黄米-小麦混合粉流变学特性的研究

研究了8种不同品种黄米粉（粳性和糯性各4种）的主要成分及黄米粉对面团流变学性质的影响。结果表明:随着黄米粉添加量的增加,面团的吸水率、形成时间、稳定时间、粉质质量指数、拉伸面积、拉伸阻力和最大拉伸阻力均呈减小趋势,延伸度先减小后基本稳定不变,拉伸比例基本不变,弱化度均呈增加趋势,但不同品种黄米粉、不同黄米粉添加量对粉质、拉伸指标的影响程度不同。此外,除拉伸比例外,黄米粉添加量与各粉质指标、拉伸指标相关性均达到极显著水平（p<0.01）。建议制作黄米-小麦混合粉面制品时,应根据产品需求及混粉流变学特性选择合适的黄米粉添加量。      

黄米淀粉的制备及流变学特性的研究

淀粉的流变学特性是影响工业化淀粉质食品品质的重要因素.本文通过碱法优化提取工艺制备了黄米淀粉产品,分析了黄米淀粉的基本理化指标,并利用Brabender糊化仪和Brookfield旋转黏度仪研究了黄米淀粉的糊化特性、流变特性以及机械剪切触变性能,为黄米淀粉在食品工业的应用提供理论依据.结果表明:黄米淀粉中蛋白质残留量为0.232%,淀粉纯度为88.98%,淀粉得率为58.6%,直链淀粉含量为18.28%,起糊温度为73.9℃;峰值黏度为702BU;与马铃薯淀粉、大米淀粉及玉米淀粉相比,黄米淀粉糊具有较强的黏度冷稳定性以及较弱的凝胶性和凝沉性;黄米淀粉糊属于非牛顿型、假塑性、剪切稀化的触变性流体;在同一剪切速率下,表观粘度随温度的增加而降低;在同一温度下,淀粉糊的表观粘度随剪切速率的增加而减小.     

添加剂对糜子淀粉糊性质的影响

以榆糜3号为材料,采用碱提法制备淀粉,研究了蔗糖、碳酸钠和明矾对糜子淀粉糊冻融稳定性、凝沉性和糊化特性的影响。结果表明,3种添加剂均改善了糜子淀粉糊的冻融稳定性和凝沉性,其中明矾对糜子淀粉糊的冻融稳定性和凝沉性影响极显著,与对照相比分别提高了40.7%和78.8%;蔗糖的存在使糜子淀粉糊的黏度增加,成胶能力和抗老化能力减弱;碳酸钠、明矾的存在均使糜子淀粉糊的成胶能力和抗老化能力增强。     

不同碾磨方式小米糠对小麦面团特性及馒头品质的影响

利用多功能粉碎机、流化床式气流粉碎机与行星式球磨机对小米糠进行物理改性,以探究不同碾磨方式、不同添加量的小米糠对小麦面团特性及馒头品质的影响。结果表明,随小米糠粒径减小,持水力、水膨胀力、持油力均提高,其中气流碾磨的效果最明显,分别提高44.29%、41.67%、39.45%。馒头硬度、胶黏性、咀嚼性随添加量和粒径增大而增加,比容随添加量和粒径增大而减小,色差L^*值随添加量的增加而下降,随粒度减小而上升。当普通碾磨米糠质量分数不高于5%,气流与球磨碾磨小米糠质量分数不高于10%时,综合感官评分最高。     

发芽对糜子酚类化合物及抗氧化活性的影响

探讨了发芽时间对糜子中酚类化合物含量、存在形式及抗氧化活性的影响。将经过表面灭菌的糜子种子放入25℃,相对湿度95%的人工气候箱中避光发芽6 d,每天取样,测定其中酚、黄酮含量及抗氧化指标（DPPH、ABTS、FRAP、ORAC）的变化。结果显示,从发芽2 d起,酚、黄酮含量及各项抗氧化指标明显增高。发芽6 d后,内糜8号总酚、总黄酮含量分别为发芽前的5.9和1.9倍,西农10-04号则分别为发芽前的4.6和1.9倍,抗氧化能力均显著增强（p<0.05）。此外,发芽4 d后芽中总酚、总黄酮含量及抗氧化能力显著高于（p<0.05）相应种子。总酚、总黄酮与抗氧化能力间均显示出极强的相关性,其中以总黄酮与FRAP相关性最高（r=0.985）。研究表明,发芽是一种有效提高糜子中酚类化合物含量及抗氧化活性的加工方式。      

Effects of feed moisture and extruder screw speed and temperature on physical characteristics and antioxidant activity of extruded proso millet (Panicum miliaceum) flour

The objective of this work was to determine the impact of extrusion variables [moisture (17–25%), screw speed (170–250 r.p.m.) and temperature (90–150 °C)] on the physical properties and antioxidant activity of proso millet extrudates. Extrusion variables were adjusted using an inscribed central composite rotatable design. Response variables were bulk density (BD), radial expansion ratio, water absorption index, water solubility index, hardness, colour (L*, a*, b*) and antioxidant activity. Moisture and screw speed were the most influential variables affecting millet extrusion: their linear, quadratic and interaction terms accounted for more than 50% of the variability in all responses except for b*. Expansion was greatest at severe conditions of low moisture and high screw speed. These conditions were also consistent with the highest antioxidant activity. This study demonstrated that high expansion and antioxidant activity can be obtained by extruding proso millet under low moisture and high screw speed conditions.     

