饲料在生产过程中产生的气味

monica

Processing
Feed raw materials sometimes have a pleasant smell, such as by-products from the fruit juice industry. But products can also have a foul odour, especially when oils and fats are involved or products are treated by pressure and temperature.
To avoid complaints of residents around a feedmill these smells need to be neutralised.
The oxygen used is directly extracted from the outside air by means of a blower and then filtered before it enters the injector.
(Photo: Aerox)
Many factors determine whether an odour is pleasant or not, even human perception can
be different to the same odour. The main reason for this subjective perception is because odour can be imagined as a cocktail of possibly hundreds of different organic components and not as just one sin-gle molecule that determines the smell. The weight concentration is mostly very low, but the odour-con-centration (=number of required dilution).
The odour-components with the lowest concentra-tions (sub-ppb-range) cannot be detected by laboratory equipment, but the human nose could very well notice them. So the main reason for a factory or feed plant to do something about odour reduction is the
sensitivity of the noses of the people that live in the vicinity of the plant. This also complicates the matter, because it is impossible to make calculations or pre-dictions on odour-emission. Each odour-component can mask or amplify another component within the cocktail. Odour is dynamic, since the components and their concentrations will vary in time due to differences in process- conditions, raw materials, weather-conditions, etc.

Nothing beats the nose
Paticles can generate odour once they are released in atmosphere, especially particles below 1 micron have a large total surface area. The human smell, although less sensitive than that of other mammals, is a source of information about chemical substances in the environment. Our nose is capable of recognising up until 4,000 smells at very weak concentrations in smelling molecules. Analytical techniques do not always succeed in reaching such a threshold in smelling molecules.To measure a smell, the best instrument still remains the nose with its olfactive mucous, which is a really reliable sensor. The stenches generated by industrial activities contain between 200 and 800 different active substances. The most frequent are sulphur-containing molecules in the smell of rotten eggs, nitrogenous molecules (such as ammonia) and ketones and aldehydes, which cause bitter and rancid smells. The human vocabulary can not exactly define a smell as it can describe a colour, but Table1tries to sum up what can be smelled from different molecules.

Molecule(s)                       Association smell
Hydrogensulphide            Rotten eggs
Mehtylmercaptan             Cabbages
Ethylmercaptan                Rotten cabbages
Allylmercaptan                 Garlic
Ammonia                         Very prickly,irritating
Methylamine                    Rotten fish
Indole,scatole                 Excrement
Cadaverine                     Decaying meat
Acetic acid                      Vinegar
Butyric acid                     Rancid butter
Valeric acid                      Sweat,perspiration
Fomaldehyde                     Acrid,close
Acetaldehyde                   Fruit,apple
Acetone                              Sweet fruit
Dimethylsulphur                   Decomposing vegetables
Thiolane                               Gas (product for odourisation of gas)

Olfactometry
It is impossible to calculate odour reduction efficiencies without olfactometric measurements. Olfactometry allows to quantify the concentration of a smelling mixture and to determine the intensity of it. What factually happens is that a sample of air is taken directly from he outlet and in a laboratory is diluted with clean air.A panel of trained people smell the most diluted samples first and continue with smelling samples that are less diluted. As soon as 50% of the panel detects a smell,this is considered to be the odour detectability threshold referring to the minimum concentration that produces an olfactory response or sensation.There are several odour thresholds that can be determined using olfactometry. They are: The detection threshold, which is defined as the lowest concentration that will elicit a response without reference to odour quality. This is reproducible and the most widely reported odour measurement in literature. The recognition threshold is defined as the minimum concentration that is recognised as having a characteristic odour quality. The description threshold is the point at which the panellist is asked to distinguish the odour.

