Evaluation of the Physico Chemical and Sensory Properties of Infant Food Produced From Maize, Soybean, and Tiger Nut
Chapter One
Aims And Objectives
Therefore, the objective of the study was to evaluate the nutritional and sensory characteristics of soybean and tigernut based infant food.
CHAPTER TWO
LITERATURE REVIEW
Tiger nut (Cyperus esculentus L.)
Tiger nut (Cyperus esculentus L.), is a memeber of the family Cyperaceae. Though popularly called “chufa” in many places it has other common names, such as earth nut, tiger nut, yellow nutsedge and “Zulu” nut. It is also called “ayaya” in Hausa and “ofio” in Yoruba (Umerie et al., 1997; Pascual et al., 2000). Five main varieties have been identified, namely;
- Cyperus esculentus var. esculentus – very common in the Mediterranean region east to India and Africa;
- Cyperus esculentus var. hermannii – cultivated in Florida
- Cyperus esculentus var. leptostachyus – very common in North America
- Cyperus esculentus var. macrostachyus – cultivated in the United States
- Cyperus esculentus var. sativa – very common in Asia.
The varieties of interest however are the esculentus and the sativa, which are commonly studied as a weed and crop in Africa, Asia and Europe (ter Borg and Schippers, 1992; Tiger nuts Traders, S.L., 2010).
Physical characteristics and nutritional value of tiger nut tubers
The tubers develop to lengths between 1.0-2.0 cm, showing an obtuse end of irregular form when dry, and round and oval after soaking in water (Coskuner et al., 2002). The tubers have a surface color of brown or black depending on the variety and whitish inside. A lightness (L*), redness (a*), and yellowness (b*) for whole and ground tubers has been reported as L*: 31.99; a*: 7.01; and b*: 10.89 and L*: 58.78; a*: 16.20 and b*: 16.20 respectively by Coşkuner et al., (2002).
The verage nutritional figures for the tubers have been quoted as protein, 3.77 %, 6.72 %; crude fiber, 4.81 %, 8.91 % and sucrose, 19.02 %, 13.4 % by Coskuner et al., (2002) and Pascual et al., (2000) respectively. Excluding histidine, Bosch et al., (2005) has been reported it to contain higher essential amino acids (mg/g protein) than those recommended for satisfying adult needs by the FAO/WHO. Tiger nuts have a fairly good amount of some essential minerals like magnesium, 43µg/g; potassium, 265µg/g; zinc, 158µg/g and 2028 % of a yellowish non-drying oil (Fatoki et al., 1995). Dubois et al., (2007) have also reported that the main fatty acids present in tiger nut oil are 14:0 (0.2%), 18:0 (3.2%), 20:0 (0.4%), 16:1 (0.3%), 18:1 (72.6%), 18:2 (8.9%), and 18:3 (0.4%), similar to olive and hazelnut oils.
Economic uses of tiger nut tubers
In Spain and Latin American countries, tiger nut is used in making the popular milk drink ‘horchata de chufa’ (Coskuner et al., 2000; Cortes et al., 2004). It is a typical product of Spain and of great economic importance. Production is estimated at 40-55million liters per year (Arranz et al., 2006). In the United States of America however, tiger nut has mainly used to attract and feed water fowls and cranes as well as ducks (Mosquera et al., 1996). In Africa, tiger nuts are an important food crop for many people. They are eaten raw after washing or after it has been soften by soaking in water for sometime. It has also been reported to be roasted and chewed like roasted groundnuts or grated and used for the production of ice creams, biscuits or as a substitute for coffee (Abbiw, 1990; Dokosi, 1998). They are also used to produce non alcoholic milky looking beverages (Sanful 2009; Ukwuru and Ogbodo, 2011)
Tiger nut milk
Tiger nut milk, called horchata de chufa in Spain is also very popular in some South American countries (Cortes et al., 2004; Corrales et al., 2012). The refreshing non-alcoholic beverage of milky appearance is normally produced from dried nuts which are ground and extracted with water (Kay, 1987). The milk beverage has a pH in the range 6.3-6.8 and is rich in starch (Cortes et al.,
2005, Belewu and Belewu, 2007). Heating the tiger nut milk beverage above 72°C therefore results in changes in the physical and organoleptic characteristics due to the gellification of the starch (Cortes et al., 2005). The physical, chemical and sensory characteristics of the tiger nut milk beverage have been found to depend on factors, such as the variety of tuber and procedure for beverage production (Belewu and Belewu, 2007; Navarro et al., 1984). The nutritional value of a typical fresh drink with 10 % sugar added has been reported as fat, 3 %; protein, 1 %; starch, 3 % and other carbohydrates, 20 % (De Venanzi, 1991). The composition of Fatty acids of the drink has been found to be very comparable to that of olive oil, with oleic acid constituting about 75 % while palmitic and the other unsaturated fatty acids mainly linoleic and linolenic were 12.5 % and 10 % respectively (Morell and Barber, 1983).
