Determination of Redusing Sugar Using Dns Method

1.0 ABSTRACT The production of reducing sugars by acid of carbohydrate cereals powder, jams (total sugar content) and jams (reducing sugar content) were performed in order to study reducing sugar production. The study involved hydrolysis carbohydrate cereals powder and jams by immersing in boiling water at environmental temperature. Acid hydrolysis was carried out through reflux boiling for 20 minutes with 10ml 0f 1.5M concentrations of diluted sulphuric acid. Reducing sugars concentrations were determined by spectrophotometry using the 3, 5 dinitrosalicylic acid (DNS) method. The first sample was operated as blank for zero. The stock solution was prepared in order to find the unknown concentration of carbohydrate cereals powder, jam (total sugar content) and jams (reducing sugar content). The absorbance of stock solution were 0.017,0.030, 0.038, and 0.099 respectively and the absorbance of carbohydrate cereals powder, jams (total sugar content) and jams (reducing sugar content) were 0.06, 0.014 and 0.138 respectively. After determining the specific absorbance of stock solution, the calibration curves was made to determine the unknown concentration of carbohydrate cereals powder, jams (total sugar content) and jams (reducing sugar content).

2.00 INTRODUCTION Determination of total reducing is of great important in the food industries especially in industries where quality control is monitored.
One method to determine the sugar concentration of reducing sugars is by heating with 3, 5 dinitrosalicylic acids (DNS) which produce a red-brown product (Miller1959) The reaction is direct, thus the method is preferred over the Benedict’s test method.

The concentration of the coloured complex can be determined with the spectrophotometer at Absorbance 540 ( http://en.wikipedia.org/wiki/3,5-Dinitrosalicylic_acid)
.The sugar concentration of unknown sample can then be read off a calibration curve(standard curve) created