甘蓝型油菜对干旱和低磷双重胁迫的生理反应Ⅰ：叶片气体交换参数及产量

通过对气体交换参数及产量的测定和分析,研究了干旱和低磷双重胁迫对油菜不同生育期叶片光合特性的影响。结果表明：油菜在不同生育期受到干旱和低磷胁迫后,叶片净光合速率（Pn）、气孔导度（Gs）、蒸腾速率（Tr）会明显降低。在干旱和低磷双重胁迫下,苗期油菜Ci降低、Ls升高,表明气孔限制是导致Pn降低的主要原因;而蕾薹期和花期Ci升高、Ls降低,表明非气孔限制是导致Pn降低的主要原因。对单一的胁迫而言,低磷胁迫对油菜叶片Pn影响最大的时期是蕾薹期,而干旱胁迫对油菜叶片Pn影响最大的时期则是花期;与对照相比,它们均显著降低了油菜的株高、每角粒数、单株有效角果数和单株产量。     

日本造纸工业现状与技术进步

2006年日本纸和纸板的总产量是5110．5万吨,仅次于美国和中国,位列世界第三。日本制浆造纸工业的特点是进口木片,然后在本土生产纸浆和纸。由于国内消费量不再增长,日本不得不慎重对待进口纸。中国的影响将成为一个大问题,而公司的社会责任则是另一个大问题。     

乙烯利在果蔬中残留量的快速分析方法

建立一种用顶空气相色谱快速测定植物生长调节剂乙烯利在果蔬中残留量化快速分析方法.在样品中添加碱液后恒温加热,吸取顶空瓶中的上层气体,采用GC-Q柱,GC-FID检测器进行测定.该方法的检测限为0.01 mg/kg,平均回收率为86.6%,相对标准偏差为2.1%～7.0%.     

超临界CO2萃取八角茴香油的GC-MS分析

八角样品在萃取釜压力为15MPa,温度为25℃;分离釜Ⅰ压力为7MPa,温度为30℃;分离釜Ⅱ压力为5MPa,温度为25℃的条件下用超临界CO2萃取2h,所得茴香油经气相色谱-质谱联用分析,共检出157个峰。对其中83个峰进行了鉴定,其中芳香族化合物为八角茴香油的主要组成物质,相对含量为95．1097％,反式茴香脑的相对含量可达92.9327％;其次为萜类化合物,相对含量为3．1454％;非萜类脂肪族化合物的相对含量较低,仅为0．7449％。     

Aroma profiles of five basil (Ocimum basilicum L.) cultivars grown under conventional and organic conditions

A headspace solid-phase microextraction (HS-SPME) method coupled to gas chromatography–ion trap mass spectrometry (GC–ITMS) has been developed and applied for profiling of volatile compounds released from five Ocimum basilicum L. cultivars grown under both organic and conventional conditions. Comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC×GC–TOFMS) was employed for confirmation of identity of volatiles extracted from the basil headspace by SPME.     

Effect of the packaging method and the storage time on lipid oxidation and colour stability on dry fermented sausage salchichón manufactured with raw material with a high level of mono and polyunsaturated fatty acids

The effects of fatty acid composition, two packaging methods (vacuum and 20% CO₂/80% N₂) and storage under refrigeration for 210 days were evaluated on a dry fermented sausage (salchichón), manufactured with raw material enriched in monounsaturated or polyunsaturated fatty acids. Fatty acid composition was determined on sausage mixtures and on ripened sausages and lipid oxidation and colour stability was determined on ripened sausage at different times during storage. The modification of fatty acid composition of the sausages raised the nutritional quality, slightly affecting the colour properties. Dry fermented sausages enriched in polyunsaturated and monounsaturated fatty acids presented higher lipid oxidation values than the control ones. Both packaging methods (vacuum and 20% CO₂/80% N₂) during 210 days of chilled storage had minor effects on the colour and the lipid oxidation stability.     

Changes of health-related compounds throughout cold storage of tomato juice stabilized by thermal or high intensity pulsed electric field treatments

The effect of high intensity pulsed electric fields (HIPEF) processing (35 kV/cm for 1500 μs in bipolar 4-μs pulses at 100 Hz, with an energy density of 8269 kJ/L) on the main bioactive compounds and antioxidant capacity of tomato juice was investigated and compared to heat pasteurization (90 °C for 1 min or 30 s) having the fresh juice as a reference. HIPEF and heat treated tomato juices showed higher lycopene and lower vitamin C levels than the untreated juice. However, no significant changes in the total phenolic content and antioxidant capacity were observed between treated and fresh juices just after processing. Lycopene, vitamin C and antioxidant capacity of both treated and untreated juices decreased exponentially during storage following a first order kinetics (R² = 0.763–0.987), whereas tomato juices maintained their initial phenolic content. HIPEF-treated tomato juice maintained higher lycopene and vitamin C content than the thermally treated juices during the storage time. Hence, the application of HIPEF may be appropriate to achieve nutritious and fresh like tomato juice.

Industrial relevance

HIPEF processing can lead to tomato juice with higher nutritional value than that thermally processed. HIPEF-treated (35 kV/cm for 1500 μs with 4-μs bipolar pulses at 100 Hz, energy input of 8269 kJ/L) tomato juice shows greater lycopene, vitamin C and antioxidant capacity just after the treatment and during the storage time than heat treated (90 °C­30 s and 90 °C­60 s) tomato juice. Therefore, HIPEF technology is a feasible alternative to thermal treatment to obtain tomato juice with a high presence of health-related compounds.     

气相色谱-串联质谱法测定食糖中18种邻苯二甲酸酯

研究建立了气相色谱-串联质谱(GC-MS/MS)测定食糖中18种邻苯二甲酸酯的方法.食糖样品经甲醇超声提取,浓缩后正己烷复溶,采用气相色谱-串联质谱进行测定,多反应监测模式(MRM)扫描,外标法定量.结果表明,18种邻苯二甲酸酯在0.01～0.2 mg/L范围内线性良好(r2>0.997),检出限为0.0003～0.0...     

反向流动注射法同时比色测定葡萄酒中的总铁和游离二氧化硫

本文利用反向流动注射分析法（ｒＦＩＡ），采用气体扩散技术，建立了一种能够在同一波长下（５６０ｎｍ）同时比色测定葡萄酒中的总铁和游离二氧化硫的方法，并获得了满意的结果。利用铁试剂测总铁线性范围０～４．０ｐｐｍ，Ｒ．Ｓ．Ｄ．＝±０．６％，检出限０．００５ｐｐｍ；用盐酸付玫瑰苯胺测游离二氧化硫，在０～５０ｐｐｍ内呈良好的线性关系，Ｒ．Ｓ．Ｄ．＝±１．０％，检出限０．２７ｐｐｍ。对样品同时测定该两种组分时，分析速度可达３７样／ｈ。方法适用于各种葡萄酒中的总铁和游离二氧化硫的同时测定，而且快速、准确、可靠。