Herbs/Spices – Antioxidant Properties Of Oleoresin And Essential Oils

Herbs/Spices – Antioxidant Properties Of Oleoresin And Essential Oils

Herbs/Spices – Antioxidant Properties Of Oleoresin And Essential Oils
Herbs and spices have long been used by ancient civilizations for culinary, medicinal and cosmetic uses. With modernization and the development of patent medicines, the use of natural cures and elixirs decrease in popularity. Nowadays, disillusionment with synthetic drugs, artificial additives and their possible sides effects has given great rise in popularity to many natural products, be it for culinary, medical or cosmetics purposes.

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In line with the world wide trend for eco-consciousness, the popularity of natural cosmetic purposes. In line with the world wide trend for eco-consciousness, the popularity of natural cosmetic products, such as those sold in red earth and the body shop, attests to the current trend (Broadhurt CL, 2000).

Spices are defined as those aromatic plants and their parts, fresh or dried, whole or ground, that are primarily used to impart flavour and fragrances to foods and drink (Prosea 1986). The term is used in a wide sense and includes the culinary herbs. Spices are indispensable in the culinary art, used to create dishes that reflect the history, the culture and the geography of a country. Well-known examples are curry powder, housing live five spices powder) Pizza herbs and fines herbs (Polansky mm, 2000) spices oils and spice oleoresins are also indispensable in the food and beverages manufacturing industry, the perfumery and cosmetic industry and the pharmaceutical industry. Some spices and derivative possess antioxidant and antibiotic properties, which has increased interest in the commercial exploitation of aromatic plants for food preservation and crop protection with the growing demand natural and organic products and the increasing clamour to dispense with synthetic flavours and artificial food colouring, the future for spices seems bright.

According to Pearson 1976 herbs and spices consist of the dried leaves, flowers, buds fruits, seeds, bark or rhizomes of various plants. They are incorporated in foods only in small amounts but they make important contributions towards the odour and flavour due to the presence of the volatile oil 9essentail oil) and fixed oil, local examples include Piper guineense (Uzuza), Xylopia gethiopica (uda), Mondora myristica (Ehuru, Tretaphleura tetraptra (Oshsho) and capsicum frutescens (Ose Nsukka).

An antioxidant is defined as any substance which is capable of delaying, retarding or preventing the development in food of rancidity or other flavour deterioration due to oxidation,. Antioxidant are only one means of fending packing or there are others such as vacuum packaging or packing under an inert gas to exclude oxygen and refrigeration, freezing, both of which greatly reduce the rate of authorization. Furthermore, it is seldom realized how little oxygen is need to initiate and maintain the oxidation process or how difficult and expensive it can be to remove the last traces of air from a product. For these reasons it is quite common to combine the use of antioxidants with inert gas packing using an antioxidant should be seen as one of several measures available, but used properly, it is generally effective, easily applied and inexpensive.

The prime justification for using an antioxidant is one of need an antioxidant can extend the shelf-life of a food, reducing wastage and complaints, it can reduce nutritional losses (oil soluble vitamins, such as vitamin A, are prone to oxidation)) and a very important point for the food technologist, it can widen the range of fat which can be used. Using an antioxidant enables the food manufacturer to smooth out differences in the stability of fats/oils and renders the food product less specific in terms of ingredient requirements. This offers more scope for cost control without jeopardizing the product quality of shelf-life, without an effective antioxidant, lard for instance, would find far fewer uses.

ANTIOXIDANTS SERVE TWO PRINCIPLE FUNCTIONS:

1. They break the oxidation chain by containing the free radicals or acting as hydrogen donor.

2. They direct the breakdown of peroxides into stable substances that do not promote further oxidation (Ihekornye and Ngoddy 1985).

An ideal antioxidant meets the following demands:

1. Safe in use.

2. Should impart no odour, flavour or colour.

3. Effective of low concentration.

4. Should be easy to incorporate

5. Should survive cooking process.

6. Should be available at now cost-in-use.

(Allen and Haninlton, 1989), John and Peterson, (1974), summarized the general used and properties of herbs and spices as the ability to:-

1. Give flavour to a flavourable base.

2. Impart a different flavour character to the basic product.

3. Disguise objectionable intrinsic flavour and boost intrinsic flavour which would otherwise be too weak.

According to Ikekornye and Ngoddy, (1985) the effectiveness and optimal utilization of a spice for its various uses depends on certain factors such as method of growing, harvesting sorting, storage and ultimately processing techniques.

