1、第一章第一章 营养学基础营养学基础(jch)(jch)碳水化合物碳水化合物Carbohydrates第一页，共六十二页。Main contents nDefinition of carbohydratesnClassification of carbohydratesnDigestion&absorption of CHOnFunctions of carbohydratesnDisorders related to CHO metabolismnDietary reference intakes of CHOs第二页，共六十二页。|Carbohydrates are one of the t
2、hree macronutrient types that provide energy to our bodies.Carbohydrates contain carbon,hydrogen,and oxygen.碳水化合物：属三大能量碳水化合物：属三大能量(nngling)营养素之一，营养素之一，主要由碳、氢、氧构成。主要由碳、氢、氧构成。一一、碳水化合物的定义、碳水化合物的定义(dngy)(dngy)What are carbohydrates?|Carbohydrate can be abbreviated as“CHO”.第三页，共六十二页。|We obtained carbohyd
3、rates predominantly from plant foods such as fruits,vegetables,and grain.Why?第四页，共六十二页。Plants make carbohydrates through the process of photosynthesisEnergy from sunCarbon dioxide from airGlucose stored in plantWaterWater+Carbon dioxideGlucose光合作用光合作用(gungh-zuyng)第五页，共六十二页。二、碳水化合物的分类二、碳水化合物的分类(fn li
4、)Classification of carbohydratesCarbohydratesSimpleComplexDisaccharidesMonosaccharidePolysaccharidesOligosaccharide寡糖寡糖单糖单糖双糖双糖(shun tn)多糖多糖(du tn)第六页，共六十二页。HOHCH2OHHOHOHHOHHHGlucoseOHOHHOHHOHCH2OHCH2OHFructoseHOOHOHOHHHHHCH2OHGalactoseThe three most common monosaccharides.ALL of them contain identi
5、cal atomsStructure of monosaccharides第七页，共六十二页。Monosaccharides-Glucose（葡萄糖）（葡萄糖）|Glucose is the most abundant sugar molecule found in our diets and in our foods.|Glucose does not generally occur by itself in foods but attaches to other sugars to form disaccharides and complex carbohydrates.|In our b
6、odies,glucose is the preferred source of energy for the brain.食物中最多的单糖，但不以单独形式存在，常与其食物中最多的单糖，但不以单独形式存在，常与其他糖形成双糖他糖形成双糖(shun tn)或多糖的形式存在，葡萄糖或多糖的形式存在，葡萄糖优先为大脑提供能量。优先为大脑提供能量。第八页，共六十二页。Monosaccharides-Fructose（果糖（果糖(gutng)）|Fructose is also called fruit sugar.|Fructose is the sweetest natural sugar,occu
7、rs naturally in fruits and vegetables.Prefix第九页，共六十二页。Monosaccharides-Galactose（半乳糖）（半乳糖）|Galactose does not occur alone in foods.It joins with glucose to create lactose,one of the disaccharides.第十页，共六十二页。Sweetest monosaccharides?The most abundant monosaccharides?The sweetest：fructoseThe most abunda
8、nt：glucose 第十一页，共六十二页。Disaccharide（双糖（双糖(shun tn)(shun tn)）|Disaccharide:A carbohydrate compound consisting of two sugar molecules joined together.The three most common disaccharides found in foods are lactose（乳糖（乳糖(r tn)）,maltose（麦芽糖）（麦芽糖）,and sucrose（蔗糖）（蔗糖）.第十二页，共六十二页。Disaccharides Lactose（乳糖（乳糖(
9、r tn)）GlucoseGalactoseLactose|Lactose:Consist of one glucose molecule and one galactose(半乳糖）半乳糖）molecule.第十三页，共六十二页。DisaccharidesMaltose（麦芽糖）（麦芽糖）|Maltose:also called malt sugar,consist of two molecules of glucose.|It does not generally occur by itself in foods,but results as a by-product of digesti
10、on.Glucose第十四页，共六十二页。DisaccharidesSucrose（蔗糖（蔗糖(zhtng)）vSucrose is composed of one glucose molecule and one fructose（果糖（果糖(gutng)）molecule.vSucrose provides much of the sweet taste found in honey,fruits,and vegetables.How about the Sucrose and fructose?vSweeter than lactose or maltose,why?第十五页，共六十二页
11、。哪种双糖最甜哪种双糖最甜-麦芽糖，蔗糖麦芽糖，蔗糖(zhtng)，乳糖？，乳糖？麦芽糖麦芽糖-2个葡萄糖个葡萄糖蔗糖蔗糖(zhtng)-1个葡萄糖个葡萄糖+1个果糖个果糖乳糖乳糖-1个葡萄糖个葡萄糖+1个半乳糖个半乳糖蔗糖蔗糖(zhtng)第十六页，共六十二页。Oligosaccharide（寡糖）（寡糖）vOligosaccharide are composed of 3 to 10 monosaccharides.vThe most common oligosaccharides are raffinose（棉籽糖）（棉籽糖）and stachyose（水苏（水苏(shu s)糖）糖）.
12、v They can not be degraded by enzymes in the small intestine,but can be broke down in the large intestine.第十七页，共六十二页。Polysaccharides（多糖（多糖(du(du tn)tn)）Polysaccharides include starch（淀粉（淀粉(dinfn)）,glycogen（糖原）（糖原）and most fibers（纤维）（纤维）.第十八页，共六十二页。PolysaccharidesStarchGlycogenFiber淀粉淀粉(dinfn)糖原糖原(tn
13、 yun)纤维纤维(xinwi)第十九页，共六十二页。Polysaccharide-Starch|Starch:A polysaccharide stored in plants and is the storage form of glucose in plants.（淀粉是葡萄糖在植物中的贮存（淀粉是葡萄糖在植物中的贮存(zhcn)形式）形式）|Excellent food sources of starch include?grains(wheat,rice,corn,oats,and barley),legumes(peas,beans,and lentils),and tubers(
14、potatoes and yams).第二十页，共六十二页。|Our bodies easily digest most starches，we call them digestible starch(可吸收淀粉）可吸收淀粉）.|根据其结构可分为直链淀粉根据其结构可分为直链淀粉（amylose）和支链和支链淀粉淀粉（amylopectin），），前者易使食物前者易使食物(shw)老化，老化，后者易使食物后者易使食物(shw)糊化糊化（gelatinization）。第二十一页，共六十二页。|However,some starch in plants is not digestible and
15、is called resistant starch（抗性淀粉）（抗性淀粉）.|抗性淀粉：指健康者小肠中不吸收抗性淀粉：指健康者小肠中不吸收(xshu)的的淀粉及其降解产物。淀粉及其降解产物。第二十二页，共六十二页。|When our intestinal bacteria try to digest resistant starch,a fatty acid called butyrate is produced.|Consuming resistant starch may be beneficial because butyrate is suggested to reduce the
16、risk of cancer.|豆科食物豆科食物（Legumes）含有的抗性淀粉比谷含有的抗性淀粉比谷类类、蔬菜、蔬菜(shci)(shci)和水果多。和水果多。Bean sproutGreen soybean第二十三页，共六十二页。|Glycogen:A polysaccharide stored in animals,including humans.|Very little glycogen exists in food.|Thus,glycogen is not a dietary source of carbohydrate.Polysaccharide-Glycogen（糖原（糖原(tn yun)）第二十四页，共六十二页。Which tissues are abundant in glycogen?We store glycogen in our muscles and liver.We can break down glycogen very quickly into glucose when we need it for energy.第二十五页，共六十二页。|Base
