Formation of melanoidins in foods and effects on health

Melanoidins are brown, high molecular weight compounds generated in the late stages of the Maillard reaction from reducing sugars and proteins or amino acids during thermal food processing. The primary source of melanoidin is bread and bakery products in the diet. Although the chemical structures of melanoidins are not precisely known, the daily dietary intake is estimated at approximately 10 g. Melanoidins exist as monosaccharides (coffee, beer, and cocoa) and melanoproteins (bread and bakery products), depending on the food composition they form. The formation of melanoidins in foods depends on conditions such as composition of products, heat treatment time and temperature, pH, water and activity of reactants. Melanoidins have many beneficial effects on health, such as prebiotic, antioxidant, antimicrobial, anticarcinogenic, antihypertensive, xenobiotic enzyme activity, appetite regulation, and energy intake. In the gastrointestinal tract, melanoidins behave as dietary fibre by promoting the growth of bifidobacteria. In addition, melanoidins can preserve the quality of food by contributing to the texture and flavour of food. This review examines the formation, amount of food, mechanism of action and effects on human health of melanoidins.