华南理工大学：《食品分析》课程PPT教学课件（Food Analysis）Chapter 7 Carbohydrates

Determination of carbohydrates

Determination of carbohydrates

Contents ·Introduction Definition Classification >Structure of carbohydrates Distribution of carbohydrates in food Function of carbohydrates in food processing Determination of carbohydrates

Contents • Introduction ➢ Definition ➢ Classification ➢ Structure of carbohydrates • Distribution of carbohydrates in food • Function of carbohydrates in food processing • Determination of carbohydrates

Introduction Definition >Chemically,carbohydrates are organic molecules in which carbon, hydrogen and oxygen bond together in the ratio:C(H2O)where x and y are whole numbers that differ depending on the specific carbohydrate to which we are referring >多羟基醛或者酮及其衍生物和缩合物 Carbohydrates are the main energy source for the human body. Carbohydrates are the most abundant class of organic compounds found in living organisms

Introduction Definition ➢ Chemically, carbohydrates are organic molecules in which carbon, hydrogen and oxygen bond together in the ratio: Cx (H2O)y where x and y are whole numbers that differ depending on the specific carbohydrate to which we are referring ➢ 多羟基醛或者酮及其衍生物和缩合物 ➢ Carbohydrates are the main energy source for the human body. ➢ Carbohydrates are the most abundant class of organic compounds found in living organisms

Classification(从组成上分) >Simple Sugars Monosaccharides::不能再被水解的多羟基醛或者酮，是碳 水化合物的基本单位。如葡萄糖、果糖、半乳糖等。 >Complex Carbohydrates Oligosaccharides:2~10个单糖分子缩合而成，水解后生 成单糖。如蔗糖、麦芽糖、乳糖等。 Polysaccharides:由许多单糖分子缩合而成，如淀粉、纤 维素、果胶等

Classification（从组成上分） ➢ Simple Sugars Monosaccharides:不能再被水解的多羟基醛或者酮，是碳 水化合物的基本单位。如葡萄糖、果糖、半乳糖等。 ➢ Complex Carbohydrates Oligosaccharides ：2～10个单糖分子缩合而成，水解后生 成单糖。 如蔗糖、麦芽糖、乳糖等。 Polysaccharides：由许多单糖分子缩合而成，如淀粉、纤 维素、果胶等

Monosaccharides >Two of the most common monosaccharides are glucose and fructose. >Both glucose and fructose have the same chemical formula (CH)however they have different structures as seen below

Monosaccharides ➢Two of the most common monosaccharides are glucose and fructose. ➢Both glucose and fructose have the same chemical formula (C6H12O6 ) however they have different structures as seen below

CHOH CHOH O CHOH H H H OH H HH HO/OH OH OH H OH OH H Glucose Fructose

Glucose Fructose

Disaccharides >have two sugar units bonded together.For example,common table sugar is sucrose a disaccharide that consists of a glucose unit bonded to a fructose unit: CH2OH CH2OH H H CH2OH OH OH

Disaccharides ➢have two sugar units bonded together. For example, common table sugar is sucrose a disaccharide that consists of a glucose unit bonded to a fructose unit:

Lactose Lactose:is found CH2OH CH2OH exclusively in the milk of mammals and consists of galactose and glucose in a B-(1,4) glycosidic bond

Lactose Lactose: is found exclusively in the milk of mammals and consists of galactose and glucose in a b-(1,4) glycosidic bond

maltose Maltose:the major CH2OH CH2OH degradation product of starch,is composed of 2 glucose monomers in an a-(1,4)glycosidic bond

maltose Maltose: the major degradation product of starch, is composed of 2 glucose monomers in an a-(1,4) glycosidic bond

Complex Carbohydrates >Definition polymers of the simple sugars. long chains of simple sugar units bonded together often referred to as polysaccharides). >Several polysaccharides 。Starch ·Cellulose ·pectin

Complex Carbohydrates ➢Definition • polymers of the simple sugars. • long chains of simple sugar units bonded together ， often referred to as polysaccharides). ➢Several polysaccharides • Starch • Cellulose • pectin