海藻酸丙二醇酯对面团流变学和面包烘焙特性的影响

采用粉质仪、拉伸仪和质构分析仪研究添加不同比例(0.1%、0.2%、0.3%和0.4%)的海藻酸丙二醇酯(PGA)对面团流变学特性和面包烘焙特性的影响。结果表明,添加PGA能改善面团的粉质和拉伸特性,能显著提高面团的吸水率,延长面团的稳定时间,提高粉质评价指数,增大面团的延展性、拉伸阻力和拉伸比值。添加PGA能增大面包比容,显著提高面包的弹性,降低面包硬度,改善面包的口感,提高面包的感官评分。PGA添加量在0.2%~0.3%时,对面团和面包的改善效果最为显著,面包品质最好。     

紫苏叶超微粉对面团特性及面包品质的影响

将紫苏叶超微粉加入到面团中,测定面团的粉质特性、拉伸特性以及发酵特性;用添加紫苏叶超微粉的面团制作面包,并对其比容、保水性、老化度及面包感官品质进行分析。结果表明:当紫苏叶超微粉添加量小于6%时,面团的粉质特性和拉伸特性变化不明显,发酵体积增大,获得的面包保水性高、老化度低、比体积大,且感官品质较好;当紫苏叶超微粉添加量为6%~8%时,面团的粉质特性、拉伸特性及发酵特性均呈现下降趋势。     

海藻酸钠对面团特性及面包品质的影响

考察了海藻酸钠添加量对混合粉粉质特性、拉伸特性、糊化特性,以及对面包比容、含水量、硬度、弹性、感官品质的影响。结果表明,添加海藻酸钠可有效改善小麦粉面团的粉质特性、拉伸特性及糊化特性,提高面包的含水量,适量添加可有效提高面包比容、面包弹性及面包感官品质,降低面包硬度。综合分析添加海藻酸钠对混合粉粉质、拉伸和糊化特性以及对面包焙烤品质的影响,确定海藻酸钠最佳添加量为0.6%,为其在焙烤食品中的应用提供了理论依据。     

低聚木糖在面包中的应用

添加低聚木糖对面团拉伸性及面包品质等影响的研究结果表明：添加低聚木糖会改变面团流变学性质．提高面包的色泽、口感和改善面包内部结构，增大面包的体积。低聚木糖面包的最佳配方为低聚木糖3.9g、酵母4．8g、蔗糖18．0g和水150g。     

燕麦麸皮对面团流变学特性和面包品质的影响研究

在本实验中,将添加了燕麦麸皮的面包粉进行焙烤,通过对焙烤面包的感官评价来研究添加燕麦麸皮对面包品质的影响.实验结果表明,燕麦麸皮对面团流变学特性影响,在于使面团的吸水量减少了2%,形成时间减少,稳定时间从9.7min增加到10.8min,弱化度增加了59%;随着燕麦麸皮添加比例的增加,拉伸面积和延伸度均呈递减趋势,拉伸面积减少了72cm2,延伸度减少了93mm,拉伸阻力和拉伸比例均呈递增趋势.适量的添加燕麦麸皮,发现面包的体积和比容增大,感官评分提高,添加2%的燕麦麸皮强化面包,内部蜂窝结构组织较细密均匀,面包心洁白、口感好、柔软、弹柔性较好,体积和比容最大,感官评分最高,从而证明了燕麦麸皮作为面粉和面包强化剂的可行性.     

