K Nn mK - Amecamex.org.mx

Food Science and Biotechnology in Developing Countries
Process viscosity study on heterogeneous foods
L. Medina Torres 1 *, E. Brito de la Fuente 2 , J.A. Gallegos Infante 3
1,2 Departamento de Alimentos y Biotecnología, Facultad de Química
Universidad Nacional Autónoma de México., 04510 México, D.F.
3 Instituo Tecnológico de Durango
Departamento de Ingenieria Química y Bioquímica
Felipe Pescador 1930 Ote., Durango, Dgo. 34080., México
Tel./Fax (5)56-22-53-08. email: luismt@servidor.unam.mx
INTRODUCTION
On the food industry there are an important group of food systems that it are
constituid by a dispersant phase, in this phase there are a lot of relative soluble
components and a disperse phase with particles with distinct physics properties.
The rheological properties are of great importance in food fluids as mermelades,
salad dressing, soups, sauces and creams [Baudi, 1996]. The knowledge of
rheological properties are very important in the industrial optimization as
pumping, mixing, cooling, drying and others. The usual viscometers are not good
for this systems cause the heterogeneous nature of the dispersion. With the
objective of a best determination of the fluid properties it has been used the
rheometry with mixing principles for heterogeneous systems. [Brito et al., 1998].
Rheological measurements.
EXPERIMENTAL METHODOLOGY
It were working three different simples of heterogeneous foods: Salad
dressing, orange mermelada and peach yogurt, at 25°C. The rheological
measurements were making in a rotational rheometer (Haake, CV20N, RV20)
with temperature control. It was used a system with helicoidal geometry adapted
to rheometer.
On the Figure 1 is shown the system used. The Viscosity data were obtained
following the method. [Brito et al., 1998].
The process viscosity was determinated with the next algoritm:
η
e
=
mK
p
( n)
K
p
N
n −1
RESULTS AND DISCUSSION
(1)