DEGRADATION OF MANDARIN JUICE CONCENTRATES TREATED AT HIGH TEMPERATURES

摘要

This work aims to characterize nonenzymatic browning of concentratednmandarin juice treated at different temperatures, identifying the differentnfactors involved and their influence, and to propose a kinetic model for theirnevolution with treatment time. For 65°Brix sample, at 98C, the evolution ofncarotenes and total sugars can be described by means of first-order kinetics,nand formol index changes according to zero-order kinetics. In the case ofn5-hydroxymethylfurfural, two types of kinetics, first-order and autocatalytic,nwere assayed. For the mandarin juices at different temperatures (70–98C) andnconcentrations (10–65°Brix), the absorbance A440 decreases according tonfirst-order kinetics. For the highest treatment temperatures and the mostnconcentrated samples, in the first stage, an increase in the brightness andndecrease of A440 attributed to carotene degradation is observed. After thencarotenes disappear, an increase in the color is observed, probably caused bynthe Maillard reaction.