糜米粉对面团特性及面包品质的影响

为研究糜米粉对面团特性及面包品质的影响,探究了糜米粉添加量(0、10%、20%、30%、40%和50%)对面团的微观结构、拉伸特性、动态流变学特性以及面包品质的影响。结果表明:随着糜米粉添加量的增加,面团的面筋网络出现了断层结构。添加糜米粉使得面团的拉伸强度和拉伸距离均呈下降趋势,面团的弹性模量和黏性模量均呈上升趋势。糜米粉的添加明显增加了面包的硬度和咀嚼度,降低了面包的弹性、粘聚性、回复性、比容和感官评分。因此,糜米粉的添加改变了小麦面团的特性和面包的品质,其添加量不宜超过30%。     

菊糖对面团流变学特性及面包品质的影响

添加不同比例的菊糖于面包粉中,对面包面团特性及面包品质变化进行研究。结果表明,添加菊糖能够明显影响面包粉的粉质和拉伸等流变特性。随着菊糖添加量的增加,面团吸水率显著下降,面团形成时间和面团稳定时间延长,弱化度减小;添加菊糖可增加面团的延伸度、拉伸面积和拉伸阻力;面粉的峰值黏度、最终黏度、衰减值和回生值也显著降低,其淀粉老化速度得到延缓;弹性模量和黏性模量显著增加,面团的网络结构得到改善;但面团发酵体积显著减小,使得面包的比容减少,面包初始硬度显著性增加,在面包贮藏过程中,添加2.5%、5%、7.5%的菊糖面包硬度明显低于未添加菊糖的面包硬度,说明适宜添加量的菊糖能够改善面包内部结构,降低其贮藏过程中的硬度和老化速率,延长面包货架期。     

两种α-淀粉酶对面包基础粉品质影响

为探讨两种α–淀粉酶(LD、XHY)对面包基础粉品质影响,采用降落值法、稠度仪法、拉伸仪法及质构分析法测定面包基础粉中淀粉酶活力、面团流变学特性、面包质构特性、面包比容和高径比。结果表明,添加两种α–淀粉酶可增强面包基础粉淀粉酶活力、增加面团跌落值和延展性、降低吸水率、缩短稳定时间;且添加XHY淀粉酶可明显增大面包比容、高径比,改善面包质构特性,故可选取其添加于面包基础粉中,适宜添加量为50 mg/kg面包基础粉。     

添加挤压膨化燕麦粉对小麦面团性质及面包品质的影响

为研究添加挤压膨化燕麦粉对小麦面团性质及面包品质的影响,将挤压膨化燕麦粉和燕麦生粉分别按照0%,8%,16%,24%和32%的比例添加到高筋小麦粉中,通过Mixolab2混合实验仪和质构仪测定面团的热机械学性质和拉伸特性,用扫描电子显微镜观察面团的微观结构。利用直接发酵法制作面包,测定面包的比容、全质构和硬化速率,并进行感官评价。结果表明,与添加相同量的燕麦生粉相比,添加挤压膨化燕麦粉后面团吸水率和稳定时间增加,面团的回生值、黏度、黏度崩解值和拉伸弹性降低。电镜结果表明,添加挤压膨化燕麦粉阻碍面筋结构的形成。添加挤压膨化燕麦粉后面包的比容和硬化速率下降,硬度、咀嚼性、弹性及回复性增加。当挤压膨化燕麦粉添加量为8%和16%时,感官评分高于添加相同量的燕麦生粉面包。     

糯玉米粉对小麦面团流变特性及面包烘焙特性的影响

为探讨糯玉米粉对小麦面粉品质的影响,将不同含量的糯玉米粉添加到小麦粉中,用粉质仪和拉伸仪测定了糯玉米面粉的面团流变学特性,并研究添加糯玉米粉对面包品质的影响。结果表明,随着糯玉米粉添加量从4%增加到16%,小麦面团的形成时间、稳定时间减少,弱化度增加,除4%添加量外其余的综合评价值均降低;面团的R5阻力、拉伸长度、最大拉伸阻力呈现先增加后减少的趋势,在添加量4%时达到较好水平;湿面筋含量、面筋指数在添加量4%时达到峰值。焙烤制得面包比容下降,感官评分在添加量为4%时高于对照组,随后随着糯玉米粉添加量的增加降低。综合研究表明,添加4%糯玉米粉有助于改善面团的流变特性及面包的品质。     

Composition and Digestibility of Alfalfa and Orchardgrass Hemicellulose Monosaccharides by Holstein Steers

