用于个体防刺服的UHMWPE纤维针刺毡的性能研究

对UHMWPE(超高分子量聚乙烯)纤维针刺毡单层样品的撕破强力、顶破强力和多层样品的抗刺穿能力进行了测试,结果表明:随着单层UHMWPE纤维针刺毡面密度的增加,试样的顶破强力增大;在20~55℃范围内,随着试样预处理温度升高,顶破强力和抗刺穿能力皆增强,但是试样的撕破强力则无这种变化趋势。     

Conditions for high pressure inactivation of Vibrio parahaemolyticus in oysters

The objective of this study was to identify the high pressure processing conditions (pressure level, time, and temperature) needed to achieve a 5-log reduction of Vibrio parahaemolyticus in live oysters (Crassostrea virginica). Ten strains of V. parahaemolyticus were separately tested for their resistances to high pressure. The two most pressure-resistant strains were then used as a cocktail to represent baro-tolerant environmental strains. To evaluate the effect of temperature on pressure inactivation of V. parahaemolyticus, Vibrio-free oyster meats were inoculated with the cocktail of V. parahaemolyticus and incubated at room temperature (approximately 21 degrees C) for 24 h. Oyster meats were then blended and treated at 250 MPa for 5 min, 300 MPa for 2 min, and 350 MPa for 1 min. Pressure treatments were carried out at -2, 1, 5, 10, 20, 30, 40, and 45 degrees C. Temperatures >/=30 degrees C enhanced pressure inactivation of V. parahaemolyticus. To achieve a 5-log reduction of V. parahaemolyticus in live oysters, pressure treatment needed to be >/=350 MPa for 2 min at temperatures between 1 and 35 degrees C and >/=300 MPa for 2 min at 40 degrees C.     

优质稻谷中直链淀粉含量测定方法的探讨

直链淀粉是评价稻米食用、蒸煮品质的一项重要指标,也是优质稻谷定级指标之一.直链淀粉测定过程中样品粉粒大小是影响测定结果的一个重要因素,国标方法要求是φ180μm细度.通过对φ180μm细度、φ150μm细度的样品分别进行测定,结果表明采用φ150μm细度的样品进行检测的重现性是好的,结果是准确可靠的.而采用φ150μm细度可同时测定稻谷中胶稠度等指标,这样在稻谷品质测报工作中可大大提高工作效率.     

我国针刺过滤毡的现状及展望

概述我国袋式除尘器用针刺过滤毡的发展现状,提出针刺过滤毡的发展方向,指出开发生产用于针刺过滤毡的高性能纤维的重要性。     

高温滤料用纤维燃烧气体释放的测试研究

燃烧气体是评价耐高温纤维阻燃性能指标之一,通过设计燃烧试验装置对四种袋式除尘器常用高温滤料纤维(聚苯硫醚纤维、间位芳纶、聚酰亚胺纤维和芳砜纶)进行高温燃烧,利用烟气分析仪器测定其燃烧产生的气体成分及其含量。结果显示,燃烧气体成分与纤维的化学结构和燃烧温度有关。CO是四种纤维的主要燃烧产物,其浓度随温度的变化曲线近似于抛物线;含有酰胺基的纤维燃烧气体中含有NOx,其浓度随温度呈阶梯状变化;芳砜纶和聚苯硫醚纤维燃烧气体中含有SO2,其浓度随温度呈波浪状变化。     

枣果中酚类物质的高效液相色谱分析

建立了一种可同时测定11种酚类物质的高效液相色谱(HPLC)法,并对枣果中的酚类物质进行了分析测定。色谱条件为:Waters Symmetry C_(18)柱(4.6 mm×150 mm,5μm),流动相为甲醇和磷酸水(pH 2.6),280 nm和320 nm双波长紫外检测,柱温30℃,进样量5μL,流速0.6 mL/min,梯度洗脱程序:0 min 15%A,15～25 min 25%A,65 min 75%A,70 min 15%A,梯度线性变化。经测定,新鲜梨枣果内中含有儿茶素、表儿茶素、没食子酸、原儿茶酸、绿原酸和芦丁等酚类物质,其中儿茶素和表儿茶素占检测到的酚类物质总量的85%以上,未成熟果含量远高于成熟果。     

