(1.2)--Chapter 2 paddy to rice粮油食品工艺学.pdf

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1、Chapter 2 Processing technology of paddy into rice（稻谷制米）稻谷制米）2-1 Primary processing of paddy 稻谷的初加工稻谷的初加工Paddy ranks the second in world crop production.稻谷是第二大谷物稻谷是第二大谷物。The planting area of paddy is about 1/5 of total crops inthe world.全世界稻谷种植面积占谷物总面积的全世界稻谷种植面积占谷物总面积的1/5。At least two-third of the p

2、opulation in our country dependson rice as its main staple.我国约我国约2/3的人口以大米为主食的人口以大米为主食。早 籼 稻早 籼 稻(early(early longlong-graingrainnonglutinousnonglutinouspaddy)paddy)分布在全国分布在全国1313个省个省、自治区自治区，主产主产8 8省：省：湖南湖南江西江西广西广西广东广东湖北湖北安徽安徽福建福建浙江浙江海南海南、云南云南、贵州贵州、四四川川、重庆的产量很小重庆的产量很小Paddy is a semi-aquatic,annual g

3、rass.水稻是一种半水生的水稻是一种半水生的、一年生的植物一年生的植物。It can be grown under a broad range of climatic conditions.种植的气候条件宽广种植的气候条件宽广。Cultivated paddy is designated as either Oryza sativa L.（亚洲栽培稻亚洲栽培稻）or Oryza glabberrima（非洲栽培稻非洲栽培稻）.Predominant speciesOnlyin AfricaThe main purpose of paddy processing is to improve t

4、heedible quality of paddy.稻谷加工是为了提高其食用品质稻谷加工是为了提高其食用品质。lower protein content Higher digestibilityand absorption ratiolower crude fiber contentHigher nutritive valueSteamed ricepleasant flavorrice noodlessticky and deliciousrice winerice cakesriceTwo methods to process paddyWet processing methoddry p

5、rocessing methodCleaning清理清理rice milling碾米碾米husking and separating of post-husking mixture砻谷砻谷及砻下物分离及砻下物分离handling of finished products and by-products成品及副产品整理成品及副产品整理dry processing method1.Processing quality of paddy稻谷的工艺品质稻谷的工艺品质Many factors affect the paddy processing.Processing quality is the in

6、herent properties of paddy whichaffect the processing effects.稻谷的加工受到很多因素的影响稻谷的加工受到很多因素的影响，而稻谷本身所具有的影响加而稻谷本身所具有的影响加工工艺效果的特性称为工艺性质工工艺效果的特性称为工艺性质。Grain shape and structureChemical compositionsPhysical propertiesMilling yieldQuality of finished productsVarieties and gradesMilling degreeprocessing metho

7、d1.1 Classification,kernel structure and chemical composition of paddy（稻谷的分类、籽粒结构和化学组成）（稻谷的分类、籽粒结构和化学组成）1.1.1 Classification of paddy（稻谷的分类）（稻谷的分类）According to the standard of GB1350-2009,paddy in China can be classified as follows:Late long-grain nonglutinous paddy晚籼稻谷晚籼稻谷Early long-grain nonglutin

8、ous paddy早籼稻谷早籼稻谷Medium to short-grain nonglutinous paddy粳稻谷粳稻谷Long-grain glutinous paddy籼糯稻谷籼糯稻谷Round-grain glutinous paddy粳糯稻谷粳糯稻谷1.1.1 Classification of paddy（稻谷的分类）（稻谷的分类）According to the standard of GB1350-2009,paddy in China can be classified as follows:Late long-grain nonglutinous paddy晚籼稻谷晚籼

9、稻谷Early long-grain nonglutinous paddy早籼稻谷早籼稻谷Medium to short-grain nonglutinous paddy粳稻谷粳稻谷Long-grain glutinous paddy籼糯稻谷籼糯稻谷Round-grain glutinous paddy粳糯稻谷粳糯稻谷white belly:large;Expansion:strong;Viscosity:weak;broken rice:easy.1.1.1 Classification of paddy（稻谷的分类）（稻谷的分类）According to the standard of G

10、B1350-2009,paddy in China can be classified as follows:Late long-grain nonglutinous paddy晚籼稻谷晚籼稻谷Early long-grain nonglutinous paddy早籼稻谷早籼稻谷Medium to short-grain nonglutinous paddy粳稻谷粳稻谷Long-grain glutinous paddy籼糯稻谷籼糯稻谷Round-grain glutinous paddy粳糯稻谷粳糯稻谷white belly:small or no;Expansion:strong;Visc