This research was to determine hemicellulose monosaccharide composition of alfalfa and orchardgrass hay and to compare digestibilities and in situ rates of disappearance of alfalfa and orchardgrass hay hemicellulose monosaccharides in Holstein steers. Orchardgrass contained more xylose and less galactose than alfalfa. Mannose in orchardgrass was more digestible than that in alfalfa, and uronic acids tended to be more digestible in orchardgrass. Xylose to glucose ratios were higher in orchardgrass than in alfalfa and were higher in feed than in feces. Xylose to arabinose ratios increased linearly with in situ removed time for alfalfa; however, orchardgrass ratio did not change significantly during the 72-h in situ studies. Xylose to glucose ratios increased with in situ fermentation time for both alfalfa and orchardgrass hay. Alfalfa hay had a higher rate of dry matter and neutral detergent fiber digestibility as compared with orchardgrass hay; however, no significant differences were detected in extent of cell wall digestion.     

生物质提取木糖工艺及木糖检测方法研究进展

木糖作为一种重要的化工原料,在食品、饮料等行业中应用广泛。综述了生物质制备木糖的工艺进展,对木糖检测方法进行了简单阐述。     

代谢木糖生产乙醇的基因工程菌研究进展

木糖广泛存在于林业及农业废弃物中 ,木糖发酵生产乙醇是再生资源的有效利用。文中报道了近几年来在利用基因工程菌发酵木糖生产乙醇方面的研究进展。重点介绍了大肠杆菌、酿酒酵母、树干毕赤酵母及运动发酵单胞菌的基因改造情况。     

Effect of Peroxidase on Textural Quality of Dough and Arabinoxylan Characteristics Isolated from Whole Wheat Flour Dough

Effect of peroxidase on arabinoxylans (pentosans) isolated from whole wheat flour and instrumental textural parameters of whole wheat flour dough were studied. Significant increase in dough hardness and decrease in adhesiveness was observed on treatment of dough with peroxidase. Arabinoxylans isolated from peroxidase treated dough had higher molecular weight, viscosity, arabinose to xylose ratio, ferulic acid, and protein contents as compared to that of untreated dough. Arabinoxylans isolated from treated dough had higher absorption at 280 and 320 nm indicating the association of proteins and ferulic acid with arabinoxylans. Thus, the treatment of dough with peroxidase may catalyze the formation of cross-linking between arabinoxylans as well as protein-arabinoxylan that could be responsible for the alteration of the whole wheat flour dough characteristics.     

乳清粉对高筋粉热力学和糊化特性及面团流变学特性的影响

采用差示扫描量热仪(DSC)、快速粘度仪(RVA)、粉质仪和拉伸仪研究乳清粉对高筋粉热力学特性、糊化特性及面团流变学特性的影响。DSC测试结果表明添加3.0%和5.0%乳清粉时,高筋粉的糊化起始温度和热焓值较空白高筋粉(未添加乳清粉)明显上升。RVA测试结果显示混合粉的峰值粘度、最低粘度、最终粘度、衰减值及回生值随着乳清粉添加量的增加呈下降趋势,糊化温度呈上升趋势。粉质试验结果表明添加乳清粉显著降低了高筋粉的吸水率和面团形成时间,增加了面团的稳定时间和粉质质量指数。拉伸试验结果显示面团的拉伸曲线面积、拉伸阻力和拉伸比例随着乳清粉含量的增加呈上升趋势,延伸度则呈下降的趋势。总体而言,添加乳清粉增强了高筋粉的热稳定性和抗老化能力,优化了面团的流变学特性。     

豌豆全粉对小麦面团特性和面包品质的影响

探讨了萌芽程度不同的豌豆全粉(添加量均为5%)对小麦面团加工特性(水分分布、黏性、发酵流变特性、动态流变特性)及面包品质(面包芯质构、面包贮藏期硬度等)的影响。结果表明:与小麦面团(WD)相比,添加未萌芽豌豆全粉(G0MD)的面团中不易流动水的比例升高,结合水和自由水的比例降低,面团发酵产气量降低,面团储能模量(G′),损耗模量(G″)显著下降,面包在储藏期内(1～7 d)面包的硬度增加缓慢。与G0MD相比,添加萌芽豌豆全粉的面团中结合水比例增加,不易流动水比例降低,黏性显著降低,G′、G″均增加,面包老化速度变慢。因此,将萌芽豌豆全粉用于面包的制作表现出良好的应用前景。     

