Proximate Analysis On Tigernut

It has many other names like Zulu nut, yellow nut grass, ground almond, and chufa, edible rush and rush nut. In Nigeria, the Hausas call it “Aya”, Yorubas “imumu”, the igbos “ofio”, “aki Hausa” in southern Nigeria . Tiger nuts which are incorrectly called “nuts” or “nutlets,” thus the origin of their common name, are small about the size of a peanut growing at the rhizome of the plant. Like other sedges, the plant is most frequently found inhabiting wet marshes and edges of streams and ponds where it grows in coarse tufts [14]. Tiger nut tubers are daily ingredients of the diet of many people in North Africa and Spain. In North Africa, the tubers are consumed in their natural form or after being soaked in water for some hours. In Spain, the tubers are consumed mainly as a drink called locally “horchata de chufa” (chufa milk). 

This plant was originally native to the Mediterranean region but its cultivation has now spread to many warm countries. It is usually sown in April and picked in November. There are mainly three varieties namely: black, brown and yellow, and only yellow and brown are readily available in the Nigerian markets. The yellow variety is preferred to all other varieties because of its inherent properties like its bigger size, attractive colour and fleshier body. The yellow variety also yields more milk, contains lower fat and higher protein and less anti-nutritional factors especially polyphones 

1.2.1 FRESH TIGER NUT 

In Northern Nigeria, the nut can be bought in the market all year round. The weight of fresh tuber ranges from 70mg to about 900mg while the weight of dried tuber ranges from 30mg to 350mg. A dried tuber nut can absorb up to three times its own weight of water. A single tuber can produce nearly 2000 plants and 7000 tubers in one growing season. It was observed that tiger nut production is predominantly the work of women farmers as high as 70% and 30% men [13]. The nuts are valued for their highly nutritious starch content, dietary fibre, digestible carbohydrate (mono, di and polysaccharides) [14, 19]. The nut was reported to be rich in sucrose (17.4 to 20.0%) and fat (25.50%) which are resistant to per oxidation, and protein (7-8%) [9, 20, 21] as indicated in Table 1. The nut is also fairly rich in mineral content (Sodium, Calcium, Potassium Magnesium, Zinc and traces of Copper) [22]. Tiger nut has been cultivated as a livestock food and for human consumption; it can be eaten raw, roasted, grated, baked or used for ice cream and beverage making for its many useful benefits [22, 23]. They taste best when dried. They are generally dried out (mostly in the sun), a process that takes one or more months with occasional turning over to ensure uniform drying to preserve them and to eliminate prevailing rot or any microbial infection. 

This secures their nutritional quality although, unfortunately, as they dry, they become wrinkled. As they dry, temperature and relative humidity are monitored. Once dry, they can be kept for several years, to be reconstituted by soaking overnight or by boiling when ready to serve those. The nutritional value of tiger nut derivatives, like oil and milk, arises from the very composition of the tiger nut. The level of anti-nutrients such as tannins, alkaloids and polyphones is drastically reduced by soaking in water for 6 hours, thereby making it free of unwanted elements especially in making the milk.

1.2.2 TIGER NUT MILK 

The origin of the use of this tuber for making milk is exclusive to the Spaniards to which it may have been introduced by the Arabs. Tiger nut milk/beverage/drink commonly called ‘kunnu aya’ in northern Nigeria is a healthy drink with many nutrients. It is a nourishing and energetic product recommended by experts to be taken during any season of the year, especially in dry season when the sun is hot. In Spain, it is called chufa de horchata. It is a rich source of nutrients such as vitamins C and E, and minerals such as phosphorus, magnesium, potassium, calcium, iron, and also carbohydrates, unsaturated fats, proteins and some enzymes which help in digestion. 

