Removal of residual pesticide, fenitrothion, in vegetables by using ozone microbubbles generated by different methods

The effects of ozone microbubbles (OMB) generated by different methods on removal of residual fenitrothion (FT) in three kinds of vegetables were examined. FT-infiltrated lettuce, cherry tomatoes and strawberries were immersed in solutions containing OMB generated by using a microbubble generator of a decompression-type or a gas-water circulating-type combined with an ozone generator at an initial OMB concentration of 2.0 ppm for 0, 5 or 10 min. Residual FT in each vegetable was removed more efficiently by the OMB treatments with the decompression type than with the gas-water circulation type, showing that the pesticide-removing effect of OMB varies with the method of OMB generation.     

Spore formation by Bacillus cereus in broth as affected by temperature, nutrient availability, and manganese

A study was done to determine the effect of interacting factors on sporulation of Bacillus cereus in broth. Vegetative cells (1.4 to 2.2 log CFU/ml) of B. cereus strain 038-2 (capable of growing at 12 degrees C) and strain F3812/84 (capable of growing at 8 degrees C) were inoculated into 30 ml of tryptic soy broth (TSB), TSB supplemented with manganese (50 microg/ml), diluted (10%) TSB (dTSB), and dTSB supplemented with manganese (50 microg/ml) and incubated at 8, 12, or 22 degrees C for up to 30, 30, or 10 days, respectively. Unheated and heated (80 degrees C for 10 min) cultures were plated on brain heart infusion agar to determine total cell counts (vegetative cells plus spores) and the number of spores produced, respectively. Both strains of B. cereus survived in TSB and dTSB for 30 days at 8 degrees C but did not sporulate. At 12 degrees C, cells grew in TSB to a population of 6.0 +/- 0.8 log CFU/ml, which was maintained for 30 days. Neither strain grew in dTSB at 12 degrees C and survived for at least 30 days. Spores were not produced in any of the test broths at 12 degrees C. At 22 degrees C, cells reached a stationary growth phase between 12 and 24 h in TSB, TSB supplemented with manganese, and dTSB supplemented with manganese, and approximately 1% of the CFU were spores. In dTSB, cell growth and spore formation were retarded at 22 degrees C and a significantly lower number of spores was produced compared with the number of spores produced in TSB, TSB supplemented with manganese, and dTSB supplemented with manganese. The addition of manganese to TSB did not affect cell growth or spore formation, but manganese did enhance sporulation in dTSB. This study provides useful information on spore formation by B. cereus as affected by conditions that may be imposed in liquid milieus on the surface of foods and on food contact surfaces in processing environments.     

Antioxidant, antimicrobial, 15-LOX, and AGEs inhibitions by pineapple stem waste

Pineapple stem has been extensively used for bromelain extraction; however, almost no attention has been given to the waste obtained during bromelain manufacturing. In this regard, antioxidant, antimicrobial, and inhibitions against 15-lipoxygenase and advanced glycation end product formations by pineapple stem waste (PSW) obtained during bromelain manufacturing process were studied. The PSW had moderate bioactivities in all the performed assays. It also showed a considerable inhibition against fungal growth, probably due to high amounts of the benzoic acid present in the sample. These results indicate that PSW could be utilized as an economic source of preventive or therapeutic agent in disease and in different functional food industries. PRACTICAL APPLICATION: A large amount of wastes are generated during bromelain manufacturing from pineapple stem. So far, these wastes are not utilized and are often considered as a burden while disposing them. However, we found some important phytochemicals with considerable bioactivities in these wastes. We believe that these wastes may have a promising usage as a cheap source of one of the ingredients in functional food based industries.     