[ 本帖最后由 monica 于 2007-12-24 17:54 编辑 ]

张安弟

我提过见议:以后发帖子,尽量把英文翻译成中文,因为每个人的文化水平都不可能与你一样高.

hn-mzj

^_^，这里可是专业英语版块！是让大家学英语的，当然因该让有兴趣的朋友来翻译了！

monica

翻译是很一件很不容易的工作，费时费力，希望能有更多的人加入进来。同时也向论坛以前发过翻译文章的所有朋友致意。

wning

Processing
Feed raw materials sometimeshave a pleasant smell, such as by-products from the fruit juiceindustry. But products can also have a foul odour, especially when oilsand fats are involved or products are treated by pressure andtemperature.
有时候某些饲料原料的气味会比较宜人，比如果汁业的副产物就是如此。不过也有些副产物饲料具有难闻的气味，尤其是当其中所含的油脂出问题或者是用压力和温度处理的时候，更是易出现气味的问题。
To avoid complaints of residents around a feedmill these smells need to be neutralised.
The oxygen used is directlyextracted from the outside air by means of a blower and then filteredbefore it enters the injector.
为了避免对饲料厂附近的居民造成不良影响，副产品饲料加工过程中出现的各种气味都有必要进行消除处理。处理所用的氧气用风箱从工厂外提取，然后在其进入注入器之前经过过滤处理。
(Photo: Aerox)
Many factors determine whether an odour is pleasant or not, even human perception can
be different to the sameodour. The main reason for this subjective perception is because odourcan be imagined as a cocktail of possibly hundreds of different organiccomponents and not as just one sin-gle molecule that determines thesmell. The weight concentration is mostly very low, but theodour-con-centration (=number of required dilution).
饲料原料最终气味的好与坏由许多因素来决定，甚至不同的人对同一种气味的感觉也是不同的。这种主观感觉差异的主要原因是由于气味并不仅仅是由一种单一的分子所决定，你可以想象一下一种鸡尾酒，其气味可能是由数百种有机成分而不是一种所产生的。
The odour-components with thelowest concentra-tions (sub-ppb-range) cannot be detected by laboratoryequipment, but the human nose could very well notice them. So the mainreason for a factory or feed plant to do something about odourreduction is the
sensitivity of the noses ofthe people that live in the vicinity of the plant. This alsocomplicates the matter, because it is impossible to make calculationsor pre-dictions on odour-emission. Each odour-component can mask oramplify another component within the cocktail. Odour is dynamic, sincethe components and their concentrations will vary in time due todifferences in process- conditions, raw materials, weather-conditions,etc.
浓度最低（十亿分之一以下范围）的气味成分不能被实验设备检测到，但是人类的鼻子却能非常清楚的感觉到它们。因此一个工厂或者饲料厂需要做些减轻气味的工作主要是由于厂子附近居民的鼻子对气味有很高的感受性。这也使得问题变得复杂了，因为不可能对气味的排放进行计算和预测。总气味成分中的每一种气味成分可以掩盖或者增强另一种气味成分的气味。气味是呈动态变化的，这是由于各气味成分和它们的浓度会由于加工条件、原材料、天气情况等等的不同而随时间而变化。

Nothing beats the nose
Paticles can generate odouronce they are released in atmosphere, especially particles below 1micron have a large total surface area. The human smell, although lesssensitive than that of other mammals, is a source of information aboutchemical substances in the environment. Our nose is capable ofrecognising up until 4,000 smells at very weak concentrations insmelling molecules. Analytical techniques do not always succeed inreaching such a threshold in smelling molecules.To measure a smell, thebest instrument still remains the nose with its olfactive mucous, whichis a really reliable sensor. The stenches generated by industrialactivities contain between 200 and 800 different active substances. Themost frequent are sulphur-containing molecules in the smell of rotteneggs, nitrogenous molecules (such as ammonia) and ketones andaldehydes, which cause bitter and rancid smells. The human vocabularycan not exactly define a smell as it can describe a colour, butTable1tries to sum up what can be smelled from different molecules.
什么东西都敌不过鼻子
物质的微小颗粒一旦释放入空气中就会产生气味，特别是对粒径在一微米一下的颗粒而言，由于总表面积巨大，所产生的气味更为强烈。人的嗅觉虽然比其他的哺乳动物要迟钝，但也是获取环境中化学物质信息的一种途径。在各种气味分极低的浓度下，我们的鼻子能够辨别出它们所产生的多达4000种气味。气味分析技术有时也不一定能达到探测出如此众多的气味分子的水平。为了测量一种气味，最好的仪器仍然是鼻子的嗅粘膜，它的确是非常可靠的感应器。工业生产活动产生的恶臭气味由200至800种不同的活性物质所产生。其中最常见的是有臭鸡蛋气味的含硫气体分子、含氮气体分子（如氨）和丙酮及乙醛，后面这些气体则产生苦味和腐臭味。人类的语言词汇不能像描述一种颜色那样准确的去定义一种气味，不过在表一中我们试图总结一下从不同的气体分子中我们可以闻出什么。

