Effect of an UV-C Light-Based Hurdle Strategy for Carrot-Orange Juice Processing on Candida parapsilosis Inactivation and Physiological State: Impact on Juice Sensory and Physicochemical Quality Parameters

• Published in: Food and bioprocess technology 2020-11, Vol.13 (11), p.1954-1967
• Main Authors: García Carrillo, M, Ferrario, M, Schenk, M, Guerrero, S
• Format: Article
• Language: English
• Subjects: Agriculture; Antioxidants; Beverages; Biotechnology; Candida parapsilosis; Chemistry; Chemistry and Materials Science; Chemistry/Food Science; Color; Deactivation; Esterase; Flow cytometry; Food quality; Food Science; Fruit juices; Inactivation; Juices; Membranes; Microorganisms; Oranges; Original Research; Pasteurization; Pectin; Pectinesterase; pH effects; Physiology; Sensory evaluation; Sensory properties; Turbidity; Ultraviolet radiation
• ISSN: 1935-5130; 1935-5149
• DOI: 10.1007/s11947-020-02540-8

In the past two decades, novel preservation technologies have been investigated to achieve sufficient microbial reduction while improving the quality of food and beverages . The effect of UV-C light (UV-C, 1720 mJ/cm 2 ) assisted by mild heat (H, 50 °C) on the inactivation and the physiological state of Candida parapsilosis ATCC 22019 in a carrot-orange juice was studied by flow cytometry. Additionally, the juice samples processed or not (control) by the single (UV-C; H) and combined (UV-C/H) treatments were analyzed for total polyphenol content (TPC), total antioxidant activity (TAA), color, turbidity, °Brix, pH, and pectin methylesterase units (PME) along 13–24-day storage (4 °C). Consumer-profiling studies were conducted on UV-C/H and a pasteurized juice. UV-C/H was highly effective in reducing C. parapsilosis by 5.5 log cycles, whereas the single UV-C and H treatments induced 2.9 and 3.9 log reductions, respectively. Flow cytometry revealed a shift with time from cells with intact membrane and esterase activity to those with permeabilized membrane and without esterase activity, which was significantly higher for UV-C/H samples (98.0%) compared with the single treatments (12.0–46.2%). UV-C/H preserved juice color, pH, °Brix, and turbidity of the juice, which exhibited equal TAA (0.7 mg/mL) and higher TPC (302.1 μg/mL) than the control (TAA = 0.7 mg/mL/TPC = 205.0 μg/mL), remaining constant throughout storage. PME decreased 42–45% for the H and UV-C/H treatments, respectively. A cluster sensory analysis revealed that one group of consumers showed a remarkable interest in the UV-C/H juice, while the conjoint study showed that it was perceived as very healthy. The CATA question determined that the UV-C/H processing prevented the juice from being perceived too particulate or with cooked or artificial taste, as happened with the pasteurized juice.