THE PHYSICO-CHEMICAL AND ANTIOXIDANT PROPERTIES OF CULINARY HERBS AND LOCAL SPIES
a comparative study was done on the physico-chemical and antioxidant properties of some culinary herbs and local spices. Piper Guiness (Uziza), Xylopia aethopica (Uda), Monodora Myristica (Ehuru) and TrtraleuraTetraopera (Oshsho). The proximate analysis of these spices were done to determine their moisture content, ash content, crude fat crude fibre and protein content. Extraction of the Oleorasin from the spices and soybean oil were done using soxhlet extraction unit with hexane as solvent. Imi of each of the Oleorasin samples of the spices was pipette into 100ml of soybean oil into four different test tubes labeled A,B, C and D. sample E contains 100ml of soybean oil with 150ppm of Butylated Hydroxyl toluene while the untreated soybean oil (sample F) was used as the control. The test-tube were shaked, plugged with cottonwood and kept at room temperature in a rack. The peroxide value of the sample were monitored for tightly for eight weeks, the thiobarbituric acid 9TBA) value were also determined on the tenth and twelfth weeks respectively. The peroxide value of the sample for the eighth week were recorded as follows: A (10), B (8) C (8), D (11), E (10) and F (22) respectively. From these results, it shows that all the spices were below the range of detectable rancidity. (i.e. between 20 to 40m Eg/kg). the thiobarbituric aid (TBA) value were recorded, for the twelfth week as follows: A (0.033), B (0.005), C (0.004), D (0.046), E (0.776) and F (2.503) respectively. Sample C Monodora Myristica (Ehuru) had the lowest Pv and TBA value, thus the best species with antioxidant property. When compared with other spices and even the artificial antioxidant, followed by sample B Xylopia aethiopica.
BACKGROUND OF THE STUDY
Herbs and spices have long been used by ancient civilsations 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. 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).
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.