11、osity:weak;broken rice:easy.1.1.1 Classification of paddy（稻谷的分类）（稻谷的分类）According to the standard of GB1350-2009,paddy in China can be classified as follows:Late long-grain nonglutinous paddy晚籼稻谷晚籼稻谷Early long-grain nonglutinous paddy早籼稻谷早籼稻谷Medium to short-grain nonglutinous paddy粳稻谷粳稻谷Long-grain gl

12、utinous paddy籼糯稻谷籼糯稻谷Round-grain glutinous paddy粳糯稻谷粳糯稻谷Shape:oval;white belly:small or no;Expansion:weak;Viscosity:strong;broken rice:difficult.1.1.1 Classification of paddy（稻谷的分类）（稻谷的分类）According to the standard of GB1350-2009,paddy in China can be classified as follows:Late long-grain nonglutinou

13、s paddy晚籼稻谷晚籼稻谷Early long-grain nonglutinous paddy早籼稻谷早籼稻谷Medium to short-grain nonglutinous paddy粳稻谷粳稻谷Long-grain glutinous paddy籼糯稻谷籼糯稻谷Round-grain glutinous paddy粳糯稻谷粳糯稻谷Shape:oval;Color:ivory-white;Opaque,or semi-transparent;white belly:small or no;Viscosity:strong.1.1.1 Classification of paddy1

14、.1.1 Classification of paddy（稻谷的分类）（稻谷的分类）According to the standard ofAccording to the standard of GB1350GB1350-20092009,paddy in,paddy in China can be classified as follows:China can be classified as follows:Late long-grain nonglutinous paddy晚籼稻谷晚籼稻谷Early long-grain nonglutinous paddy早籼稻谷早籼稻谷Medium

15、 to short-grain nonglutinous paddy粳稻谷粳稻谷Long-grain glutinous paddy籼糯稻谷籼糯稻谷Round-grain glutinous paddy粳糯稻谷粳糯稻谷Shape:oval or slimline type;Color:ivory-white;Opaque or semi-transparent;Viscosity:strong.1.1.2 Grain shape and structure of paddy稻谷子粒的形态结构稻谷子粒的形态结构Glume(hull)颖（外壳）颖（外壳）caryopsis(brown rice)糙

16、米糙米Brown rice is the husked paddy.制米加工中稻壳经砻谷机脱去而成为颖果，又称为糙米。制米加工中稻壳经砻谷机脱去而成为颖果，又称为糙米。Brown rice糙米糙米pericarp and seed coat:2%nucellar layer and aleurone layer:56%Embryo:2.53.5%;Rice bran米糠米糠Endosperm:8893%high nutrient valuepericarpRich in:ProteinFatdiet fibervitamin B mineralseed coataleurone layer1.

17、1.3 Chemical composition of paddy稻谷的化学成分稻谷的化学成分waterproteinmineralfiberstarchfatvitaminProtein content in rice endosperm is 78%,while thebiological value(生物价生物价)of rice protein is one of thehighest in all of the grain protein.虽然大米胚乳中的蛋白质含量较少虽然大米胚乳中的蛋白质含量较少（78%），但它是谷但它是谷物蛋白质中生理价值最高的一种物蛋白质中生理价值最高的一种。P

18、rotein content in rice endosperm is 78%,while thebiological value(生物价生物价)of rice protein is one of the highestin all of the grain protein.Amino acid content is balanced in rice protein.Lysine(赖氨酸赖氨酸)is about 3.5%of the total rice protein.其氨基酸组成比较平衡其氨基酸组成比较平衡，赖氨酸含量约占总蛋白的赖氨酸含量约占总蛋白的3.5%。Protein conten

19、t in rice endosperm is 78%,while thebiological value(生物价生物价)of rice protein is one of highest inall of the grain protein.Amino acid protein is balanced in rice protein.Lysine(赖氨酸赖氨酸)is about 3.5%of the total rice protein.The main protein in rice is rice glutelin(米谷蛋白米谷蛋白),which isabout 80%of the tot

20、al rice protein.大米蛋白质以米谷蛋白为主要组成大米蛋白质以米谷蛋白为主要组成，约占总蛋白的约占总蛋白的80%。Protein content in rice endosperm is 78%,while the biologicalvalue(生物价生物价)of rice protein is one of highest in all of the grainprotein.Amino acid protein is balanced in rice protein.Lysine(赖氨酸赖氨酸)is about 3.5%of the total rice protein.Th

