Pigments coloured

Pigment/Binder Ratio the ratio of total pigment (white and/or coloured pigment plus extender) to binder (q. v.) in a paint preferably expressed as a ratio by volume. 

Saito, K., A new enzymatic method for extraction of precarthamin from dyer s saffron (Carthamus tinctorius) florets, Z. Lebensmitt. Untersuch. Forsch., 197, 34, 1993. Cserhati, T. et ah. Separation and quantitation of colour pigments of chili powder (Capsicum frutescens) by high-performance liquid chromatography-diode array detection, J. Chromatogr. A, 896, 69, 2000. 

Brown Algae, such as rhodophyta and phaeophyta. They consist of numerous compilations of thread-like cells, which contain specific brown coloured pigments, like Fe2+ and Mn2+. 

In centuries prior to the industrial revolution, before the development of manufactured paints, a painter was not only an artist, but also a formulator of paints , thus experimenting with a multitude of materials as paint. Organic paint binders typically were adhesive to the ground layer and also provided a matrix capable of suspending the coloured pigments. Specific binders were needed to form stable films with aesthetic visual properties. In European artwork,... 

Figure 2.2 Optics of a single coloured pigment particle in a medium when struck by a ray of white light. The light becomes increasingly coloured as it travels from point B to point C...

If total internal reflection does occur at point C, the amount of absorption could be doubled. Too long a path within the particle, or a very high absorption coefficient, could mean that all the light is absorbed and the colouring power of the particle will thus be lost. This demonstrates one reason why the mean particle size of the coloured pigment must be arranged to minimise this possibility. 

Figure 2.4 Combination of a coloured pigment particle and a very small white pigment particle...

The efficacy of various normal and RP-TLC systems for the separation of the colour pigments of Capsicum annuum was compared. Neutral aluminium oxide, silica gel, diatomaceous earth, silica gel-diatomaceous earth 1 1, cellulose, cyano, diol- and amino modified silicas were employed as stationary phases for adsorption TLC. Polyamide and modified silica layers were used for RP-TLC as received, the other stationary phases were impregnated by overnight predevelopment in n-hexane - paraffin oil, 95 5 v/v. 

Fig. 2.2. Separation of the colour pigments of chilli powder on impregnated diatomaceous earth eluted with acetone-water (17 3 v/v). Reprinted with permission from T. Cserhati et al. [15].

COMPOSITION OF GRADIENT ELUTION FOR THE SEPARATION OF COLOUR PIGMENTS OF PAPRIKA CAPSICUM ANNUUM) POWDERS IN NORMAL (150 X 4 MM I.D.) AND MICROBORE (150 X 2 MM I.D.) OCTADECYLSILICA COLUMNS. A = ACN - METHANOL (1 4, V/V) B = BIDISTILLED WATER. EACH GRADIENT STEP WAS LINEAR. FLOWRATES FOR NORMAL AND MICROBORE COLUMNS WERE 2 ML/MIN AND 0.6 ML/MIN, RESPECTIVELY... 

GRADIENT ELUTION FOR THE REVERSED-PHASE HIGH-PERFORMANCE LIQUID CHROMATOGRAPHIC SEPARATION OF COLOUR PIGMENTS IN THE EXTRACTS OF PAPRIKA (<CAPSICUM ANNUUM). ELUENT A, METHANOL-ACETONITRILE (80 20, V/V) ELUENT B, BIDISTILLED WATER... 

A similar RP-HPLC method has been employed for the determination of the effect of reduced glutathion (GLT) and hydroxypropyL/Tcyclodcxtrin (HP-/LCD) on the stability of the colour pigments of paprika. Samples were prepared by mixing 5 per cent GLT (w/w) and 5 per cent HP-/TCD (w/w) with paprika powder and stored at room temperature (22 1°C) in diffuse light in Petri dishes covered by glass plates. Samples without additives served as a control, lg of paprika was taken after 14, 28, 42 and 56 days of storage... 

Fig. 2.6. Separation of colour pigments of paprika powders extracted with water-acetone (10 90, v/v chromatogram a) and water-THF (75 35, v/v, chromatogram b). Reprinted with permission from G. A. Csiktusnadi-Kiss el al. [30].

Fig. 2.8. Reversed-phase HPLC chromatograms (430 nm) of colour pigments of paprika powder after 56 days of storage time, a = control, b = 5 per cent GLT, c = 5 per cent HP-/3-CD. Peak indentification 1 = capsanthin 2 = zeaxanthin 3 = /3-carotene. Reprinted with permission from T. Cserhati el al. [32].

Fig. 2.11. Separation of colour pigments of chilli powders, a origin Malaysia, detection wavelength 340 nm b origin Malaysia, detection wavelength 440 nm c origin Thailand, detection wavelength 340 nm d origin Thailand, detection wavelength 440 nm. Reprinted with permission from a. Kosa et al. [35].

Fig. 2.138. Densitograms of colour pigments of raisins. Alugram RP-18/UV254 plates mobile phase water-THF (3 7) raisin 8, detection wavelength 340 nm (a) raisin 3, detection wavelength 340 nm...

Fig. 2.140. Densitograms of colour pigments of chestnut sawdust on silica (a) and impregnated silica (b) layers at 340 nm. Multistep gradient development water-THF 1 1 (v/v) for 3cm water-THF 3 7 (v/v) for 8cm then water-THF 1 4 (v/v) to the end of the development. Reprinted with permission from T. Cserhati et al. [313].

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