Determination of glyoxal and methylglyoxal in Thai fish sauce and their changes during storage test

Recently more research attention has been given to glyoxal (GO) and methylglyoxal (MG) in relevant to their role in biological and food systems. In this study, pre-column derivatization using 5,6-diamino-2,4-hydroxypyrimidine sulfate (DDP) for fluorescence detection on HPLC was optimized for fish sauce matrix. DDP–GO and DDP–MG derivatives detected had fluorimetric wavelengths coincided with the spectral characteristics reported. Standard addition experiment showed that the detection method was free from interference and matrix effect with good recovery (90–115 %) and precision (less than 8 % RSD at 88–242 ng/mL). Limit of detection for GO and MG were 11.7 and 10.9 ng/mL respectively. Prolonged storage of the fish sauce sample under 4, 25, 40, and 60 °C showed that GO increased at 40 and 60 °C while MG increased at 25, 40, and 60 °C. The results also suggested possible role of molecular oxygen in these formations. Together with GO and MO, browning development and Strecker aldehydes were also monitored.     

Milking of cows in late pregnancy: milk production during this period and during the succeeding lactation.

Fifteen lactating cows were milked throughout pregnancy, and the effects on milk performance were studied during this period and during the succeeding lactation, relative to 11 conventionally managed cows (2 months dry before calving) as controls. During the last 2 months of pregnancy, only nine cows did not dry off spontaneously. Protein and fat concentrations in milk increased rapidly, but the concentration of lactose, corrected for milk yield, did not change. The ratios of individual caseins to total protein decreased with the quantity of milk produced, but only for yields below approximately 6 kg/d. The relative proportion of kappa-casein tended to decrease in the last milkings. During the succeeding lactation (first 15 weeks after calving and first 6 weeks of grazing) continuously milked cows yielded 4 kg milk/d less than the cows of the other group. The protein content of their milk was higher (2-3 g/kg depending on the period) than that of the control group, and the lactose content tended (P less than 0.10) to be lower. Changes in the relative proportions of nitrogenous fractions with time were not different in the two groups. Differences between the two groups in the concentration of protein in milk, and in the concentration of glucose and non-esterified fatty acids in the plasma, suggest a better energy balance for the continuously milked cows during the succeeding lactation.     

21世纪纤维发展方向

本文展望了21世纪纤维的发展方向,认为传统化纤业受到挑战,健康纤维将有较大发展,新的特种纤维将不断涌现。     

纺织品染色的电荷效应和阳离子试剂开发应用(续一)

2.3染后固色剂和其他试剂的功能阳离子试剂的另一重要功能性就是可以提高阴离子染料染色后的色牢度,特别是湿牢度,因此许多固色剂是阳离子型的.为了防止未固色染料脱落,往往染后用阳离子固色剂来处理纺织品,不仅可以提高色牢度,还可以减轻水洗负担,节约用水.在染色加工早期,纺织品染色大量应用色牢度不     

继二十年之往 开新世纪之来——写在“新世纪中国食品工业发展论坛”召开之前

<正> 今年12月,将被载入中国食品工业的发展史册之中。 在12月2～4日短短的3天中,中国食品工业协会将庆祝其20华诞、召开四届四次理事会、进行行业表彰,同时,还将举办新世纪中国食品工业发展论坛。此次“论坛”受到了国内外食品业界的高度关注,很有可能成为中国食品工业发展史上一个重要的里程碑。 如今,各行各业的论坛很多,而面向食品工业全行业的高层论坛,这是改革开放以来的第一次,也是新中国成立以来的首次。届时,来自国内外的食品工业经营管理和科技前沿的精英们,将     

浅谈平压两用木工刨床传动系统的耐久试验

本文主要讨论了平压两用刨床传动系统耐久试验的必要性。以及平压两用刨床传动系统耐久试验的试验方法作了简单的介绍     

The contents of lignans in commercial sesame oils of Taiwan and their changes during heating

