Use este identificador para citar ou linkar para este item: https://locus.ufv.br//handle/123456789/23938
Tipo: Artigo
Título: Thermal diffusivity and specific heat of bovine milk affected by temperature and composition
Autor(es): Veríssimo, Lizzy Ayra Alcântara
Souza Jr., Evaldo Cardozo
Fontan, Rafael Costa Ilhéu
Sampaio, Vanessa Santos
Silva, Willian Soares
Bonomo, Renata Cristina Ferreira
Veloso, Cristiane Martins
Abstract: The sizing of equipment used in food processing, particularly heat exchangers and other equipment that require pumping of products, requires accurate data of thermophysical properties. Milk is one of the most processed liquid food fluids in the world and currently data on its thermophysical properties are limited. In a previous paper (Alcântara et al., 2010) density and dynamic viscosity data of bovine milk were presented and how these properties are affected by temperature and composition, in ranges commonly encountered in food processing. Here the thermal diffusivity and specific heat data for milk are presented, evaluating the effect of composition (moisture, fat, lactose, protein and minerals contents) and temperature (only for thermal diffusivity). Linear regression was used and the best models were selected based on the determination coefficient (R2), lack of fit, significance parameters and root mean square error (RMSE) values. Predictive ability of fitted models was compared with Choi and Okos (1986) correlations. Thermal diffusivity ranged from (1.00 to 9.03) × 10-7 m2•s-1 and specific heat from (3.078 to 4.121) kJ•kg-1•K-1. Thermal diffusivity presented a polynomial quadratic behavior affected by temperature and composition, except for lactose concentration which showed no significant effect (p>0.05). For specific heat, increase in the moisture content led to an increase in the specific heat while elevations in fat, protein, lactose and mineral contents promoted a decrease of this property. In both cases the fitted models showed satisfactory R2 values, non- significant lack of fit (p>0.05) and significant parameters (p<0.05), with RMSE values lower than Choi and Okos (1986) correlations. From the properties presented here and in the earlier paper, accurate calculations can be made for correct sizing and adaptation of equipment, as well as provide information of other thermophysical properties such as thermal conductivity and thermal expansion coefficient.
Palavras-chave: Modeling
Thermophysical properties
Major constituents
Milk
Editor: International Journal of Food Engineering
Tipo de Acesso: Open Access
URI: https://doi.org/10.1515/1556-3758.2307
http://www.locus.ufv.br/handle/123456789/23938
Data do documento: 2012
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