21、e main protein in rice is rice glutelin(米谷蛋白米谷蛋白),which isabout 80%of the total rice protein.Other three proteins in rice are albumin(清蛋白清蛋白),globulin(球蛋球蛋白白)and prolamine(醇溶蛋白醇溶蛋白).Prolamine content is the lowest in rice protein,which is onlyabout 35%of total protein.其它三种为清蛋白其它三种为清蛋白、球蛋白和醇溶蛋白球蛋白和醇溶

22、蛋白，其中以醇溶蛋白含量其中以醇溶蛋白含量最低最低，仅占总蛋白的仅占总蛋白的35%。Starch:7780%Amylopectin支链淀粉支链淀粉Amylose直链淀粉直链淀粉 Almostamylopectin inglutinous rice About 20%amyloseinround-grain rice Thehighestamylosecontentin long-grain riceAmyloseEdible qualityhigherlower Long-grainrice is suitablefor rice noodle.Round-grain rice andglut

23、inousriceissuitable for rice cake oreat directly.The vitamin and mineral content in rice are lower thanthose in paddy,resulting in lower nutrient value.大米中维生素和矿物质含量较低大米中维生素和矿物质含量较低，比稻谷原粒中的含量低比稻谷原粒中的含量低，导致了营养价值的下降导致了营养价值的下降.Parboiled rice蒸谷米蒸谷米 Fortified rice强化米强化米1.2 Physical properties of paddy稻谷子粒

24、的物理性质稻谷子粒的物理性质 Husk content（谷壳率谷壳率）Husk content is the percentage of husk to clean paddy.是指稻壳占净稻谷质量的百分率是指稻壳占净稻谷质量的百分率。Husk contentLate paddyLong-grain paddyEarly paddyRound-grain paddyLower thanLower thanCrossbreaking means the transverse crack on the ricegrain.米粒上的横向裂纹称为爆腰米粒上的横向裂纹称为爆腰。Crossbreaking

25、percentagemeansthepercentageofcracked rice to the test samples.爆腰率是指爆腰米粒占试样的百分率爆腰率是指爆腰米粒占试样的百分率。Broken rice Milling yield Unsuitable for rice ofhigh qualityPercentage of brown rice（出糙率出糙率）Percentage of brown rice is the percentage of the totalbrown rice quality(the quality of unsound kernel iscalcul

26、ated by the half)to the test paddy quality.指一定数量稻谷全部脱壳后获得全部糙米质量指一定数量稻谷全部脱壳后获得全部糙米质量（其中其中不完善粒折半计算不完善粒折半计算）占稻谷质量的百分率占稻谷质量的百分率。An important index Evaluate the qualityandgradeofcommercial paddyHigh husk contentdifficultbe huskedLowpercentage of brown rice So is the reverse.Cleaning清理清理rice milling碾米碾米hu

27、sking and separating of post-husking mixture砻谷及砻下物分离砻谷及砻下物分离handling of finished products and by-products成品及副产品整理成品及副产品整理dry processing method小型大米小型大米加工成套机组加工成套机组2 Clean of paddy稻谷的清理稻谷的清理2.1 Purpose and demand of clean清理的目的与要求清理的目的与要求Impurity substancesSeed selectionplantingdryingshellingharveststo

28、ragetransportPurpose of clean:Guarantee the safety storage and reduce the harmduring processing of paddy,such as stone,metal,etc;Improve the efficiency of machine,such as impuritywith large volume;Affect the health of workers,such as the smallimpurity of silt,dust,etc;Improve the purity and quality

29、of finished products.The primary objective of rice processing:to clean and remove impurity.因此加工的首要任务是清理除杂。因此加工的首要任务是清理除杂。Requirement of clean:Husking with cleaned paddy.稻谷清理要力求做到净谷上砻稻谷清理要力求做到净谷上砻。Impurity in cleaned paddy before husking should belower than 0.6%.进入砻谷工段的净谷含杂总量不应超过进入砻谷工段的净谷含杂总量不应超过0.6%

30、。Among the cleaned paddy,sand and stone should belower than 1 grain/kg;barnyard grass should be lowerthan 30 grain/kg.其中其中，含沙石不应超过含沙石不应超过1粒粒/kg；含稗不应超过；含稗不应超过30粒粒/kg。2.2 Method and mechanism of clean清理的方法及机理清理的方法及机理The principle of cleaning:According to the difference between the physicalproperties o

