ISHS Acta Horticulturae 566: II International Symposium on Application of Modelling as an Innovative Technology in the Agri-Food Chain; MODEL-IT
EFFECT OF ASCORBIC ACID SUPPLEMENTATION ON ORANGE JUICE SHELF LIFE |
| Authors: | M.C. Manso, F.A.R. Oliveira, J.M. Frķas |
| Keywords: | orange juice, ascorbic acid, browning, shelf life, supplementation, modeling |
| DOI: | 10.17660/ActaHortic.2001.566.65 |
| Abstract:
Ascorbic acid (AA) is an important indicator of orange juice quality and its degradation is often the limiting factor of shelf life of aseptically packed orange juice. Shelf life might thus be extended by addition of AA, but the benefits of such addition depend on the kinetics of AA degradation in these conditions, as well as the kinetics of browning. The main objective of this work was to study the effect of adding L-AA on the shelf life of orange juice (based on the kinetics of browning and L-AA degradation during storage, in a range of temperatures). Single strength orange juice with five different added L-AA contents (100, 200, 300, 400, and 500 mg/L), as well as control without added L-AA was filled into hard-thick screw capped tubes,  33 mL volume, which were screwed without headspace, sealed with silicone, protected from light and immersed in thermostatic baths at 20, 25, and 30 °C. These tubes were stored for 2 months, and monitored (replicate samples) for L-AA, browning, degree brix, dissolved oxygen and pH.
The initial oxygen content was 156 ± 23 μmol/L (variations within batch <6%) and the final content was 3 ± 2 μmol/L. Degree brix was constant throughout the experiment with a value of 11 ± 0.5, and pH values varied from 3.79 ± 0.01 to 3.91 ± 0.06. The results showed that addition of L-AA to orange juice slows down its degradation rate but promotes browning, especially at high temperatures. L-AA was found to be the critical factor that limits orange juice shelf life, except when L-AA is added to the juice at concentrations higher or equal to 400 mg/L at 20 and 25 °C and higher or equal to 300 mg/L at 30 °C. Mathematical models for L-AA and browning kinetics were developed, which allow the prediction of the orange juice shelf life as a function of different temperatures and added L-AA. | |
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