粮油加工工艺学 课件 Chapter 6 淀粉加工

第六章

淀粉加工Chapter6Starchprocessing第五章

淀粉加工Chapter5Starchprocessing教学要求：知识要求：1.掌握淀粉生产的基本工艺流程；2.了解淀粉的性质；3.掌握淀粉制糖工艺。能力要求：1.具备实际生产淀粉的能力；2.根据淀粉的性质，开发相应的产品。素质要求：1.培养创新精神，严谨的科学素养淀粉组成StarchComposition01CONTENTS目录淀粉性质Starchproperties02淀粉分离Starch

Isolation03淀粉制糖Starch

hydrolysates04一、

淀粉组成StarchComposition直链淀粉（Amylose）

D-葡萄糖基以a-(1,4)糖苷键连接的多糖链聚合度（degreeofpolymerization，DP）:180-320,分子量（molecularweight，MW）~106.Branchapproximatelyevery200glucoseunits支链淀粉（Amylopectin）a-（1，4）糖苷键的糖链外，还有a-（1，6）糖苷键连接的分支MW~108Amylose:amylopectin~1:3WaxystarchesallamylopectinHighamyloseupto70%amylose第五章

淀粉加工Chapter5StarchprocessingAmyloseLinearcomponentofstarch1,4-α-糖苷键Molecularweight:lessthan0.5million可形成线圈（coils），包埋碘（iodine）而变蓝第六章

淀粉加工Chapter5StarchprocessingAmylopectinBranchedcomponentofstarchContains1,4-alpha-glucosidicaswellas1,6-alpha-glucosidicbondsMolecularweight:50-500millionLimitedcoilingcausespurplish-red（紫红色）colorwheniodineadded第五章

淀粉加工Chapter5StarchprocessingStarchGranule支链淀粉在同心圆中形成，直链淀粉分散在中间通过氢键结合在一起颗粒在水中受热时发生溶胀由于淀粉具有不溶于冷水和比重大于水两个基本特征，这是淀粉得以制取的根本原因。由于制取淀粉的过程中需要大量用水，故有“水磨法”之称（wet-milled）。第五章

淀粉加工Chapter5Starchprocessing

Amaranth（苋菜籽）starch(Bar:1µm)Arrowroot（竹芋）starch

(Bar:20µm)Buckwheat（荞麦）starch

(Bar:5µm)

Cassava[kəˈsɑ:və]starch

(Bar:10µm)Cornstarch

(Bar:10µm)Oatstarch

(Bar:5µm)

Potatostarch

(Bar:50µm)Ricestarch

(Bar:2µm)Kidneybeanstarch

(Bar:20µm)二、淀粉性质

Starchproperties1.糊化（Pasting）、糊化（胶凝）（Gelatinization）当淀粉在水中加热时,氢键断裂，水进入颗粒,颗粒膨胀,直链淀粉从颗粒中迁移出来水和支链淀粉之间的氢键增加自由水的减少改变了淀粉混合物的粘度，使其增稠第五章

淀粉加工Chapter5StarchprocessingStarchgelatinizationisthecollapse(disruptionofmolecularorder)withinthestarchgranule,manifestedinirreversiblechangesinproperties

suchasgranularswelling,nativecrystallinemelting,lossofbirefringence（双折射）

andstarchsolubilization.”Unheatedpotatostarchgranule（25℃）Heatedstarchgranule1.糊化（Pasting）、糊化（胶凝）（Gelatinization）“Pastingisthephenomenonfollowinggelatinizationinthedissociationofstarch.

Pasting是淀粉在解离过程中发生糊化后的现象Itinvolvesgranularswelling,exudation渗出ofmolecularcomponentsfromthegranule;andeventuallythetotaldisruptionofthegranules.”第五章

淀粉加工Chapter5StarchprocessingRaw,uncookedstarchgranulesheatedinwaterSwellingisevidentNoticelossofamylosefromthegranulesGelatinizationandpastingarecomplete

Somegranuleshavecollapsed.Nowwestarttocool.GelationNoticeareasofassociation.Thesearecalledjunctionzones.Thispictureisnotyetcompleteaswehaven’taccountedforthewaterinthesystem.waterwaterwaterwaterwaterwaterThisisastarchgelEffectofcontinuousheatinginexcesswaterResultsinformationofstarchpastedueto:furthergranuleswellingbeyondreversiblepointadditionalleachingofsolublecompoundstotaldisruptionofgranulesViscosityandTypeofStarch纤维素纳米晶对甘薯淀粉糊化特性的影响Gel

连接起来的分子或粒子形成的连续的三维网络，将大量的连续液相包裹起来，就像海绵一样在许多食品中，凝胶网络由聚合物分子或由聚合物分子通过氢键、疏水缔合、离子交叉桥、缠结或共价键连接在结合部位形成的纤维组成，液相是低分子量溶质和部分聚合物链的水溶液。三、淀粉分离StarchIsolationStarchcanbeextractedusingvariousprocesses,dependingontheplantsourceandenduseofthestarch.Wetmillingprocessingiswidelyusedincerealstarchproduction.

