標(biāo)題: 飼料在生產(chǎn)過(guò)程中產(chǎn)生的氣味 [打印本頁(yè)] 作者: monica 時(shí)間: 2007-12-24 17:52 標(biāo)題: 飼料在生產(chǎn)過(guò)程中產(chǎn)生的氣味 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 編輯 ]作者: 張安弟 時(shí)間: 2007-12-24 21:29
我提過(guò)見(jiàn)議:以后發(fā)帖子,盡量把英文翻譯成中文,因?yàn)槊總€(gè)人的文化水平都不可能與你一樣高.作者: hn-mzj 時(shí)間: 2007-12-24 23:17
^_^，這里可是專(zhuān)業(yè)英語(yǔ)版塊！是讓大家學(xué)英語(yǔ)的，當(dāng)然因該讓有興趣的朋友來(lái)翻譯了！作者: monica 時(shí)間: 2007-12-25 08:42
翻譯是很一件很不容易的工作，費(fèi)時(shí)費(fèi)力，希望能有更多的人加入進(jìn)來(lái)。同時(shí)也向論壇以前發(fā)過(guò)翻譯文章的所有朋友致意。作者: wning 時(shí)間: 2007-12-25 11:21 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.
有時(shí)候某些飼料原料的氣味會(huì)比較宜人，比如果汁業(yè)的副產(chǎn)物就是如此。不過(guò)也有些副產(chǎn)物飼料具有難聞的氣味，尤其是當(dāng)其中所含的油脂出問(wèn)題或者是用壓力和溫度處理的時(shí)候，更是易出現(xiàn)氣味的問(wèn)題。
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.
為了避免對(duì)飼料廠附近的居民造成不良影響，副產(chǎn)品飼料加工過(guò)程中出現(xiàn)的各種氣味都有必要進(jìn)行消除處理。處理所用的氧氣用風(fēng)箱從工廠外提取，然后在其進(jìn)入注入器之前經(jīng)過(guò)過(guò)濾處理。
(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).
飼料原料最終氣味的好與壞由許多因素來(lái)決定，甚至不同的人對(duì)同一種氣味的感覺(jué)也是不同的。這種主觀感覺(jué)差異的主要原因是由于氣味并不僅僅是由一種單一的分子所決定，你可以想象一下一種雞尾酒，其氣味可能是由數(shù)百種有機(jī)成分而不是一種所產(chǎn)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.
濃度最低（十億分之一以下范圍）的氣味成分不能被實(shí)驗(yàn)設(shè)備檢測(cè)到，但是人類(lèi)的鼻子卻能非常清楚的感覺(jué)到它們。因此一個(gè)工廠或者飼料廠需要做些減輕氣味的工作主要是由于廠子附近居民的鼻子對(duì)氣味有很高的感受性。這也使得問(wèn)題變得復(fù)雜了，因?yàn)椴豢赡軐?duì)氣味的排放進(jìn)行計(jì)算和預(yù)測(cè)?？倸馕冻煞种械拿恳环N氣味成分可以掩蓋或者增強(qiáng)另一種氣味成分的氣味。氣味是呈動(dòng)態(tài)變化的，這是由于各氣味成分和它們的濃度會(huì)由于加工條件、原材料、天氣情況等等的不同而隨時(shí)間而變化。
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.
什么東西都敵不過(guò)鼻子
物質(zhì)的微小顆粒一旦釋放入空氣中就會(huì)產(chǎn)生氣味，特別是對(duì)粒徑在一微米一下的顆粒而言，由于總表面積巨大，所產(chǎn)生的氣味更為強(qiáng)烈。人的嗅覺(jué)雖然比其他的哺乳動(dòng)物要遲鈍，但也是獲取環(huán)境中化學(xué)物質(zhì)信息的一種途徑。在各種氣味分極低的濃度下，我們的鼻子能夠辨別出它們所產(chǎn)生的多達(dá)4000種氣味。氣味分析技術(shù)有時(shí)也不一定能達(dá)到探測(cè)出如此眾多的氣味分子的水平。為了測(cè)量一種氣味，最好的儀器仍然是鼻子的嗅粘膜，它的確是非常可靠的感應(yīng)器。工業(yè)生產(chǎn)活動(dòng)產(chǎn)生的惡臭氣味由200至800種不同的活性物質(zhì)所產(chǎn)生。其中最常見(jiàn)的是有臭雞蛋氣味的含硫氣體分子、含氮?dú)怏w分子（如氨）和丙酮及乙醛，后面這些氣體則產(chǎn)生苦味和腐臭味。人類(lèi)的語(yǔ)言詞匯不能像描述一種顏色那樣準(zhǔn)確的去定義一種氣味，不過(guò)在表一中我們?cè)噲D總結(jié)一下從不同的氣體分子中我們可以聞出什么。
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.
氣象色譜
沒(méi)有氣象色譜的測(cè)量就不可能計(jì)算減輕氣味措施的效率。氣象色譜可以用來(lái)測(cè)量一種氣體混合物的濃度，并且還可以測(cè)定氣味的強(qiáng)度。具體的過(guò)程是先直接從氣體出口采集氣體樣品，讓后講樣品在實(shí)驗(yàn)室用清潔的空氣稀釋。一旦有50％的顯色板檢測(cè)到一種氣味，這時(shí)的氣體濃度就可以看作是能夠檢測(cè)出該氣味的閾值，也就是可能產(chǎn)生一種嗅覺(jué)反應(yīng)或者感覺(jué)的最小濃度?？梢杂脷庀笊V測(cè)定幾種氣味濃度閾值。它們分別是：檢測(cè)閾值，它被定義為能夠明確的對(duì)某種不能說(shuō)出性質(zhì)的氣味產(chǎn)生反應(yīng)的最低濃度。這是已有文獻(xiàn)中具有可重復(fù)性和最廣泛報(bào)道的氣味測(cè)量；辨別閾值被定義為能被辨別具出特有氣體性質(zhì)的最小濃度。描述閾值為色譜板操做人用來(lái)辨別氣味的濃度值。