Traditionally, spices are sued to prepared food for nursing mothers, it is believed to be very useful in cleaning the uteral lining after child birth. It is believed to have contract the womb to its normal size after birth. It is used in preparing native concoction for the treatment of convulsion and “jedi-jedi” in infant, a diseases which gives rise to greenish stool, stomach upset and inflamed. It is generally used in treating some minor ailment such as stomach upset, headaches, malaria, bronchitis and many others (Uba, 1997).

1.1 OBJECTIVES OF THE PROJECT

Herbs and spices are known to be incorporated in food only in small amounts but they make important contributions towards the odour and flavour due to the presence of the volatile oil (essential oil) and fixed oil and little or on work has been done on most local culinary herbs and spices. The aim of this project is to extract these oleoresin and essential oils in herbs and spices that impart flavours and fragrances present for the manufacture of foods, beverages, perfumery, cosmetics and pharmaceutical products, and to determine the antioxidant properties of these local spices and herbs for food products, cosmetics and pharmaceuticals.

2.0 LITERATURE REVIEW

Herbs and spices have been grown and used for thousand of years to preserve and flavour foods. The ability of herbs and spices to delay food spoilage is due in large part to their rich content of antioxidants, (substance which help to protect against damage that radicals). The unique flavours associated with different herbs are provided by the aromatic properties of their essential oils and oleoresins (natural plant substances). The actual strength of their flavours or “pungency” is due to the herbs alkaloid (organic compound) content. In addition, some herbs such as paprika and turmeric add red and yellow colours to food with the current emphasis on easting more healthful diets that are low in fat and salt, it is a good idea to think about using various herbs and spices to flavour your food. The wide variety of culinary herbs and spices that can be used to enhance the flavour of vegetables, soups, salads, stir-trys and pasta dishes can be derived from the bark, buds, flowers, leaves, fruit, seeds stems or roots of a plant (Zleng.w, 2001)

According to Kawakishi.S. Morimitsy (1994) freshly picked herbs add rich and vigorous flavour to food. Dried herbs usually smell and taste somewhat differently from their fresh counterparts. During the herb drying process there is usually a loss in the fragrant oils from the fresh herbs, leaving some of the more bitter flavours behind furthermore, the flavour of most dried herbs tends to diminish with time so any bottles containing dried herbs that are older than 12 months should probably b discarded so, for a flavour some meal, try to used either fresh herbs or “fresh: dried herbs.

2.1 NATURAL HEAL PERSPECTIVE OF CULINARY HERBS AND SPICES

Good nutrition from eating a healthy diet is the foundation of all natural health healing therapies. Better nutrition will improve your personal health. Cooking with herbs and spices is a quick way to add diversity to your diet. Anyone interested in improving their food with herbs and spcies (Martinez-Tome M, 2001).

Fruits and vegetables have long been viewed as a rich source of antioxidant compounds and other plant factors that promote good health. The health establishment has also been urging people for years to eat more fruits and vegetable. Herbs and spices are used to flavour foods. They are what define the different regional cuisines of the world. Herbs and spices changes plain foods into tasty dishes. Seasoning will develop and extend the natural flavours of the raw materials used in your meals. Herbs and spices have been used to preserved food for thousands of years before modern refrigeration was developed.

The antioxidant activity of culinary herbs and spices suggest that in addition to imparting flavour to food, they possess potential health benefits by inhibiting lipid per oxidation. Research indicates that auditing a moderate amount of herbs and spices to your food goes a long way towards boosting the health value of a meal. Think of them as a quick and easy way to get a concentrated source of antioxidants and other plant factors without all the extra calories of whole foods. They are also a quick way to add diversity to your diet.

Herbs are the leaves of herbaceous plant, spices come from the other parts of the plant such as the bark, root, bud or berry. Herbs act usually have been shown to have higher antioxidant activity than fruits, vegetables and some spices, including garlic. The green leaves in general are richer in antioxidants than other plant parts because that’s where the oxygen in the plant is produced after metabolism process (photosynthesis).

In general, fresh herbs and spices are taste better and contain higher antioxidant levels compared to their processed counterparts, for maximum spice flavour, buy spices whole and grind then prior to use to release the flavour of dried leaves or herbs, crush them just before using. It is suggested that you grind up dried herbs in a culinary mortar and pedestal for maximum flavour, use whole springs to infuse long cooking dishes with flavour, but before serving. Remember that anything that improves your health is work doing. So there is nothing seriously wrong with cooking with dried herbs and spices. Some herbs suitable for steeping as teas are oregano, rosemary peppermint, sage, spearmint, savory and thyme, all of which have been shown to contain significant levels of antioxidants, the antioxidant activity of herbs were retained even after boiling for 30 minutes (Bdroadhurst CL, 2000).

