Proximate Composition, Microbial and Sensory Properties of Biscuits Produced From the Blends of Tigernut and Soy Flour
Objective of the Study
The objective of the study was to determine the phytochemical, microbial and sensory properties of biscuits produced from the blends of tigernut and soy flour.
Tiger nut (Cyperus esculentus L)
Origin of Tigernut (Cyperus esculentus L)
Tigernut has been considered a foodstuff since ancient times (Pascual et al., 2000). In those times in Egypt, Cyperus esculentus tubers were roasted and used as sweetmeat. It was discovered that there are almost no contemporary records of this plant in other parts of the Old World. Nowadays, tigernuts are cultivated in Northern Nigeria, Niger, Mali, Senegal, Ghana, and Togo where they are used primarily uncooked as a side dish. Tigernut is an important representative crop of the Spanish Mediterranean region, with nearly 2450 ha and an annual production of 9000 metric tons (CRDO, 2012).
This plant was originally native to the Mediterranean region but its cultivation has now spread to many warm countries (Mohamed et al., 2005). It is usually sown in April and picked in November. Tigernut is also cultivated in American countries like Chile (Ormeno-Nunez, 2008), Brazil (De Abreu matos et al., 2008), and the USA, in such states as Lousiana, Missouri (Kelley and Fredickson, 2001), New Mexico (Taylor and Smith, 2005), and Florida where it is mainly used as animal feed. However, in many countries, Cyperus esculentus is considered a weed and it is underutilized (Adejuyitan, 2011; Ukwuru and Ogdobo, 2011).
Morphology and Cultivation of Tigernut
Tigernut is a tough erect fibrous-rooted perennial plant, 1 to 3 ft high, reproducing by seeds and by many deep, slender rhizomes, which form weak runners above the ground, and small tubers or nutlets at the tips of underground stems (Consejo, 2006). Young tubers are white, while older tubers are covered by a yellow outer membrane; they are usually found within 6 inches of the ground surface. High temperatures and low nitrogen levels increase tuber production and an increased day length (by lighting) will reduce tuber formation. The tuber epidermis (skin) contains substances, which inhibit sprouting of tubers; the plant grows best in moist sandy-loam soils but will grow in the hardest clay, tolerates high soil moisture and is intolerant to shade (James et al., 2001; Oderinde and Tairu, 2008).
The plant produces small, oblong tubers in abundance, which is sweet and rich in fat (Aliyu and Sanni, 2009). Like other sedges, the plant is most frequently found inhabiting wet marshes and edges of streams and ponds where it grows in coarse tufts (Aliyu and Sanni, 2009). Tiger-nut (Cyperus esculentus L.) belongs to the Division– Magnoliophyta, Class–Liliopsida, Order– cyperales and Family–Cyperaceae and was found to be a cosmopolitan, perennial crop of the same genus as the papyrus plant.
The tubers are about the size of peanuts and are abundantly produced in Nigeria. It has many other names like Zulu nut, yellow nutgrass, ground almond, chufa, edible rush and rush nut. It is known in Nigeria as Aya in Hausa, Ofio in Yoruba and Akiausa in Igbo where three varieties (black, brown and yellow) are cultivated. Among these, only two varieties, yellow and brown are readily available in the market. 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 upon extraction contains lower fat and more protein and possess less anti-nutritional factors especially polyphenols (Okafor et al., 2003). Tiger-nut has been cultivated since early times (chiefly in south Europe and West Africa) for its small tuberous rhizomes which are eaten raw or roasted, used as hog feed or pressed for its juice to make a beverage.
Product Derived from Tigernut
Tigernut milk (“Horchata”)
The Horchata is vegetable milk extracted directly from the tigernut. It is a refreshing drink, superb as substitute of traditional cow milk with a natural sweet taste. 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. It is ideal milk for persons that do not tolerate gluten (celiacs) or that are allergic to cow milk and its derivate (Belewu and Abodunrin, 2006). It helps in reduction of LDL (“bad”) cholesterol and increases HDL (“good”) cholesterol because of its high contents of oleic acid and Vitamin E, which has an antioxidant effect on fats. The high content of oleic acid and the enzyme arginine prevents arteriosclerosis.
The high content of fibre has a good effect on digestion, as it stimulates digestive juices, contributes to a longer feeling of fullness and speeds up transit in the intestinal tract and so prevents constipation. It has a high content of minerals, phosphorus, calcium, magnesium, iron and vitamins, where the content of vitamin C and E is especially considerable Recommended for persons with digestion disorders, flatulence and diarrheas, because of the content of digestive enzymes (lipase, catalase, amilase).
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 considered good flour or additive for the bakery industry, as its natural sugar content is high, avoiding the necessity of adding extra sugar (Anderson et al., 2009). The flour is used to make cakes and biscuits and the oil is used for cooking (Wise, 2009).
This is high quality oil extracted by a cold, virgin process in order to ensure that it retains all the unique nutritious qualities of the Tigernut itself. Tigernut oil was first used by Egyptians 4000 years ago in preference to olive oil. Indeed, it is generally considered a healthier alternative. 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) (Ezebor et al., 2005), enough to cover daily minimum needs for an adult (around 10 g) and low acidity, and so is excellent for the skin. They are high in Vitamin E (alpha and gamma-tocopherol) which prevents ageing. 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. The oil is a potential source of biodiesel and much research has been conducted (He et al., 2006).
MATERIALS AND METHODS
Tigernut (Cyperus esculentus L) and Soybean (Glycine max) were bought from a local market in Owo, Ondo State Nigeria, and other ingredients used for this study were purchased at the same local market Owo. This research work was carried out in Department of Food Science and Technology, Rufus Giwa Polytechnic Owo, Ondo State, Nigeria.
Methods of Preparation
Preparation of tiger nut flour
2 kg of tiger nut were weighed using scale balance, the tiger nut was then sorted to remove dirt after which it was rinse using portable water, it was then oven dried at 60oC for 24 hours. After drying it was milled using attrition mill then sieved using 600um aperture size. It was then packaged in polythene prior to analysis.
RESULT AND DISCUSSION
Table 4.1: Proximate Analysis of biscuits from Tiger nut –soybean flour blends
CONCLUSION AND RECOMMENDATION
From the result it is discovered that TSE contain significantly (p>O.05) higher amount of fat and fibre and protein compare to TSA, TSB, TSC and TSD while TSA was higher in Ash and Carbohydrate compared to other samples. The microbial content of the study shows that sample TSC contains the highest amount of bacterial load compared to four samples. The least bacterial load was observed in sample TSB, the yeast and mould count revealed that sample TSB and TSD are significantly higher than that of other three samples. The result also shows that TSA had better sensory parameter than sample TSB, TSC, TSD and TSE.
TSE (50% tiger nut flour + 50% soybean flour) generally can be recommended for malnourished infants and preschool children based on its Nutritional contents. Since the mineral content of TSC is higher, the formulation method of sample TSD should be adopted.
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