Sesame lignans have multiple functions and were recently reported to have potential as sources of phytoestrogens. Sesame oils used in Taiwan are expelled from roasted sesame seeds with dark colour and strong flavour. This study analyzed lignan contents of 14 brands of sesame oils, and found their mean of total lignans to be 11.5 mg/g; 82% and 15% of the lignans were sesamin, and sesamolin, respectively. Sesamol contents were relatively higher in those with darker colour. In use as a cooking oil, heating at 180 °C for 4 min did not change the content of lignans, but the level of sesamol increased after heating at 180 °C for 20 min. Heating at 200 °C for 20 min caused a significant loss of sesamolin and sesamol. From our calculation, ingestion of 10 g of sesame oil is adequate to provide the level of lignans that might benefit cardiovascular health, as found by other studies. Cooking at temperatures above 200 °C will cause loss of some lignans, but sesamin, a source of phytoestrogen, is relatively heat-stable.     

中华人民共和国科学技术部原副部长中国生产力促进中心理事长韩德乾在中国日用五金行业专家委员会工作会议上的讲话

目前在世界五金行业中,有我们中国人的一席之地,而且今后在市场领域里面会越来越大.从五金行业这方面来讲,坦率的说,我是个学生,今天给我创造这个机会,也是给我上的第一课.但是,我来参加这个会,我也找了一些同志了解了一下,也看了一些资料,中国现在在五金行业不管是炊具行业、还是拉链行业、还是锁具行业、还是打火机行业,还是刀剪行业等等,确实发展的很快,产品在中国市场,包括国际市场上真是五彩缤纷,令人眼花缭乱.     

Variation in optic zone radii of a contact lens during manufacturing and the effects of temperature on this variation

There is little information in the literature on the causes of variation in the optic zone radii of a contact lens and the effects of temperature on this variation. In this study, the lathe cutting method of producing contact lenses was reviewed. The cause of the variation in the back optic zone radius was then identified as change in the operating condition from that of the calibrating one. Also, using finite element and theoretical methods, it was found that the effect of an increase in lens blank temperature is to make the back optic zone radius obtained steeper than that required, and this effect was verified experimentally.     

Changes in the initiation of climacteric ethylene in harvested avocado fruits during their development

Climacteric ethylene production was found to start close to the pedicel, at the proximal part of “Hass” avocado (Persea americana Mill.) fruits in the immature stages, and at the distal part of mature fruits. The start of ethylene production corresponded closely to the softening patterns in immature and mature fruits. The possibility is discussed that this phenomenon is a result of differential levels of factors which inhibit ethylene production, arriving from leaves and regulated by the sink properties of the growing seed.     

The importance of the furanones HDMF and HEMF in the flavour profile of Japanese barley miso and their production during fermentation

All 13 samples of Japanese barley miso accepted for the Kumamoto Prefecture Miso Competition of 1995 were assessed by tasting and by GC analysis using FID, SIM and olfactometric detection. Forty three compounds were separated by GC, of which 15 had a detectable aroma. Consideration of the chemical and sensory analyses of this latter group showed that only the two furanones, 4-hydroxy-2,5-dimethyl-3(2H)-furanone (HDMF) and 4-hydroxy-2(or 5)-ethyl-5(or 2)-methyl-3(2H)-furanone (HEMF), correlated significantly with the quality of miso flavour (P < 0·05). Experimental fermentations of salted barley koji and full barley miso mash with Zygosaccharomyces rouxii resulted in alcoholic fermentation in all cases investigated. In contrast, production of the three furanones, HMMF (4-hydroxy-5-monomethyl-3(2H)-furanone), HDMF and HEMF, was very sensitive to the conditions used. Negligible amounts were found in the absence of soy beans and the highest levels occurred when the full mash was incubated at 37°C for 14 days before inoculation of the yeast. When pre-incubation was carried out, the concentration of HMMF was maximal at the end of mashing and declined during fermentation whilst the amount of both HEMF and HDMF increased. The time courses were consistent with synthesis of HEMF, and then HDMF, by the yeast from HMMF. © 1998 Society of Chemical Industry.     

