Flavour oils

Mention should also be made of glutamic acid and invert sugar which are used in foodstuffs and demand the use of hydrochloric acid-resistant material in manufacture, and of the essential flavouring oils which should preferably be stored and prepared in stainless steel and aluminium equipment. 

Adjuvants (density adjustment for flavouring oils in beverages, diluent for colours and other food additives, encapsulating agent, excipient) Adsorbants (decolourizing agent)... 

Microencapsulation using extrusion is mainly described for glassy carbohydrate matrices [14-16, 28-29]. The glassy carbohydrates, such as starch and maltodextrins, are melted at elevated temperature and low water contents and are intensively mixed with the active in the extrusion barrel. Extrusion has been used for volatile and unstable flavours. The shelf life of flavour oils could be extended from several months to 5 years, compared with 1 year for spray-dried materials. The main drawbacks of the technology are the high investments costs and the formation of rather large particles (500-1,000 pm). 

The aroma of citrus fruit is a speciality. It consists of the so-called water phase and the oil phase. Citrus juices contain small amounts of volatile oils (0.03-0.06%). During processing there is always a small amount of peel oil that gets into the juice. Also the juice contains a small amount of oil, called juice oil. During evaporation these oils get into the aroma where they create the so-called oil phase. This oil has a very special aroma and is different from the peel oil by analysis (gas chromatography) as well as flavour. Oil and water phase are kept separately and added back to the juice according to individual requirements. Properly applied, the oil phase imparts the special fresh note to the juice which cannot be achieved by adding the water phase only. 

The taste of this decorative fruit is very acid, refreshing, fruity and juicy. The flavour is aldehydic fatty, especially on the skin fine droplets of a strongly flavoured oil develop when ripe. 

The rapeseed oil (RSO) was a gift from St. Ivel (Swindon, UK) and the flavour oil D-limonene (> 97%, L-2129, Lot 78H3488) was purchased from Sigma Chemicals (St Louis, USA). Sugar beet pectin was provided by Degussa Tex-turant Systems (Carentan, France). 

Important natural flavour. Oil with strong herbaceous odour. Bp 136°, Bp o 58°. 

In the Food Industry the choice of stabiliser is restricted by legislation but there are a wide range of natural copolymers to choose from, notably proteins and also certain polysaccharides such as gum Arabic. The latter consists of three molecular fi-actions, one of which has a wattle-blossom type structure in which branched carbohydrate blocks are linked to a common polypeptide chain (Figure 1.4) [15]. Gum Arabic is widely used to stabilise concentrated flavour oils for application in beverages and it has been argued that the polypeptide anchors the molecules to the surface of the oil droplets while the carbohydrate blocks protrude out into solution and confer stability through electrostatic and steric mechanisms. There is considerable interest nowadays in forming polysaccharide-protein complexes to... 

Gum Tragacanth E413 Plant exudate Astragalus species Iran, Turkey L-arabinose, D-galactose, D-galacturonic acid, L-rhamnose Confectionery icings, dressings, flavour oil emulsions... 

The L.CQz of ground fenugreek gives about 2% of an intensely rich flavoured oil, with all of the active components of the spice. However, as with all fenugreek extracts, it is recommended that an oil-soluble antioxidant such as alpha-tocopherol is added, if the extract is to be stored before use, as these lipids seem sensitive to oxidation. 

Table 6.25 Amount of surfactants (cetomacrogol and polysorbate 20) required to solubilize 1 % flavouring oils in water...

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