Accelerated glucose discoloration method - A quick tool for glucose stability assessment

Abstract: The non-enzymatic browning of glucose was investigated by accelerating the glucose degradation with or without heating glucose solutions for 1 h at 100°C with different reagents. Evaluation of the glucose degradation was performed using two types of glucose, glucose A and glucose B, in order to investigate the influence of the glucose manufacturing process on glucose discoloration. The color formation was determined by measuring the UV-absorbance between 260-605 nm. The glucose degradation was also investigated by the formation of 5-hydroxymethylfurfural and 2-furfural, which were determined by HPLC. The accelerated glucose discoloration method was optimised in order to differentiate between different glucose qualities with respect to color stability, i.e. the conditions selected were based on maximizing the difference in glucose discoloration for glucose A and B. Direct measurement of the absorbance difference at 350 nm, on 33 % (w/w) glucose/water solution kept at room temperature for 1 h was found to be the optimum conditions for differentiating between glucose A an B. Further investigation on Maillard reactions was made, and for the investigated conditions, the reaction was found to be most accelerated for the glucose samples, 33% (w/w), heated at 100°C for 1 hour in the presence of L-alanine.