ABUSED THERMAL-TREATMENT IMPACT ON DEGRADATION PRODUCTS OF CHILLED PASTEURIZED ORANGE JUICE

Kinetic analyses of data generated on the degradation products of fres h-chilled, pasteurized orange juice submitted to severe heating time a nd temperature protocols (75, 85, and 95 degrees C for 15, 30, and 60 min) are presented. The influence of pH (3.1, 3.8, and 4.5) and oxygen content (deaerated and oxygenated) on 2-hexanal, furfural, alpha-terp ineol, p-vinylguaiacol, and other degradation byproducts was studied u sing gas chromatography/mass spectrometry. The effects of elevated tem perature protocols on the generation of p-vinylguaiacol and alpha-terp ineol were demonstrated. The reaction mechanisms are pseudo-zero-order . The study on the influence of pH indicated that the acid-catalyzed h ydration-dehydration pathway (ACHD) was the main reaction yielding p-v inylguaiacol and alpha-terpineol. d-Limonene was lost to only a minor extent through one of the two competing pathways, the well-known ACHD pathway, as none of the typical oxidation byproducts were detected in either the deoxygenated or aerated orange juice in which d-limonene wa s deliberately added.