Effects of pH, Temperature, and Reactant Molar Ratio on l -Leucine and d -Glucose Maillard Browning Reaction in an Aqueous System

The effects of pH, temperature, and reactant molar ratios on l -leucine and d -glucose Maillard browning reaction in an aqueous system were studied. At pH 9 and 10, glucose consumption rate increased with time for all temperatures and molar ratios. At 100 °C and pH 9 and 10, samples with excess leucine had higher mean values for color than the mean color values for samples using glucose/leucine ratios of 1:1 or 2:1. At 122.5 °C and pH 9 and 10, samples with glucose/leucine ratios of 1:2 had a significantly higher rate of glucose loss than samples containing glucose/leucine ratios of 2:1 and 1:1 at the corresponding pH. Temperature and the initial pH of the sample were positively correlated with glucose loss ( r = 1.0 and 0.85, respectively). Typically, sample browning rate was greater at 122.5 °C than at 100 °C. Browning rate was positively correlated with pH ( r = 0.94).