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1、Chapter 4 Processing technology of vegetable oil第四章第四章 植物油脂的加工工艺植物油脂的加工工艺Vegetable oils and fatsthe major components of foodanimportantsource of energy fat-soluble vitamins vitaminA vitamin E essential fatty acids linoleic acid linolenic acid arachidonic acidfeedmedicineindustrial applications1.Vari
2、eties and Compositions of Vegetable oilseeds植物油料种子的种类和组成植物油料种子的种类和组成1.1 Varieties of vegetable oilseeds植物油料种子的种类植物油料种子的种类Vegetable oils and fats are extractedfruitsoilseedsnutsoilseedsthe largest sources of vegetable oilsprotein-rich foodsClassification of oilseedsthe plant seeds and fruit pulp with
3、 oil content above 10%oilseedsoilseeds with high oil contentoilseeds with low oil content oil content 30%peanut colza cottonseed sesameClassification of oilseedsthe plant seeds and fruit pulp with oil content above 10%oilseedsoilseeds with high oil contentoilseeds with low oil content oil content 30
4、%oil content 20%Soybean rice bran corn embryo1.2 Structure of vegetable oilseeds植物油料种子的结构植物油料种子的结构testaembryoendospermorcotyledonhuskoutside of seed Protect:embryoendospermtestastorage proteinprotoplasm原生质体原生质体orspherosomeprotein bodiesoils1.3 Main components of oilseeds油料种子的主要化学成分油料种子的主要化学成分triglyc
5、eridesphospholipidssterolscarbohydratesproteinstocopherols pigments gossypol carotene chlorophyll1.3.1 Oil（油脂油脂）Definition of Lipids（脂质的定义脂质的定义）Lipids are defined as a wide variety of natural productsincluding fatty acids and their derivatives(steroids,terpenes,carotenoids,and bile acids),which is s
6、oluble inorganic solvents such as diethyl ether,hexane,benzene,chloroform,or methanol.脂质是天然食品中的一大类成分脂质是天然食品中的一大类成分，包括脂肪酸及其衍生包括脂肪酸及其衍生物物（如类固醇如类固醇、萜烯类萜烯类、类胡萝卜素类胡萝卜素、胆汁酸类胆汁酸类），它它们易溶于有机溶剂如乙醚们易溶于有机溶剂如乙醚、己烷己烷、苯苯、氯仿氯仿、甲醇等甲醇等。oiltriglyceride1 of glycerol3 of fatty acids12232OCORCH|OCOCHR|OCORCH(2)Physical c
7、haracteristics of oilacid valueiodine valuesaponification valueperoxide value Acid value（酸价酸价）Acid value is defined as the number of milligrams ofpotassium hydroxide required to neutralize the freeacids in 1g of sample.中和中和1g油脂样品中的游离脂肪酸所需的油脂样品中的游离脂肪酸所需的KOH mg数数。an index FFA content degree of lipidra
8、nciditythe degree of lipid rancidityAcid valuehighhighdifficult to storage与油脂的酸解有关，与不饱和度无关Free fatty acidNot exist in pure oilimmatured oilseedAbnormal storage or processingHydrolysisof oil Iodine value（碘价碘价）Iodine value(IV)measures the unsaturation degree oflipid and is defined as the number of gra
9、ms of iodineabsorbed by 100g of lipid.100g脂类样品所能吸收的碘脂类样品所能吸收的碘g数数，表示油脂的不饱和程度表示油脂的不饱和程度。the unsaturation degree of lipidiodine valuehighhighiodine valuelipidNon-drying oilSemi-drying oilDrying oilIV8080IV130 Peroxide value（过氧化值过氧化值）Peroxidevalueisdefinedasthemillimolesofperoxidises per kilogram of sa
10、mple.过氧化值是指过氧化值是指lkg油脂中过氧化物的毫摩尔数油脂中过氧化物的毫摩尔数。titrimetric(滴定滴定)determination2 Pretreatments of vegetable oilseeds植物油料的预处理植物油料的预处理Lipids in nature are associated with other moleculesinteraction between lipids and proteinscovalent bonding among lipids,carbohydrates,and proteins.Therefore,to obtain trig
11、lycerides with high yield andpurity from a complex cellular matrix,different chemicaland physical treatments must be administered.cleaningdehullingcrackingconditioningflakingexpandingcooking2.2 Dehulling of oilseeds油料的剥壳 Compared with meat,hulls always contain low oil content.20%without organic solv
