CONICET | Buscador de Institutos y Recursos Humanos

Salts may affect important properties of sugar systems. The kinetics of non-enzymatic browning (NEB), caused by amino-carbonyl condensations, and hydrolysis reactions were observed to be affected by several salts. Both reactions lead to quality loss. However, there is a lack of information on the effect of salts on the kinetics of these important reactions. The purpose of the present work was to analyze the effect of MgCl2 on condensation and hydrolysis reactions of sugars, as alternative to formulate NEB inhibitors. Solid systems consisted of freeze-dried solutions containing 20% trehalose and 1% glycine equilibrated at 22 and 44% R.H. Liquid systems contained 40% trehalose and 0.1% glycine. Trehalose hydrolysis was analyzed by measuring glucose release. Solutions containing 5% glucose and 0.5% glycine were employed to follow the progress of NEB, which was determined by fluorescence and absorbance in the visible range. The systems were incubated at various temperatures (55-100°C). All the systems were prepared in phosphate buffer, pH 5.0 and MgCl2 was added (2.5-8% on sugar basis); controls without MgCl2 were prepared. Both in liquid and solid systems the presence of MgCl2 quantitatively delayed the formation of fluorescent compounds and brown pigments, without affecting their spectral characteristics. Trehalose hydrolysis, in turn, was accelerated. However, in the hydrolyzed trehalose the presence of MgCl2, counteracted the higher glucose concentration in the NEB degree. The adequate selection of salts has important implicances on deteriorative reactions. NEB inhibition may help to avoid the addition of sulphites. Sugar hydrolysis, on the other hand, may be accelerated and should be controlled.

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