The replacement of artificial with natural dyes is one of the most challenging research fields in the food production area. Recent studies have shown that some frequently used synthetic colours, called the “Southampton 6 Colours” may be linked with hyperactivity in children. The purpose of this work is to analyse the degradation behaviour of black carrot, a natural, red dye commonly used for colouring food products, and subsequently improve its stability during heat and storage conditions. The stability of the black carrot mixture to heat exposure was investigated at a range of pH values by heat-treating aqueous solutions in a domestic oven at around 180oC to maintain the temperature at 100oC and the powdered material in a furnace at 180oC (typical baking conditions). 1H NMR (800 MHz) spectroscopy was used for the assignment of the aromatic chemical shifts of the black carrot mixture by overlaying them with the characterised 1H NMR chemical shifts of the individual components separated by RP-HPLC. Integration of high-resolution 1H NMR (800 MHz) spectra was used to follow the relative degradation of each of the components. Different procedures for the complexation of black carrot with metal oxides were developed, for which colourants of different colour shades were prepared. Spectroscopic techniques were used to follow the degradation of the complexes which were heat-treated at 180oC. Nano-scale investigation of the metal oxide powders was also carried out. The optimised colourants were tested on a bench scale and subsequently on an industrial scale in food pilot procedures. The successful complexes produced were found to be more heat stable compared to the commercial black carrot dye. The developed technologies are cheap and easy-to-produce methods to create intense heat and storage stable coloured pigments which can be used for the replacement of existing artificial dyes during food processing.

<p>The use of spectrophotometers for color measurements on printed substrates is widely spread among paper producers as well as within the printing industry. Spectrophotometer measurements are precise, but time-consuming procedures and faster methods are desirable. Previously presented work on color calibration of flatbed scanners has shown that they can be used for fast color measurements with acceptable results. Furthermore, the rapid development of digital cameras has made it possible to transfer the methods to a camera-based system, and in this work a moderately priced consumer digital camera is used for color measurements. </p><p>Earlier presented methods for color calibration have been implemented in the camera-based system and new modifications that can improve their performance are proposed. Moreover, if the spectral sensitivities of the color filters in the camera sensor can be characterized, this can further improve the performance of the color measurements. Two methods for characterization of the color filters are presented in this work together with methods that use the camera characteristics for color measurements. </p><p>The findings of this work show that a consumer digital camera can be used as a fast and inexpensive alternative to spectrophotometers for color measurements on printed substrates.</p>

The use of spectrophotometers for color measurements on printed substrates is widely spread among paper producers as well as within the printing industry. Spectrophotometer measurements are precise, but time-consuming procedures and faster methods are desirable. Previously presented work on color calibration of flatbed scanners has shown that they can be used for fast color measurements with acceptable results. Furthermore, the rapid development of digital cameras has made it possible to transfer the methods to a camera-based system, and in this work a moderately priced consumer digital camera is used for color measurements. Earlier presented methods for color calibration have been implemented in the camera-based system and new modifications that can improve their performance are proposed. Moreover, if the spectral sensitivities of the color filters in the camera sensor can be characterized, this can further improve the performance of the color measurements. Two methods for characterization of the color filters are presented in this work together with methods that use the camera characteristics for color measurements. The findings of this work show that a consumer digital camera can be used as a fast and inexpensive alternative to spectrophotometers for color measurements on printed substrates.