Solvent-like flavours

Besides classical headspace analysis, simultaneous distillation-extraction and solvent extraction, new sampling and enrichment developments include solvent-assisted flavour evaporation (SAFE) [3] and sorptive techniques like SPME solid-phase microextraction (SPME) [4,5] and stir-bar sorptive extraction (SBSE) [6], which are treated in a dedicated chapter in this book. This contribution will deal with advanced developments of GC techniques for improvement of separation and identification (classical multidimensional GC, or... 

The sample material is diluted with demineralized water and extracted with organic solvent like pentane/dichloromethane by using the fuimel-separator or rotation-perforator method over a longer period. The extract is dried and concentrated by solvent evaporation. The concentrated extract can be applied to GC-analysis. This method is applicable for liquid extracts and flavouring compounds [4]. 

EtOH extraction was the most efficient way to improve the flavour of the phloem. A solvent/solid ratio of at least 10 1/kg was needed to achieve a significant change in the taste. The loss of catechins was approximately 27% and that of lignans was 35%. All the catechins and lignans were found from the EtOH extract. Losses of lignans and catechins were smaller with other sovents, but either the taste was not modified or the cost of solvent treatment would be too high. Phenolic compounds like lignans and catechins also have a bitter taste and some improvement in flavour may have occurred because of the lower concentration of these. The disappearance of the characteristic... 

Supercritical C02 extraction coupled with a fractional separation technique is used by producers of flavours and fragrances to separate and purify volatile flavour and fragrance concentrates. Like any solvent, supercritical C02, it allows processing chemicals by predpita-tion or recrystallisation, obtaining partides of controlled size and shape, without excessive fines without thermal stresses and controlling the shape of a polymorphic substance. 

These can be the natural material itself one example would be pieces of vanilla pod or an extract, e.g. vanilla extract. Extracts can be prepared in several ways. One is to distil or to steam distil the material of interest. Another is to extract the raw material with a solvent, e.g. ethyl alcohol. Alternatively, some materials are extracted by coating the leaves of a plant with cocoa butter and allowing the material of interest to migrate into the cocoa butter. These techniques are also used in preparing perfumery ingredients, indeed materials like orange oil are used in both flavours and perfumes. 

They are used in many food products and pharmaceuticals to add flavours. Some of these families are manufactured for use as solvents (i.e., acetone) and for preparing materials like adhesives, paints, resins, perfumes, plastics, fabrics, etc. 

An official definition of essential oils and related products is available in ISO 9235 1997 Aromatic natural raw materials - Vocabulary . In this standard not only essential oils but also related solvent extracts like oleoresins, concretes, absolutes and resinoids are defined. To stress the impact of ISO standards for the quality management in the flavour industry, an overview of all relevant standards concerning essential oils is given in Table 3.27 at the end of this chapter. ... 

Polymer capsules Core-shell Flavour composition entrapped in capsule consisting of solvent core covered by protein shell Dry product or liquid dispersion Limited (oxidative) stability of encapsulated flavour Flavour can be loaded in empty particles Flexible particle size Relatively slow release/burst-like release... 

Flavourings and fragrances which include thousands of substances, sometimes blended in complex proportions by experts to produce prized odours. Some of these products may be hazardous in their own right like mirbane oil syn. nitrobenzene which has an almond smell, but they are often associated with solvents to aid handling and use. 

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