Food Flavours

The essence of flavour: oils and oleoresins
By Graeme Nealie

Many foods derive their distinct flavour profiles from aromatic chemicals present at minute levels. Herbs and spices have been used for food and therapeutic applications for many thousands of years, with extraction processes such as distillation used to concentrate these aromatics. It is believed that as far back as 3,500 BC the Egyptians adopted distillation methods from the Mesopotamians.

Despite the large array of synthetic chemicals available to today’s flavourists, much reliance is still placed on natural ingredients such as essential oils and oleoresins, usually as key components of flavours and seasonings. The trend towards natural ingredients has further increased their use.

Essential oils
Essential oils are made by either steam distillation or by a combination of water extraction and cold pressing expression to produce oil soluble liquids with high intensity flavour.

Steam distillation evolves off the volatile essences of the herb or spice, resulting in an extremely concentrated aroma and flavour. However, the hot components of some spices such as chillis (capsaicin), peppers (piperine) and gingers (gingerine) are not volatile and do not occur in distilled oils.

Expressed oils: cold pressed and water extraction
Citrus oils are often produced using a combination of two processes: pelatrice which involves the scraping and washing of the citrus skin and sfumatrice which involves the extraction of the oil from the inner fruit. Both the pelatrice and sfumatrice processes use only cold water extraction, generally yielding the best quality oils.

Expressed oils tend to have better aromatic profiles than distilled oils, due to the absence of heat during processing and the retention of many flavour components that would not be volatile in steam. Citrus oils all have a high content of terpenes, (unsaturated compounds vulnerable to oxidation) and therefore are usually produced this way.

Oleoresins
Oleoresins are extracts from the named herb or spice, or from a mixture of materials. They contain both the volatile and non-volatile components, giving a fuller, more authentic flavour of the origin herb, spice or mixture.
Oleoresins are produced by macerating the plant materials in a suitable organic solvent, draining off the liquid and then gently evaporating off the solvent to leave the pure plant extract.

Oleoresins are usually thick, viscous liquids that are dispersible in oil, and are usually coated onto sugar or salt before being added to food products. Typically 2-5kg of oleoresin is equivalent to 100kg of fresh spice, although the exact ratio varies dramatically from oleoresin to oleoresin. They are very stable and will typically have a shelf life of at least three years stored at room temperature in the original sealed packaging.

Oleoresins are concentrated and fully natural, and due to their processing have extremely low microbial levels. This is a particular advantage over some unsterilized spices as these spices can potentially introduce large microbial loads to food products. Oleoresins can be used as a booster to restore the full flavour profile of processed foods, or as the basis of your own unique flavour combinations. Due to their high concentration they require careful handling and accurate dispensing to achieve optimal results.

For more information contact:
Graeme Nealie, Hawkins Watts Ltd,
Tel: 09 622 2720 or Email:
graeme@hawkinswatts.com