Possible consequences of the sucrose replacement by a fructose-glucose syrup

The fructose-glucose syrup is currently used instead of sucrose in bakery products for economic and technological reasons. The authors investigated the extent to which this change affects the formation of non-enzymatic browning products (Advanced Glycation End - AGE-Products and melanoidins). Formation of these products in model systems - mixtures of various sugars (sucrose, fructose, glucose - concentration 6%) with glycine (concentration 0.7%) or/and lysine (concentration 0.3%), heat-treated 60 - 100 °C for 15, 30, 45 and 60 min, was studied. The formation of AGE products and melanoidins was determined on the basis of absorption at 294 nm (AGE-products) and 420 nm (melanoidins), respectively. The results pointed out notable difference in the AGE-products and also melanoidins formation for a variety of sugars. The reactivity of sucrose was low even at 100 °C/60 min. Fructose and glucose originated a significantly increasing of the non-enzymatic browning products formation. The reactivity of fructose was in the caramelisation and also in Maillard reactions the highest in any combination of composition. Lysine is the most reactive amino acid which takes part in Maillard reactions even if it is bound to protein. The non-enzymatic browning reactions result in the formation of non-digestible cross-linked proteins. Lysine is also the limiting essential amino acid of most cereals. Due to the lysine properties, reduction in protein quality is the most important nutritional effect of Maillard reactions in food. The sucrose replacement by fructose-glucose syrup in bakery products leads to more extensive non-enzymatic browning reactions, i.e. caramelisation and also Maillard reactions, while changes are in the Maillard reaction more pronounced.