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

TAROCCO ORANGE

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

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

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.

High pressure supercritical CO2 equipment

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, 0.770 gCO2/gjuice 130 bar, 36 ± 1 °C, 0.770 gCO2/gjuice 130 bar, 36 ± 1 °C, 0.385 gCO2/gjuice

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

Changes of physicochemical parameters 1.

Changes of physicochemical parameters B 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.

Changes of physicochemical parameters B 263.27 % 109.59 % 145.01 % 3.

Changes of antioxidant components B A AB B a a b 1.

Changes of antioxidant components AB a b B b 2.

Changes of antioxidant components B C 3.

Changes of antioxidant components B ab B b 4.

Changes of antioxidant components AB AB B B 5.

Changes of antioxidant components B A a B B ab b 6.

Storage study 1.

Storage study 2.

Storage study 3.

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.