Effect of additives on physicochemical properties in amorphous starch matrices

The effect of the addition of non-reducing sugars or methylcellulose on the matrix physical properties and rate of non-enzymatic browning (NBR) between exogenous glucose + lysine in a starch-based glassy matrix were studied, using the methods of luminescence and FTIR Amorphous starch-based matrices were formulated by rapidly dehydrating potato starch gel mixed with additives at weight ratios of 7:93 (additive:starch). Data on the phosphorescence emission energy and lifetime from erythrosin B dispersed in the matrices indicated that sugars decreased starch matrix mobility in a T-g-dependent manner, except for trehalose that interacted with starch in a unique mode, while methylcellulose, the additive with the highest T-g, increased the molecular mobility. Using FTIR, we found that methylcellulose decreased the strength of hydrogen bond network and sugars enhanced the hydrogen bond strength in the order: trehalose > maltitol > sucrose. Comparing those changes with the rate of NBR between exogenous glucose + lysine, we suggest that NBR rates are primarily influenced by matrix mobility, which is modulated by the hydrogen bond network, and interactions among components. (C) 2014 Elsevier Ltd. All rights reserved.