糜子品种理化特性与体外抗氧化性研究

对39个粳性、糯性糜子品种的品质特性进行分析。结果表明,不同糜子品种的红绿值a*、粗脂肪、灰分、直链淀粉、溶解度、膨胀度、DPPH·清除率和糊化特性差异较大。糜子的平均淀粉含量73.91%,蛋白11.37%,粗脂肪4.02%,灰分0.55%,直链淀粉11.81%,支链淀粉62.10%;糜子的多酚、黄酮含量分别为8.20 mg/g、59.00 mg/100 g,对DPPH·和ABTS+·有一定的清除作用。糯性糜子较粳性糜子色泽鲜黄,具有较高的吸水性、溶解度和膨胀度。除破损值外,粳性糜子的各糊化指标值高于糯性糜子。聚类分析将糜子品种分为4类,可满足不同的加工需求。     

不同品种黍子营养成分及功能活性成分差异化分析

目的:研究黍子营养及功能活性成分的品种差异化。方法:选取8个品种的黍子,对水分和灰分等基本组分和淀粉、蛋白质、脂肪等营养组分及多酚、黄酮、低聚糖等功能活性成分的含量进行了检测分析。结果表明:不同品种黍子样品中,基本组分水分的变异系数为8.43%,变幅为9.38%~12.39%;灰分的变异系数为23.48%,变幅为0.94%~1.79%。营养组分粗淀粉的变异系数为2.77%,品种间含量较为稳定,但冀张黍1号和安塞黄糜子所含慢消化淀粉和抗性淀粉含量比例相对较高;粗蛋白的变异系数为8.04%,品种之间差异显著(p<0.05),其中龙黍18总氨基酸最高,约为149.06 mg/g,且必需氨基酸可达总氨基酸含量的44.54%;此外,粗脂肪的变异系数为23.23%,品种之间差异显著(p<0.05),其中宁糜9号不饱和脂肪酸占总脂肪酸比例最高,为87.06%。功能活性成分中,总黄酮的含量差异最为显著,变异系数为73.07%,变幅为0.89~10.17 mg/g;总多酚含量变异系数为67.78%,变幅为0.74~3.44 mg/g;同时,低聚糖含量的品种间差异也较大。本研究结果对于保留和选育黍子优良品种及黍子食品和保健品的开发具有指导意义。      

不同磨粉方式对青稞全粉理化特性的影响

采用锤式旋风磨、多功能、超离心和超微粉碎机对青稞米进行研磨以获得青稞全粉(出粉率为89％～99％),比较研究了磨粉方式对青稞全粉微观结构、粒径、破损淀粉、糊化和流变等理化特性的影响.结果表明,超离心粉碎样品的破损淀粉质量分数(35.07％)、亮度L*(87.89)、β-葡聚糖质量分数(5.65％)、吸水率(8.65 g...     

Effect of adding zein,soy protein isolate and whey protein isolate on the physicochemical and in vitro digestion of proso millet starch

Mixtures of proso millet starch with zein (15%, w/v), soy protein isolate (SPI, 15%, w/v) and whey protein isolate (WPI, 10%, w/v) as starch–protein composites were prepared through heat–moisture treatment, and the effects of protein addition on the physicochemical, structural and digestibility properties of starch were investigated. Rapid Visco Analysis showed that the addition of zein, SPI and WPI gave significantly decreased setback values to 240.7cp, 192.0cp and 83.0cp, respectively, and setback values decreased reflected the excellent cold paste properties. Thermal analysis showed that each protein reduced the enthalpy, but especially WPI (reduced by 94.7%), suggesting that the double helices of the starch granules were decreased. X-ray diffraction showed that starch crystallinity was decreased after protein addition. The digestibility studies revealed that the addition of zein, SPI and WPI decreased the content of rapidly digestible starch and increased the resistant starch content to 8.4%, 14.6% and 17.5%, respectively. The whey protein displayed a more obvious impact on the digestibility of proso millet starch. These results will help guide the production and processing of starchy foods with desirable properties.     