In fact this drink contains more iron, magnesium and carbohydrates than the cow’s milk. It has also the advantage of not containing lactose, casein, sugar or proteins of the milk, or cholesterol and is therefore an ideal drink for people who do not tolerate gluten or cow’s milk. The nutritional value of tiger nut beverage is, however, insufficient given that its protein content is low (6.05%) 

1.2.3 TIGER NUT FLOUR 

Tiger nut flour has a unique sweet taste, which is ideal for different uses. It is a good alternative to many other flours like wheat flour, as it is gluten free and good for people who cannot take gluten in their diets. It is also used in the confectionery industry it is considered good flour or additive for the bakery industry, as its natural sugar content is fairly high, avoiding the necessity of adding too much extra sugar. Also, it can be used as a flavoring agent for ice cream and biscuits. 

In the Keta area of Ghana, the sun-dried tubers are ground to a fine powder to which sugar can be added to be stored till required. Roasted tubers may be similarly ground to a powder known in Vhe (Awlan) as fie-dzowe. These meals may be eaten alone or with water added to make a beverage. 

In addition, tiger nut has been demonstrated to contain higher essential amino acids than those proposed in the protein standard by the FAO/WHO [28] for satisfying adult needs. Therefore, tiger nut, with its inherent nutritional and therapeutic advantage, could serve as good alternative to cassava in the baking industry. 

Furthermore, tiger nut flour does not lose any of its nutritious properties in the milling process. The fine ground tiger nut flour gives baits a smooth, creamy texture with a distinctive taste fish love, and can be incorporated into any mix as base ingredient, allowing baits to retain moisture. 

Incidentally, cutting part or all of the skins off tiger nut hook baits makes them more effective. Part of tiger nuts’ attraction is that they are rich in lysine, a major fish feeding stimulant though tiger nuts also contain many other extremely important and stimulatory dietary essential amino acids for fish, including methionine, cystine, arginine and histidine.

The edible and stable oil obtained from the tuber is said to be superior oil that compares favorably with olive oil. The oil is golden brown in colour and has a rich, nutty taste. The oil remains in a uniform liquid form at refrigeration temperature. This makes the oil suitable for salad making. It has a high oleic acid and low polyunsaturated fatty acid (linoleic acid and linolenic acid) [36, 37], enough to cover daily minimum needs for an adult (around 10 g) and low acidity, and so is excellent for the skin. It also has higher oxidative stability than other oils, due to the presence of polyunsaturated fatty acids and gamma-tocoferol [37]. 

It is regarded as high quality oil due to its extraction without adding any external heat (cold pressed oil), and is highly recommended for cooking over other oils because it is more resistant to chemical decomposition at high temperatures [38]. Furthermore, less fat is absorbed into the food as it creates a crust on the surface during cooking, preventing the oil itself being absorbed into the product. In the textile industry, the oil is used to waterproof textile fibres. The oil compares well with corn, soybean, olive and cotton seed oil and can thus serve as a substitute for these oils especially in times of scarcity [39]. The oil is a potential source of biodiesel and much research has been conducted.

The edible and stable oil obtained from the tuber is said to be superior oil that compares favorably with olive oil. The oil is golden brown in color and has a rich, nutty taste [17]. The oil remains in a uniform liquid form at refrigeration temperature. This makes the oil suitable for salad making. It has a high oleic acid and low polyunsaturated fatty acid (linoleic acid and linolenic acid) [36, 37], enough to cover daily minimum needs for an adult (around 10 g) and low acidity, and so is excellent for the skin. It also has higher oxidative stability than other oils, due to the presence of polyunsaturated fatty acids and gamma-tocoferol  It is regarded as high quality oil due to its extraction without adding any external heat (cold pressed oil), and is highly recommended for cooking over other oils because it is more resistant to chemical decomposition at high temperatures [38]. 

Furthermore, less fat is absorbed into the food as it creates a crust on the surface during cooking, preventing the oil itself being absorbed into the product. In the textile industry, the oil is used to waterproof textile fibres. The oil compares well with corn, soybean, olive and cotton seed oil and can thus serve as a substitute for these oils especially in times of scarcity [39]. The oil is a potential source of biodiesel and much research has been conducted.

