1. Sez. di Tecnologie Agro-alimentari, University of Catania, Italy
STABILIZATION OF BLOOD ORANGE JUICE BY HIGH PRESSURE SUPERCRITICAL CARBON DIOXIDE TREATMENT
Simona Fabroni
Dofata – Dipartimento di orto-floro-arboricoltura e tecnologie agro-alimentari
Sez. di Tecnologie Agro-alimentari, University of Catania, Italy
Tutor: Prof. Emanuele Maccarone
Co-Tutor: Dott. Paolo Rapisarda

2. TAROCCO ORANGE

3. Fresh Unpasteurized Juice
Minimal treatment after extraction
before packaging and distribution
Must be stored at 4 °C
Excellent flavor, but shelf life < 3 days

4. Preservation Techniques in Orange Juice Processing
Required to:
Destroy microbial contaminants
Inactivate enzymes
(e.g.: PME to stabililize cloud)
Extend shelf-life
Traditional thermal methods
Emerging non-thermal methods

5. Cold-pasteurization by Supercritical CO2
Hypothesis of microbial inactivation:
Cell wall rupture due to increased internal pressure;
Extraction of cell wall lipids;
Alteration of the pH within the cell;
Rapid depressurization of the system.

6. High pressure supercritical CO2 equipment

7. Freshly squeezed blood orange juice
Experimental trials
Freshly squeezed blood orange juice
Untreated juice (UJ)
CO2 treated juice (TJCO2)
Thermally pasteurized juice (TJTP)
230 bar, 36 ± 1 °C, gCO2/gjuice
130 bar, 36 ± 1 °C, gCO2/gjuice
130 bar, 36 ± 1 °C, gCO2/gjuice

8. Assessment of the performance
Physicochemical parameters
TSS pH TA
CIE L*a*b*
Cloud / PE activity
Antioxidant components
Vitamin C
Total Anthocyanins
Total Flavanones
Total Hydroxycinnamic acids
Total Phenolics
ORAC units
Microbial survival
Mesophilic viable count (MVC)
Yeasts and moulds count
Spoilage microrganisms count

9. Changes of physicochemical parameters1.

10. Changes of physicochemical parametersB A B AB A A B B A A A A B B B B C A A A a a B B b B 2.

11. Changes of physicochemical parametersB % % % 3.

12. Changes of antioxidant componentsB A AB B a a b 1.

13. Changes of antioxidant componentsAB a b B b 2.

14. Changes of antioxidant componentsB C 3.

15. Changes of antioxidant componentsB ab B b 4.

16. Changes of antioxidant componentsAB AB B B 5.

17. Changes of antioxidant componentsB A a B B ab b 6.

18. Storage study 1.

19. Storage study 2.

20. Storage study 3.

21. Conclusions
Looking forward an industrial scale implementation of the process, results showed that treatment at lower operative pressure (130 bar) and lower amount of carbon dioxide (0.385 gCO2/gjuice) can assure:
the enhancement of cloud;
a significative reduction of PME activity;
a very good microbial inactivation (especially on yeasts and moulds), considering 106 cfu/ml the unacceptable microbial load for juice quality;
an extension of fresh orange juice shelf-life;
enhanced retention of antioxidant compounds.