Extraction of Spices and Herbs

Spices and herbs are mainly used to improve the taste of food. Parts of used plants can be seeds, leaves, flowers and parts of flowers, barks, roots, or fruits and are used fresh or dried for transportation and/or storage and available as whole, broken, ground, or mbbed shape on the market For many different applications, such conditions do not meet the requirement with regard to the necessary low microbiological contamination, consistent quahty, and longer storage stabUity [9, 22]. 

Spices and herbs are processed in medium-sized extraction plants, equipped with two or three extractors, with payload volumes of 2001-10001, and in most cases two separators andaredesignedaccordingto their product mix between300bar and550 bar. 

The feed is normally placed in multiple baskets for easy product handling and the plant has to be designed for frequent and simple cleaning. 

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The antioxidant activity of rosemary and sage (leaves and extracts) were most effectively investigated [96,97], Traditional extracts of spices and herbs are obtained by steam distillation (essential oil) or by extracting the botanical with solvents such as alcohol, hexane, or acetone, and removing the solvents by evaporation. The SFE process for production of the inherent natural antioxidants is now the most gentle and effective method [70],... 

Brandy or alcohol extracts of spices and herbs may be used for flavoring vermouth (Rizzo, 1957). Spices like anola, and ginger are known to possess medicinal properties, as well as antimicrobial activities (Joshi and John, 2002). The precise details of extraction differ among manufactures. The more important botanical constituents include coriander, cloves, chamomile, dittany of Crete, orris, and quassia. Additional flavorant may include allspice, angelica, anise, bitter almond, cinchona, coriander, juniper, nutmeg, orange peel, and rhubarb. 

Most multipurpose plants are equipped with two or more extractors switched in cascade mode, which enables to come as dose as possible to phase equilibrium and are equipped with a multiple separation system, operating at different reduced pressures for fractionation. Such design is mainly used for the extraction of spices and herbs, allowing concentration of pungent substances like piperine from pepper or capsaicin from chili in a first step and the corresponding volatile oil afterward in one additional separator. In case that the valuables are highly concentrated in the raw material and also relatively highly soluble in the dense gas, installation of only two... 

Figure 8.15 shows the relative investment cost for the high-pressure part of different sizes of supercritical fluid extraction plants, not including costs for infrastructure and erection. A plant with two extractors, eacii with a payload volume of 8501 -representing an economical size for the extraction of spices and herbs - with an investment of about 3 500 000 - was selected as basis for the comparison. 

Application of Supercritical Fluid Extraction for Spices and Herbs with Pressures up to 800 bar... 

Si )ercritical extraction (SCE) has significant advantages in the production of flavor extracts from spices and herbs. Hi quality extracts are produced in hi yield, by a process perceived as "natural, leatving no solvent residues. 

In the search for environmentally benign chemicals that might deter birds such as starlings, crows, or pigeons from roosting en masse, spices and herbs such as rosemary, cumin, and thyme look promising. In some experiments, the birds feet were immersed in oil extracts of the spices. Starlings also avoided perches treated with starch mixes of (R)-limonene, (S)-limonene, (3-pinene, or methiocarb. The first three occur in rosemaiy, cumin, and thyme (Clark, 1997). 

The extraction result is further influenced by the moisture content. For spices and herbs this concentration should be in general between 8 and 15 %. At higher values the water is extracted preferentially and/or the co-extraction of polar substances is at a low level. Low... 

The extraction of spice oleoresins is relatively new, and industrial plants have been in operation for about the last ten years. Because the CO2 extracts are different to the conventional processed oleoresins, the acceptance in the food industry is growing slowly. The spice plants are much smaller than the decaffeination and hop plants, and use extractors of between 200 and 8001. The same is true for medical herbs and high value fats and oils, which are more or less at the beginning of development. 

These plants, with the greatest number of industrial application so far, are used mainly for the extraction of plant materials such as spices and herbs. The extraction volumes are in the range of 200 to 800 1 in which, in most cases, cascade-mode operation with 2 to 4 extractors is applied. The design pressure-range is up to 550 (800) bar. Fig. 8.1-2 illustrates a multipurpose extraction unit for spices and herbs. 

The spices and herbs most commonly used in Europe are listed in Table 9.6-1, indicating the characteristic components of each as well. There are several commercial plants using carbon dioxide to extract flavour, aroma and other valuable components from plants, such commercial production is also indicated in Table 9.6-1. 

For the extraction of spices, herbs and aromas medium-sized plants are used. These plants are equipped with two or three extractors with a payload volume ranging from 200 to 800 1... 

PLATE 8.1 Spices and herbs used in the preparation of extract (Source Abrol, 2009). 

Sensory quality is important to the final acceptance of any product. In case of vermouth, the type and quantity of the spices and herbs are particularly central to its sensory attributes. Nonetheless, alcohol and other constituents are also critical. For example, plum-based vermouths were considered optimal at 15% alcohol (Joshi et al, 1991), and apple-based vermouths preferred at 5% alcohol, 4% sugar, and 2.5% spices extract (Joshi and Sandhu, 2000). 

Plant materials, such as spices and herbs, can be superoritically extracted for flavor, fragrance, and pharmaceutical applications. Using nontoxic carbon dioxide as a solvent, supercritical extraction (SCE) leaves no harmful residues. Food materieds produced with SCE are viewed as natural and have been shewn to be of hi quality, often with siperior properties not obtainable with other separation techniques. Hie purpose of this paper is to discuss the advantac of SCE for flavor applications, to describe a preliminary design for a coimnercial plant, and to present economics for this pplication. 

A wide range of flavouring substances is used in powdery or pasty convenience foods. Reaction flavours based on hydrolysed plant proteins, natural flavours, artificial flavours and meat, vegetable, yeast and spice extracts are added to the products to generate the desired flavour profile. The most common savoury flavour types used for dehydrated convenience foods are chicken, beef and vegetable flavours. However various other flavour types are used while formulating dehydrated convenience foods. Amongst them are mutton, crawfish, fish, wine and various spice and herb flavours. 

Okoli, C.O., PA. Akah, S.V. Nwafor, U.U. Ihemelandu, and C. Amadife. 2007. Anti-inflammatory activity of seed extracts of Aframomum melegueta.. Herbs Spices Med. Plants 13(1) 11-21. 

Also companies designing SCF processes and equipment are steadily growing. Companies such as NATEX (Natex, 2015) or Uhde High Pressure Technologies (Uhde, 2015) have designed supercritical fluid industrial plants for extraction of spices, herbs, hops, nutraceuticals or edible oil as well as for cork purification or rice treatment among other. 

Total extraction has the target to obtain the highest possible yield of soluble substances, whereas a single separation results in a so-called total extract, hut multiple separations allow fractioned products. Typical examples are the extraction of spices, herbs, and hops. One likes to obtain the exhaustive lead substances as a-acids from hops or piperine from pepper, or gingeroles from ginger, or carotinoids from paprika and so on on the one hand and the corresponding aromas on the other. The extraction residue from the extractor is mostly without any value, hut can sometimes be used as fertilizer basis or animal food addition. 

Figure 8.11 Flow sheet of a multipurpose supercritical fluid extraction plant for spices and herbs.

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