技术装备和管理的现代化与新世纪的中国啤酒

简要回顾了我国啤酒工业的发展历程,概述了我国啤酒工业的现状,分析了我国啤酒工业与世界同行业先进水平的差距,展望了新世纪中国啤酒的发展。     

Growth of bifidobacteria in soymilk and their survival in the fermented soymilk drink during storage

Growth of Bifidobacterium infantis CCRC 14633 and B. longum B6, in soymilk was investigated in the present study. It was found that soymilk could support the growth of both organisms tested. B. infantis grew better than B. longum in soymilk. Supplementation of bifitose (isomaltooligosccharie), glucose, lactose or galactose to soymilk increased the growth of B. infantis and B. longum as determined after 48 h of fermentation. On the other hand, addition of yeast extract, peptone, tryptone, casitone or N-Z-Case plus to soymilk enabled B. infantis to reach its maximum population in a shorter cultivation time of 24 h. Acid production by B. longum and B. infantis in soymilk was mainly non-growth associated, while in the yeast extract-supplemented soymilk, acid produced by B. infantis was found to be growth-associated. Populations of B. longum reduced more than did B. infantis in the prepared fermented soymilk drink during storage period. Viable population of both test organisms reduced less in the fermented drink held at 5 degrees C than at 25 degrees C. After a 10-day storage at 5 degrees C, viable B. infantis and B. longum reduced by 0.44 and 3.18 log CFU/ml, respectively, in the fermented drink. Addition of sucrose to the fermented drink resulted in an increased reduction of viable bifidobacteria during the storage period. This phenomenon was most prominent with B. infantis in the fermented drink held at 25 degrees C.     

Assessing the relationship between extensive use of organochlorine pesticides and cooling trend during the mid-20th century in the southeastern United States

In contrast to global warming, temperatures in the southeastern United States have exhibited a decreasing trend of up to 1-2 degrees C over the last century. We investigated the relationship between this cooling trend and the extensive use of organochlorine pesticides--particularly dichloro-diphenyl-trichloroethane (DDT) and toxaphene--in the southeastern U.S. from the mid-1940s through the 1970s. Based on annual use and soil residue estimates, it is shown that enthalpies associated with the endothermic evaporation of pesticides from soil resulted in surface temperature decreases of up to -0.2 degrees C. This is the first study to show the inverse correlation between surface air temperature and pesticide use. These findings highlight the potential contribution of the extensive use of organochlorine pesticides to changes in the surface air temperature, especially in regions of intensive agriculture and pesticide use.     

Proficiency test for the determination of heavy metals in mineral feed. The importance of correctly selecting the certified reference materials during method validation

In 2008, the International Measurement Evaluation Programme, IMEP®, organised two proficiency tests (PTs) for the determination of heavy metals in mineral feed, named IMEP-105 and IMEP-27, respectively. IMEP-105 was organised in support of the activities of the European Union Reference Laboratory for Heavy Metals in Feed and Food, and participation was restricted to the officially nominated National Reference Laboratories (NRLs). IMEP-27 was open to all interested control laboratories in the field. The test material used in the two PTs was the same and the timeframe of the two exercises overlapped. The measurands in both exercises were total Cd, Pb and As and extractable Cd and Pb, as defined in Directive 2002/32/EC of the European Parliament and the Council on undesirable substances in animal feed. Forty-nine laboratories from 25 countries reported results to the two exercises, 29 to IMEP-105 and 20 to IMEP-27. In both PTs, external reference values were used instead of consensus values derived from the participants' results. It was shown that the concentration of total and extractable Cd according to Directive 2002/32/EC were identical, while the concentration of extractable Pb was ～80% of total Pb. The main outcome of these comparisons was that an underestimation of the concentrations of the addressed measurands, in particular total Pb, took place due to an erroneous estimation of the bias of the analytical methods used by most of the participants. It appeared that the nature of the certified reference materials chosen for method validation and recovery estimation was the cause of the problem (insufficient matching of the matrix characteristics between these materials and the test sample). No significant difference between the results reported to IMEP-105 and to IMEP-27 was observed.     