31、f impurity and paddy.清理的主要原理是借助杂质与谷物物理性质的不同进清理的主要原理是借助杂质与谷物物理性质的不同进行分选行分选。Method,mechanism,machine and function of paddy cleaning稻谷清理的方法、原理、常用设备及作用稻谷清理的方法、原理、常用设备及作用Method,mechanism,machine and function of paddy cleaning稻谷清理的方法、原理、常用设备及作用稻谷清理的方法、原理、常用设备及作用Method,mechanism,machine and function of pad

32、dy cleaning稻谷清理的方法、原理、常用设备及作用稻谷清理的方法、原理、常用设备及作用The continued table续上表续上表The continued table续上表续上表The continued table续上表续上表The indexes to evaluate the cleaning effect are:separation ratio of clean paddy(净粮提取率)removal ratio of impurity(杂质去除率)100 100 清理前杂质量清理后杂质量清理前杂质量杂质去除率清理前净谷量清理后净谷量净粮提取率%100cleaning

33、beforequalityimpuritycleaningafterqualityimpuritycleaningbeforequalityimpurityimpurityofratioremoval%100cleaningbeforepaddytotalofqualitycleaningafterpaddycleanofqualitypaddycleanofratioseparation 100 100 清理前杂质量清理后杂质量清理前杂质量杂质去除率清理前净谷量清理后净谷量净粮提取率%100cleaningbeforequalityimpuritycleaningafterqualityim

34、puritycleaningbeforequalityimpurityimpurityofratioremoval%100cleaningbeforepaddytotalofqualitycleaningafterpaddycleanofqualitypaddycleanofratioseparationCleaning清理清理rice milling碾米碾米husking and separating of post-husking mixture砻谷及砻下物分离砻谷及砻下物分离handling of finished products and by-products成品及副产品整理成品及副

35、产品整理dry processing method3 Husking and separation of post-husking mixture砻谷及砻下物分离砻谷及砻下物分离Husking means the technological procedure of removingthe husk from paddy.稻谷加工中脱去稻壳的工艺过程称为砻谷稻谷加工中脱去稻壳的工艺过程称为砻谷。Paddy is unsuitable to be milled directly.high energy consumptionlow outputhigh broken rice contentlo

36、w milling yieldpoor in color,purity and quality of finished products.Thus,clean paddy must be husked first before milling inmodern milling factory.因此因此，现代化碾米工厂中现代化碾米工厂中，净稻均需砻谷后净稻均需砻谷后，才能进行碾才能进行碾米米。The post-husking mixture means the mixtures after thehusking of paddy.稻谷砻谷后的混合物称为稻谷砻谷后的混合物称为砻下物砻下物。Brow

37、n riceGreen paddyBrokenbrown riceRough branhuskUn-husked paddyThe husking procedure is composed as follows:砻谷工段的组成如图所示砻谷工段的组成如图所示:Un-husked paddy 未脱壳谷粒未脱壳谷粒 Handling of hull broken brown rice 稻壳整理稻壳整理 碎糙米碎糙米 Handling of hull broken brown rice 稻壳整理稻壳整理 碎糙米碎糙米 Clean paddy huller husk separation husk r

38、ice separation brown rice grading clean brown rice 净谷净谷 砻谷机砻谷机 谷壳分离谷壳分离 谷糙分离谷糙分离 糙米分级糙米分级 净糙净糙 3.1 Husking（砻谷）（砻谷）According to the structural characteristics of paddy,husking is operated by the mechanical force from the rice-huller.砻谷是根据稻谷结构的特点砻谷是根据稻谷结构的特点，由砻谷机施加一定的机械力由砻谷机施加一定的机械力而实现的而实现的。The patter

39、n of mechanical forceStrike husking撞击脱壳撞击脱壳End pressure rubbing husking端压搓撕脱壳端压搓撕脱壳Extrude rubbing husking挤压搓撕脱壳挤压搓撕脱壳3.1.1 Extrude rubbing husking挤压搓撕脱壳挤压搓撕脱壳Extrude rubbing husking meansthat the rice husk is removed byextruding and rubbing between twoworkingsurfacesmovingatdifferent speed on both

40、sides ofpaddy.挤压搓撕脱壳是指谷粒两侧受两个挤压搓撕脱壳是指谷粒两侧受两个不等速运动的工作面的挤压不等速运动的工作面的挤压、搓撕搓撕而脱去颖壳的方法而脱去颖壳的方法。Rubber roller husker(胶辊砻谷机胶辊砻谷机)Rubber roller husker(胶辊砻谷机胶辊砻谷机)made of either elastic rubber(橡胶橡胶辊辊)or polyester synthetic(聚酯聚酯);moved in relation to each other atdifferent speed(相向不等速运动相向不等速运动);causing the hu

