Abstract
Rheological properties of purées made from small fruits like blueberries are important for application in handling and thermal processing where their physical and/or chemical attributes can be altered. Flow of purées made from highbush blueberry (Vaccinium corymbosum L.) was investigated in the 10-1000 s-1 shear rate range with the objective of determining the influence of temperature and solids content on the rheological properties. The rheological behavior was well described by the three-parameter Sisko model. The activation energy of flow (Ea) calculated with respect to apparent viscosity at 100 s-1 increased from 11.4 to 17.1 kJ/mol for purée with 10% and 25% total soluble solids, respectively. When evaluated in terms of consistency coefficient, the activation energy varied between 10.7 and 21.7 kJ/mol within the same range of solid contents. For the conditions investigated, a mathematical model that is suitable for describing the influence of temperature and dissolved solids on the apparent viscosity of blueberry purée was obtained. The rheological behavior of 10-20 Brix blueberry purée was well predicted (R2 = 0.99). Further investigation is needed to improve the model to cover a wider Brix range.
Original language | English (US) |
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Pages (from-to) | 292-299 |
Number of pages | 8 |
Journal | LWT |
Volume | 40 |
Issue number | 2 |
DOIs | |
State | Published - Mar 2007 |
Externally published | Yes |
Keywords
- Activation energy
- Evaporation
- Refractance Window
- Viscosity model
ASJC Scopus subject areas
- Food Science