Effect of soy protein on intestinal absorptive ability of calves by the xylose absorption test

Five calves per group were fed whole milk (control) or one of three milk replacers with one-thrid of the total protein provided by a soy product. Soy products were Promocaf (a commercial soy protein concentrate), an experimental soy flour. After a 24-h fast, calves were fed xylose solution. Urine was collected for 5 h. Jugular blood was sampled at 0, .5, 1, 1.5, 2, 2.5, 3, 4, and 5 h after xylose administration. Xylose tests were weekly on each calf through 5 wk of age. Urinary xylose excretion, as a percentage of xylose fed, was higher in the control group during the last 4 wk than in groups fed milk replacers. Mean urinary xylose excretions during 5 wk from calves sampled 5 h after xylose administration were 12.4, 4.2, 4.2, and 4.3% of xylose administered for calves fed milk, soy flour, soy protein concentrate, and Promocaf, respectively. Mean increases in peak of xylose concentration in plasma were 55.7, 44.4, 42.8, and 45.3 mg/100 ml. Peak values for control calves were higher than those for calves fed soy products at wk 4 and 5. Times required to reach peak value did not differ significantly. Neither xylose concentration of plasma nor urinary xylose excretion differed among the groups fed soy products.     

添加荞麦多肽粉对面团流变学特性的影响

将不同水解条件下得到的荞麦多肽粉按不同浓度梯度分别添加到强筋和弱筋面粉中,探讨荞麦多肽粉对面团流变学特性的影响。结果表明:添加不同量荞麦多肽粉的面团,吸水率均随荞麦多肽粉添加量的增加而不断降低,当超过8%添加量后,吸水率受到的影响较小;面筋的含量随着荞麦多肽粉添加量的增加呈现先增加后减小的趋势;面团形成时间和稳定时间随荞麦多肽粉添加量的增加均呈先减小后增加的趋势,弱化度呈上升趋势,评价值也呈现一直增加的趋势。从拉伸特性来看,随着荞麦多肽粉添加量的增加,面团的延伸性变好,拉伸阻力在高浓度添加量的情况下比原面粉大,拉伸能量则呈现一直增加的趋势。总体而言,添加荞麦蛋白粉及其多肽粉对面团粉质及拉伸特性均具有促进作用。     

Turnover of hexosamines in the lens and glycoproteins in the blood of rats given a xylose-containing diet

To elucidate the action of xylose admixtures during the biotechnological production of monosaccharides, rats were given rations containing xylose that comprised 2.10 and 20% of the total amount of carbohydrates. Hexosamines of the lens and general blood globulin fraction were isolated and their turnover was investigated. The activity of glucoso-6-phosphate dehydrogenase, and the content of reduced and oxidized glutathione were assayed in the eyes and red blood cells. The content of xylose was determined in the plasma, eyes and red blood cells. Xylose inclusion into the ration of rats induced a pronounced increase in the half-life of hexosamines in the lens. The general blood globulin fraction turnover was unchanged. The activity of glucoso-6-phosphate dehydrogenase and the amount of total and reduced glutathione in red blood cells were decreased. Xylose content in the eyes and red blood cells was unchanged, while in the plasma it rose proportionally to the increase of its amount in the ration.     

酶改性大豆磷脂对面团流变学特性的影响

对添加酶改性大豆磷脂的面团流变学特性进行了研究 ,结果显示 ,酶改性大豆磷脂对面团的形成时间、面团的稳定时间、抗拉伸强度等有不同程度的提高 ,改善了面团的流变学特性 ,提高了面粉的焙烤品质。