2.2 MORPHOLOGY AND DESCRIPTION OF SOME PARTICULAR CULINARY HERBS AND SPICES

1. Piper Cuineense (West African Black Pepper “Uziza)

Uziza which is botanically called piper guineese is a spices that belong to the piperacear family uziza is of vegetable origin. It is found in high forest area, occupres forest clearing and clings on remaining tress in secondary forest. It is widely distributed uziza which is obtained from plant has a slender creeping or climbing perennial plant the fruits from uziza occurs as racemes and green when unripe, red when ripe and black when dried ( carol 1968).

Uziza is highly medicinal it is found to have a stimulating property like pepper and excellent flavouring properties. The seeds are used in preparing pepper soup, especially for lactating others. It is traditionally believed that uziza functions as an ointment for amounting corpses. “God Uziza” is of economic significance in international trade cannot be eaten or consumed. Raw, rather the goodness in uziza and the world-wide demand for it derives from certain of its attributes, which have been found to e very useful as additives blending of food and pharmaceutical industries the attributes are the aroma, the extraction of which is the sole object of processing uziza either into oleoresin, essential oil, uziza powder or similar concentrates which can later be used in the manufacture of confectionery, beverages and pharmaceutical products (Oletunji 1980).

The oleoresins of uziza as the name implies are generally mixture of the volatile and essential oil, the non-volatile resinous materials and sometimes other active materials (Health 1980). Spices flavourings are compounded in the form of oleoresin essential oils and flavour essence, which are found in the spices raw materials. Spices are edible plant materials that have antioxidants and antiseptic properties and can be incorporate into food as condiments to season the food.

When piper guineense is extracted, oleoresins is produced with the help of solvent extractor and oleoresins may be separated into two fractions by steam distillation. The volatile fraction which comes over in steam distillation is called the essential oil, the oleoresin portion remaining behind is called the fixed oil. Spices vary markedly in their total oleoresin content (Health, 1986)

2. Xylopia Aethiopica (Guinea Pepper) “Uda”

The Xylopic plant belongs to the family annoneceae. It is ever green aromatic dicotyledenous plant species commonly found in forest areas mostly left for communal forming. It grows wide, it contains xylopia acid in the resins, saponinsavocems essential oils, alkaloid and tannin (Oliver 1960). The stem is about 4.5. – 20m high with a stringent it has branches and branch lets. The leaves are simple and alternate. There fruits are cylindrical thick and are green when unripe, reddish when ripe and black when dry (Uka 1988). They contains 3 – 9 seeds in each fruits.

3. Mondera Myristica (Arican Nutmeg) “Ehuru”

The Monodera plant belongs to the family of plant called Annonace . The plant is an ever green tree nature to the Malacca and cultivated in East India, Malaya, Ceylon, West India and Africa (Merory 1963). It is a medium sized evergreen tree. It is miro-rekuculate. It could be propagated by stem cutting and budding (Okafor 1989). The matured fruit resemble calabash and it is also called-nutmeg (Uphef, 1959).

4. Tetrapleura Terapters “Oshosho”

Oshosho is a medium sized deciduous forest tree the tree grows up to 80ft high and over 4ft girth with grayish thin smooth bark. The leaves are glabrous minutely hairly with a common stalk 15 – 30cm long, slightly channeled on the upper surface usually with 5 – 9 pairs of pinnae 5 to 10cm long mostly opposite bit sometimes alternate. It is 12 – 25mm long by 6 – 12cm broad slightly econged allipticm rounded of both and apex.

The plant usually flowers the month of January to April and fruits June to July. The fruit mature from September to November. The flower appear after new pink or cream in colour and densely crowded in spike the fruits are very persistent hanging at the end of the branch on stout hard and woody and other two filled with a soft sugary pulp. The fruit is reddish to brown in colour and fairly hard. The seeds are embedded in the body of the pod which does not split open. The seeds are small black and hard when sectioned it is green inside and contain oil and sugar. The fruits also contain tannise and a little saponin which is said to cause their leathering in water. They have a Carmel like smell and are commonly used in flavouring, example soup.

USES: The uses of “Oshosho” are amny in various part of Africa. It is grown as shade tree for coffee in Uganda. The scent from the fruits and flower are added as perfume to pomade made from palm oil. The pulp is sometimes put into wine as flavouring. In Ivory Coasts, the seeds and the pulp are added to wine to make it stronger. The seeds are put into soup as a thicker by the Binis. The powered and fermented seed are sued as a condiments in soup. The seed contain sugar tannins and a saponis which is probably responsible for their ability to poison fish. They are roasted and ground to make black soup or sauce in places like Akwa Ibom State and Calabar.

