Kinetics of non-enzymatic browning and loss of free amino acids during different storage temperature (4, 25, 37 °C) were investigated. Changes of browning degree (A420), color parameters, Vitamin C (Vc), free amino acids and 5-hydroxymethylfurfural (5-HMF) were analyzed to evaluate the non-enzymatic browning reactions, which were significantly affected by storage temperature. The lower temperature (4 °C) decreased the loss of Vc and the generation of 5-HMF, but induce the highest loss of serine. At the end of storage, loss of serine, alanine and aspartic acid were mainly lost. Results showed that zero-order kinetic model (R2 > 0.859), the first-order model (R2 > 0.926) and the combined kinetic model (R2 > 0.916) were the most appropriate to describe the changes of a* and b* values, the degradation of Vc and the changes of A420, L* and 5-HMF during different storage temperatures. These kinetic models can be applied for predicting and minimizing the non-enzymatic browning of fresh peach juice during storage.
Keywords: 5-HMF; Color; Kinetic model; Non-enzymatic browning; Peach juice.