Determination of Reducing Sugar and Asparagine in Potatoes

Reducing sugars and asparagine levels were determined in four varieties of Spanish potatoes purchased from a local supermarket. A gas chromatography method was used to analyze glucose, fructose, and saccharose, an HPLC technique was used to analyze asparagine, and two unspecific volumetric methods were also used to study reducing sugars and amino acid groups. Two ethanolic extractions were required to obtain maximum recovery. The reducing sugar content ranged from 0.55% to 2.01%, and the asparagine content from 0.13% to 0.17%. Significantly different results were obtained by volumetric and chromatographic methods, but the correlation obtained between them was high, therefore volumetric methods can be used in the food industry for automatic control of raw potatoes used to prepare chips.