As non-enzymatic browning is one of the major causes of color change in fruit products, the effect of heating temperature and processing time on the accumulation of HMF and brown pigment formation were investigated in this study.
The relationship between relative HMF content ðHMF=HMF0Þ and processing time at different temperatures applied is shown in Fig. 5.
It was observed that heating temperature had a marked effect on the formation of HMF.
The results indicated that HMF increased linearly with time and the higher amounts were found at the higher heating conditions.
The relationship between relative A420 ðA420=A0 420Þ and time was also observed to be linear, similar to HMF development.
Therefore, zero order kinetics was applied to describe the change of both substances and the equation used is shown as: