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1、食品专业英语3 Lipid电子课件 食品专业英语食品专业英语Unit 3 Lipids一.词汇讲解二.课文阅读三.课后小结四.课堂练习Part 2 食品科技英语的阅读食品科技英语的阅读psolubility n.溶解度，溶解性，可溶性溶解度，溶解性，可溶性pnonpolar solvent 非极性溶剂非极性溶剂pester n.酯酯pcholesterol n.胆固醇胆固醇pSteroid n.类固醇化合物，甾族化合物类固醇化合物，甾族化合物ptriacylglycerol n.三酰基甘油三酰基甘油pcarboxylic adj.含羧基的含羧基的paqueous adj.水的，含水的，水成的水
2、的，含水的，水成的phydrocarbon n.烃烃pmelting point 熔点熔点pfatty acid n.脂肪酸脂肪酸psaturated adj.饱和的饱和的Unit 3 LipidsPart 2 食品科技英语的阅读食品科技英语的阅读 Lipids are a family of naturally occurring compounds grouped together on the basis of their relative insolubility in water and solubility in nonpolar solvents.These are natura
3、lly occurring molecules that can be isolated from cells and tissues by extraction using nonpolar organic solvents.Unit 3 Lipids 脂类是一类天然化合物家族，其在水中具有不溶解性和在非极性溶剂里具有溶解性。它们可以通过非极性有机溶剂的萃取作用而从细胞和组织中获得。译文Para.1Part 2 食品科技英语的阅读食品科技英语的阅读 There are two classes of lipids:i)those with ester linkages that can be
4、hydrolyzed,for example,fats and waxes;ii)those without ester linkages and so cannot by hydrolyzed,for example,cholesterol and steroids.脂质可以分为两类：i)一类含有酯键，它们可以被水解，例如脂肪和蜡质；ii)另一类不含酯键，它们不能被水解，例如胆固醇和类固醇。译文Para.2Unit 3 LipidsPart 2 食品科技英语的阅读食品科技英语的阅读 Fats and oils are triacylglycerols.They are triesters o
5、f glycerol(probane-1,2,3-triol)with three long chain carboxylic acids.Reaction with aqueous sodium hydroxide yields glycerol and the three fatty acids.脂肪和油脂都是三酰基甘油。它们是甘油用三个长链羧酸连接成三个酯健。用氢氧化钠水解后可产生甘油和三个脂肪酸。译文Para.3Unit 3 LipidsPart 2 食品科技英语的阅读食品科技英语的阅读 Fatty acids are usually unbranched and contain an
6、 even number of carbon atoms,usually from 12 to 20.If there are any double bonds,they tend to have cis geometry.Fats containing one double bond are monounsatrated and those with more than one double bond are polyunsaturated.脂肪酸通常是无支链，包含12 到20个的偶数碳原子。如果含有双键，它们易形成顺式构型。含有1个双键的脂肪酸是单不饱和脂肪酸，含有1个以上双键的为多不饱和
7、脂肪酸。译文Para.4Unit 3 LipidsPart 2 食品科技英语的阅读食品科技英语的阅读 Saturated fats have a uniform shape that allows them to pack together in a crystal lattice.Unsaturated fats have double bonds that introduce kinks into the hydrocarbon chain making crystal formation more difficult.饱和脂肪酸具有相同的构型使得它们被冰晶晶格包裹在一起，而不饱和脂肪酸含
8、有双键使得烃链中形成了扭结，因此冰晶结构更难形成。译文Para.4Unit 3 LipidsPart 2 食品科技英语的阅读食品科技英语的阅读 This is why saturated fats have higher melting points and are solids at room temperature compared to unsaturated fats that tend to be liquids(oils).The most abundant lipid in olive oil is glyceryl trioleate,a trimester formed fr
9、om glycerol and oleic acid,a mono-unsaturated fatty acid with a cis double bond in the middle of the C18 chain.这就是为什么饱和脂肪酸比不饱和脂含有更高的熔点，并且饱和脂肪酸在室温下是固态的，而不饱和脂在室温下是液态（油）的原因。橄榄油中含量最大的是三油酸甘油酯，这是一种由甘油和油酸形成的三酯，油酸是由18个碳原子形成的长链中间含有一个顺式双键的单不饱和脂肪酸。译文Para.4Unit 3 LipidsPart 2 食品科技英语的阅读食品科技英语的阅读 Waxes are mixtur
10、es of esters of long chain carboxylic acids and long chain alcohols.The carboxylic acids usually have an even number of carbon atoms,ranging from 16 to 36,and the long chain alcohols also have an even number of carbon atoms,ranging from 24 to 36.蜡质是由长链羧酸和长链醇形成的酯类混合物，这些羧酸往往含有16-36个偶数碳原子，而长链醇也含有24-36个
11、偶数碳原子。译文Para.5Unit 3 LipidsPart 2 食品科技英语的阅读食品科技英语的阅读In both animal and plant foods,three groups of naturally occurring organic compounds are very important oils and fats,carbohydrates and proteins.These are essential nutrients which sustain life.Oils and Fats have a simple molecular structure.Oils a
12、nd fats belong to a naturally occurring substances called lipids.英译汉Unit 3 LipidsPart 2 食品科技英语的阅读食品科技英语的阅读在动物和植物源食品中，有三种重要的天然在动物和植物源食品中，有三种重要的天然存在的有机化合物：油脂、碳水化合物和存在的有机化合物：油脂、碳水化合物和蛋白质，这些是维持生命的必需营养素。蛋白质，这些是维持生命的必需营养素。油和脂肪分子结构简单，他们是一种天然油和脂肪分子结构简单，他们是一种天然的脂类物质。的脂类物质。参考译文Unit 3 LipidsPart 2 食品科技英语的阅读食品科
13、技英语的阅读Lipid OxidationDuring the processing and storage of foods,lipids undergo complex chemical changes and react with other food constituents,producing numerous compounds both desirable and deleterious to food quality.Lipid oxidation of unsaturated fatty acids is the main reaction responsible for t
14、he degradation of lipids and one of the major causes of food spoilage.英译汉Unit 3 LipidsPart 2 食品科技英语的阅读食品科技英语的阅读在食品的加工和保藏过程中，脂质会发生复在食品的加工和保藏过程中，脂质会发生复杂的化学变化，并与其他食品成分发生反杂的化学变化，并与其他食品成分发生反应，从而产生许多对食品质量有利和有害应，从而产生许多对食品质量有利和有害的化合物。脂质中不饱和脂肪酸的氧化是的化合物。脂质中不饱和脂肪酸的氧化是导致脂质降解的主要反应，也是食物腐败导致脂质降解的主要反应，也是食物腐败的主要因素之一。的主要因素之一。参考译文Unit 3 LipidsBelive yourself!You will succeed!