TY - JOUR
T1 - Mathematical modeling of the viscosity of tomato, broccoli and carrot purees under dynamic conditions
AU - Tibäck, Evelina
AU - Langton, Maud
AU - Oliveira, Jorge
AU - Ahrné, Lilia
PY - 2014
Y1 - 2014
N2 - Different viscosity models were developed to describe the viscosity of unprocessed fruit and vegetable purees under dynamic conditions. Temperature hysteresis cycles were carried out for three purees with different structural characteristics (tomato, carrot, and broccoli), with heating and cooling phases from 10 to 80°C with isothermal (holding) phases at 10, 30, 60 or 80°C. The apparent viscosity was measured continuously with a rotational rheometer and the data was analyzed with time-independent and time-dependent models (quantifying rheopexy, thixotropy, or both). The results revealed clear thixotropic behavior in tomato puree, attributed to shearing effects, and rheopectic in broccoli puree, attributed to gel formation at the higher temperatures. Although carrot puree data from the isothermal periods could be quantified satisfactorily with no time dependency, analysis of the nonisothermal periods proved that rheopectic effects also needed to be included.
AB - Different viscosity models were developed to describe the viscosity of unprocessed fruit and vegetable purees under dynamic conditions. Temperature hysteresis cycles were carried out for three purees with different structural characteristics (tomato, carrot, and broccoli), with heating and cooling phases from 10 to 80°C with isothermal (holding) phases at 10, 30, 60 or 80°C. The apparent viscosity was measured continuously with a rotational rheometer and the data was analyzed with time-independent and time-dependent models (quantifying rheopexy, thixotropy, or both). The results revealed clear thixotropic behavior in tomato puree, attributed to shearing effects, and rheopectic in broccoli puree, attributed to gel formation at the higher temperatures. Although carrot puree data from the isothermal periods could be quantified satisfactorily with no time dependency, analysis of the nonisothermal periods proved that rheopectic effects also needed to be included.
KW - Gelling
KW - Isothermal
KW - Non-isothermal
KW - Rheopexy
KW - Shearing
KW - Thixotropy
U2 - 10.1016/j.jfoodeng.2013.09.031
DO - 10.1016/j.jfoodeng.2013.09.031
M3 - Journal article
AN - SCOPUS:84886710709
SN - 0260-8774
VL - 124
SP - 35
EP - 42
JO - Journal of Food Engineering
JF - Journal of Food Engineering
ER -