电感耦合等离子体发射光谱法测定柠檬酸中铁、铬、镁、钙、钠、钾等6种金属元素含量

采用电感耦合等离子体发射光谱法测定柠檬酸中铁、铬、镁、钙、钠、钾等六种金属元素含量。采用标准加入法,降低基体影响,在光谱图检查中,适当调整谱峰中心位置和积分基线背景校正点位置,以取得更为准确的结果。该方法所有元素的线性相关系数均大于0.999,各元素检出限在0.04μg/L~0.94μg/L之间,回收率在95.4%~101.8%之间,相对标准偏差在0.49%~2.78%之间。此法具有快速、简便、灵敏度高等优点,实验结果令人满意。     

HPLC-ELSD法测定微胶囊中阿拉伯糖、果糖、葡萄糖、蔗糖、麦芽糖、乳糖含量

建立高效液相色谱-蒸发光散射法(High performance liquid chromatography with evaporative light-scattering detection,HPLC-ELSD)同时测定微胶囊中阿拉伯糖、果糖、葡萄糖、蔗糖、麦芽糖、乳糖含量的高效液相色谱方法。样品经乙腈水超声波浸取,采用Waters Amide色谱柱(4.6×250mm3.5μm)分离,以1%氨水和乙腈为流动相,使用蒸发光散射检测器进行检测。结果表明,阿拉伯糖:0.44~7.06mg/mL、果糖:0.30~4.74mg/mL、葡萄糖:0.40~6.45mg/mL、蔗糖:0.32~5.04mg/mL、麦芽糖:0.40~6.47mg/mL及乳糖:0.41~6.61mg/mL范围内线性关系良好;方法检出限为0.02~0.03mg/mL;回收率为95.31%~105.33%,6种糖含量相对标准偏差在2.30%~3.50%之间。该方法前处理简单、灵敏度高和检测速度快,适用于微胶囊中阿拉伯糖、果糖、葡萄糖、蔗糖、麦芽糖、乳糖的定量检测。     

ICP-MS测定饼干中的铅、砷、铬、镉、铜、锌、铁和锰

探讨了应用电感耦合等离子体质谱仪测定饼干中铅、砷、铬、镉、铜、锌、铁和锰8种重金属元素的方法。运用微波消解系统对样品进行消解,以铋、锗、钪和铟作为内标物,用ICP-MS对消解液进行检测,并采用国标方法对其结果进行验证。利用加标回收率试验和国家标准物质小麦(GBW 10052)检测试验考察了方法的准确性和可靠性。结果表明,该方法所测元素在标准溶液浓度范围内呈线性关系,相关系数均大于0.999,方法检出限在0.002~0.500 mg/kg之间,相对标准偏差均小于6.55%,本法与国标方法测量结果的相对偏差在3.73%~8.40%之间,加标回收率在88.0%~106%之间,标准物质的测定值与标准参考值符合要求。     

Uptake by foods of tetrachloroethylene, trichloroethylene, toluene, and benzene from air

Transition rates from air into food as well as equilibrium concentrations in air and critical foods were determined for tetrachloroethylene, trichloroethylene, benzene and toluene. From these data, maximum concentrations of the four substances in air were estimated that keep contamination of critical foods at an acceptable level. A simple and rapid method allowed us to determine the risk of food contamination from the air, e.g. in shops and kitchens, by the analysis of the air. Estimations showed that concentrations in the air of shops should not exceed 1 mg/m3 if tetrachloroethylene concentrations in foods are limited to 100 micrograms/kg (slightly higher concentrations can be accepted for the other three compounds); in kitchens of restaurants and households, even 0.3 mg/m3 cause the target concentration to be exceeded rather frequently If the limit in foods is 50 micrograms/kg, recommended maximum concentrations in air are 0.5 and 0.15 mg/m3. The data also shows that the recommended limits for concentrations in air conflict with the accepted emission limits: If emission at the accepted limit occurs near shops or households, contamination of foods far exceed that considered as tolerable.     

Uptake by foods of tetrachloroethylene, trichloroethylene, toluene, and benzene from air

Summary Transition rates from air into foods as well as equilibrium concentrations in air and critical foods were determined for tetrachloroethylene, trichloroethylene, benzene and toluene. From these data, maximum concentrations of the four substances in air were estimated that keep contamination of critical foods at an acceptable level. A simple and rapid method allowed us to determine the risk of food contamination from the air, e.g. in shops and kitchens, by the analysis of the air. Estimations showed that concentrations in the air of shops should not exceed 1 mg/m³ if tetrachloroethylene concentrations in foods are limited to 100 g/kg (slightly higher concentrations can be accepted for the other three compounds); in kitchens of restaurants and households, even 0.3 mg/m³ cause the target concentration to be exceeded rather frequently. If the limit in foods is 50 g/kg, recommended maximum concentrations in air are 0.5 and 0.15 mg/m³. The data also shows that the recommended limits for concentrations in air conflict with the accepted emission limits: If emission at the accepted limit occurs near shops or households, contamination of foods far exceeds that considered as tolerable.

