Protection of polyphenols in blueberry juice by vacuum-assisted block freeze concentration.
Block freeze concentration allows produces high-quality cryoconcentrates with important protection of valuable components from fresh fruit juices. The aim of this study was to investigate the use of vacuum-assisted block freeze concentration under different experimental conditions to protect polyphenols in the elaboration of concentrated blueberry juice. Fresh blueberry juice was radial or unidirectional frozen at -20 and -80 °C for 12 h and vacuum process was performed at 80 kPa during 120 min. Results showed a significant solute increased in the concentrated fraction in all treatments, and the best treatment was - 20 °C/unidirectional with a value of ≈63 °Brix, equivalent to an increase of 3.8 times in the total polyphenol content (76% of retention). The color of concentrated samples was darker than the initial sample, with ΔE* values of >25 CIELab units in all treatments. The vacuum-assisted block freeze concentrations was an effective technology for protecting polyphenols and obtain a concentrated with a higher concentration of solids from blueberry juice, as well as interesting values of process parameters.
Department of Food Engineering, Universidad del Bío-Bío, Av. Andrés Bello s/n, Casilla 447, Chillán, Chile. Electronic address: patorell@alumnos.ubiobio.cl.
Patricio
P
Orellana-Palma
Department of Food Engineering, Universidad del Bío-Bío, Av. Andrés Bello s/n, Casilla 447, Chillán, Chile; Group of Emergent Technology and Bioactive Components of Food, Universidad del Bío- Bío, Chillán, Chile.
Guillermo
G
Petzold
Department of Food Engineering, Universidad del Bío-Bío, Av. Andrés Bello s/n, Casilla 447, Chillán, Chile.
Lissage
L
Pierre
Department of Biochemical Engineering, Instituto Tecnológico de Durango, Durango, Mexico.
José Manuel
JM
Pensaben
D029798:Blueberry Plants / Q000737:chemistry*; D005519:Food Preservation / Q000295:instrumentation / Q000379:methods*; D005615:Freezing; D005638:Fruit / Q000737:chemistry; D000067030:Fruit and Vegetable Juices / Q000032:analysis*; D059808:Polyphenols / Q000737:chemistry*; D014618:Vacuum
D059808:Polyphenols
Block freeze concentration; Blueberry juice; Polyphenols; Solutes; Vacuum