Effect of dense phase carbon dioxide processing on microbial stability and physicochemical attributes of Hibiscus Sabdariffa beverage
Reyes-De Corcuera JI
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Hibiscus beverage was treated with dense phase carbon dioxide (DPCD), and inactivation was determined using yeasts and molds (Y&M) and aerobic plate counts (APCs). A central composite design with pressure (13.834.5 MPa) and residence time (58 min) at constant temperature (40°C) and %CO2 was used. A storage study (14 weeks at 4°C) included the DPCD treated (34.5 MPa, 8% CO2, 6.5 min and 40°C), thermal treated (HTST) (75°C for 15 s) and untreated (control) beverages monitoring microbial growth, pH,degrees Brix, titratable acidity (TA) and color. A minimum of 5 and 0.85 log reductions for Y&M and APC was achieved for all DPCD treatments. APC remained similar to 2 logs during the 14 weeks of storage, while Y&M were reduced similar to 3 logs and remained stable for both DPCD and HTST samples. degrees Brix and pH were not affected by DPCD treatment, whereas TA increased. A slight decrease was observed for a*, b*, hue angle and chroma for all treatments. Overall results showed that DPCD can be competitive with HTST process producing a shelf stable product while minimally affecting its physicochemical attributes. PRACTICAL APPLICATIONS Hibiscus beverage processing requires an extraction step followed by a preservation method. New processing technologies such as dense phase carbon dioxide require little to no heat and may help to maintain the fresh-like color, flavor and nutrients of the beverage. This research pursues the optimal processing conditions for a hibiscus beverage by comparing dense phase carbon dioxide processing with traditional pasteurization, and following the microbial stability and physicochemical attributes of these beverages after processing and during storage.