---

Übergang von Tri- und Tetrachlorethylen, Benzol und Toluol aus der Luft in Lebensmittel

Zusammenfassung Für Tri- und Tetrachlorethylen, Benzol und Toluol wurden Übergangsgeschwindigkeiten aus der Luft in Lebensmittel sowie Gleichgewichtskonzentrationen in Luft und kritischen Lebensmitteln bestimmt. Aus diesen Daten ließen sich maximale Konzentrationen in der Luft abschätzen, welche die Verunreinigung kritischer Lebensmittel in akzeptablen Grenzen halten. Das erlaubt uns, das Risiko von Lebensmittelverunreinigung aus der Luft, z. B. in Läden und Küchen, durch Luftanalyse zu bestimmen, wofür eine einfache Methode benutzt wird. Unter der Annahme einer maximalen Tetrachlorethylen-Konzentration in Lebensmitteln von 100 g/kg (z. B. deutsche Höchstmengenverordnung) wird abgeschätzt, daß Konzentrationen in Läden 1 mg/m³ nicht überschreiten dürfen (die Gehalte der anderen drei Substanzen dürfen leicht höher sein). In Küchen von Gaststätten oder Haushalten wird die Zielkonzentration in Lebensmitteln bereits bei 0,3 mg/m³ ziemlich häufig überschritten. Für die Schweiz (50 g/kg für Lebensmittel) werden 0,5 und 0,15 mg/m³ vorgeschlagen. Die Resultate zeigen aber auch, daß die empfohlenen Maximalkonzentrationen in der Luft leicht mit den Emissionsgrenzwerten in Konflikt geraten: Bei legalen Emissionen in der Nähe von Läden oder Haushalten kann die Lebensmittelkontamination die Grenzwerte bei weitem übersteigen.

     

In vitro binding of bile acids by bananas,peaches, pineapple,grapes, pears,apricots and nectarines

The in vitro binding of bile acids by bananas (Musa × paradisiaca), peaches (Prunus persica), pineapple (Ananus comosus), grapes (Vitis spp.), pears (Pyrus communis), apricots (Prunus armeniaca) and nectarines (Prunus persica, nectarina) was determined using a mixture of bile acids secreted in human bile at a duodenal physiological pH of 6.3. Six treatments and two blank incubations were conducted, testing various fresh fruits on an equal dry matter basis. Considering cholestyramine (bile acid binding, cholesterol lowering drug) as 100% bound, the relative in vitro bile acid binding percentages on dry matter (DM), total dietary fibre and total polysaccharides basis were 2–9%, 15–101% and 10–101%, respectively. Bile acid binding, on a DM basis, for bananas was significantly (P ? 0.05) higher and that for nectarines significantly lower than those for peaches, pineapple, grapes, pears and apricots. The bile acid bindings for peaches and pineapple were similar and significantly higher than those for grapes, pears and apricots. Binding values for grapes and pears were significantly higher than apricots. These results point to the relative health promoting potential of bananas > peaches = pineapple > grapes = pears > apricots > nectarines, as indicated by their bile acid binding on a DM basis. The variability in bile acid binding between the fruits tested maybe related to their phytonutrients, antioxidants, polyphenols, flavonoids (anthocyanins, flavonols, and proanthocyanidins), structure, hydrophobicity of undigested fractions, anionic or cationic nature of the metabolites produced during digestion or their interaction with active binding sites. Animal studies are planned to validate in vitro bile acid binding of fruits, observed herein, to their healthful potential, atherosclerosis amelioration and cancer prevention.     

