Quantification of the Browning Kinetic on Pita Bread Using Fractal Method

Non-enzymatic browning of a composite puree of Choerospondias axillaris, snow pear, and apple: kinetic modeling and correlation analysis

Choerospondias axillaris, snow pear, and apple composite fruit puree can be affected by non-enzymatic browning during storage decreasing the market value of the product. This study aimed to explore, using kinetic methods, the effects of non-enzymatic precursors (polyphenols and ascorbic acid) and intermediates (5-hydroxymethylfurfural) on fruit puree stored at 4 °C for 35 days. The results showed that ascorbic acid fitted the first-order reaction model, while the 5-hydroxymethylfurfural was consistent with the complex reaction model. Furthermore, the 5-hydroxymethylfurfural content was 1.53 ± 0.18 mg/L, (corresponding to an increase of 565%), and the ascorbic acid content was 0.88 ± 0.22 mg/100 g, (corresponding to a decrease of 98.5%). The results also demonstrated a change in the titratable acid, soluble solids, and pH of the fruit puree. Finally, the correlation results revealed a significant correlation between non-enzymatic browning and 5-hydroxymethylfurfural, titratable acid, and pH (p < 0.05). Overall, the results suggest that the Maillard reaction could be responsible for the non-enzymatic browning of fruit purees during storage.

Nonenzymatic Browning of Amorphous Maltose/Whey Protein Isolates Matrix: Effects of Water Sorption and Molecular Mobility

Nonenzymatic browning (NEB) reactions often affect the nutritional quality and safety properties of amorphous food solids. Developing a proper approach to control the NEB reaction has been of particular interest in the food industry. An NEB reaction in an amorphous maltose/Whey protein isolates (WPI) matrix containing L-lysine and D-xylose as reactants were studied at ambient temperatures aw ≤ 0.44 and 45~65 °C. The results indicated that the presence of NEB reactants barely disturbed the water sorption behavior of the matrix. The Guggenheim–Anderson–de Boer (GAB) constants and Qst values of the studied samples were affected by storage conditions as the migration of sorbed water among monolayers occurred. The rate of color changes and 5-hydoxymethylfurfural (5-HMF) accumulation on the matrix were accelerated at high ambient temperatures aw, reflecting the extent of NEB reaction increases. Since the strength concept (S) could give a measure of molecular mobility, the extent of the NEB reaction was governed by the molecular mobility of the matrix as the activation energy (Ea) of 5-HMF production minimized at solids with high S values. We found that the S concept had a considerable potential usage in controlling the NEB reaction on amorphous sugar–protein solids. This data set has practical significance in the comprehensive understanding of manipulating the diffusion-limited chemical reactions on low-moisture food solids.