Article

Thermophysical Properties of Lemon Juice as Affected by Temperature and Water Content

Journal of Chemical & Engineering Data (Impact Factor: 2.04). 08/2009; 54(8). DOI: 10.1021/je900155c

ABSTRACT

To design equipment for food processing and estimate process times for refrigerating, freezing, heating, or drying of foods, the thermophysical properties must be known. Since the thermophysical properties of foods are strongly dependent upon chemical composition and temperature, composition and temperature based models provide a means of estimating these properties. In this work, the thermophysical properties of lemon juice were determined at a water mass fraction of (0.381 to 0.900) and a temperature of (273.45 to 353.75) K. Density and thermal conductivity varied from (962.3 to 1282.8) kg·m−3 and (0.344 to 0.624) W·m−2·K−1, respectively. Heat capacity and thermal diffusivity varied from (2446.5 to 4060.1) J·kg−1·K−1 and (0.1160·10−6 to 0.1785·10−6) m2·s−1, respectively. Simple polynomial functions were fitted to the experimental data, and good agreements were obtained. In the tested range, water content showed greater influence on the thermophysical properties.

Download full-text

Full-text

Available from: Lizzy Ayra Alcântara Veríssimo
  • Source
    • "Thermal diffusivity was high at low fat content and higher temperature for coconut milk and linearly related with fat content as well as with temperature (Tansakul and Chaisawang, 2006). Several authors reported thermal diffusivity increased linearly with moisture content as well as temperature, water content had strong influence on thermal diffusivity than temperature for fruit juices such as orange, grape, pineapple, lemon, cashew, black berry, yellow mombin and other products (Telis-Romero et al., 1998; Yang et al., 2002; Azoubal et al., 2005; Assis et al., 2006; Cabral et al., 2007; Minim et al., 2009; Muramatsu et al., 2010). Thermal diffusivity of mango and papaya purees decreased with increase in total soluble solid content whereas it increased with temperature. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Investigation was carried out to evaluate thermophysical properties such as density, Newtonian viscosity, thermal conductivity, specific heat and thermal diffusivity of enzyme clarified sapota (Achras sapota L.) juice at different moisture contents ranging from 38.01% to 88.64% (wet basis) corresponding to a water activity in the range of 0.839 to 0.987. The investigation showed that density and Newtonian viscosity of enzyme clarified sapota juice decreased significantly (p < 0.05) with increase in moisture content as well as water activity, whereas thermal conductivity increased significantly (p < 0.05) with increase in moisture content and water activity. The specific heat and thermal diffusivity were markedly affected by moisture content as well as water activity. Empirical mathematical models were established relating to thermophysical properties of enzyme clarified sapota juice with moisture content/water activity. Results indicated that there was a high significant (p < 0.0001) correlation between thermophysical properties with moisture content/water activity of enzyme clarified sapota juice. A significant (p < 0.0001) positive correlation between thermal properties and moisture content/water activity, whereas significant (p < 0.00001) negative correlation between physical properties with moisture content/water activity was observed. In general, the thermophysical properties of enzyme clarified sapota juice were markedly affected by moisture content/water activity.
    Full-text · Article · Jan 2014 · International Food Research Journal
  • Source
    • "Gravimetric determination of samples density (ρ) was conducted using an analytical balance (Model AG200, Gehaka, São Paulo, Brazil) with given uncertainty ±0.0001 g and standard volumetric pycnometer (~25 mL) (Fontan et al., 2009; Minim et al., 2009). The pycnometer was previously calibrated with distilled water for each temperature kept constant using a thermostatic bath (Model Q214S2, Quimis, São Paulo, Brazil), uncertainty of ±0.1 K. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Cited By (since 1996): 1, Export Date: 15 February 2013, Source: Scopus, Art. No.: 11
    Full-text · Article · Jan 2012 · International Journal of Food Engineering
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Thermophysical properties of enzyme clarified lime (Citrus aurantifolia L.) juice were evaluated at different moisture contents ranging from 30.37 % to 89.30 % (wet basis) corresponding to a water activity range of 0.835 to 0.979. The thermophysical properties evaluated were density, Newtonian viscosity, thermal conductivity, specific heat and thermal diffusivity. The investigation showed that density and Newtonian viscosity of enzyme clarified lime juice decreased significantly (p < 0.05) with increase in moisture content and water activity, whereas thermal conductivity and specific heat increased significantly (p < 0.05) with increase in moisture content and water activity and the thermal diffusivity increased marginally. Empirical mathematical models were established relating to thermophysical properties of enzyme clarified lime juice with moisture content/water activity employing regression analysis by the method of least square approximation. Results indicated the existence of strong correlation between thermophysical properties and moisture content/water activity of enzyme clarified lime juice, a significant (p < 0.0001) negative correlation between physical and thermal properties was observed.
    Full-text · Article · Nov 2012 · Journal of Food Science and Technology -Mysore-
Show more