酿造工艺对甜面酱风味成分影响研究

采用气相色谱-质谱联用仪作为检测手段,研究了不同的甜面酱酿制工艺对风味物质形成的影响,结果显示发酵时接种两种乳酸细菌的样品得到的酯类、醛类和风味成分总数均高于接单一细菌的样品;光照能促使醛类物质的生成;使用分离得到的菌种混合制曲能生成更多的风味物质;选用小麦对酯类和醛类的生成有利。     

超高效液相色谱-质谱联用法快速测定豆酱中PC、LPC和GPC的含量

建立快速、简单、准确测定豆酱中活性成分磷脂酰胆碱(PC)与其降解产物溶血磷脂酰胆碱(LPC)和甘油磷脂酰胆碱(GPC)含量的超高效液相色谱-质谱联用(UPLC-MS)分析方法。将豆酱样品经过预处理后,以乙腈、醋酸铵为流动相,使用Waters ACQUITY UPLC超高效液相色谱仪,经ACQUITY UPLC BEH HILIC色谱柱(2.1×100mm,粒径1.7μm)分离,利用质谱定性定量测定其含量。质谱在电喷雾正离子模式下,对m/z782、m/z520和m/z258进行选择离子监测。该方法下PC、LPC和GPC分别在0.191～1.910μg/mL,0.236～2.360μg/mL和0.016～0.160μg/mL范围内峰面积和浓度呈良好的线性关系,相关系数R2PC=0.9959、R2LPC=0.9986和RG2PC=0.9991;PC、LPC和GPC的最低检测限分别为0.05、0.07、0.005μg/mL,最低定量限分别为0.19、0.24、0.016μg/mL;方法的平均回收率为93.2%～97.8%,相对标准偏差为1.5%～3.5%。此方法准确,灵敏度高,样品处理简单,分析时间短,可快速测定豆酱中PC与其降解产物LPC和GPC含量。     

豆酱挥发性风味物质的分析

对工厂化生产的豆酱SPM04 和传统酿制的豆酱SPS06 样品进行了初步的感官评价,采用顶空固相微萃取(HS-SPME)吸附并结合气质联用(GC-MS)的方法对两种样品的挥发性成分进行分析鉴定。结果表明：共鉴定出化合物61 种,SPM04 与SPS06 豆酱分别为39 种和38 种,这些化合物包括醇2 种、酸1 种、醛7 种、酮4 种、酯13种、酚7 种、烷烃8 种、含氮杂环化合物5 种、呋喃7 种、以及其他化合物7 种等10 类;其中苯甲酸乙酯、苯乙酸乙酯、安息香醛、风信子醛、苯乙醇、麦芽酚、2- 乙酰基吡咯和对乙烯基愈创木酚8 种化合物在两个样品同时检出,且含量相对比较高,分别占总的风味物质含量的43.1% 和48.49%,对豆酱的风味起着重要作用。传统豆酱在色泽、气味和体态方面均优于工业化生产的豆酱。     

O-羧甲基壳聚糖在防止成品大豆酱再发酵中的应用

成熟大豆酱中的酵母菌是造成大豆酱再发酵的主要原因，利用羧甲基壳聚糖的防腐作用，将添加到大豆酱中，对引起大豆酱再发酵的酵母菌群有明显的抑制作用，且不影响大豆酱的品质。     

基于自适应方向模板搜索的FPC走线薄浆检测

本文薄浆是柔性印刷电路板(FPC)导电涂层的一种缺陷,为避免其对电路性能产生不良影响而造成经济损失,将薄浆 位置检测出来进行修补或直接剔除板材均是合理的处理方式。 然而由于薄浆缺陷尺寸不定、光照不均致使图像灰度分布不均 匀、走线区域与背景纵横交错等问题,使得走线上薄浆的检测具有一定难度。 针对该问题,在对薄浆纹理及 FPC 走线形态特征 进行详细分析的基础上,提出了一种基于自适应方向模板(ADT)和灰度差分法的检测方案。 首先,使用定义的 ADT 模板按照 骨架跟踪流程对预处理所得图像的走线区域进行遍历,分别搜索相对于该 ADT 模板尺寸而定义的大、小尺度薄浆纹理的端部 和全部候选像素,从而将预处理图像分割成若干小区域;然后,根据各小区域的能量倾向值与预设阈值的数值关系对其中的边 缘噪声区域加以排除;最后,采用灰度差分法对上述两个步骤处理所得结果中的非缺陷区域进行再次筛查,从中提取出大尺度 薄浆纹理的中间区域,至此实现全部薄浆纹理的检测。 在自建图库 SUT-F2 上进行了测试,结果显示本文方法对薄浆缺陷检测 的等误率仅为 3. 92%,相对于其他典型纹理特征提取和薄浆检测方法其等误率至少降低了 5. 28%,表明了本文方法的高效性, 具有实际应用价值。     

