哈医大精品课程营养与食品卫生学第一章营养学基础VIP专享VIP免费

第一章营养学基础碳水化合物CarbohydratesMaincontentsDefinitionofcarbohydratesClassificationofcarbohydratesDigestion&absorptionofCHOFunctionsofcarbohydratesDisordersrelatedtoCHOmetabolismDietaryreferenceintakesofCHOsCarbohydratesareoneofthethreemacronutrienttypesthatprovideenergytoourbodies.Carbohydratescontaincarbon,hydrogen,andoxygen.碳水化合物：属三大能量营养素之一，主要由碳、氢、氧构成。一、碳水化合物的定义Whatarecarbohydrates?Carbohydratecanbeabbreviatedas“CHO”.Weobtainedcarbohydratespredominantlyfromplantfoodssuchasfruits,vegetables,andgrain.Why?PlantsmakecarbohydratesthroughtheprocessofphotosynthesisEnergyfromsunCarbondioxidefromairGlucosestoredinplantWaterWater+CarbondioxideGlucose光合作用二、碳水化合物的分类ClassificationofcarbohydratesCarbohydratesSimpleComplexDisaccharidesMonosaccharidePolysaccharidesOligosaccharide寡糖单糖双糖多糖HOHCH2OHHOHOHHOHHHGlucoseOHOHHOHHOHCH2OHCH2OHFructoseHOOHOHOHHHHHCH2OHGalactoseThethreemostcommonmonosaccharides.ALLofthemcontainidenticalatoms……StructureofmonosaccharidesMonosaccharides-Glucose（葡萄糖）Glucoseisthemostabundantsugarmoleculefoundinourdietsandinourfoods.Glucosedoesnotgenerallyoccurbyitselfinfoodsbutattachestoothersugarstoformdisaccharidesandcomplexcarbohydrates.Inourbodies,glucoseisthepreferredsourceofenergyforthebrain.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或多糖的形式存在，葡萄糖优先为大脑提供能量。Monosaccharides-Fructose（果糖）Fructoseisalsocalledfruitsugar.Fructoseisthesweetestnaturalsugar,occursnaturallyinfruitsandvegetables.PrefixMonosaccharides-Galactose（半乳糖）Galactosedoesnotoccuraloneinfoods.Itjoinswithglucosetocreatelactose,oneofthedisaccharides.Sweetestmonosaccharides?Themostabundantmonosaccharides?Thesweetest：fructoseThemostabundant：glucoseDisaccharide（双糖）Disaccharide:Acarbohydratecompoundconsistingoftwosugarmoleculesjoinedtogether.Thethreemostcommondisaccharidesfoundinfoodsarelactose（乳糖）,maltose（麦芽糖）,andsucrose（蔗糖）.Disaccharides–Lactose（乳糖）＋GlucoseGalactoseLactoseLactose:Consistofoneglucosemoleculeandonegalactose(半乳糖）molecule.Disaccharides—Maltose（麦芽糖）Maltose:alsocalledmaltsugar,consistoftwomoleculesofglucose.Itdoesnotgenerallyoccurbyitselfinfoods,butresultsasaby-productofdigestion.＋GlucoseDisaccharides—Sucrose（蔗糖）Sucroseiscomposedofoneglucosemoleculeandonefructose（果糖）molecule.＋Sucroseprovidesmuchofthesweettastefoundinhoney,fruits,andvegetables.HowabouttheSucroseandfructose?Sweeterthanlactoseormaltose,why?哪种双糖最甜--麦芽糖，蔗糖，乳糖？麦芽糖--2个葡萄糖蔗糖--1个葡萄糖+1个果糖乳糖--1个葡萄糖+1个半乳糖蔗糖Oligosaccharide（寡糖）Oligosaccharidearecomposedof3to10monosaccharides.Themostcommonoligosaccharidesareraffinose（棉籽糖）andstachyose（水苏糖）.Theycannotbedegradedbyenzymesinthesmallintestine,butcanbebrokedowninthelargeintestine.Polysaccharides（多糖）Polysaccharidesincludestarch（淀粉）,glycogen（糖原）andmostfibers（纤维）.PolysaccharidesStarchGlycogenFiber淀粉糖原纤维Polysaccharide--StarchStarch:Apolysaccharidestoredinplantsandisthestorageformofglucoseinplants.（淀粉是葡萄糖在植物中的贮存形式）Excellentfoodsourcesofstarchinclude?grains(wheat,rice,corn,oats,andbarley),legumes(peas,beans,andlentils),andtubers(potatoesandyams).Ourbodieseasilydigestmoststarches，wecallthemdige...