高温流化α-化工艺对酿造黄酒风味的影响

以传统蒸饭黄酒为参照,分析了高温流化α-化工艺对酿造黄酒风味的影响。结果表明:高温流化α-化米黄酒和蒸饭黄酒的酒精度、糖分、酸度和挥发酯含量基本相同,但氨基酸含量降低。呈味物质中,甜味、鲜味、涩味氨基酸含量相差不大,但苦味氨基酸含量明显低于蒸饭黄酒,有机酸含量则高于蒸饭黄酒;主要呈香物质中,酯类物质的种类增多,含量也高于蒸饭黄酒,以丙醇、异丁醇、异戊醇为代表的高级醇含量明显高于蒸饭黄酒,含氮杂环类香味化合物无论从种类上还是从含量上都明显高于蒸饭黄酒,赋予黄酒特殊的香味。由于2种黄酒的酿造工艺相同,说明大米高温流化α-化工艺是影响酿造黄酒风味的主要因素。     

高水分组织化花生蛋白产品干燥和复水特性研究

采用双螺杆挤压机研制的高水分组织化花生蛋白产品中(HM-TPP)蛋白质含量高,具有与动物肌肉类似的纤维状结构和口感,可作为食品原料和配料。文中主要分析了高水分组织化花生蛋白产品的干燥和复水特性。干燥试验结果表明:随干燥温度的增加制品中水分含量达到10%以下所需干燥时间明显缩短,在40、50和60℃下,分别需干燥4.5、7和13 h。其中,60℃下的干燥速率明显高于50℃和40℃下的干燥速率。干制HM- TPP产品的复水试验结果显示:在复水前期(1 h),水温40℃和60℃时的复水速率明显高于20℃的,但40℃和60℃的复水速率无明显区别。复水2.5～3.5 h后,复水产品中水分含量基本达到饱和状态。所得复水产品质地柔韧、表面光滑,富有弹性,基本可以恢复到新鲜产品的品质特性。     

A market study on the quality characteristics of eggs from different housing systems

To study the differences among commercial eggs from four housing systems i.e. cage, barn, free range and organic, 41 physical and chemical parameters were evaluated on 28 fresh egg samples from the Italian market. The univariate statistic analysis evidenced that organic eggs had the highest whipping capacity and foam consistency but the lowest freshness (the highest air cell height) and albumen quality (the lowest Haugh Unit); cage eggs presented instead the lowest whipping capacity and the highest shell resistance to breaking. The multivariate technique discriminant partial least-squares regression was unable to correctly classify the eggs from the four housing systems but successfully differentiated cage eggs from alternative (organic + barn + free range) eggs. The variables with the most discriminant power were shell breaking resistance, overrun, protein content, and shell thickness.     

Changes of intramuscular phospholipids and free fatty acids during the processing of Nanjing dry-cured duck

In this study, changes of intramuscular phospholipids and free fatty acids were tracked during the processing of Nanjing dry-cured duck. Phospholipids were identified and quantified by high performance liquid chromatography combined with UV and evaporative light scattering detectors. The types and quantities of free fatty acids and fatty acids derived from phospholipids were analyzed by capillary gas chromatography. The results showed that raw duck meat had high quantities of phosphatidylethanolamine, and phosphatidylcholine (37.95% and 54.07% of total phospholipids, respectively), which contained high percentages of polysaturated fatty acids. The percentages of total phospholipids, phosphatidylethanolamine, and phosphatidylcholine decreased during processing, with a concomitant increase in quantities of free fatty acids. The lipolysis of phospholipids, especially phosphatidylethanolamine is the main contributor to the increase of free fatty acids.