超声波提取-原子吸收光谱法测定谷物中镉、铜、铅和锌的含量

优化超声波辅助提取-原子吸收光谱法测定大米等谷物中Cd、Cu、Pb和Zn含量的方法。结果表明：0.1g谷物(粒径＜50μm)中加入5mL HNO3 -H2O2溶液(2:1,v/v),先预超声10min,再放入60℃超声水浴中超声提取10min后,Cd、Cu、Pb和Zn均可以被定量回收,加标回收率在96.0%～107.5%之间。t检验结果表明超声提取法与常规湿式消解法分析结果差异不显著。方法的相对标准偏差(RSD)为4.9%～7.0%,检出限为0.007～0.019mg/L。     

HPLC法同时测定湘莲中芦丁、金丝桃苷及槲皮素含量

目的:建立高效液相色谱法同时测定湘莲中芦丁、金丝桃苷及槲皮素的含量。方法:采用Agilent ZORBAX SB-C₁₈色谱柱(4.6 mm×250 mm, 5μm),以甲醇—0.6%磷酸水溶液为流动相，梯度洗脱，流速1.0 mL/min,柱温30℃,检测波长255 nm。结果:20批湘莲样品中芦丁、金丝桃苷及槲皮素含量分别为1.32～2.06,1.36～2.43,1.41～3.26 mg/kg;芦丁、金丝桃苷和槲皮素检测质量浓度线性范围均为5～200μg/mL(R²=0.999 9),在相应的线性范围内，3种黄酮类物质线性关系好，灵敏度高，精密度、稳定性、重复性及回收率试验相对标准偏差(RSD)均小于4.0%;芦丁、金丝桃苷及槲皮素的平均加标回收率分别为96.6%,96.9%,97.4%。结论:该方法操作便捷且结果准确，可用于湘莲中黄酮类成分的含量测定和质量评价。     

微波消解-MPT-AES法同时测定绿茶中锰、锌、铜、铁、铬、硒

绿茶样品经微波消解处理,用微波等离子体炬原子发射光谱法（MPT-AES）测定其中的锰、锌、铜、铁、铬和硒六种微量元素含量。详细考察了分析谱线、微波功率、载气流量、工作气流量、氧屏蔽气流量等实验参数,并分析了酸效应、易电离元素的干扰情况。采用正交实验方法研究了消解过程中微波压力、消解温度及消解时间三因素对消解结果的影响。在优化的实验条件下,测得锰、锌、铜、铁、铬和硒的检出限分别为8.2、46、18、28.8、4.4、4.5ng·mL-1,加标回收率在96.89%～102.32%之间,相对标准偏差（n=11）均小于3.25%。结果表明,MPT-AES是一种简便、快速、准确、无污染的绿色环保方法。     

Flesh Quality in Snapper, Pagrcrs auratus, Affected by Capture Stress

Muscle metabolites in resting, tank acclimated snapper, Pagrus auratus, were monitored for 72 hr postmortem and compared with values from exercised or commercially caught fish. The physiological status of the live animal was quantified by plasma cortisol and blood chemistry. Cortisol levels were lowest in unstressed controls (6.8 ± 2.1 ng mL^?1) while exercised laboratory fish had highest levels (67.7 ± 11.2 ng mL^?1). Control fish maintained a constant K-value for 72 hr in chilled storage; all other groups had significant increases. Onset of rigor development and muscle ATP depletion was delayed in unstressed fish and was more rapid in line-captured than exercised fish. Commercial users minimizing stress would maintain high flesh quality.     

Oxytetracycline, Sulfadimethoxine, and Ormetoprim Residues in Channel Catfish by HPLC

HPLC methods and modified extraction procedures were used to analyze residues of oxytetracycline (Terramycin, OTC) or sulfadimethoxine (SDM) and ormetoprim (OMP) in channel catfish fed OTC or Romet-30 under controlled conditions. Mean recovery rates in fish muscle were 92.5% for OTC over concentrations of 0.05–1.0 ppm and 86.3% for OMP and 87.9% for SDM over 0.05–5.0 ppm. SDM and OMP were rapidly depleted from large catfish (about 345g) after 5 days feeding with Romet-30 at 50–100 mg/kg body weight. By day 2 post-treatment, no residue was detected. Residues of OTC, SDM and OMP were also detected in fingerling channel catfish (about 20.3g) after 4 and 8 wk of feeding with Romet-30 or OTC at 12.5, 25, or 50 mg/kg body weight, but not after a 3-wk-withdrawal period.     

