Kinetic study for ascorbic acid degradation, hydroxymethylfurfural and furfural formations in Orange juice

In this study, changes in ascorbic acid-(AA), hydroxymethylfurfural-(HMF) and furfural content of orange juice (OJ) were investigated during processing with different thermal treatments and storage conditions. According to the AA degradation kinetics; the half-lifes of thermally processed OJ at 70, 75, 80, 85 and 90 degrees C ranged between 666.5-1136.3 s. D-values for the same temperatures were calculated as 3774.7, 3337.1, 2914.7, 2646.6 and 2214s, respectively. z, Ea and Q10-values of AA were also calculated as 86.32 degrees C, 26.87 kJ mol- 1, and 1.31; respectively. HMF formation kinetics showed that the doubling time of thermally processed OJ (70-90 degrees C) were determined between 42.0 and 77.0 s. D-values at those temperatures ranged from 139.6-255.8 s. z, Ea and Q10values of HMF were also calculated as 75.98 degrees C, 31.34 kJ mol- 1, and 1.35, respectively. For furfural formation kinetics, doubling time of thermally processed OJ at 70-90 degrees C was determined between 52.1-74.5 s. The Dvalues of furfural were calculated between 173.1-274.1 s at the same temperatures. z, Ea and Q10-values of furfural were also calculated as 100.21 degrees C, 24.98 kJ mol- 1, and 1.26, respectively. The most obvious changes were determined during storage at 25 degrees C for the investigated compounds when compared to 4 degrees C. OJ samples processed at moderate temperatures performed better AA retention, and lower HMF and furfural formation was determined for those samples during shelf-life.