1.3 ECONOMICS AND NUTRITIONAL BENEFITS OF TIGER NUT 

According to Mason [13], tiger nuts have long been recognized for their health benefits as they have a high content of soluble glucose and oleic acid, along with high energy content (starch, fats, sugars and proteins), they are rich in minerals such as phosphorous and potassium, calcium, magnesium and iron necessary for bones, tissue repair, muscles, the blood stream and for body growth and development and rich in vitamins E and C. Sugar-free tiger nut milk is suitable for diabetic people and also helps in weight control [41], due to its content of carbohydrates with a base of sucrose and starch (without glucose), and its high content of Arginine, which liberates the hormone that produces insulin [25,42]. 

It is recommended for those who suffer from indigestion, flatulence and diarrhoea because it provides digestive enzymes like the catalase, lipase and amylase. The high content of oleic acid has positive effect on cholesterol, thereby preventing heart attacks, thrombosis and activates blood content of soluble glucose. Tiger nut reduces the risk of colon cancer. It prevents constipation. Tiger nut contains a good quantity of vitamin B1, which assists in balancing the central nervous system and helps to encourage the body to adapt to stress [25, 43]. The milk supplies the body with enough quantity of Vitamin E, essential for fertility in both men and women. Vitamin E also delays cell aging, improves elasticity of skin and helps to clear the appearance of wrinkles, acne and other skin alterations. 

In China, tiger nut milk is used as a liver tonic, heart stimulant, drank to heal serious stomach pain, to promote normal menstruation, to heal mouth and gum ulcers, used in Ayurvedic medicines and is a powerful aphrodisiac (sexual stimulant). The black species of the tiger nut is an excellent medicine for breast lumps and cancer. The tubers have a relatively high total antioxidant capacity, because they contain considerable amounts of water-soluble flavonoid glycosides. Consumption of antioxidants could protect the immune system of malnourished populations. 

The intake of antioxidant-containing foods may delay the progression of HIV infection to AIDS [44]. For many years, the tiger nut tubers have been considered to have adequate properties to fight respiratory infections, and some stomach illnesses. To this date, the Horchata de chufa is considered an effective remedy for diarrhea, according to popular tradition in Valencia, Spain. It promotes the production of urine and this is why it is a preventive measure for cyst, prostrate, hernia, rectum deformation and prolapsed (anal feature-small painful flesh at the tip of the anus) and to prevent endometriosis or fibrosis as well as blockage of the tip of the fallopian tube. The oil reduces low density lipoprotein-cholesterol (LDL-C) and increases high density lipoprotein-cholesterol (HDL-C) [23], reduces levels of triglycerides in blood and the risk of forming bloody clots, thereby preventing arteriosclerosis. 

It also stimulates the absorption of calcium in bones and the production of new bony material, due to short and medium chain fatty acids, oleic acid and essential fatty acids [14]. It is also recommended for infants and the elderly because of its high content in Vitamin E and its antioxidant benefits in the cell membrane [43]. 

In the United States, the primary use of tiger nut as a crop is to attract and feed game, particularly wild turkeys. Turkey’s love tiger nut tubers; as natural scratchers, once discovering a plot of chufa, they will return again and again, all winter long, or until spring arrives and other food is readily available [25]. 

Tiger nut tubers have been planted so that pigs could be attracted to the fields to fatten and improve the taste of pork. The tubers have been used as hog feed, pastured in the field in states such as Florida, Georgia, and Alabama. Tubers of tiger nut have also been identified as valuable food for waterfowl and cranes. Ducks dive for them when wetland fields are flooded. It is also used in seed mixes for wetland restoration, mitigation, and erosion control. The caramel from malted tubers of Cyperus esculentus may be used to add body, flavor, or color to certain baked products, non-alcoholic malt beverages and dark beers, and in the production of condiments. The starches obtained from tiger nut and rice showed similar properties; the solutions of the starch exhibited a good paste stability, clarity, and adhesive strength. 

The starch can be used in many starch-based foods as well as in the cosmetic industry, and for laundry, glazing and stiffening. The waste residue after oil extraction could be further modified to produce syrups, flours, or livestock feeds.