Quality changes of pasteurised mango juice during storage. Part II: Kinetic modelling of the shelf-life markers.

The present work shows the potential of the integrated fingerprinting-kinetics approach in evaluating shelf-life changes of pasteurised mango juice (cv. 'Totapuri'). Seven mango juice formulations (i.e. control (mango puree and water), ascorbic acid-enriched (AA250 and AA500), citric acid-enriched (CA, CA+AA250 and CA+AA500) and sugar-enriched (S) samples) were pasteurised and stored at 42°C for 8weeks. In this part, the kinetics of the shelf-life markers selected from the multivariate fingerprinting approach was modelled. Changes in selected targeted parameters could be best described by a zero-order (colour values, °Brix, furfural, HMF), a first-order (ascorbic acid), a fractional conversion (fructose, glucose, oxygen) and a second-order model (sucrose). Differences in the rate constant were observed, with faster ascorbic acid degradation and furfural formation in AA-enriched samples and faster hydrolysis of sugars and HMF formation in CA-enriched samples compared to control samples. To describe changes in selected volatiles (terpenes, sulphur compounds, acids, ketones and esters), different kinetic models were selected. Two trends were observed: changes as affected by different mango juice formulations (e.g., faster reaction in CA-enriched samples or in a lower pH condition) and changes irrespective of the formulations. Referring to the literature, in general, acid-catalysed reactions, ascorbic acid degradation and oxidation reactions are the main reactions responsible for the observed quality changes in stored mango juice.