Proficiency test for the determination of heavy metals in mineral feed. The importance of correctly selecting the certified reference materials during method validation

In 2008, the International Measurement Evaluation Programme, IMEP?, organised two proficiency tests (PTs) for the determination of heavy metals in mineral feed, named IMEP-105 and IMEP-27, respectively. IMEP-105 was organised in support of the activities of the European Union Reference Laboratory for Heavy Metals in Feed and Food, and participation was restricted to the officially nominated National Reference Laboratories (NRLs). IMEP-27 was open to all interested control laboratories in the field. The test material used in the two PTs was the same and the timeframe of the two exercises overlapped. The measurands in both exercises were total Cd, Pb and As and extractable Cd and Pb, as defined in Directive 2002/32/EC of the European Parliament and the Council on undesirable substances in animal feed. Forty-nine laboratories from 25 countries reported results to the two exercises, 29 to IMEP-105 and 20 to IMEP-27. In both PTs, external reference values were used instead of consensus values derived from the participants' results. It was shown that the concentration of total and extractable Cd according to Directive 2002/32/EC were identical, while the concentration of extractable Pb was ~80% of total Pb. The main outcome of these comparisons was that an underestimation of the concentrations of the addressed measurands, in particular total Pb, took place due to an erroneous estimation of the bias of the analytical methods used by most of the participants. It appeared that the nature of the certified reference materials chosen for method validation and recovery estimation was the cause of the problem (insufficient matching of the matrix characteristics between these materials and the test sample). No significant difference between the results reported to IMEP-105 and to IMEP-27 was observed.     

猪肉冷链加工与物流微生物危害分析与控制

基于微生物危害分析,测试冷却分割猪肉冷链加工与物流过程的微生物数量和温度分布,明确关键污染环节和物流过程温度波动,建立关键控制点及其控制措施,制定冷却猪肉冷链加工与物流HACCP计划,提出重点改善卫生管理和温度监控措施,使产品微生物数量控制在可接受水平,确保加工流通过程产品质量安全。     

Effects of aryl hydrocarbon receptor-mediated early life stage toxicity on lake trout populations in Lake Ontario during the 20th century

Lake trout embryos and sac fry are very sensitive to toxicity associated with maternal exposures to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and structurally related chemicals that act through a common aryl hydrocarbon receptor (AHR)-mediated mechanism of action. The loading of large amounts of these chemicals into Lake Ontario during the middle of the 20th century coincided with a population decline that culminated in extirpation of this species around 1960. Prediction of past TCDD toxicity equivalence concentrations in lake trout eggs (TEC(egg)s) relative to recent conditions required fine resolution of radionuclide-dated contaminant profiles in two sediment cores; reference core specific biota--sediment accumulation factors (BSAFs) for TCDD-like chemicals in lake trout eggs; adjustment of the BSAFs for the effect of temporal changes in the chemical distributions between water and sediments; and toxicity equivalence factors based on trout early life stage mortality. When compared to the dose-response relationship for overt early life stage toxicity of TCDD to lake trout, the resulting TEC(egg)s predict an extended period during which lake trout sac fry survival was negligible. By 1940, following more than a decade of population decline attributable to reduced fry stocking and loss of adult lake trout to commercial fishing, the predicted sac fry mortality due to AHR-mediated toxicity alone explains the subsequent loss of the species. Reduced fry survival, associated with lethal and sublethal adverse effects and possibly complicated by other environmental factors, occurred after 1980 and contributed to a lack of reproductive success of stocked trout despite gradually declining TEC(egg)s. Present exposures are close to the most probable no observable adverse effect level (NOAEL TECegg = 5 pg TCDD toxicity equivalence/g egg). The toxicity predictions are very consistent with the available historical data for lake trout population levels in Lake Ontario, stocking programs, and evidence for recent improvement in natural reproduction concomitant with declining levels of persistent bioaccumulative chemicals in sediments and biota.     

上海证券市场收益率的正态性检验

就上证综合指教收益率是否服从正态分布给出了正态概率图和JB检验两种检验方法，得出了收益率分布与正态分布有明显的偏差，厚尾现象比较严重。并且对日收益率用t分布进行拟合，效果比较好。