12、ent low oil yieldlight colorgood flavor3.1.2 Principle of hard pressing压榨法制油的原理压榨法制油的原理During hard pressing,two different changes of the liquidsand solids in flaked cake will occur under the high pressure.在榨油过程中在榨油过程中，在强大压力的作用下在强大压力的作用下，榨料的液体部分和榨料的液体部分和固体部分发生固体部分发生2个不同的变化个不同的变化。oil squeezed from the
13、 flaked cakefirm cake formed by elastic deformationpressureviscosityformation of cakeprimary impetusessential conditionfactors affecting the hard pressingAs the flaked material is conveyed through the barrel cageof screw press,the surface of flaked material is enclosedinto plastic cake and the size
14、of pore on the internalsurface reduces quickly.当料坯在挤压机的榨笼内推进时当料坯在挤压机的榨笼内推进时，榨料的外表面被封闭形榨料的外表面被封闭形成塑性饼成塑性饼，内表面的孔道迅速缩小内表面的孔道迅速缩小。Till the pore reduces to a certain degree,atmospheric oilwill be changed into high pressure oil.孔道小到一定程度时孔道小到一定程度时，常压液态油变成高压油常压液态油变成高压油。If the pressure is high enough,the hig
15、h pressure oil willseparate from plastic cake.当压力大到一定程度时当压力大到一定程度时，高压油与塑性饼分离高压油与塑性饼分离。Hydraulic press machine液压榨油机液压榨油机Screw press machine螺旋榨油机螺旋榨油机3.2 Solvent extraction溶剂浸出法制油溶剂浸出法制油most widely used method3.2.1 Characteristics of solvent extraction浸出法制油的特点浸出法制油的特点high oil yieldresidual oil:0.51.0%
16、good quality of mealextraction vegetable proteinsolventflammabilityexplosivenesstoxicityunsafety for production poor quality of crude oilimpuritiesdark color3.2.2 Principle of solvent extraction溶剂浸出法制油的原理溶剂浸出法制油的原理leachingdiffusiondialysisconvective diffusionmolecule diffusionFor flakes,the larger p
17、roportion of easily extractable oil isderived from ruptured cells,especially near the surface.浸提过程中浸提过程中，大量油脂从油料细胞大量油脂从油料细胞（尤其是细胞表面尤其是细胞表面）中中溶出溶出。For flakes,the larger proportion of easily extractable oil isderived from ruptured cells,especially near the surface.The transfer of oil from distorted in
18、terior cells probably isgoverned by capillary flow,and the rate of oil transfer ispartly dependent on viscosity of the miscella.细胞内油脂的迁移主要依靠毛细管流动作用细胞内油脂的迁移主要依靠毛细管流动作用，迁移速率部迁移速率部分取决于混合油的黏度分取决于混合油的黏度。For flakes,the larger proportion of easily extractable oil isderived from ruptured cells,especially ne
19、ar the surface.The transfer of oil from distorted interior cells probably isgoverned by capillary flow,and the rate of oil transfer ispartly dependent on viscosity of the miscella.A portion of the slowly extracted oil is contained withinintact undistorted cells and must be transferred byosmosis.迁移速度
20、慢的油脂仍存在于完整的迁移速度慢的油脂仍存在于完整的、未破坏的细胞中未破坏的细胞中，必必须通过渗透作用来取得须通过渗透作用来取得。For flakes,the larger proportion of easily extractable oil isderived from ruptured cells,especially near the surface.The transfer of oil from distorted interior cells probably isgoverned by capillary flow,and the rate of oil transfer i
21、spartly dependent on viscosity of the miscella.A portion of the slowly extracted oil is contained withinintact undistorted cells and must be transferred byosmosis.This transfer is very slow.solventoilMiscella with more solventMiscella with more oilNearly all the cells are ruptured and the pellets ar
22、e porous,leaching process is very important.几乎所有油料的细胞被破坏几乎所有油料的细胞被破坏，且多孔性增加且多孔性增加，因而溶剂的浸润因而溶剂的浸润作用很重要作用很重要。3.2.5 Mode of solvent extraction浸出的方式浸出的方式direct solvent extractionprepress solvent extraction Direct solvent extraction（直接浸出直接浸出）Oil is directly extracted by solvent,without any priorpressing
23、or expanding.油料预先不经压榨而直接用溶剂浸提的方法油料预先不经压榨而直接用溶剂浸提的方法。soybeanoilseed with 20%oil Prepress solvent extraction（预榨浸出预榨浸出）Prepress solvent extraction means that a portion of theoil is removed from flaked material by hard pressingand the residual oil in the pressed cake is extracted withan organic solvent.
