木薯全粉的功能特性

开发推广木薯源大宗食物,充分发挥木薯的资源优势,拓展人们日常消费的食物资源,积极应对日益严重的粮食危机.通过对木薯全粉与鲜木薯、木薯淀粉中的营养成分的测定对比,及对木薯全粉的黏度特性、透光率、膨胀度等进行分析,并对木薯全粉的营养成分保留及功能性质进行评价,探讨木薯全粉在食品工业中的潜在应用范围.结果表明,木薯全粉相对于鲜木薯、木薯淀粉营养成分保持良好,食用安全,同时具有较好的加工性能,在食品工业中应用前景广阔.     

十二烷基硫酸钠对大豆基木材胶黏剂的改性作用

采用10.0g·kg^-1的十二烷基硫酸钠（SDS）改性质量分数为250.0g·kg^-1的大豆粉浆液,制成SDS改性大豆基木材胶黏剂（SF）,运用单因素和正交试验法考察了pH值、反应温度和反应时间对改性SF胶耐水胶合强度的影响。试验结果表明,SDS改性大豆基木材胶黏剂的最佳工艺：pH8,反应温度35℃,反应时间4h。改性后的SF胶Ⅱ类耐水胶合强度为0.70MPa。由红外光谱分析可知,SDS改性使大豆蛋白质分子大量的非极性基团外露,增加了蛋白质分子的疏水性,提高了改性SF胶的耐水胶合强度。图4表3参10     

红外光谱结合多元线性回归法快速测定木塑复合材料中木粉含量

采用KBr压片法对杉木/聚丙烯(PP)复合材料样品进行了红外光谱分析,确定杉木特征吸收谱带为1740~1730、1610~1590、1270~1260、1060~1050以及1040~1030 cm-1,以PP在1377 cm-1处吸收强度(I)为内标,对木塑复合材料(WPC)中木粉含量和杉木特征峰相对吸收强度进行相关性分析,并采用逐步多元线性回归法建立木粉含量与相对峰强间的多元线性回归方程。结果表明,选取I(1060-1050)/I1377、I(1270-1260)/I1377为回归变量建立的二元线性回归方程和以I(1060-1050)/I1377、I(1040-1030)/I1377及I(1270-1260)/I1377为回归变量建立的三元线性回归方程,具有较高的预测精度。木粉含量的预测值和参照值之间具有强烈的相关性,校正决定系数(R2c)超过0.98,验证决定系数(R2p)超过0.96。外部验证结果表明,线性回归方程预测准确性较高,预测相对偏差范围为0.9%至7.4%,其中三元线性回归方程预测准确性稍好于二元线性回归方程。     

海滨锦葵块根粉和酶制剂对断奶仔猪生长和免疫的影响

以断奶仔猪为试验对象,探讨海滨锦葵块根粉和酶制剂对断奶仔猪生长和免疫的影响。64头28日龄断奶仔猪随机分为4组,对照组饲喂基础日粮,试验I、Ⅱ、Ⅲ组分别饲喂基础日粮添加0．02％复合酶制剂、0．50％和1．00％海滨锦葵块根粉。试验期28d。结果表明,酶制荆和海滨锦葵块根粉对断奶仔猪的日采食量和日增重有提高趋势,但差异不显著（P〉0．05）;与对照组相比,酶制剂和海滨锦葵块根粉对断奶仔猪血清中溶菌酶活性无显著影响（P〉0．05）;有降低血清中TNF-Ⅱ含量的趋势,但差异不显著（P〉0．05）;与对照组相比,酶制剂可以显著降低IL-6含量（P〈0．05）,海滨锦葵块根粉也降低了IL6含量,但差异不显著（P〉0．05）;与对照组相比,酶制剂组、0．50％和1．00％的海滨锦葵块根粉组的猪瘟疫苗抗体效价分别提高了15．27％（P〉0．05）、18．18％（P〉0．05）和5I．64％（P〈0．05）。结果提示,酶制剂与海滨锦葵块根粉对断奶仔猪生长性能有提高趋势,同时也可以提高断奶仔猪的机体免疫力。     

Effects of superfine grinding on the quality characteristics of whole-wheat flour and its raw noodle product

Four particle size distributions of whole-wheat flour (WWF) with mean particle sizes (MZ) of 125-μm, 96-μm, 72-μm, and 43-μm were obtained by superfine grinding. Starch damage and Farinograph water absorption were significantly affected by the reduction of particle size, while dough development time, stability, tolerance index and time to breakdown of WWF were little changed. The peak viscosity, trough, and final viscosity of WWF significantly decreased as particle size reduced. Although finer WWFs produced by superfine grinding caused more discoloration of whole-wheat noodle (WWN) after 24 h storage, they still showed brighter noodle appearance (higher L^∗) than coarser WWFs. A significant increase in the cooking yield of WWN was noticed from the 125-μm WWF group to the 43-μm group, perhaps due to increasing damaged starch, while the 72-μm group exhibited the smallest cooking loss of WWN. Additionally, the hardness, cohesiveness, and resilience values of texture profile analysis (TPA) of cooked WWN significantly increased from the 125-μm group to the 72-μm group, and scanning electron microscope (SEM) analysis showed that the 72-μm group revealed the largest coverage of starch granules and degree of protein network connectivity among the WWF groups. The results demonstrated that the superfine grinding technique could improve the quality of WWN by significantly reducing the particle size of WWFs.     

