- Background of the Study
Cashew, (Anacardium occidentale L.) belongs to the family Anacardiaceae. Cashew is indigenous to South America and was introduced into Nigeria by Portuguese explorers in the 15th and 16th centuries (Sasivame, 2002). In Nigeria commercial plantations of cashew were developed simultaneously by the Eastern and Western Nigerian Development Corporations at Oghe and Eruwa respectively (Togun, 1997). From these locations, it’s planting spread to other parts of Nigeria (Oluyinka, 2012).
The cashew tree (Anacardium occidentale) is a medium-sized tropical evergreen tree usually cultivated for its fruit (cashew nut) and pseudofruit (cashew apple). It can grow as high a 14 metres (46 ft), but the dwarf cashew, growing up to 6 metres (20 ft), has proved more profitable, with earlier maturity and higher yields (FAO, 2001). It is also a multipurpose species that provides a broad range of services. About 30-40% cashew kernels are discarded during the process of roasting and are then fed to livestock (Topper, 2002).
The cashew seed is served as a snack or used in recipes, like other nuts, although it is actually a seed. The cashew apple is a light reddish to yellow fruit, whose pulp can be processed into a sweet, astringent fruit drink or distilled into liquor. The shell of the cashew seed yields derivatives that can be used in many applications from lubricants to paints, and other parts of the tree have traditionally been used for snake-bites and other folk remedies (Geron et al., 2013).
Cashew apples are an important by-product of cashew nut industry. Most of the fruits, at present, are not utilized in the country. Cashew apples contain astringent and acrid principles which produce an unpleasant biting sensation on the tongue and throat when as such. The fruits are highly susceptible to injury and rapid microbial deterioration. These factors together with the difficulties experienced in collection of fruit. It has been found possible to remove astringent principles by simple methods like steaming, brine curing or by chemical treatment and then utilize the fruit for conversion into several edible product. These products include claries and cloudy cashew apple juice, cashew apple juice blended with other fruit juices and pulps like lime, pineapple, orange, mango, and papaya, cashew apple juice concentrate, cashew apple preserve and candy, cashew apple jam, cashew apple mixed fruit jam, cashew apple pickle and chutney (Asogwa et al., 2008).
Cashew nuts (kernels) are nutritious; they contain good amounts of fats, protein, carbohydrate, vitamins and minerals. Kernels can be processed for oil extraction and then yield cashew nut meal or cake that can be used in livestock feeding. However, cashew nut meal is often referred to as discarded cashew nuts rather that as extracted oil meal (Orwa et al., 2009). Cashew nuts are good source of minerals (Magnesium Phosphorus, Copper, and Manganese), vitamins (vitamin C), carbohydrates, sugar, soluble and insoluble fiber and amino acids but very low in saturated fatty acid, cholesterol and sodium (Ashante et al., 2002). Cashew nuts (kernels) must be extracted from their poisonous shell with caution in order not to be contaminated by the toxic substances embedded in the mesocarp. Once extracted from the nut, the kernels are roasted to destroy the remaining toxins (Orwa et al., 2009; Morton, 1987). The kernels are a nutritious food as they contain large amounts of fats, protein, carbohydrates, vitamins and minerals(Orwa et al., 2009). In the literature they are often referred to as cashew nut meal or cashew nut reject meal. They are used to feed livestock. Cashew apples (pseudofruit) are too fragile to be suitable for transport and relished only in areas of production, such as Brazil, Mozambique and Indonesia. They can be eaten fresh in salads, pressed to make juices, cooked in syrup or made into jams to preserve them. Cashew pulp is the residue of the separation of the nut from the pseudofruit, and cashew bagasse (cashew pomace, cashew apple waste) is the residue of the juice extraction from the pseudofruit. Both products are suitable for livestock feeding. It should be noted that the term "cashew pulp" is ambiguous and sometimes used for the bagasse (Geron et al., 2013). Cashew nut oil meal, or cashew nut oil cake, is the residue of the oil extraction from kernels. It is suitable for livestock feeding. Cashew nut testa are the red skins that are manually or mechanically removed in the final step of preparing cashew nuts for confectionery. These skins may contain pieces of broken kernels and can be used as feed (Donkoh et al., 2012). Cashew tree leaves can be cut and eaten fresh or cooked. Cashew tree timber provides good firewood and can make valuable charcoal. The nut shells can be burnt to produce heat to be used in the processing of Cashew Nut Shell Liquid. Cashew Nut Shell Liquid (CNSL), also known as cashew shell oil, is contained in the fruit mesocarp. It is a mixture of 70% anacardic acid (a salicylic acid analog, and a strong skin irritant) with 18% cardol, and 5% cardanol. The two latter components are caustic phenolic substances that readily polymerize and are used for epoxy resins, varnishes, and many high-tech materials that can withstand high temperatures, such as brake linings (Orwa et al., 2009; Duke, 1983). CNSL is also used as a pesticide against termites in timber, and the bark gum is repellent to insects (Duke, 1983).
The cashew tree is a multipurpose species, and cashew products have a wide range of uses. The kernel of the cashew nut, the pseudofruit (cashew apple) and the leaves are edible. Almost all parts of the cashew tree are reported to have ethnomedicinal properties (Morton, 1987). The cashew leaves have reportedly been underutilized by some researchers as herbal therapy to solving most health related issues which necessitated this research of carrying out some elemental and mineral analysis on young and old cashew leaves and also evaluating their acceptability as herbal tea and constituents.
1.3 AIM AND OBJECTIVES
To carry out some elemental analysis on young and old cashew leaves and to determine its benefits as an herbal tea for different ailments.
The objectives of the research are to:
- Determine the mineral concentration of the young and old cashew leaves samples in different nature (liquid and dried).
- Determine the pH, moisture and ash contents of the young and old cashew leaves samples.
iii. Evaluate the acceptability of cashew leaf as an herbal tea.