In some parts of Umuahia the fruit are roasted and added to drinking water to increase the flavour of the water. In some part of Anambra State, it is repellent against snake and mosquitoes. This is usually done by burning the fruit and allow the snake to disperse (Olainyi et al, 1980).

2.3 CHEMICAL CONSTITUENTS OF CULINARY HERBS AND SPICES

The constituents responsible for the spicy properties of plant are always secondary metabolism products in other words they are not involved in primary metabolism (production of plant tissue and production or use of energy storing molecules) thus they are not vital for the plant. In some cases, it is supposed that the aroma molecules are essentially products of metabolism in most cases. Through, they play an important role in attracting pollinators or drive away herbivorous animals. It is somehow paradox that plants are grown and spread word wide, as food enhancers, although their tasty constituents intention is to discourage the consume of the plant (Zgeng w, Wang SY Nov 2001)

Although there are large numbers of classes of plant constituents, most plants contain only few of them. It is frequently observed that botanically related plants contain similar or even the same constituents this also explains why spices appear clustered in some plant families while other families do not contain any aromatic plant. Only a small fraction of the many biochemical found in plant are relevant for spices for of some classes nearly all members taste somewhat unpleasant or are not harmless aft all. The following classes are most common:

1. TERPENSES: This is by far the most important class of aroma compound. Many of them exhibit an aromatic frequency reminiscent to turpentine which is a tempera mixture distilled from various fir species). Terrenes are widely distributed secondary metabolism products, showing low boiling point and thus strong aroma the name terpene properly is reserved for hydrocarbons made up from isoprene units, but is frequently extended to derivatives of these (alcohols either’s, carboxylic acids esters) which should be called terpere derivatives. Furthermore, benzoid dehydration product of terpenes appear in plants e.g. the phenol thymol which is responsible for the aroma of thyme and ajwain.

Depending on molecule size, we discriminate between mono-sesqui-di-and triterpenes, having 10, 15, 20 and 30 carbon atoms, respectively. Of these groups monoterpens are of utmost importance, 90% all monterpenes are not specific for a species bit occur in many different plant; thus the characteristic aroma of a spices is caused by a specific mixture of monotepenes not by specific individual compound monoterpenes are formed in all plant families, but are most numerous and highly – concentrated in the mint family (Lamiacear and the parsley family (Apiaceae), both of which contain a large number of spice plants.

Higher terpenes are less volatile and therefore, of less olfactoric importance, while sesequiterpenes are moderately common constituents in aroma plants (though in small concentrations) di-and triterpenes are rather exotic and rare in spices. Among the sesquiterpenes some are common to many families but generally, the higher terpenes tends too be specific to a family genus or even species. Sesginterpene are of some importance for the fragrance of cinnamon conifers (juniper) and other plants of the ginger family (zingiberacear) like tumeric and galangale).

Triterpefre glucosides are known as saponins and some of hem are highly toxic due to their hemolytic power., but due to poor resorption this does usually not apply to oral route. Glycyrrhizin (from licorice) is a rare example of a saponin with pleasant taste of the tetraterpenes the most important group are carotenoids this term includes characteristically (yellow to orange) coloured unsaturated tetraterpenes hydrocarbons and derivatives of such hydrocarbons; and fruits owe their orange colour to them. Usually, they are soluble in fat; thus small drops of grease will take up all the colour in soups of sauces spiced with paprika. A rare example of a water soluble caroteniod is found in saffron.

2. PHENYLPROPANIODS

This class of aroma compound is rather small and appears most frequently in the magnoly order (, e.g. cinnaminic acid in cinnamon; but phenylpropaniods are by no mean restricted to that class, other representative includes the toxic safrol (also spelt safrole; see sassafras nutmeg) and eugenol (cloves); yet another related compound is vanillin in vanilla beans, lastly, coumsrin 9woodruff, Tonka bean) must be mention as a wide-spread phenypropaniod. Similar to terpenes, phenylpropaniods are frequently volatile, essential oils, which are won by distillation, are mostly made up from these two classes of compounds.

3. DIARYLHEPTANIODES

This group of on volatile compounds is only found in the rhizomes (rootstocks) of spices of the ginger family (zingiberacear) e.g. zedoary and finger root; diarylheptaniods are responsible for the pungent taste of these spices and for the yellow colour of turmeric.

Biochemically they are related to phenylpropaniods; their basic structure, though substituted and modified; in humerous ways is 1,7-diarylyyeptan -3-one structurally related but simpler 1-aryl-alkanones appear in ginger and grains of paradise.

