Factors affecting the formation of reducing compounds from biacetyl

Antioxidative properties go with principal attributes of the Maillard reaction. Biacetyl, a reactive carbonyl intermediate formed in the initial stage of sugar transformations in the presence of amino acids, was found as an efficient precursor of several compounds with significant reducing activity which can act as antioxidants in real food systems. In this work, simple model systems of biacetyl were investigated under different conditions (amino compound involved, concentration, concentration ratio, reaction time, temperature and pH) to gain maximum yield of reducing power. Distribution of reducing power in different fractions of the reaction mixtures characterised by polarity and molecular size was evaluated. The fractionation procedure and HPLC separation step was developed to enable isolation of the major reducing products. Their characterisation was accomplished by use of photodiode-array (UV-VIS spectra) and electrochemical detection (half-wave potentials). The structures of the isolated products having reducing activity were identified by series of MS measurements and by comparison with synthesised standards.