Smoked colour

One of the simplest, and hence cheapest smoke colouring agents is an azo dye known as l-(phenylazo)-2-naphthol which is bright orange in colour and also used as a pyrotechnic distress signal. The dye is made by a diazotisation process involving aniline and 2-naphthol as shown in Scheme 10.1. 

In the majority of coloured smokes, even with some physical smokes, colour change generally occurs during the generation of the smoke. A clear beautiful colour changes gradually to a whitish or yellowish one, or suddenly a flame appears and burns out the smoke particles to make them invisible. 

The smoke colour of para red is orange red, and generally it is not used alone, but in combination with rhodamine B for red smoke. 

This is used for white smoke composition in combination with zinc dust and hexachloroethane, It seems that the higher the purity is, the whiter the smoke colour is. The smoke composition is generally packed in a tin case, and the apparent specific volume is important in manufacture if it is too small the can is not filled and if it is too large, the case cannot be filled with the amount defined in the specification. The apparent specific gravity of this material on the market lies between about 0.5 hg and 1.0 kg per litre. 

Application of natural aqueous smoke flavourings to meat is done in large part for the purpose of producing smoked colour. Smoke solutions are applied to the surface of meat where smoked product colour is desired. The carbonyls are known to be the initiators of a brown smoked colour. While aqueous smoke solutions are innately a reddish brown colour, virtually none of this colour is imparted to the product through a staining effect. Rather, carbonyls first react with amines to produce Schiff bases which eventually end up as mealnoidins through complex, multiple-step reactions which are driven by heat and dehydration. 

As noted above, the water-soluble fraction of wood smoke is the most widely used fraction, particularly where smoke colour is most important. Where only smoke flavour is desired, there are several methods which can be used to produce a natural smoke flavour without forming a significant colour. Through a liquid-liquid extraction process, the less polar smoke constituents are extracted to produce a smoked flavoured vegetable oil [7],... 

In the atomisation process, the brined fish or fillets are placed on smoke sticks or trays and loaded into the processing oven. The fish are dried until a tacky product surface is obtained before the atomised smoke is applied. This pre-drying step is necessary to remove excess moisture from the surface of the fish and to aid in the solubilisation of protein on the surface to produce a glossy surface. It also aids in the retention of the atomised liquid smoke on the fish surface and development of the desired smoke colour. Heat processing after the smoke application should be sufficient to meet processing requirements set by the applicable regulatory agencies. 

Beef sticks are produced similarly to other dry sausages. Normally, smoke flavourings can be added to the emulsion to provide the optimum smoke flavour intensity. Aqueous base flavourings may also be atomised on the exterior surface during processing to provide a uniform smoke colour. 

Smoke colour White Light grey Ught grey... 

Figure 11.4 Total yield and ripe fruit yield. Ethephon = E ( /ha) (a) not mulched (b) smoke-coloured mulch (c) transparent mulch (d) not mulched + E (1.5 + 1.5) (e) smoke-coloured mulch + E (0.5) (f) transparent mulched + E (0 5) (g) not mulched + E (3), (h) smoke-coloured mulch + E (1), (i) transparent mulch + E (1) (I) not mulched + E (1.5) (m) smoke coloured mulch + E (1 5). (n) transparent mulch + E(1.5).

Coloured smoke compositions White smoke compositions (except those in Group 5) Compositions with <35% chlorate... 

Coloured smoke devices Sealed table bombs White smoke devices... 

Coloured smoke compositions Low/medium Large firework shells ... 

Aspects of special effects described in this chapter include fuses (quickmatch and plastic fuse), lances (small coloured flares), set-pieces and devices (assemblies consisting of various types of fireworks linked together), flash, bang and whistle compositions and daylight fireworks (smoke puffs and coloured smokes). Finally, the electrical firing of firework displays is discussed. 

For coloured smoke puffs, pigments based on metal chromates are utilised, the pigment being intimately mixed with a fuel such as magnesium. On combustion in free air, a smoke cloud is produced that has residual colour due to the chromate. 

Although blue dyes usually appear to be blue-black in bulk, a blue colour is seen when they are viewed at the edge of a smoke cloud. This is related to the spectral characteristics, concentration and particle size of the dye. 

Solvent dyes are also used in the coloration of any solvent or wax based product, including polishes, cosmetics, crayons, candles, inks, stains and adhesives. They are also in the coloured smokes that are used in outdoor displays, for instance coloured trails from aircraft, and in safety and security applications. 

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