The reducing sugar was determined by the modified method of
Miller (1959). Briefly, 0.5 ml of 1% 3,5-dinitrosalicylic acid (DNS)
was added to an aliquot of sample (20–500 ll), and the volume adjusted
to 5 ml with distilled water. After shaking, the mixture was
heated in boiling water for 5 min and cooled to room temperature;
2.5 ml of distilled water were added to the mixture. The absorbance
was measured at 540 nm, and the total reducing sugar was
calculated with D-glucose as a standard reducing sugar. Total polysaccharide
was the subtraction of reducing sugar from the total
carbohydrate.