高效液相色谱-荧光检测法测定蜂蜜中的果糖、葡萄糖和麦芽糖

建立反相离子对色谱法同时测定蜂蜜中果糖、葡萄糖、麦芽糖含量的方法。样品经对氨基苯甲酸衍生化后,采用ODS柱,以0.1mol/L磷酸盐缓冲液(20mmol/L四丁基硫酸氢铵,pH2.5):乙腈=95:5为流动相,荧光检测器检测,外标法定量。结果表明,果糖、葡萄糖、麦芽糖的检出限分别为210、96、240μg/kg,线性范围分别为130～140、52～98、154～98mg/kg,在其线性范围内相关系数r≥0.9988;该方法加标回收率在98.2%～101.2%之间,RSD在3.4%～5.4%之间。该方法灵敏、结果可靠。     

Effect of corn silage hybrid on dry matter yield, nutrient composition, in vitro digestion, intake by dairy heifers, and milk production by dairy cows

Three corn hybrids, Mycogen TMF94, Cargill F337 (which contains a brown midrib trait), and Pioneer 3861 were compared in a plot trial, an intake trial, and a lactation trial. In the plot trial, the three corn hybrids were planted in replicated 15.2 x 385-m plots. Mycogen TMF94 and Cargill F337 had lower yields of dry matter (DM), higher concentrations of neutral detergent fiber, and higher in vitro true DM disappearance compared with Pioneer 3861. Mycogen TMF94 had a higher yield of DM than Cargill F337 despite having a lower plant population. However, Cargill F337 had a higher in vitro true DM disappearance than Mycogen TMF94. In the intake trial, six individually penned Holstein heifers were blocked and assigned randomly to one of three total mixed rations containing 79% (DM basis) Mycogen TMF94, Cargill F337, or Pioneer 3861 corn silages in replicated 3 x 3 Latin squares. Heifers fed the Pioneer 3861-based TMR had lower DMI than heifers fed Mycogen TMF94 and Cargill F337-based TMR. In the lactation trial, 75 midlactation Holstein cows were blocked and assigned randomly to one of three total mixed rations containing 31% (DM basis) Mycogen TMF94, Cargill F337, or Pioneer 3861 corn silages used in the intake trial. Milk production was highest for cows fed Cargill F337-based total mixed rations. It is concluded from this study that Mycogen TMF94 was higher yielding, but less digestible, and resulted in lower milk production by lactating cows than Cargill F337. In addition, Mycogen TMF94 had higher in vitro true DM disappearance, and similar DM yield and milk production by lactating cows when compared with Pioneer 3861.     

Near-field commercial aircraft contribution to nitrogen oxides by engine, aircraft type, and airline by individual plume sampling

Nitrogen oxides (NOx) concentrations were measured in individual plumes from aircraft departing on the northern runway at Heathrow Airport in west London. Over a period of four weeks 5618 individual plumes were sampled by a chemiluminescence monitor located 180 m from the runway. Results were processed and matched with detailed aircraft movement and aircraft engine data using chromatographic techniques. Peak concentrations associated with 29 commonly used engines were calculated and found to have a good relationship with N0x emissions taken from the International Civil Aviation Organization (ICAO) databank. However, it is found that engines with higher reported NOx emissions result in proportionately lower NOx concentrations than engines with lower emissions. We show that it is likely that aircraft operational factors such as takeoff weight and aircraftthrust setting have a measurable and important effect on concentrations of N0x. For example, NOx concentrations can differ by up to 41% for aircraft using the same airframe and engine type, while those due to the same engine type in different airframes can differ by 28%. These differences are as great as, if not greater than, the reported differences in NOx emissions between different engine manufacturers for engines used on the same airframe.