Molecule(s)                       Association smell
分子                                  有关的气味
Hydrogensulphide            Rotten eggs
硫化氢                             臭鸡蛋味
Mehtylmercaptan             Cabbages
甲基硫醇                          卷心菜味
Ethylmercaptan                Rotten cabbages
乙基硫醇                          腐败卷心菜味
Allylmercaptan                 Garlic
[size=-1]烯丙硫醇                           大蒜味
Ammonia                         Very prickly,irritating
氨气                                 强刺激性气味，
Methylamine                    Rotten fish
甲胺                                  烂鱼味
Indole,scatole                 Excrement
吲哚，粪臭素                   粪臭味
Cadaverine                     Decaying meat
尸碱                                腐肉味
Acetic acid                      Vinegar
乙酸                                  醋味
Butyric acid                     Rancid butter
丁酸                                腐败黄油味
Valeric acid                      Sweat,perspiration
正戊酸                              汗臭味，
Fomaldehyde                     Acrid,close
甲醛                                   辛辣刺激
Acetaldehyde                   Fruit,apple
乙醛                                   水果味，苹果味
Acetone                              Sweet fruit
丙酮                                    甜水果味
Dimethylsulphur                   Decomposing vegetables
二甲基硫                               腐败蔬菜味
Thiolane                               Gas (product for odourisation of gas)
噻吩                                       气油味

           
Olfactometry
It is impossible to calculateodour reduction efficiencies without olfactometric measurements.Olfactometry allows to quantify the concentration of a smelling mixtureand to determine the intensity of it. What factually happens is that asample of air is taken directly from he outlet and in a laboratory isdiluted with clean air.A panel of trained people smell the most dilutedsamples first and continue with smelling samples that are less diluted.As soon as 50% of the panel detects a smell,this is considered to bethe odour detectability threshold referring to the minimumconcentration that produces an olfactory response or sensation.Thereare several odour thresholds that can be determined using olfactometry.They are: The detection threshold, which is defined as the lowestconcentration that will elicit a response without reference to odourquality. This is reproducible and the most widely reported odourmeasurement in literature. The recognition threshold is defined as theminimum concentration that is recognised as having a characteristicodour quality. The description threshold is the point at which thepanellist is asked to distinguish the odour.
气象色谱
没有气象色谱的测量就不可能计算减轻气味措施的效率。气象色谱可以用来测量一种气体混合物的浓度，并且还可以测定气味的强度。具体的过程是先直接从气体出口采集气体样品，让后讲样品在实验室用清洁的空气稀释。一旦有50％的显色板检测到一种气味，这时的气体浓度就可以看作是能够检测出该气味的阈值，也就是可能产生一种嗅觉反应或者感觉的最小浓度。可以用气象色谱测定几种气味浓度阈值。它们分别是：检测阈值，它被定义为能够明确的对某种不能说出性质的气味产生反应的最低浓度。这是已有文献中具有可重复性和最广泛报道的气味测量；辨别阈值被定义为能被辨别具出特有气体性质的最小浓度。描述阈值为色谱板操做人用来辨别气味的浓度值。

[ 本帖最后由 monica 于

[ 本帖最后由 wning 于 2007-12-25 12:13 编辑 ]

金御

就是嘛，翻译一下就好看多了。收藏了

蓝海泪

受教啦！谢谢楼主！

夏明亮

5楼的哥哥很强大。。。。收藏之。。。

across

平时不磨刀，英语不过关。----多谢5楼，分享

畜牧刀客

对于英语，不磨刀真不行哦