Determination of Carbohydrate SMK Negeri 13 Bandung
Carbohydrate in food Carbohydrate exist especially in food of plant source In plant, carbohydrate formed by photosyntesis process, reaction of CO2 and H2O with sunray assistance Carbohydrate contributes to character of food, i.e : taste, color and texture Some classes of carbohydrate produce fibers (dietary fiber) which has good function in digesting.
Carbohydrate in Human Body Carbohydrate is cheap calory source main calory source Carbohydrate in human body contributes to: - Avoid ketosis - Avoid over protein decomposition in human body - Avoid mineral lost - Help fat and protein metabolism In human body carbohydrate formed of several amino acid and part of fat glycerol
STRUCTURE OF CARBOHYDRATE Carbohydrate molecule consist of Carbon (C), Hiyrogen (H), and Oxygen (O). These unsure combine in chemical bonding with the common formula Cm(H2O)n. Number of m and n various depend on the type of carbohydrate Monosaccharide and disaccharide have sweet taste caused by the hydroxyl group. Teknologi dan Rekayasa
Classification of Carbohydrate Monosaccharide Simple carbohydrates cannot be hydrolyzed They are aldehydes or ketones with two or more hydroxyl groups Oligosaccharide Composed of longer chains of monosaccharide units Contain between two and ten monosaccharide units Polysaccharide Contain greater than ten monosaccharide units Teknologi dan Rekayasa
Classification of Monosaccharide Placement of its carbonyl group Aldose, If the carbonyl group is an aldehyde Example : Glucose, Galactose Ketose, If the carbonyl group is a keton Example : Fructose Number of carbon atoms it contains Trioses, 3 carbon atoms (glyceraldehyde, ketotriose) Tetroses, 4 carbon atoms (Erythrose, Threose) Pentoses, 5 carbon atoms (Ribose, Arabinose, Xylose, Ribulose, etc) Hexoses, 6 carbon atoms (Glucose, Galactose, Fruktose) Teknologi dan Rekayasa
Reducer Sugar Reducer sugar is class of sugar which could be oxidized by weak oxidizing agent as Tollens, Fehling, Barfoed reagent, etc. Oxidation product of aldehide or aldose group is polyhydroxy carboccilic acid, called aldonic acid Aldose or ketose could be reduced by carbonyl reducing agent Reducing property of sugar used in : - Qualitative analysis to identify carbohydrate - Quantitative analysis to determine the content of carbohydrate in sample Teknologi dan Rekayasa
Identification of Carbohydrate Reagent Identification for Object Molish, -naphtol in conc.H2SO4 Carbohydrate present Purple colored layer Fehling, basic solution of Cu2+ Reducer sugar present Cu2O, brick red colored precipitate Benedict, basic solution of Cu2+ Barfoed, acidic solution of Cu2+ Tollens, basic solution of Ag+ Ag2O silver mirror Selliwanof, Recorcinol in conc. HCl Ketose present Cherry red colored solution Teknologi dan Rekayasa
Determination of Carbohydrate Quantitative carbohydrate analysis based on the ability of aldehyde or ketone group -of monosaccharide unit- to be oxidized by weak oxidizing agent like Cu 2+ in basic solution. According to this property, there are 2 method for determination of carbohydrate : - Luff Schoorl Method - Muller Method Teknologi dan Rekayasa
Luff Schoorl Method for Determination of Carbohydrate Before Invertion To determine the reducer sugar (Monosaccharide) content Weak Invertion To determine non reducer sugar (Disaccharide) content Strong Invertion To determine starch (Polysaccharide) content Teknologi dan Rekayasa
Determination of Monosaccharide Weighing Dissolving Measured transferring and Luff Schoorl adding Reflux 10’ KI and acid adding Titration with Na2S2O3 Teknologi dan Rekayasa
Determination of Disaccharide Reflux 10’ Weighing Diluting Weak invertion 25% HCl (70oC) 1 hour Measured transferring & Luff Schoorl adding KI and acid adding Titration with Na2S2O3 Teknologi dan Rekayasa
Determination of Disaccharide Reflux 10’ Weighing Diluting Weak invertion 25% HCl (100oC) 3 hour Measured transferring & Luff Schoorl adding KI and acid adding Titration with Na2S2O3 Teknologi dan Rekayasa
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