4. ALKALOIDS

This important class of biochemicals contains several well-known poisons and medicines latropin from belladonna, morphin from poppy cocain from the South American cocoa shrub and coniin from hemlock, just to name a few.

Because of high toxicity and generally bitter taste they are rarely founding spices and then mostly not responsible for the taste (e.g. nigellin in nigella or boldin in boldo leaves). Yet the pungent principles of chilies and black pepper closely related to alkaloids since they are mostly not volatile alkaloids do not exhibit aroma and do not show up in essential oils.

5. GLYSCOSIDES

This is a large and inhomogeneous group of biochemical their feature is that they consist of two parts; a carbohydrate (sugar), mostly glucose and another non sugar –like part, which is generally termed colycon. According to the chemise identify of the aglycon several types of glycosides are discriminated. It is important to realize that the chemical bond binding the sugar to the aglycon (called glycosidical bond) is weak and easily cleaved, yielding the tree aglycon. Glycosides are generally non volatile and this lack fragrance, but the aglycon itself may well be volatile and then, show up in the essential oil.

Some plants store aggressive compounds that could be harmful for the plant itself in form of glycoside; the dangerous substance can if needed produced readily by enzymatic reaction. A well-known example are cyno-glycosides contained in the seeds of a picots, cherries or bitter almonds; on cleavages of the glycosidical bond, they yield the highly toxic hydrocyanic acid.

6. TANNINES

Members of this inhomogeneous class of biochemical are found in rarely all plant families; their taste is tart and unpleasant, thus, they are not valued in spice plant. High tannine content is considered a sign of bad quality (see cassia0 but in small amounts, even tannine has some culinary merite (see rosemary, sumac).

7. FRUIT ACIDS

This term includes some chemically related di-and tricaboxylic acids of which citric acid is before tartic and malic acid, the most important, all these acids features the same, purely sour taste and lack specific fragrance, the typical aroma by which we distinguish between lemon, orange, pomegranate or mango is solely determined by other, volatile compounds.

8. CARBOHYDRATES

All green plants are capable of synthesizing sugars (primarily, glucose) from water air and light, glucose in furn, act s a kind of fuel, which can be combusted and thereby yields energy. Other sugar types are produced from glucose, sweetness fruits serves to attract animals to spread the seed they frequently contain, besides glucose the chemically related fructose. A suitable compound to store glucose is starch which is therefore, frequently found in perennial plant part (for example substerranean stalks called rhizomes; potatoes or ginger) or in seed (e,g, cereals).

9. SULPHUR COMPOUNDS

Many sulphur compound featuring sulphur in low oxidation state manta a strong, rather unpleasant small (e.g. thioles, sulphides and di-and polysulpindies). As bio chemicals, they are most prominent in the onion family (Alliaceae garlic and onion), but appear also in the botanically unrelated asafetida.

10. LIPIDS

Lipids are commonly known as fats if solid and as oils if liquid; there is no further difference between fat and oil besides the melting point which reflects gradually different composition. Lipids are an efficient form to store energy and occur, in the plant kingdom, mainly seeds, vegetable oils and fats are nearly exclusively composed of triglycerides, it esters of the alcohol glycerol with three molecules of fatty acids. Fatty acids are long-chain carboxylic acids, ranging in chain length from 12 (lauric acid) to 22 (behenic acid); shorter or longer chains are rarely found in significant amounts. Plant cannot synthesize fatty acids with an old number of carbon atoms.

Besides contributing a flavour of their own, oil are most important as a cooking medium that allows various techniques of high temperature cooking, resulting in brown, crispy and tasty surfaces. But there is another point since most aroma compound dissolve more easily in fat than in water (Chemist call such a behaviour lipophilic) small amount of vegetables or animal fat tend to improve the taste of every dish since they extract the aroma from the spice pieces. Indians like try their spices shortly in hot oil, which is even more effective because the high temperature increases the solubility and speed of solution.

2.4 ESSENTIAL ROLES OF CULINARY HERBS AND SPICES

Since time immemorial, spices have played a vital role in world trade due to their varied properties and applications. We primarily depend on spices for flavour and fragrance as well as colour, preservative and inherent medicinal qualities.

