REDUCING SUGARS IN POTATO GRANULES USING DINITROSALICYLIC ACID REAGENT urpose To enable reducing sugar contents of potato granules to be determined Modifications in weights and dilutions allow its application to other food products: Principle Sugar is extracted from the sample using cold water(thus minimising interference from protein and fat). A filtered aliquot is then heated with dinitrosalicylic acid reagent. A coupling reaction occurs and produces an orange red colour, which can be measured at a wavelength of 580mm using a simple filter colorimeter Apparatus Boiling water bath Test tubes approx 25 by 150mm 5ml Pipettes Measuring cylinder Magnetic stirrer Colorimeter with appropriate filters Beakers Graduated flasks Funnels Filter papers Test tubes Dinitrosalicylic Acid Reagent 1g of Dinitrosalicylic acid is dissolved in 20ml of Sodium Hydroxide solution (1.6g pellets in 20ml water). Reaction is complete when the dinitrosalicy lic acid has all changed colour. Then add 50ml water to 20g Potassium Sodium (+) Tartrate. Dissolve by gentle warming if necessary then dilute to 100ml with Dilute DNSA Reagent Dilute 2 volumes of DNSA reagent with 3 volumes of water. Standard Glucose Solution Prepare fresh standard solutions containing 100mgm of dried glucose per 100cm of water. This solution contains Imgm Glucose per mlREDUCING SUGARS IN POTATO GRANULES USING DINITROSALICYLIC ACID REAGENT Purpose To enable reducing sugar contents of potato granules to be determined. Modifications in weights and dilutions allow its application to other food products: Principle Sugar is extracted from the sample using cold water (thus minimising interference from protein and fat). A filtered aliquot is then heated with dinitrosalicylic acid reagent. A coupling reaction occurs and produces an orange red colour, which can be measured at a wavelength of 580mm using a simple filter colorimeter. Apparatus Boiling water bath Test tubes approx 25 by 150mm 5ml Pipettes Measuring cylinder Magnetic stirrer Colorimeter with appropriate filters Beakers Graduated flasks Funnels Filter papers Test tubes Balance Reagents Dinitrosalicylic Acid Reagent lg of Dinitrosalicylic acid is dissolved in 20ml of Sodium Hydroxide solution (1.6g pellets in 20ml water). Reaction is complete when the dinitrosalicylic acid has all changed colour. Then add 50ml water to 20g Potassium Sodium (+) Tartrate. Dissolve by gentle warming if necessary then dilute to 100ml with water. Dilute DNSA Reagent Dilute 2 volumes of DNSA reagent with 3 volumes of water. Standard Glucose Solution Prepare fresh standard solutions containing lOOmgm of dried glucose per 100cm of water. This solution contains lmgm Glucose per ml. 243