Bovine serum albumin gelation as a result of the Maillard reaction

The thermal gelation of mixtures of bovine serum albumin (BSA) with the reducing sugars, xylose and ribose, has been studied using oscillatory rheometry. Solutions of 1% BSA and 3% ribose in distilled water gelled after heating at 90 degrees C for 80 min. One cause of this time-induced gelation is the fall in pH as the result of the production of acidic byproducts from the Maillard reaction. By comparing the effect of xylose and ribose concentration on gelation time with the rate of pH fall during heating, it was shown that the pH required for gelation decreased with increasing concentration and reactivity of the reducing sugar present. This suggested that gelation in this system is also influenced by changes in protein charge as the result of chemical modifications due to the Maillard reaction.