India, with its favourable climatic and soil conditions for growing spices and other semi-tropical herbs, is in the fore-front among the spice-producing countries, the spices that India can offer in abundant quantities are pepper, ginger, turmeric, chilli, cardamom, celery, fenugreek, fennel, cunin, dill, coriander cinnamon, ajowan, cassia, cloves, nutmeg and mace. (Zheng.W. Wang 2001)

Spice extracts were developed to meet the new demands of the food processing industry, they have the following advantages:-

1. Consistency in flavour

2. not affected by Bacterial contamination

3. much longer shelf life

4. Easier storage and handling

5. Full release of flavour during cooking

6. Can easily be blended to achieve the desired characteristics.

The food industry across the globe is tuning more and more to spice oils and oleoresins to create newer verities of food. New flavour system are being developed to introduce new products in the market and create competitive advantages. The India spice oils and oleoresin industry is engaged in continuous innovation and up gradation of process and products to meet the new global demand.

The use of spices, particularly pepper, in the manufacture of meat products, is traditional to impart flavour and keeping quality to the products, it is also applicable in fish, soups, sauces, chutneys and dressing the increasing demand for convenience products available in the form of a dry mix for ready reconstitution has caused a rapid move from conventional seasoning towards dispersed or encapsulated oleoresins and oils.

Spices extracts are unlikely to be uses cheese and daring products as the spices provide the flavouring plus visual impact. However, spices oil and oleoresins will have significance in processed cheeses and savoury spreads. The move from the spice to their oleoresins has been effectively taking place for many years for ease of handling and simplicity in manufacture filling, biscuits, confectionery, snacks, cheese and dairy products is also increasing steadily.

Spice extracts e.g. essential oils and oleoresins sourced far and wide are sue in the manufacture of perfumery, cream, soaps, shampoos, lacquers, lipsticks and aerosols (i.e. fresheners, polishes, many cleansing agents as well as waxes etc), products like toothpastes, mouthwashes etc, depend on essential oils to provide their pleasing flavour making them not only acceptable but pleasant to use. Both oils and oleoresins are widely used in pharmaceutical product, to provide either pleasant taste or aroma to render the medicinal products which would otherwise be difficult to accept, pleasing and easy to use. These include medications, skin creams, cold remedies etc. (Shobana .S. 2000).

2.5 ESSENTIAL OILS

Essential oil are odoriferous, volatile. Component of plant origin that contribute the characteristic aroma. Essential oil plant and culinary herbs include a broad range of plant species that are used for their aromatic value as flavouring in foods and beverages and as fragrances in pharmaceutical and industrial products.

Essential oils are natural plant products which accumulate in specialized structures such as oil cells, glandular trichomes and oil or resin ducts. The formation and accumulation of essential oils in plants have been reviewed by Croteau (1986), Guenther 91972) chemically, the essential; oils are primarily composed of mono-and sesquiterpene and aromatic polypropaniods synthesized via the mevalonic acid pathway for terpenes and the shikinic acid pathway for aromatic polypropanoids. The essential oils from aromatic plants are for the part volatile and thus, lend themselves to several methods of extraction such as hydrodistillation, water and steam distillation direct steam distillation and solvent extraction (ASTA 1968, Guenther 1972, Health 1981). The specific extraction method employed is dependent upon the plant material to be distilled and the desired end-product, the essential oils which impact the distinctive aromas are complex mixtures of organic constituents, some of which being less stable, may undergo chemical alterations when subjected to high temperature. In this case, organic solvent extraction is required to ensure no decomposition or changes have occurred which would alter the aroma and fragrance of the end-product. Newer method of essential oil extraction such as using super critical fluid extraction (SCEE), the most advanced extraction technology, which yield very high quality oils are commercially used, but are less common and beyond the financial means of most processors.

The recovery of nonvolatile essential oils are also obtained by solvent extraction although the process is more difficult and complex then the recovery of the volatiles. This process yields an aromatic resinous product known as an oleoresin, which is more concentrated than an essentials oil and which has wide application in the food industry (Health 1981).

2.6 OLEORESINS

Oleoresins are obtained by solvent extraction of dried ground spices, followed by complete removal of solvents from the extract and also with super critical fluid extraction (SCFE), the most advanced extraction technology.

Oleoresins are total extracts of the natural spices and herbs, representing the volatile and the non-volatile compound of the spices/herbs. These may be standardized if required with a permissible diluents or emulsifier (FDA), As these are concentrated extracts, they are typically used in the following manner to match the desired strength of the ground spices/herbs.

– As a diluted dispersion plated on a neutral dry carrier.

– As a diluted blend in a solubilizing medium such as vegetable oil.

2.7 ADVANTAGES OF OLEORESINS OVER CONVENTIONAL SPICES/HERBS

1. Free from physical impurities and extraneous matter-clean product.

2. Free from pathogens and microbiological containments-sterile product.

3. Standardized product: active ingredients/colour, flavour and physical properties are standardized and hence facilitates consistency in end-use, which is not always possible in raw spices.