In a study on the composition of tiger nut milk by Cortes et al., (2005) arginine, glutamic acid and aspartic acids were the major acids recorded. The following essential amino acids; isoleucine, leucine, lysine, methionine, phenylanine, threonine, tryptophan and valine were also found to be in appreciable quantities. The flavor of horchata de chufa has been described differently by researchers as nutty, pleasant and refreshing, chalky coconut, and vanilla-like (Reid et al., 1972; Barber, 1981; Linssen et al., 1989, De Venanzi, 1991).
CHAPTER THREE
MATERIALS AND METHODS
Procurement of Material
The maize (Zea mays L.), soybean (Glycine max L.) and tiger-nut tubers (Cyperus esculentus) used for the study were purchased from Itam market in Uyo, Akwa Ibom State, Nigeria. The reagents were obtained from the Department of food science and technology, University of Uyo; and were of analytical grade.
Preparation of materials
After cleaning and removal of broken seeds and extraneous materials, the soybean seeds were washed and soaked in 4-times volume of potable water for 12 h to reduce flatulence – causing oligosaccharides by leaching them into the water. The seeds were drained and cooked for 30 min with potable tap water twice its volume and then dehulled. The soybeans were dried in an oven (Gallenkamp Plus 11) at 65ºC for 24 h and then milled using a hammer mill (Christy & Norris Ltd., Chelmsford, England), to pass through a 250 µm stainless sieve (W. Styler Co., Mentor, Ohio, USA) to obtain soybean flour (SF) (Akapo et al., 1995).
The method of Ade-Omowaye et al. (2008) was used in the production of tigernut flour (TF). Tigernut tubers were sorted to remove damaged and other extraneous materials, washed with potable water and soaked for 96h in potable water 4 times its volume. The sample was dried in a cabinet dryer at 65ºC for 24h and then milled to pass through 250µm sieve size to obtain tigernut flour (TF). The flour samples were stored in high density polyethylene pouches at -4ºC until used for analysis.
CHAPTER FOUR
RESULTS AND DISCUSSION
Chemical Composition
The chemical compositions of the samples were significantly (P<0.05) different (Table 2). Moisture content values ranged from 3.10 ± 0.18% to 4.01 ±0.25%, with the highest value for control. The moisture content of the samples was below the moisture standard of 5-10% set by the Protein Advisory Group, (PAG, 1971). The low moisture content of the FWD would have a positive effect on shelf stability, as moisture could lead to product spoilage due to oxidation reactions (Bassey, 2004). The ash content of the samples ranged from 2.49±0.15% to 3.06±0.34%. The FWD had significantly (P<0.05) higher ash content, and the highest value was for STF3. The increased ash content of STF3 could be due to the high ratio of both the tigernut and soybean, as both are good sources of minerals.
CHAPTER FIVE
CONCLUSION AND RECOMMENDATION
CONCLUSION
The potential suitability of tigernut flour in weaning food formulation was shown in this study. Although all the formulated diets met the benchmark for infant food, taking into consideration the dietary attributes and sensorial ratings, STF3 (tigernut 55%; soybean 35%, 10% FCM) was found to be the most promising formulation among three investigated variants. This indicates that underutilized tigernut tubers could be exploited to produce adoptable household cheap weaning food with soybean that can compare favorably with commercial brand. This could be a sustainable way of curbing malnutrition in sub-Saharan Africa.
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