制粉过程中各系统面粉流变学特性的研究

在生产面包及饼干专用粉的制粉过程中,粉路各系统不同出粉部位面粉的流变学特性呈现出明显的差异,这为粉流选择性混配提供了条件,使粉路在线配粉成为可能。研究表明,面包专用粉宜选择皮磨、渣磨、中路心磨及一部分前路心磨的面粉,饼干专用粉选择前路皮磨、前路渣磨及一部分心磨的面粉进行混配,由此能够配制出质量稳定的优质专用粉。     

热处理小米粉对米面混合粉品质的影响

在不同温度下对小米粉进行热处理,然后以20%添加到小麦粉中制成混合粉,通过测定混合粉的粉质特性和馒头的感官评价确定热处理小米粉对混合粉品质改善的最佳工艺条件。结果表明,最优条件是加热温度110℃、时间15 min。将不同比例热处理小米粉添加到小麦粉,研究对混合粉品质的影响。结果表明,热处理可以明显提高小米粉的糊粘度,显著降低馒头的硬度,改善馒头的品质。感官评价表明,在添加10%热处理小米粉时,用混合粉制做的馒头品质有显著改善。     

超高压处理对小米粉理化特性的影响研究

对米水比例为1∶1、1∶2(w/w)的小米在600 MPa下分别处理15 min、30 min,探讨不同处理条件对小米粉理化特性的影响。结果表明：与空白组相比,超高压对4组不同样品小米粉颗粒形貌、粒径和晶体特性均有影响。全粉中淀粉颗粒形貌由分散的不规则球体变为与其他物质络合粘结成块结构,颗粒平均粒径显著降低,颗粒整体缩小,晶体结构由天然A型转变为B型,米水比为1∶2时对微观结构影响尤为显著。动态流变表明超高压处理后小米粉糊G’和tanδ均高于原粉,G’’均低于原粉,表明高压处理可提高小米淀粉弹性和黏性,该技术可作为有效的物理改性方法改善小米粉的物理特性。     

不同比例黑麦粉对黑麦面包品质的影响

为了改善黑麦面包的加工性能和食用品质,以高筋小麦粉为主要原料,添加不同比例的黑麦粉,采用直接发酵法制作黑麦面包,通过烘焙试验研究不同比例的黑麦粉对黑麦面包质量的影响。结果表明:当黑麦粉比例增大时,面团不耐揉和,弹性、光泽及发酵效果等评价指标下降,面包感官评价值降低,硬度、黏合性增加,确定最适宜黑麦粉添加量为50%~70%,制作的面包结构细腻柔软、纹理均匀、香气浓郁,评分较高。     

Effect of phenolic acids on the rheological properties and proteins of hard wheat flour dough and bread

BACKGROUND: The effects of different phenolic acids on the rheological properties and gluten proteins of hard wheat flour dough and bread were investigated. Caffeic, ferulic, syringic and gallic acids were each blended with hard wheat flour at a concentration of 4.44 µmol L^?1 g^?1 flour. RESULTS: Mixing time and tolerance were reduced with the addition of phenolic acids. The phenolic acids reduced the maximum resistance to extension (R_max) and increased the extensibility of dough, with effects in the following order: gallic < syringic < ferulic < caffeic acid. The effect on R_max was more pronounced in overmixed dough. Loaf volume was most significantly decreased with the addition of caffeic acid. Extraction of sodium dodecyl sulfate‐soluble high‐molecular‐weight proteins was increased in both mixed and fermented doughs by the addition of ferulic and caffeic acids. The order of influence of the phenolic acids on the rheological properties and protein structure of dough and bread was consistent with that of their antioxidant activity. CONCLUSION: The addition of caffeic and ferulic acids reduced R_max and increased the extensibility of hard wheat flour dough by modifying the high‐molecular‐weight gluten, which resulted in decreased bread volume. Copyright © 2011 Society of Chemical Industry     

不同食品胶对面包烘焙特性的影响研究

研究了不同食品胶(海藻酸钠、黄原胶、羧甲基纤维素钠、刺槐豆胶和羟丙基甲基纤维素)对面包烘焙特性的影响。结果表明,添加适量的食品胶可以有效提高面包的焙烤品质,增大面包的比容,提高面包的整体接受度,改善面包的质构特性,增加面包的弹性和内聚性,显著降低面包的硬度和咀嚼性,有较好的抗老化效果,延长产品的货架期。海藻酸钠和羟丙基甲基纤维素改善效果最好,黄原胶改良效果最差。     

含不同粗粮粉面包的营养、质构特性、风味化合物

以小麦粉为主要原料,分别添加一定量马铃薯全粉、荞麦粉、薏苡粉、燕麦粉制作粗粮面包,以氨基酸组成、质构、色泽、风味为评价指标,分析粗粮面包营养特性(主要是游离氨基酸含量)、质构特性、色泽变化和挥发性风味化合物的特征,同时以普通面粉面包为对照。结果表明:从质构特性来看,粗粮粉添加量不应超过12%;除薏苡组外,其余组的氨基酸综合评分均高于对照组;粗粮组面包风味较对照组浓郁,风味物质的总量和种类均高于对照组;添加粗粮粉制作的面包会产生一些特别的风味物质,如壬醇、3-甲基十五烷、十八烷、植烷、3-甲基丁酸、2,6-二甲基吡嗪等。因此,添加适量的粗粮粉既能丰富面包的营养,又能产生浓郁的风味物质,而对面包色泽影响不大。