4. Versatility and ease of use.

– The concentrated extract can be diluted to varying strength to meet required end-use flavour, colour taste etc.

– The extract can be delivered in multiple forms

(a) as dry dispersion on appropriate carrier.

(b) as liquid dispersion in appropriate media such as oil or water.

– Flexibility to develop multiple spice bends if required.

5. Uniform dispersion of spice extract provides.

– Instant flavour release.

– Full release of flavour resulting in lower costs due to higher relative replacement than the ground spices.

6. Concentrated form reduce storage space and bulk handling and transport requirements.

7. Concentrated and virtually moisture-free form of oleoresin ensures longer shelf life due to minimal oxidative degradation or loss of flavour and eliminates deterioration due to pests, mould etc.

Oleoresins are extracted by process of solvent extraction, followed by removal of the solvent to extremely low levels typically less than 25 – 30 parts per million. The quality of a n oleoresins is typically evaluated on the basis of:-

1. Presence of the active ingredients in desired levels – the “bite” giving resin portion containing combination of alkaloids, gums, pigments etc.

– the aroma giving volatile/essential oil component.

2. The comparison of the flavour/aroma profile of the oleoresin in comparison with the natural spice in application.

3. The ease of use in terms of pourability, dispensability, blending etc.

4. The consistency of flavour, colour, viscosity over repeated batches.

5. the acceptability of the extraction solvent used and minimal residual levels present there-of: acetore, hexare, alcohol, ethylene dichloride, methylene, chloride, Co2 are commonly used solvents though chlorinated solvents are gradually getting phased out in most parts of the world due to concerns about potential for their carcinogenicity.

Ranges of oleoresins includes oleoresin black pepper, oleoresin whit pepper, oleoresin capsicum chillies, oleoresin-paprika, oleoresin cassia, oleoresins celery, oleoresins ginger, oleoresin garlic oleoresin mace, oleoresins turmeric and oleoresin coriander etc.

2.8 OLEORESIN MANUFACTURE

Inspection – precleaning – sizing – extraction

Filing & packing – blending – desolvantisation

2.9 RELATIVE FLAVOUR STRENGH OF SOME SPICES; OLEORESIN (91:X)

Range – 10-50

Capsicum (chilli) 15 8-25

Cardamom 20 18-25

Cinnamon 25 17-40

Clove 15 5-18

Coriander 15 8-33

Fenugreek 35 –

Ginger 20 20-28

Nutmeg 12 2-17

Pepper 15 8-25

Tumeric 25 –

Spices Essential oil content

Pepper 5-26(20-26)

Ginger 12-35(28)

Capsicum (chilli) not applicable

turmeric Not applicable

Cardamom To 60(-)

Celery seed To 14(7)

Nutmeg -(50)

Coriander -(40)

Fenugreek Not applicable

2.10 AUTOXIDATION

According to Ihekoronye and Ngoddy (1985) Auto-oxidation is an autocatalytic process involving oxidation by molecular oxygen. This property to undergo spontaneous oxidation is also exhibited by many substances including among others many of the natural aroma, flavour and colouring substance which make food attractive and a number of the vitamins essential for adequate nutrition.

The resulting quality changes in a product after authorization include flavour deterioration, giving off-odour and of-flavours; colour changed which are affected through accelerated browning reactions; the nutritive value is impaired as essential amino acids and unsaturated fatty acids may be induced from the resulting reactions and the texture of the oil may change as a result of side reaction between intermediate product and the product of fat oxidation. This oxidative deterioration of lipids is considered as a spoilage factor affecting all the aspect of the food acceptability and adversely affects its market ability.

2.11 LIPID DETERIORATION

One of the major problems in the storage of any food material is the prevention of deleterious changes resulting in the production of off-flavours, colour defects and down-grading of the product: on of the major changes taking place in lipid is generally referred to as rancidity. (Gunstome, F.D. 1967). Fat deterioration can be classified into four main types, namely; hydrolysis oxidative rancidity, flavour reversion and polymerization.

– Hydrolytic clearage of fats involves the formation of free fatty acids, di-and mono-clyuceride and glycerol, resulting in the production of a soapy flavour. Fatty acids have a distinct flavour only when their chain length is shorten than C14. hydrilysis may be spontaneous or caused by intrinsic enzymes. Enzynic hydrolysis occurs particularly with vegetable oil produced from fruits coats with a high moisture content such as olive oil or palm oil (Hoffman, 1962).

