Flow Properties of Low‐Pulp Concentrated Orange Juice: Serum Viscosity and Effect of Pulp Content

Abstract

65"Brix serum samples from four concentrated orange juice (COJ) samples, between -19 and 30aC, were mildy shear-thinning fluids with negligible yield stress. The power law model described well the flow data. For one sample, the Powell-Eyring model also described the data. The activation energy of flow (E,) for the samples was between 11.2-13.6 kcaI/gmole. The power law parameters were determined for a 65'Brix sample as a function of pulp content (O-11%) between -19 and 30°C. At a fixed temperature, the apparent viscosity and the consistency index increased exponentially with pulp content. E, decreased with increase in pulp content and reached a constant value of about 10.2 kcaI/gmole. Data on a highpulp (21.2%), 65OBrix, sample indicated the presence of yield stress, particularly at low temperatures. The Mizrahi-Berk model predicted reliable values of the yield stress.

Effect of various pretreatment methods on permeate flux and quality during ultrafiltration of mosambi juice

“…The viscosity and density of ultrafiltered juice have been reduced significantly and they are close to water density and viscosity. It may be noted from Table 3, the viscosity of the permeate is almost same at 1.03 mPa s for all the processes whereas the feed has a viscosity in the range of 1.05-2.1 mPa s. Since, the pectinous materials and suspended solids are almost completely removed by UF, the filtered juice results has very low viscosity (Vitali & Rao, 1984).…”

Recent Advances in the Use of High Pressure as an Effective Processing Technique in the Food Industry

“…Many other numerical representations for viscosity of fluid systems as a function of temperature have been published by Seeton (2006). For liquid food systems over limited ranges of concentration, the effect of solids concentration on viscosity of liquid food can be described by either exponential (Vitali and Rao 1984) or a power type of relationship (Rao et al 1986). The dynamic relationship with viscosity and pressure, however, is not so well documented.…”

Rheological characteristics and thermal degradation kinetics of beta-carotene in pumpkin puree

“…The power law model with or without yield term has been employed to describe the flow behavior of viscous food over wide ranges of shear rates (Vitali & Rao, 1984).…”