APPLICATION OF AN IN-LINE RHEOLOGICAL CHARACTERIZATION METHOD TO CHEMICALLY MODIFIED AND NATIVE CORN STARCH

The application of an in‐line ultrasonics‐based rheological characterization method for measuring the rheological properties of 6% (w/v) acid‐thinned and native corn starch suspensions and gels was studied. The measurements were performed in steady, laminar pipe flow using a 5 MHz frequency transducer to determine the radial shear rate distribution. Two pressure transducers were used to measure the pressure drop allowing the shear stress distribution to be calculated through the conservation of linear momentum. It was possible to obtain shear viscosity over a range of shear rates, 1–50 1/s, from a single velocity profile. A comparison of the shear viscosity function at different flow rates showed that this method could be a valid method of process rheometry during the manufacturing of starch‐based products. Both ultrasonics and rotational rheometry results showed that acid‐thinned and native corn starch suspensions exhibited Newtonian behavior before heat treatment and non‐Newtonian behavior after heating. Power law consistency index and flow behavior index of the acid‐thinned corn starch gel at 39°C were 0.60 Pa.s ^0.68 and 0.68, respectively; whereas those of the native corn starch were 5.90 Pa.s ^0.37 and 0.37 at 38C. Their consistency index increased and flow behavior index decreased with cooling and a thermoreversible change in the flow behavior index was observed in the native corn starch after storage.     

Effect of salting processes on chemical composition,textural properties and microstructure of duck egg

BACKGROUND: Salted eggs have been produced in Thailand and consumed nationwide. Salted egg can be made by brining eggs in saturated saline or by coating the egg with soil paste mixed with salt. The achievement of salting is generally indicated by the textural development of egg yolk. Yolk property is therefore a prime factor governing consumer acceptability and market demand. The objective of this study was to determine chemical composition, textural properties and microstructure of duck egg obtained from the coating and immersing methods at different salting times. RESULTS: Decreases in moisture content with coincidental increases in salt content in both egg white and yolk were observed during salting, regardless of salting process. However, no difference in salt content was noticeable in yolks (P > 0.05). The paste coating method tended to yield greater oil exudation of egg yolk than the immersing method. Maximum transition temperature (T_max) of egg proteins and thiobarbituric acid‐reactive substance (TBARS) value in yolk increased with increasing salting time. A similar hardening ratio of yolk was observed in both processes. Higher hardness and adhesiveness were found in yolk with the paste coating method, whereas greater fracturability, springiness, gumminess and chewiness were observed with the immersing method. Nevertheless, both processes rendered the yolk with similar cohesiveness. Yolk granules were aligned closely when salting proceeded, irrespective of salting process. CONCLUSION: Dehydration and release of lipids in egg yolk increased with increasing salting time and were more pronounced with the paste coating method. Therefore salting processes affected the properties of salted eggs. Copyright © 2009 Society of Chemical Industry     

火试金重量法测定导电银浆中银量

报导运用火试金重量法测定导电银浆中银含量的方法。考察了称样载体、焙烧温度、铅箔用量、灰吹温度对银含量分析结果的影响,结果表明样品用铅箔作称重载体,250 ℃焙烧,15 g铅箔包裹,900 ℃灰吹是比较理想的方案。实验称取与样品中银量相当的金属银按试样的测定步骤和环境条件分析,银量的回收率作为补正因子k对试样分析结果进行补正。方法回收率为99.6 %～100.2%。对实际样品进行分析,测定值与推荐值相一致,相对标准偏差为0.51%和0.71 %（n=5）。     

Volatile Components in Salt-Fermented Fish and Shrimp Pastes

Volatile compounds in salt-fermented anchovy, big-eyed herring, hair tail viscera, and shrimp pastes were compared by simultaneous steam distillation-solvent extraction/gas chromatography/mass spectrometry (SDE/GC/MS). A total of 155 volatile compounds were detected. Of these, 111 were positively identified consisting mainly of aldehydes, ketones, alcohols, esters, aromatics, nitrogen-, and sulfur-containing compounds. Lipid-derived components, such as aldehydes, alcohols, and esters, comprised the majority of volatile compounds from fish pastes, while heterocyclic nitrogen-containing compounds, such as pyrazines, were predominant in shrimp paste.     

透明起绉印花浆FS-417A

将透明起皱印花浆FS-417A用于纯棉织物的透明印花和起绉透明印花工艺中,讨论了焙烘温度、焙烘时间、NaOH质量分散、堆置时间及印花浆FS-417A的黏度对透明印花效果的影响.在印花浆FS-417A黏度为1 000cP,焙烘温度150℃,3 min时,透明印花效果最好.起绉透明印花时,NaOH质量分数为38％,堆置时间24 h,印花织物的起绉效果最好.