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Journal of food physicsVol. 23. (2010.)


  • L. Priatková ,
    Z. Hlaváčová ,
    Á. Kertész :
    Hunter colour determination of blueberry cultivars18-21en [139.04 kB - PDF]EPA-02408-00005-0030

    Abstract: Colour has been shown of primary importance in the judgment of food, ultimately influencing the acceptance or rejection of food. Colour is one of the important quality attributes on food. The measurements were done with 10 cultivars of blueberries. The colour was measured by determining Hunter L* (lightness), a* (redness/greenness) and b* (yellowness/blueness) values of blueberries cultivars. Treatment differences were tested using Duncan’s Multiple Range test, α = 0.05.

  • L. Zeleňáková ,
    R. ®idek ,
    M. Čanigová :

    Abstract: In the present work we studied the use of ELISA method for the detection of the lab-prepared adulteration of sheep milk and cheese with cow milk. The analyses were focused on laboratory testing and evalutation of qualitative parameters commercially used ELISA tests (Casein ELISA set, SEDIUM R&D) based on detection of cow milk casein. Casein was determined in 16 samples of milk and 16 samples of cheese. Measurement of absorbance values were repeated twice under different combination of mixing (0; 0.5; 5; 50; 75 and 100 % of raw and heat treament cow milk in sheep milk). The results showed that this assay takes only about three hours and is suitable for detection of lots of sheep milk adulterated with 0.5 to 50 % cow milk (regression equations with R2 determination coefficient: R2 = 0.965). Our experiments shown that used ELISA test is not suitable to reliably detect the presence of cow milk casein in sheep cheese (R2 = 0.022).

  • S. P. Zheljazkov ,
    E. Vozáry ,
    G. Zsivánovits ,
    G. Exner ,
    M. G. Marudova-Zsivánovits ,
    Á. Krisán :
    Rheological parameters of fruit gums “haribo” gold bears27-31en [212.00 kB - PDF]EPA-02408-00005-0050

    Abstract: Mechanical hysteresis and force relaxation curves of “Haribo” gold bears consisting of glucose syrup, sucrose, gelatine, dextrose, citric acid, vegetable oils, fruit extracts, were measured with Stable Micro System TA-XT2 texture analyser. Loading-unloading curves were determined at room temperature with probe speed of 0.3, 0.5, 0.7, 0.9 and 1.1 mm/s, and in the temperature range from 5 °C up to 55 °C with 0.1 mm/s probe speed. The maximal deformation was 5 mm. The force-deformation curves had linear character up to about 1 mm deformation and at higher deformations the slope of the curves increased with the increasing of the deformation. The degree of elasticity defined as the ratio of unloading work to loading work decreased at temperatures lower than 20 °C and higher than 40 °C. The degree of elasticity decreased with the increasing of the probe speed. The measured force relaxation curves at constant 5 mm deformation were approached with a three elements generalized Maxwell-model. The relaxation time of all the three components decreased and the amplitude decreased for the two slower components and increased for the quickest component as the probe speed increased.

  • L. Severa :
    Different approaches for coffee bean shape and contour determination33-40en [227.39 kB - PDF]EPA-02408-00005-0060

    Abstract: Selected Arabica (Coffea arabica L.) coffee beans (13 different types from 13 different countries) were monitored and variability of their shape and size was analysed. The basic analysis was based on evaluation of main dimensions. Several tools were employed for performing of the objectives – determination of main dimensions ratios, determination of sphericity (parameter for the calculation of processing and handling operations), calculation of shape variability using elliptic Fourier descriptors, and calculation of curvature radius. All three approaches proven significant differences among individual coffee samples. The least variable bean parameter was bean depth with a coefficient of variation 0.05, followed by bean width with a coefficient of variation of 0.18, and bean length with a coefficient of variation of 0.85. The experiments improved previous findings concerning the relationship between length, width, and depth of Arabica beans. Sphericity also ranged and its value can be used for the design and evaluation of processing and handling operations. Reconstructed shapes (by use of Fourier descriptors) indicated that the first principal component (which represents the length-to-width ratio) is a suitable measure of the total shape variation (70.87 to 74.64 % of the total shape variation).

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