flour

Between 2007 and 2009, 160 wheat samples were harvested at four growing locations in Quebec (Eastern Canada) and evaluated individually for their performance in whole‐grain bread (all grain fractions) and white bread prepared with a long‐fermentation process (3 h). Combination of results from both baking tests allowed the most complete evaluation of the gas retention capacity of wheat samples. Compared to cultivar and crop year, growing location had a minor effect on the overall bread making potential of wheat samples. In whole‐grain bread, the four winter wheat lines had a poorer performance than the twenty‐one spring wheat cultivars. Little correlation was seen between dough mixing stability and gas retention properties. Determination of strong gluten content (dry gluten × gluten index) might be a useful screening tool for early‐generation wheat cultivars.     

Comparative studies on physicochemical and baking properties of newly harvested and stored indian varieties of wheat

Comparative studies on the progressive changes in distribution pattern of proteins, and in rheological and baking properties, were carried out with seven newly harvested and stored wheat varieties. Freshly harvested wheat contained a larger amount of low molecular weight gliadins, which were aggregated during storage in air. This resulted in improvement of the rheological and baking properties of stored grains. Thus, gluten content in wheat or, more precisely, the interchange reactions between thiol and disulphide during storage, governed the dough rheology. The same effects could be achieved by addition of an oxidising agent such as KBrO₃. Radiation treatment (up to 200 krad) also improved the baking quality of newly harvested wheat by modifying some of its rheological properties. A significant correlation between SS/SH ratio and loaf volume was observed. Lower loaf volume in newly harvested wheat was associated with its low SS/SH ratio, high maximum gelatinisation viscosity and low gas retention capacity.     

Dough characteristics of wheat flour milled from wheat grains stored in spike form

This study compares the effects of storage form (grain and spike) of wheat as well as grain moisture content (12%, 14% and 16%), storage time (0, 3, 6 and 9 months) and temperature (10, 20 and 30 °C) on rheological (farinograph and extensograph) characteristics of dough obtained from stored wheat. While water absorption, stability and degree of softening of wheat stored in spike form were 61.2%, 15.8 min and 25.9 Brabender unit (BU), these values of wheat stored in grain form were 60.8%, 14.1 and 29.1 BU, respectively. Resistance to extension and dough energy of wheat stored in grain form were significantly higher than those of wheat stored in spike form, while extensibility was significantly lower. Storage in spike form had a positive effect on all farinograph and extensograph characteristics of wheat stored under nonoptimal storage conditions such as high grain moisture content, high temperature and long storage time.     

Natural levels of ethyl formate in stored grains determined using an improved method of analysis

Ethyl formate was readily determined with a gas chromatograph (GC) equipped with a flame ionisation detector. Natural levels of ethyl formate in Australian wheat, barley, oats, and canola were analysed by GC, after extraction with ammonium nitrate solution. Background levels of ethyl formate were present in newly harvested and stored grain. The levels of ethyl formate (0.1-0.6 mg kg⁻¹) in grains varied with commodity, temperature, moisture and period of storage. The values ranged from 0.1 to 0.2 mg kg⁻¹ for newly harvested wheat, barley and oats, and 0.3-0.4 mg kg⁻¹ for newly harvested canola. Ethyl formate was present in grains at harvest, increased during the first 7 months of storage, and then began to decline, particularly at grain temperatures higher than 25°C and moisture contents higher than 12.5% (for wheat, barley and oats) and 6.5% (for canola). The natural levels of ethyl formate should be considered when establishing maximum residue limits.     