41、sk to be cracked andseparated from the brown rice underthe force of extruding and rubbing.3.1.2 End pressure rubbing husking端压搓撕脱壳端压搓撕脱壳End pressure rubbing husking meansthat the rice husk is removed by pressingandrippingbetweentwoworkingsurfaces moving at different speed onboth lengthwise ends of p

42、addy.端压搓撕脱壳端压搓撕脱壳是指谷粒长度方向的两端是指谷粒长度方向的两端受两个不等速运动的工作面的挤压受两个不等速运动的工作面的挤压、搓搓撕而脱去颖壳的方法撕而脱去颖壳的方法。Emery sheller(disk husker,砂盘砻谷机砂盘砻谷机)3.1.3 Strike husking撞击脱壳撞击脱壳Strike husking means that the rice husk isremoved by the collision between movinggrain with high speed and fixed working face.撞击脱壳撞击脱壳指高速运动的粮粒与固

43、定工作面撞指高速运动的粮粒与固定工作面撞击而脱去颖壳的方法击而脱去颖壳的方法。Centrifugal husker(离心砻谷机离心砻谷机)3.2 Husk separation谷壳分离谷壳分离Husk separation means the process of the paddy huskseparated from the post-husking mixtures.谷壳分离谷壳分离是指从砻下物中将稻壳分离出来的过程是指从砻下物中将稻壳分离出来的过程。After husk separation:paddy grain in every 100kg rice husk should be

44、no morethan 30 grains;砻下物经稻壳分离后砻下物经稻壳分离后，每每100kg稻壳中含饱满粮粒不应稻壳中含饱满粮粒不应超过超过30粒；粒；rice husk in post-husking mixtures should be no morethan 1.0%(0.8%for emery sheller);谷糙混合物中含稻壳量不应超过谷糙混合物中含稻壳量不应超过1.0%(胶砻为胶砻为0.8%)；rice husk in brown rice should be no more than 0.1%.糙米中含稻壳量不应超过糙米中含稻壳量不应超过0.1%。Husk separati

45、on is mainly based on the difference in physicalproperties between rice husk and brown rice.谷壳分离主要利用稻壳与谷糙在物理性质上的差异使之相互谷壳分离主要利用稻壳与谷糙在物理性质上的差异使之相互分离分离。As husk and brown rice is highly different in suspensionvelocity,pneumatic separating(airflow separation)is themost popular way of husk separation.由于稻壳

46、与谷糙在悬浮速度上存在较大的差异由于稻壳与谷糙在悬浮速度上存在较大的差异，风选法风选法是谷是谷壳分离的首选方法壳分离的首选方法。For most rice huskers,husk separation device is mounted onthe lower part.一般砻谷机的下部均带有谷壳分离装置一般砻谷机的下部均带有谷壳分离装置。3.3 Separation for paddy and brown rice(husk rice separation)谷糙分离谷糙分离The purpose of husk rice separation:to separate the brown r

47、ice from the un-husked paddyafter husk separation.谷糙分离是对分离稻壳后的砻下物进行分选谷糙分离是对分离稻壳后的砻下物进行分选，使糙米与未使糙米与未脱壳的稻谷分开脱壳的稻谷分开。There are two methods for husk rice separation.sifting by the difference in granularity between paddy and brown ricethe difference of density,elasticity and superficial properties betwee

48、n paddy and brown ricescreening by screen sieveCleaning清理清理rice milling碾米碾米husking and separating of post-husking mixture砻谷及砻下物分离砻谷及砻下物分离handling of finished products and by-products成品及副产品整理成品及副产品整理dry processing method4 Rice milling碾米碾米The purpose of rice milling:to remove the rice bran from the su

49、rface of brown rice.碾米的目的主要是碾除糙米的皮层碾米的目的主要是碾除糙米的皮层。Nutrients in rice brandifficult to storageLow edible qualityproteinfatfiberPoor dilatability膨胀性膨胀性Poor moisture absorptionThe rice bran removing degree is an important parameterto judge rice milling degree.糙米去皮的程度是衡量大米加工精度的依据糙米去皮的程度是衡量大米加工精度的依据。The

50、more rice bran is removed,the higher milling degreeof rice will be in the process.即糙米去皮越多即糙米去皮越多，成品大米精度越高成品大米精度越高。Two basic methods of rice milling：chemical milling（化学碾米）（化学碾米）mechanical milling（机械碾米）（机械碾米）Mechanical milling is the most popular method in theworld.世界各国普遍使用的碾米方法是机械碾米世界各国普遍使用的碾米方法是机械碾米