24、预榨浸出是指先利用压榨法取出榨料中的部分油脂预榨浸出是指先利用压榨法取出榨料中的部分油脂，然后用再有机溶剂浸提留在饼粕中的油然后用再有机溶剂浸提留在饼粕中的油。The prepressed and solvent-extracted oils are usuallymixed before refining.采用这两种工艺制得的油混合后进行精炼采用这两种工艺制得的油混合后进行精炼。pressed cakesoilseeds with 3050%oilcottonseedsunflowerseedpeanuthigh oil yield3.3 Supercritical fluid extrac
25、tion超临界流体萃取法制油超临界流体萃取法制油Supercritical fluid extraction means that oil is extractedfrom oilseed using fluid at supercritical state as extractionsolvent.超临界流体萃取技术是用超临界状态下的流体作为溶剂对超临界流体萃取技术是用超临界状态下的流体作为溶剂对油料中油脂进行萃取分离的技术油料中油脂进行萃取分离的技术。3.3.1 Principle of SC-CO2SC-CO2的原理的原理When carbon dioxide is compressed
26、 above its critical point(temperature of 31.1C and pressure of 7.3MPa),it doesnot liquify but attains a viscosity with gaseous state thatbehaves like a solvent.CO2的临界温度为的临界温度为31.1，临界压力为临界压力为7.3MPa。高于临界高于临界点时点时，CO2不液化不液化，但是具有接近于气体的黏度但是具有接近于气体的黏度、表现出表现出液体密度的状态液体密度的状态。Thus,it is called supercritical CO
27、2(SC-CO2).30MPa,liquid4530MPaSC-CO24590MPaoil456MPaGas CO2water-5-106MPaliquid3.3.2 Characteristics of SC-CO2SC-CO2的特点的特点 reduces the use of organic solvents,avoids waste disposalproblems,eliminates the use of potentially toxic andflammable solvents,and reduces the extraction time.利用超临界利用超临界CO2萃取油脂能
28、够大大降低有机溶剂的使用萃取油脂能够大大降低有机溶剂的使用，避免油脚处理问题避免油脚处理问题，免于使用有毒和易燃的溶剂免于使用有毒和易燃的溶剂，缩短萃缩短萃取时间取时间。3.3.2 Characteristics of SC-CO2SC-CO2的特点的特点 reduces the use of organic solvents,avoids waste disposalproblems,eliminates the use of potentially toxic andflammable solvents,and reduces the extraction time;not subject
29、ed to high temperatures采用这种方法萃取油脂不需要高温条件采用这种方法萃取油脂不需要高温条件。3.3.2 Characteristics of SC-CO2SC-CO2的特点的特点 reduces the use of organic solvents,avoids waste disposalproblems,eliminates the use of potentially toxic andflammable solvents,and reduces the extraction time;not subjected to high temperatures;oil
30、 recovery of 97%;油脂的提取率油脂的提取率97%3.3.2 Characteristics of SC-CO2SC-CO2的特点的特点 reduces the use of organic solvents,avoids waste disposalproblems,eliminates the use of potentially toxic andflammable solvents,and reduces the extraction time;not subjected to high temperatures;oil recovery of 97%;The main
31、drawback of SC-CO2is of expensive equipmentsand the extraction of nonfat materials,such as water.SC-CO2萃取油脂的缺点是设备昂贵萃取油脂的缺点是设备昂贵，提取过程中水等非脂物质一同被萃取出来提取过程中水等非脂物质一同被萃取出来。3.4 Aqueous extraction水溶剂法制油水溶剂法制油Aqueous extraction is an oil extraction method accordingtotheoilseedcharacteristics,differencesbetwee
32、nphysicochemical properties of oil and water(such as oil isdissoluble in water,while protein is soluble in water,oil islighter than water).The extraction solvent is usually water.水溶剂法制油是根据油料特性水溶剂法制油是根据油料特性，水水、油物理化学性质的差异油物理化学性质的差异，以水为以水为溶剂溶剂，采取一些加工技术将油脂提取出来的制油方法采取一些加工技术将油脂提取出来的制油方法。通常情况下通常情况下，油不溶于水油不