新收获小麦后熟过程中蛋白质和氨基酸含量的变化

分析了储存在4℃和室温条件下新收获的软麦和硬麦在后熟过程中的生理生化变化。新收获小麦在20℃的发芽率超过80%,在收获后3~4个月中呼吸有2次高峰,尤其第1个呼吸峰非常明显,室温条件较4℃提高第1个呼吸峰值。当呼吸速率趋于不变时,软麦硬度增大在第4个月,硬麦在第5个月。水溶蛋白、盐溶蛋白及谷蛋白各有2次合成高峰。硬麦醇溶蛋白在第60天有一个积累高峰,软麦至少有2个积累高峰,分别在第30天和60天。谷蛋白合成最高峰在第90天,与水溶蛋白类似,而醇溶蛋白合成最高峰在第60天,与盐溶蛋白类似。随着醇溶蛋白和游离巯基含量减少,谷蛋白迅速积累。常温条件下谷蛋白的氧化聚合较低温条件下迅速,积累量大。软麦谷蛋白氧化聚合过程较硬麦早。谷蛋白积累之前,绝大部分氨基酸急剧积累,在室温条件较4℃下积累明显。半胱氨酸含量在90~120天时增加到最大,之后迅速减少。     

臭氧处理对新收获小麦品质的影响

为了探讨臭氧处理应用于加速新收获小麦后熟的可行性,在室温、臭氧处理质量浓度为5mg/L、处理时间0.5~2.0h条件下分别处理新收获小麦,研究臭氧处理对新收获小麦基本成分、破损淀粉含量、湿面筋含量、面团流变学特性的影响。结果表明,与未处理组相比,臭氧处理对新收获小麦的粗蛋白含量无显著影响(P0.05),但对粗淀粉含量、破损淀粉含量、湿面筋含量、面团流变学特性有显著性影响(P0.05)。     

Utilization of a Maltotetraose‐Producing Amylase as a Whole Wheat Bread Improver: Dough Rheology and Baking Performance

A maltotetraose‐producing enzyme (G4‐amylase) was utilized to improve the baking performance of whole‐grain wheat flour. Whole‐grain bread dough prepared with G4‐amylase showed reduced water absorption and increased development time, while the dough stability was not affected. Also, the G4‐amylase‐treated samples exhibited lower Mixolab torque values than the control upon heating and cooling. Rheological measurements showed the decreased ratio of R_max/E and increased tan δ, clearly demonstrating that the viscous characteristics of whole‐grain bread dough became dominant with increasing levels of G4‐amylase. The use of G4‐amylase produced whole‐grain wheat breads with a variety of maltooligosaccharides, primarily maltotetraose that positively contributed to the bread volume (1.2‐fold higher than the control). Moreover, G4‐amylase delayed the crumb firming of whole‐grain wheat bread during a 7‐d storage period, showing that it can function as an antiretrogradation agent to enhance the quality attributes of whole‐grain wheat bread.     

The effects of soy on freezable bread dough: a magnetic resonance study

Hygroscopic soy ingredients were hypothesised to slow the rate of water migration in unleavened bread dough during frozen storage. Thawed soy (18% dry weight) and wheat dough samples were assessed using non-destructive nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) for up to 8 wks frozen storage time. MRI suggested a spatially homogeneous, net increase in proton mobility with frozen storage and, with solution state proton NMR, distinct "free" and "bound" states were discerned. T(2) relaxation times of the majority proton population suggested increased mobility with frozen storage time, and statistical difference from the fresh sample was seen later for the soy samples than the wheat samples. As seen by (13)C-solid state NMR, the crystallinity of the starch was not affected by either soy addition or frozen storage. In conclusion, addition of soy to bakery products led to slightly enhanced preservation of "fresh" characteristics of the dough during frozen storage.     

Effects of freezing and frozen storage conditions on the rheological properties of different formulations of non-yeasted wheat and gluten-free bread dough

Empirical and fundamental rheological measurements were made on fresh and frozen dough to study the effects of freezing and frozen storage conditions. Frozen dough was stored at two different temperatures, −18 °C and −30 °C, and for 1, 7 and 28 days. Four dough formulations were tested: a standard wheat dough, a fibre-enriched wheat dough, a standard gluten-free dough and a gluten-free dough containing amaranth flour. No yeast was used in any formulation. The wheat dough is more affected by freezing and by the first days of storage whereas the gluten-free dough is more affected by a longer storage time. A storage temperature of −30 °C alters dough rheological properties more than a storage temperature of −18 °C. The addition of dietary fibres to the wheat dough increases its resistance to freezing and frozen storage. The addition of amaranth flour to gluten-free dough also increases its resistance to freezing but decreases its resistance to storage conditions.