Modelling of rheological behaviour of pummelo juice concentrates using master-curve
2009
Chin, N.L. | Chan, S.M. | Yusof, Y.A. | Chuah, T.G. | Talib, R.A.
The rheological behaviour of freeze-dried-concentrated pummelo juice was modelled to investigate the effects of temperature and concentration on its fluid type and viscosity using a rotational viscometer at shear rates ranging from 1 to 400s⁻¹. The effect of concentration measured by its total soluble solids content resulted in the juice concentrates behaving towards shear thinning or pseudoplastic behaviour with flow behaviour index values, n <1. Temperature increase from 6 to 75°C produced a reversing effect of the shear thinning behaviour from the increase of n values at all three investigated concentrations, 20, 30 and 50°Brix. The consistency coefficient decreases with temperature but increases with total soluble solid contents. Modelling the rheological behaviour of pummelo juice concentrates using the master-curve yielded results over a range of temperature to overlap on a single line, which allows generalisation of flow behaviour and characteristics. The master-curve plots confirmed that the juice viscosity and pseudoplasticity increase with concentration with high regression coefficients, R ² >0.98.
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