33、溶于水，而蛋白质可溶于水而蛋白质可溶于水，并且油比水轻并且油比水轻。Supercritical CO 2 extraction has been used for the extraction of microalgal,antioxidant pigment at industrial scale but to our knowledge,supercritical fluid extraction(SFE)has not been bused yet for the industrial extraction of vegetable oils.CO 2 contributed posit
34、ively on the oxidative stability due to an increase in the amount of antioxidant components.For instance,the content of phytosterolincreased by 51%compared to the hexane extracted oil.Aqueous enzyme-assisted extraction(AEE)is an environmentally friendly alternative technology for the extraction of e
35、dible oil from seeds.Oil extracted using this method is considered superior in quality and is also safe for human consumption as it does not use toxic solvents such as hexane.Enzymes such aspectinases,cellulases,and hemicellulases break the structureof the cotyledon of grounded or flaked seeds,makin
36、g theseeds structure permeable and hence facilitates the release ofoil from the cotyledons cell walCharacteristics of aqueous extraction method eliminates the use of potentially toxic and flammablesolvents.以水为溶剂以水为溶剂，食品安全性好食品安全性好，无有机溶剂近体的易燃无有机溶剂近体的易燃、易爆之虑易爆之虑。Characteristics of aqueous extraction me
37、thod eliminates the use of potentially toxic and flammablesolvents.obtaining oil of high quality and low denatured protein.在制取高品质油脂的同时在制取高品质油脂的同时，可以获得变性程度较小的蛋可以获得变性程度较小的蛋白质以及淀粉渣等产品白质以及淀粉渣等产品。Characteristics of aqueous extraction method eliminates the use of potentially toxic and flammablesolvents.ob
38、taining oil of high quality and low denatured protein.Oil with light color,low acid value,good quality.水剂法提取的油脂颜色浅水剂法提取的油脂颜色浅，酸价低酸价低，品质好品质好，无需精炼无需精炼即可作为食用油即可作为食用油。Characteristics of aqueous extraction method eliminates the use of potentially toxic and flammablesolvents.obtaining oil of high quality
39、and low denatured protein.Oil with light color,low acid value,good quality.The oil yield of aqueous method lies between solventextraction and hard pressing.与浸出法相比与浸出法相比，水剂法的出油率稍低；与压榨法相比水剂法的出油率稍低；与压榨法相比，水剂法的工艺路线长水剂法的工艺路线长。机械压榨法制油、溶剂浸提法、SC-CO2、水溶剂法制油各自的原理、优缺点？原理优缺点：提油率、安全性、油的品质（色泽、风味、滋味）、设备损耗4 Refinem
40、ent of vegetable oil油脂的精炼油脂的精炼Crude oil means the unrefined vegetable oil extracted byhard pressing or solvent extraction.经压榨或浸出法得到的经压榨或浸出法得到的、未经精炼的植物油脂一般称之为未经精炼的植物油脂一般称之为毛油毛油（粗油粗油）。Consumers usually want bland-flavored or flavor-neutral,light-colored,and stable oils.消费者通常希望食用油具有气味纯正消费者通常希望食用油具有气味纯正
