Extracts, flavouring, liquid

Aromatic liquids Beverage extract (concentrate) Camphor oil, 3.3 Extract, aromatic or flavouring Extracts, aromatic, liquid, 3, 3.2,3.3 Extracts, flavouring, liquid,... 

There are a number of published applications in which spices are extracted with liquid carbon dioxide to isolate a flavour- or aroma concentrate [22,48,54], Liquid CO2 dissolves the essential oils and lighter fractions of the oleoresins. Supercritical CO2 is generally a better extracting-solvent than liquid CO2, because higher densities, equivalent to higher solubility, can be achieved by raising the pressure. 

A different mode of operation, characterised as bubble flow, is possible if the continuous phase is the liquid to be extracted. The liquid level is kept constant at the top of the column and the supercritical gas which is introduced at the bottom is bubbled through the liquid for extraction. This method is mainly used if small amounts of dense gas are sufficient for complete extraction, i.e. if the solvent ratio of dense gas/ liquid feed is around 1 kg/kg. Examples are the extraction of flavours from wine and fruit juice where only very small amounts of extract can be expected. 

Flavouring liquids Other regulated substance, aromatic extract or flavouring Terpene hydrocarbons, n.o.s., 3.3 Terpenes, n.o.s. 

Costs for the isolation of flavour and perfume ingredients by solvent extraction with liquid CO2 compared with solvent extraction with supercritical carbon dioxide and steam distillation. Because of the higher pressures involved, the extraction equipment required for supercritical extraction with CO2 costs more (typically IV2 times as much) than that required for subcritical extraction. In some applications this factor is more than offset by the higher loadings of extract in the solvent phase obtained in the supercritical case which result in lower compressor and separator costs (see chapter 10). For this... 

CH3 CH0H CH20H, a colourless, almost odourless liquid. It has a sweet taste, but is more acrid than ethylene glycol b.p. 187. Manufactured by heating propylene chlorohydrin with a solution of NaHCO under pressure. It closely resembles dihydroxyethane in its properties, but is less toxic. Forms mono-and di-esters and ethers. Used as an anti-freeze and in the preparation of perfumes and flavouring extracts, as a solvent and in... 

One of the oldest production methods for the production of dry flavours is the plating of a liquid flavour or extract onto a solid carrier. Carriers of main importance for the food industry are salt, lactose, starch and maltodextrin [64]. 

Fig. 23.5 Aqueous-organic two-liquid-phase system for microbial production of flavour compounds. Here the formation of 2-phenylethanol from L-phenylalanine is exemplarily shown [120]. The organic solvent used for in situ extraction has to be carefully selected on the basis of multiple criteria, such as biocompatibility, non-flammability and legislative regulations. For a more detailed description of flavour production in two-phase systems, see Chap. 24 by Larroche et al.

The pure oleoresin produced by solvents normally contains only pure curcumin, in a crystalline form. It is hardly soluble in liquid- and supercritical CO2- Even at an extraction pressure of 450 bar, and with 2 hours extraction time at 65°C, only 20% of the initial curcumin can be extracted. On the other hand, all the volatile oil and fatty oil is extracted, and a fat-free curcumin-starch mixture with a very low flavour-content can be produced. The total extraction yields are between 5 to 12%, with mostly fatty oil and volatile oil, and about 10% curcumin in the extract. 

A soft extract is produced initially as a liquid extract but the concentration stage is continued until the resultant extract has the moisture content of 30% or less. The extract has the texture of a thick paste or viscous syrup and is usually dark brown in colour and often caramelised in flavour. 

Cumin oil is usually obtained by steam distillation of the milled spice hydrodiffusion gives a higher yield and, more recently, supercritical gaseous extraction is claimed to give oil closer to the aroma and taste of the spice (Eikani et al., 1999). The yields of cumin seed oil with steam distillation are 2.3-3.6%, with liquid carbon dioxide it is 4.5% and with ethanol it is 12%. The major components are cuminaldehyde, cuminyl alcohol, p-mentha and 1.3-dien-7-al, the minimum perceptible levels being at 0.2 ppm. Naik et al. (1989) reported that liquid C02 extraction was quicker than steam distillation for the quantitative extraction of cumin oil without loss of active flavour components, at 58 bar and 20°C. 

Naik, S.N. and Lentz, H. (1 989) Extraction of perfumes and flavours from plant materials with liquid carbon dioxide under liquid-vapor equilibrium conditions. Fluid Phase Equilibria 49, 115-126. 

In Figure 2, the interfacial tension of coffee oil with a high content of volatile flavours against CC>2 is depicted. Mixtures like this are of particular interest for high pressure spray extraction. At increasing density of the fluid CO2 -phase, interfacial tension is decreased by dissolution of CO2 at the interface. In this case, presence of surface active material in the liquid phase, e.g. proteins, rather seem to be of subordinate importance. With respect to foam formation these surfactants neither show their known stabilising effect as long as no polar phase such as water is added. 

Solid-liquid extraction is applied on an industrial scale to produce oils and fats from oil-bearing seeds. In the food and flavour industry, extracts and resins, such as hop, chamomile, peppermint, valerian, vanilla, red pepper and liquorice, are obtained from herbs, roots, seeds and drugs. The technology has also found application in the pharmaceutical industry for the extraction of antibiotics, alkaloids and caffeine. 

These features render the liquid-liquid extraction process a powerful tool for the food and flavour industries. 

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],... 

---