湿磨加工在谷物淀粉生产中应用广泛。Thepurposeofwetmillingistoseparatethekernel(grain)intoitsconstituentchemicalcomponents.湿磨的目的是将籽粒(谷物)分离成其组成化学成分Figure7.1presentsthemajorproceduresforextractingstarchesfromcerealgrainsandtubers.第五章

淀粉加工Chapter5Starchprocessing玉米淀粉生产的基本工艺流程Themainpurposesofthesteepingprocessaretoloosenthegranulesinthepackedcellstructure.

浸泡过程的主要目的是疏松堆积细胞结构中的颗粒。flashdryer气流干燥器四、淀粉制糖Starchhydrolysates淀粉糖是以淀粉为原料，通过酸或酶的催化水解反应生产的糖品的总称，是淀粉深加工的主要产品。Thehydrolysisofstarchtosweetenersbymineralacidwasdiscoveredin1811.Enzymesareemployedtoproducestarchfromsyrupswithapreponderanceofmaltoseorglucoseandtoisomerizesomeoftheglucoseinhigh-glucosesyrupstofructose,soastoenhancesweetness.酶被用来从以麦芽糖或葡萄糖为主的糖浆中生产淀粉，并将高葡萄糖糖浆中的一些葡萄糖异构化为果糖，以提高甜度。第五章

淀粉加工Chapter5Starchprocessing1.淀粉糖的种类与性质

TypesofStarchhydrolysatesGeneralclassificationsofsweetenersareasfollows1.Cornsyrup(glucosesyrup):Thepurified,concentratedaqueoussolutionofnutritivesaccharidesobtainedfromediblestarchandhavingaDEof20ormore.玉米糖浆(葡萄糖浆)：从食用淀粉中获得的、DE为20或更多的营养性糖的纯化、浓缩水溶液2.Driedcornsyrup(driedglucosesyrup):Cornsyrupfromwhichthewaterhasbeenpartiallyremoved.2.干玉米糖浆(干燥葡萄糖糖浆)：部分去除水的玉米糖浆。3.Dextrosemonohydrate:PurifiedandcrystallizedD-glucose,containingonemoleculeofwaterofcrystallization.

水合葡萄糖：纯化结晶的D-葡萄糖，含有1分子结晶水。4.Dextroseanhydrous:PurifiedandcrystallizedD-glucosewithoutwaterofcrystallization.

无水葡萄糖：纯化结晶的D-葡萄糖，不含结晶水。1.淀粉糖的种类与性质

TypesofStarchhydrolysates5.Maltodextrin:Apurified,concentratedaqueoussolutionofnutritivesaccharidesobtainedfromediblestarchorthedriedproductderivedfromsaidsolutionandhavingaDEoflessthan20.5.麦芽糖糊精：从食用淀粉或从该溶液中提取的干燥产品中获得的营养糖的纯化、浓缩水溶液，其DE值小于20。6.HFCS(High-fructosecornsyrup):Apurified,concentratedaqueoussolutionofnutritivesaccharidesobtainedfromediblestarchandhavingaportionoftheglucoseisomerizedtofructose.6.HFCS(高果糖玉米糖浆)：一种纯化的、浓缩的营养性糖水溶液，从食用淀粉中获得，部分葡萄糖异构化为果糖。1.淀粉糖的种类与性质

TypesofStarchhydrolysates淀粉糖工业常用葡萄糖值(dextroseequivalent)简称DE值(糖化液中还原性糖全部当做葡萄糖计算，占干物质的百分率称葡萄糖值)来表示淀粉水解的程度。DEofaproductofhydrolysisisitsreducingpowerasa%ofreducingpowerofpuredextrose(D-glucose)1.淀粉糖的种类与性质

TypesofStarchhydrolysates2.生产方法

ProductionmethodsStarch,gelatinizedbyheat,maybehydrolyzedbyacid,enzyme,orbyacombinationofthetwo,dependingonthepropertiesrequiredintheproduct.淀粉经热糊化后，可能被酸、酶或两者的组合水解，这取决于产品所需的性质。Thekeytogoodconversionisuniformityoftreatmentsoastominimizeresidualtracesoflong-chainmolecules,whichtendtoreassociate,givingahazyproduct-partofthephenomenonofretrogradation.良好转换的关键是处理的均匀性，以尽量减少长链分子的残留，这些分子往往会重新结合，从而产生一种模糊的产品--部分老化现象。（1）Acidhydrolysis(conversion)Apartialhydrolysisofstarchisreadilycarriedoutbytreatmentwithacidathightemperature.淀粉的部分水解很容易通过高温下的酸处理进行。Moderninstallations

utilizecontinuous-flowpressurizedreactorsinwhichtheacidifiedstarchismaintainedatatemperatureof135-150℃for5-8min.现代装置采用连续流动加压反应釜，其中酸化淀粉在135-150℃的温度下保持5-8分