41、、色泽浅色泽浅、稳定性高稳定性高的特点的特点。Crude oils are usually unsuitable for eating until numerousnonglyceridecompoundshavebeenremoved,whichknown as refining.毛油只有脱除大量非脂杂质后才能食用毛油只有脱除大量非脂杂质后才能食用，这一过程也称为这一过程也称为精炼精炼。degummingsmall amount of proteinphosphatidesundesirable natural flavors and odorsfatty acidspigmentswaxw
42、atercrude oildeodorizationremoving FFAbleachingdewaxing毛油中的杂质种类有哪些，对制油工艺有怎样的影响？4.1 Degumming（脱胶）（脱胶）Phosphatidescanbespontaneouslyhydratedduringstorage.所以脱胶又称为脱磷所以脱胶又称为脱磷。Hydration makes phosphatides insoluble in the oil,andprecipitating.Oil becomes unattractive because of unsightly sludge orgums.Ph
43、osphatides can degrade and cause dark colors when theoil is heated as in the later deodorization step.Phosphatides are also surfactants.If present in frying oils,it can cause dangerous foaming.Phosphatides,also known as lecithin,are important foodemulsifiers.hydration degummingheat degummingacid deg
44、umming Hydration degumming（水化法脱胶水化法脱胶）The gums are insoluble in oil by hydrating with 13%water.在油中加入在油中加入13%的水的水，使磷脂水化使磷脂水化，则导致胶溶性物则导致胶溶性物质不溶于油中质不溶于油中。加入加入磷酸或柠檬酸磷酸或柠檬酸可以促进非水化磷脂转化为水化型可以促进非水化磷脂转化为水化型磷脂磷脂settlingfilteringcentrifugatingremove 90%of phosphatide4.2 Neutralization(Alkali refining,removing
45、FFA)（中和、碱炼，脱酸）（中和、碱炼，脱酸）the most important proceduresoapstockcentrifugation4.3 Bleaching（脱色）（脱色）The purpose of bleaching:to improve oil color by removing pigments with neutral clays,activated earths,and carbon black;breakdown of peroxides;cleanup of residual traces of soaps and phosphatides.pigmentc
46、arotenoidsgossypolchlorophyllred-browngreen4.4 Dewaxing（脱蜡）（脱蜡）Waxes can harm the appearance of bottled oil by causingcloudiness or sediments.corn oilrice bran oilsesame oilsunflower oilWinterization68centrifugation4.5 Deodorization（脱臭）（脱臭）The objective of deodorization:to remove compounds responsib
47、le for undesirable odorsand flavors.to remove peroxide decomposition products.alcoholsFFAketonessteam distillationAlthough deodorizaton removes most peroxides,it cannotreclaim rancid oxidized oils.虽然脱臭可以去除大部分过氧化物虽然脱臭可以去除大部分过氧化物，但氧化酸败的油脂不但氧化酸败的油脂不能通过脱臭改善质量能通过脱臭改善质量。Generally,deodorized oils have impr
48、oved flavor,odor,andcolor.一般的一般的，脱臭油的风味脱臭油的风味、气味及色泽均有很大的改善气味及色泽均有很大的改善。Question/思考题名词解释acid value问答题问答题Please describe the method and mechanism of oil refiningPlease describe the method and mechanism of oil refining（植物油精炼）（植物油精炼）.Please describe the conception,mechanism and Please describe the conception,mechanism and characteristics of four kinds for oil processing technology.characteristics of four kinds for oil processing technology.Briefly describe the pretreatment of vegetable oils Briefly describe the pretreatment of vegetable oils processingprocessing（植物油预处理）（植物油预处理）