Mathematical modeling of thin-layer solar drying and organoleptic properties of eland jerky was investigated in this study. Eland jerky was compared to the traditional beef jerky, inasmuch as both were treated with traditional jerky marinade (TM), TM with fresh pine apple juice (TMP), TM with honey (TMH), TM with Coca Cola (TMCCL) and compared to an untreated control (C). The influence of the marinades on the drying process was statistically significant. Based on the coefficient of determination, the root mean square errors and the chi-squares, the Two-term model was found to be the most suitable model for describing the solar drying kinetics of eland jerky. The mean effective moisture diffusivities of solar dried eland meat for the C and selected pre-treatments TM and TMH samples were 2.07 x 10-10, 1.45 x 10-10 and 1.43 x 10-10 m2.s-1, respectively. The activation energy values for solar dried eland jerky were 23.75, 26.22 and 26.97 kJ.mol-1 for C, TM and TMH, respectively. Organoleptic properties of dried eland meat was assessed by the 22 member degustation panel. The best scored pre-treatment was TMP, which has significant effect on texture, color and taste. Effect of the different pre-treatments on the overall combined color was calculated. Generally for both meat dried in both driers TMH marinade was evaluated as the one with the highest total difference contrariwise meat dipped in TMP pre-treatment has the lowest total difference.

This study quantifies discolouration on the surface of Pinus radiata boards during kiln drying, particularly kiln brown stain (KBS), and models it as a function of chemical compounds present in the wood closest to the surface. The discolouration was investigated with two experimental factors: drying time, which consisted in drying at 70/120 ℃ for 0, 8, 16 and 24 hours; and leaching, done at three levels, noleaching, mild and severe, to reduce the soluble compounds present in wood suspected of developing coloured compounds. The colour change was quantified using a reflectance photometer (colour system CIE Yxy, brightness) and by the analysis of digital photographs (colour system CIE Lab). The chemical analysis of the wood closest to the surface of the boards determined fructose, glucose, sucrose (HPLC), total sugar (sum of fructose, glucose and sucrose), total nitrogen (combustion gas analysis), and phenols discriminated by molecular weight (Folin-Ciocalteu method). In the cause-effect analysis, colour was the dependent variable, and drying time and the determinations of chemical compounds were independent variables. After statistical analysis (ANOVA and MANOVA) the dependent variables to be included in the models were luminance factor (Y), brightness (R457 and the blue-to-yellow scale of CIE Lab (b); and the independent variables were drying time, nitrogen, total sugar, and high-molecular-weight phenols. Linear (multivariate regression) and non-linear models (Neural Networks) showed that discolouration during kiln drying was best predicted when the luminance factor (Y) was used to quantify colour change as a function of the content of nitrogen-containing compounds and drying time. Furthermore, the data were fitted into an empirical model based on simple reaction kinetics that considered the rate of discolouration as a function of nitrogen concentration. The results suggest that nitrogen could act as a limiting reactant in Maillard-type reactions that produce colour during kiln drying.

The thesis deals with colors - their representation in digital devices and how to provide the best color preservation accross different devices. In the first part of the work, the knowledge of colors and human vision is briefly summarized. Then color models and color spaces are elaborated, mainly those device independent. Spectrum of colors viewable or printable on a device - the gamut - is different for every device and there's a need of precise reproduction or record of color. That's why the system of color management is described further and especially the gamut mapping approaches and algorithms are mentioned. In the second part of the work, the implementation of how two algorithms of color gamut mapping (HPMINDE, SCLIP) can be implemented in MATLAB is described. In the third and last part of the work, the results of implemented algorithms are presented and discussed. These results are compared to results of commonly used color gamut mapping technique (Adobe Photoshop).