Herbs, spices and extracts - a tradition and a new beginning?

Introduction

In the early days man used spices and herbs for healing to placate his gods and to flavour his food. They were also the currency with which soldiers and rents were paid. Indeed we can trace the search for spices back to the beginning of recorded history. In more recent times they have been the specialist flavour ingredient of the snack flavour, the ready meal, soup and the "little something" to finish off a meat flavour be it hydrolysate blend and/or reaction system. However spices and herbs have been the poor relation of the aroma chemical compound. In the same way the skilled blender of spices, seasonings and herbs has often been considered inferior to the more traditional blender of aroma chemicals - the flavourist - the perfumer. Unless of course he became a top chef! Perhaps this view is supposed to reflect the quality and quantity of spices and herbs generally available compared to for example the several thousand aroma chemicals in common use. The trend today for using compounded flavours and essential oils in seasonings and flavours needs a cautious approach. When incorporated into a flavour formulation, essential oils cannot act as a substitute for a well produced natural extract. The natural extract imparts body and mouthfeel to the product, is heat stable and acts as a fixative for the other ingredients whilst subtly rounding off the overall flavour.

There is now an enormous demand for ethnic and tropical flavours and for products that can add life to microwaveable prepared food. Products prepared in a microwave oven often lack the cooked/roast flavours found in products cooked in a convection oven. Although simple re-heating is not a problem in flavour terms manufacturers do find it difficult to exactly match products prepared from a conventional home cooker process. A lot of work has been done with packaging, roast flavours and/or precursor systems. More recently work has been done with combination products. A special precursor system is combined with substances that increase the microwave energy absorption and the mixture applied to the food surface. The intention is to create temperatures required for Maillard reactions to take place. However, until satisfactory results are obtained the food manufacturer will rely heavily on extracts, spices and seasonings to add life to microwaveable foods and give an edge to ethnic and tropical recipes.

A variety of botanicals in convenience form are still available to add that something extra to the more traditional oleoresin blend. The rest of the article gives an insight into the manufacture of botanicals and some ideas for the application of perhaps less commonly used herb, spice and natural extracts.

Capturing the Flavour

Whilst some herbs and spices are extracted on or around the harvesting area most botanicals are transported to the specialist manufacturer as whole roots, bark, buds or fruits and stored in the whole form. Large particles stay fresher. When required for processing mechanical grinders mill and sift the material to their optimum particle size for maintaining aroma, flavour, colour and taste. Grinding too small can rupture surface oil glands causing evaporation of essential oils and loss of aroma by oxidation and resinification.

There are three different methods used to capture the flavour and characteristics of the botanicals to prepare all extracts oleoresins and essential oils.

Infusion or Maceration 

Just like the brewing of tea the botanicals are placed directly into a solvent system (water, ethanol, etc.) and allowed to steep until the flavour has been extracted. The time taken can vary from one day to one month depending on the size of the botanical, the extracting solvent, the temperature and whether mechanical stirring takes place.

Percolation 

Using a method exactly the same as extracting soluble coffee extracts from coffee a solvent is allowed to flow through the botanical placed either in a basket or bag. Frequently a circulation system is used. The nature of the botanical determines whether the solvent is heated and what solvent is used.

Distillation

The leaves, peels and/or seeds are placed in a still and covered with a solvent system. Distillation occurs either atmospherically or under reduced pressure. Depending on the solvent system the flavour can be soluble or insoluble in the distillate (steam distillation). The resultant distillates are always colourless as compared to maceration and percolation procedures which tend to retain colour.

Solid extracts are generally prepared from an alcohol-water extraction utilising either percolation or maceration procedures and then concentrating to a 70% to 80% solid content. At this concentration we can eliminate any microbial activity but retain a pourable extract.

Oleoresins present the most concentrated form of a botanical. They are prepared by extracting the botanical with solvents such as alcohol, acetone etc. The solvents extract oils and resinous matter. Upon removal of the solvent by careful evaporation of the solution in a vacuum, a viscuous semi solid is obtained. The oleoresin produced contains all the odours and the flavouring of the plant as well as non volatile constituents. The solvent used is selected with great care and achieves the optimum yields yet conforms to local legislation on solvents and solvent residues. The final traces of some solvents are difficult to remove even under high vacuum.

The common herbs, extracts and oleoresins are well known and well used but those flavourists looking to replace flavour compounds and the unsatisfactory properties of essential oils or perhaps add that something extra might wish to consider the use of some of the "less common" products mentioned below:

Botanical            Form         Characteristic       Application

Fenugreek            Powder       Maple type           Butter, Maple
  Roast              Extract                           Butterscotch
  Unroasted                                            Good for rounding

Licorice             Powder       Bittersweet          Butter, Caramel
                                                       Chocolate

St Johns Bread       Powder       Sweet, vanilla       Fruit, Chocolate
(Carob)              Extract      Chocolate            Caramel, Vanilla
  Roast
  Unroasted

Chicory              Powder       Aromatic             Coffee, Mapple, Nut,
  Roast              Extract                           Chocolate, Caramel,
                     Root                              Vanilla

Chestnut             Extract      Green                Green note eg. in
  Leaves                                               Fruit flavours,
                                                       Vegetable

Damiana              Extract      Aromatic             Berry

Kelp                 Extract      Fish                 Fish

Lovage               Extract      Warm celery          Condiments, Maple
  Powder                          Caramel
  Root

Mate                 Extract      Rich herbaceous      Tea astringent
Green

Mountain Maple       Extract      Warm woody           Maple, caramel
                                  Butterscotch

Oak                  Extract      Woody                Good rounder, Nuts

Rye                  Extract      Malt, Molasses       Cereal, Coffee
                                  Maple

Tamarind             Extract      Sweet fruity         Condiments
Powder

Valerian             Extract      Warm, balsamic       Fruit, Maple
  Powder                          Condiments

Wild Cherry          Extract      Cheery, Woody        Good rounder

Alfalfa              Extract      Green fig            Deep background
  Powder                          Fruit/Vegetable

Walnut               Extract      Bitter, Astringent   Nutty, Coffee

Samples of all these products are available from Frutarom (UK) Ltd. Tel:0442
876611. Fax:[phone].