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。     

云南烤烟复烤叶片陈化过程香味成分的变化及与感官评价的关系研究

使用同时蒸馏萃取装置、以及气相色谱仪(GC)和气相色谱/质谱联用仪(GC/MS),对约3年自然陈化过程云南中部和上部烤烟复烤叶片的香味成分进行了分析研究,并进行了感官质量评价。结果表明,烤烟复烤叶片在约3年的自然陈化过程中,4-环戊烯-1,3-二酮、二氢猕猴桃内酯等香味成分含量持续增加;茄酮、β-苯乙醇等陈化前期含量增加,达到峰值后含量开始缓慢下降;2,4-庚二烯醛含量一直降低。复烤叶片陈化过程吸食品质有所改善,到30个月左右,感官质量最好。另外,进行了复烤叶片陈化过程香味成分的变化与感官质量的相关性研究,陈化过程两种烟叶香味物质总量、酮类物质总量与感官质量的相关性良好,相关系数均大于0.90。      

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     

沙门氏菌能力验证样品的研制及其应用

目的研制沙门氏菌分离培养及血清分型能力验证样品,并应用于沙门氏菌的能力验证。方法能力验证样品包括5瓶,其中3瓶阳性,2瓶阴性。阴性样品仅含有背景细菌,阳性样本在背景菌的基础上添加有沙门氏菌,3件阳性样品分别含有不同的血清型沙门氏菌。为防止数据串通,将参试实验室随机分成5组,每组实验室获得的质控样组合不同。为进行沙门氏菌能力验证样品评价,随机抽取冻干质控样品20瓶,参照本次能力验证推荐的GB 4789.4-2010对样品进行均匀性检验,阳性样品至少检出1种血清型沙门氏菌,阴性对照样品应不得检出沙门氏菌。将沙门氏菌能力验证样品分别在-30、4、25和37℃下储藏28 d监测其储藏稳定性。结果沙门氏菌的质控样在均匀性、储藏稳定性和运输稳定性均能满足质控样使用的要求。在166家实验室反馈结果中,123家结果评定为满意,占74.1%;28家结果为不满意,占16.9%;15家结果评定为可疑,占9.0%。结论沙门氏菌的能力验证样品可以满足此次能力验证的需求,本次能力验证可以真实的反应参试单位的检测水平。     

食品中副溶血性弧菌检验能力验证样品的研制及其应用

目的研制食品中副溶血性弧菌检验能力验证样品,并应用于副溶血性弧菌能力验证试验中。方法能力验证样品包括0～3瓶阳性样品和0～3瓶阴性样品。阴性样品仅含有背景细菌,阳性样本在背景菌的基础上添加有副溶血性弧菌。为防止数据串通,编制1～180的随机数字表,其中90个随机数字作为阳性样品编码,另外90个随机数字则用为阴性样品编码。随机抽取冻干质控阳性样品、阴性样品各20瓶,参照本次能力验证推荐的GB4789.7-2013对样品进行均匀性检验,阳性样品均需要检出副溶血性弧菌,而阴性对照样品应不得检出副溶血性弧菌。将副溶血性弧菌能力验证样品分别在?30、4℃储藏30d监测其储藏稳定性,同时在25和37℃下储藏7 d监测其运输稳定性。结果副溶血性弧菌的质控样在均匀性、储藏稳定性和运输稳定性均能满足质控样使用的要求。在39家实验室反馈结果中,36家结果评定为满意,满意率为92.3%。结论食品中副溶血性弧菌能力验证样品可以满足此次能力验证的需求,国内实验室大部分能满足考核要求,仍有部分实验室需要提高检验检测能力。     

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.     

The influence of label information on the snacks parents choose for their children: Individual differences in a choice based conjoint test

Labels have been reported to influence children's perception and choice of foods. However, the influence of label information on parents’ food choices for their children has not received as much attention in the literature yet. In this context, the objectives of the present study were: i) to evaluate the impact of label information on parents' healthiness perception and choice of two popular snack products, and ii) to explore individual differences in how label design influences parents' healthiness perception and their choice of snack products for their children. A total of 1213 Uruguayan mothers participated in an online survey. A choice-based conjoint test was performed to study the influence of cartoon characters, nutritional claims and nutrient content information on the choice and healthiness perception of chocolate milk and sponge cake labels. Half of the parents were asked to indicate which of the products they would choose as a snack for their children and the other half were asked which of the products was healthier. Data was analyzed by means of a Mixed Logit Model followed by multivariate approaches to explore individual differences (Hierarchical Cluster Analysis and Principal Component Analysis). Results showed that, regardless of the product, nutrient claim had the strongest effect, increasing healthiness perception and encouraging mothers’ choice. For both choice and healthiness perception, two groups of mothers who differed in the relative importance attached to cartoon characters and nutrient content were identified, highlighting the need to investigate individual differences. Results stress the need to regulate the use of nutritional claims, cartoon characters, and other persuasive elements in products of poor nutritional quality targeted at children.     

速食食品纸桶包装冲泡过程的矿物油迁移试验研究

目的 建立速食食品纸桶在冲泡过程中产生矿物油迁移的化学溶剂替代试验,并且以此考察市售纸桶包装的矿物油迁移情况。方法 首先将100 ℃的玉米油倒入空纸桶,自然放置30 min以模拟冲泡过程;然后以该植物油为参考,分别考察换作正己烷和95%乙醇的迁移数据,寻找纸桶在食品冲泡过程中矿物油迁移试验的替代化学溶剂。结果 冲泡过程中纸桶及其外层印刷油墨均会迁移矿物油至玉米油中,其中饱和烃（mineral oil saturated hydrocarbons, MOSH）的迁移量为2.26~22.73 mg/kg;纸桶迁移矿物油至正己烷的数据与其迁移到植物油的具有较好的可比性,因而确定正己烷为纸桶的矿物油迁移的化学替代溶剂,从而建立了纸桶冲泡过程的迁移试验,即100 mL正己烷在常温下置于空纸桶30 min,然后测定迁移液中MOSH和芳香烃（mineral oil aromatic hydrocarbons, MOAH）。结论 纸桶包装在冲泡过程会不同程度地迁移出矿物油,其中白桶的迁移量普遍高于牛皮纸桶,部分白桶的MOAH迁移量超出欧盟限量（0.05 mg/kg）。考虑到MOAH有致癌和遗传毒性,建议予以重视。     

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。     

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.