Manufacture and characterization of pasta made with wheat flour rendered gluten-free using fungal proteases and selected sourdough lactic acid bacteria

Wheat flour, which was rendered gluten-free by sourdough lactic acid bacteria fermentation and fungal proteases, was used for manufacturing experimental gluten-free pasta (E-GFp), according to a traditional process with low temperature drying cycle. Chemical, technological, structural, nutritional and sensory features were characterized and compared with those of commercial gluten-free (C-GFp) and durum wheat pasta (C-DWp). As shown through immunological analyses, the residual concentration of gluten of the hydrolyzed wheat flour was below 10 ppm. E-GFp showed rapid water uptake and shorter optimal cooking time compared to the other pastas. Despite the absence of the gluten network, the supplementation with pre-gelatinized rice flour allowed structural properties of E-GFp, which were comparable to those of C-GFp. The in vitro protein digestibility of E-GFp resulted the highest. Probably due to proteolysis during sourdough fermentation; chemical scores, essential amino acid profile, biological value and nutritional index of E-GFp were higher than those of C-DWp. The hydrolysis index (HI) of E-GFp was ca. 30% lower than that found for C-GFp. As shown by sensory analysis, the characteristic of E-GFp were acceptable. The manufacture of E-GFp should be promising to expand the choice of gluten-free foods, which combine sensory and nutritional properties.     

Development of a standard test for dough-making properties of oat cultivars

Bread is consumed all over the world. However, so far, production of large volume bread is only possible with wheat. Alternatives, such as oats, are less suitable but this is partly due to the lack of knowledge about their functionality for other purposes than porridge, which is their most common use. Existing standard tests for the dough making characteristics of wheat flour are not suitable for oat flour, hampering research to optimize oats for bread-making purposes. We therefore set out to develop a test to evaluate oat in relation to mixing and dough making properties using wheat as a model. It was possible to reproduce the profile of various qualities of wheat flour using mixtures of oat flour and gluten in different proportions. Our standard test was based on a dough system composed of 87.2% oat flour and 12.8% gluten and it presented similar properties to a wheat flour with regard to resistance to extension. This dough system was sensitive and reliable (coefficient of variation lower than 10%) for detecting differences among oat cultivars, and it can be used to screen oat varieties and individual oat components in relation to relevant properties for bread-making purposes.     

Quantitative proteomic analysis of wheat grain proteins reveals differential effects of silencing of omega-5 gliadin genes in transgenic lines

Novel wheat lines with altered flour compositions can be used to decipher the roles of specific gluten proteins in flour quality. Grain proteins from transgenic wheat lines in which genes encoding the omega-5 gliadins were silenced by RNA interference (RNAi) were analyzed by quantitative 2-dimensional gel electrophoresis (2-DE). The precise effects of the genetic modifications on the proteome were assessed in four homozygous lines generated with the same RNAi construct. Two of the lines showed >80% decreases in omega-5 gliadins with only small changes in the levels of other gluten proteins. In the other two lines, omega-5 gliadins were not detectable by 2-DE. However, there were notable reductions in all omega-1,2 gliadins. Small decreases in several other gluten proteins were also detected in one of the lines. The other line showed notable decreases in three HMW-GS and an s-type LMW-GS, increases in two m-type LMW-GS and several alpha gliadins, as well as increases in both serpins and triticin. The study demonstrates that the same RNAi construct can have differential effects on the wheat grain proteome and highlights the importance of detailed proteomic analyses of transgenic grain prior to selecting lines for further assessment of flour quality and allergenic potential.     

微波消解-原子荧光光谱法测定豆粉中总汞的不确定度评定

为了得到准确而完善的检测结果,对微波消解-原子荧光光谱法测定豆粉中总汞结果的不确定度进行了评定,结合各不确定度分量对测定方法中不确定度的主要来源进行了分析。结果表明:样品的前处理方法以及试样的重复性对获得准确测定结果尤为重要,标准曲线的配制也是重要的不确定度来源,同时需要确保仪器的稳定性,而试样定容和样品称样引入的不确定度极低,可以忽略。通过不确定度的评定,明确了测定过程中主要误差的来源,为降低检测过程中的误差提供了依据。     

腰果酚基增塑剂对乙酰木粉复合材料的性能影响(英文)

利用熔融挤出-注塑的方法制得乙酰化木粉(AWF)/低密度聚乙烯(LDPE)复合材料,在制备过程中分别将腰果酚基乙酸酯(CA)和环氧腰果酚基乙酸酯(ECA)增塑剂添加到复合材料中。对复合材料的力学性能、吸水率、表面能、增塑剂热迁移和热机械性能(TMA)进行了研究。结果表明:随着增塑剂含量的增加,材料的力学性能不断下降,但整体而言由CA制备的复合材料的力学强度相比更高;吸水率测试显示材料的疏水性能在增塑剂质量分数为5%时差别不大,但添加量为15%时由CA制备的材料具有更好的疏水性;接触角测试也验证了其界面极性最小。在85℃及100 min内ECA的热迁移常数(4.35×10-4)相比CA的(5.48×10-4)要小,同时随着时间延长至3 700 min时ECA在材料中的保留更好。TMA结果显示随着温度的增大材料的膨胀加剧,加入15%的ECA的复合材料在高温段的线膨胀系数(3 758μm/(m·℃))要明显高于对应的加入CA的材料的线膨胀系数(3 182μm/(m·℃))。