– Oxidative rancidity of lipid oxidation and resultant flavour impairment has seriously limited the storage potential of most fat containing foods. It is a more serious problem than hydalytic rancidity because all fats and fat containing food contain some unsaturated fatty acids and hence are potentially susceptible to oxidative rancidity. 9Ihekoronye 1985).

– Flavour reversion takes place in unstable oils this is a flavour degradation process brought about by the autoxidation of all oils containing linolenic or higher undaturated fatty acids. These include linseed oil, soybean oil and marine oil among others. Flavour reversion of oil may occur very rapidly, soybean oil my degrade within half an hour of de-odourization , without acquiring a detectable peroxide value.

– Polymerization is a major reaction in autoxidazing lipids. It is normally employed to describe the cross linking of unsaturated fats between two carbon atoms other types of polyomers formed by carbon-carbon bonds may originate by the interaction of alkyl type free radicals. These account for most of the compound found in oxidized lipids.

UNSATURATED FATTY ACIDS

Free radical

Oxygen

Hyroperoxides

2.12 CONTROL OF OXIDATION

Different techniques have been used to control lipid oxidation. One approach is to decrease the oxygen content by gas flushing or pulling a vacuum on the food and package, which may be fortified by packing in low-oxygen barrier to prevent any regain of oxygen. Another method is to add antioxidants. It must have in addition to low order toxicicity potency in a wide variety of fats, lack odour and colour under sue conditions and approval by the government agency of the country in which the product is used, the permitted list of antioxidants used in foods include butyrate hydroxyl toluene (BHT), butylated hyroxy anisole (BHA), propyl gallta (PG); L-ascorbicacid (including the sodium and cacium salts), acorbyl palmitate and the natural occurring tocopherols some substance which enhance the potency of these antioxidants called synergists include citric a cid and lecithin.

Antioxidants may act in variety of ways to check oxidation which include:-

i) The competitive binding of available oxygen with the free radicals, thus slowing down the rate of peroxy-radicals formation.

ii) The retardation of the limitation step by greatly decreasing the activation energy or block induction site or immediate combination with the free radical formed.

iii) The blocking of the propagation stage by destroying or binding the free radicals to form stable compounds and the chain reaction is checked.

iv) The inhibition of catalysts, by serving as metal chelating agents, forming complexes with them and effectively binding them.

v) The stabilization of hydroperoxides to form stable complexes, thereby checking degradation and further free radical formation an the odoriferous short chained carbonyl compound are not produced of all these and other mechanisms, the most acceptable is blockage propagation (Pottern, 19788).

vi)

2.13 MECHANISMS OF ANTIOXIDANT REA CTION

In food systems, the most effective antioxidants function by interrupting the free radical chain mechanisms as follows:-

R0 + AH RH + A0 (AH = antioxidant)

ROO0 + AH ROOH- + A0

RO0 + A0 RA

RO0 + A0 ROA

Where

AH = Antioxidant

ROO0 = Peroxy radical

ROOH = Hydroperoxide

A0 = Antioxisant radical

Other antioxidants, such as ascorbic cid function by being referentially oxidized and they afford relatively little protection (Ihekoronye and Ngoddy 1985).

5.0 CONCLUSION AND RECOMMENDATION

5.1 CONCLUSION

Quality change in terms of oxidative rancidity in fats and oil could be accelerated by some environmental factors like temperature, enzyme, oxygen, light etc, but not withstanding these environmental factors, oleoresin of the local spices used in the analysis carried out in this work were able to retard the rate of rancidity more effectively than the artificial antioxidant used in food at concentration of 15ppm.

Therefore, oleoresin of these selected local spices can serve as good substitute to other commercial artificial antioxidant great care should be taken to avoid damaging their flavour characteristics by high temperature and recommended solvent like N-hexane should be used during extraction to achieve a good and desired and product.

5.2 RECOMMENDATION

It should be recommended that extracts from these spices should be standardized and used in food processing industries to replace some of the artificial antioxidants and food processors should be enlightened on the benefits of alternative use of the oleoresin as preservatives. More research work should be done on other culinary herbs and local spices extracts for antioxidant characteristics and the extract concentration of the different of spice extract that i.e suitable for preservation of different food materials.

Moreover, government should provide more sophisticated equipment and machineries to encourage mass production of these spices extracts there by making them more available and less expensive.

Finally, government and non-governmental bodies including co-operate and private company owners in Nigeria should invest in the area of oleoresin/flavour extraction since the source of raw material is cheap and always available.

Herbs/Spices – Antioxidant Properties Of Oleoresin And Essential Oils

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