Effect of Fermentation on the Proximate Composition and Organoleptic Properties of Cookies Produced From Wheat, Sweet Potato, and Soy Flour Blend
Objective of the Study
This project is aimed to determine the effect of fermentation on the chemical composition and organoleptic properties of cookies produced from wheat, sweet potato, and soy flour
The specific objectives include the followings;
- To ferment and produce flours from sweet potato and soybean
- To produce cookies from the flour blends
- To determine the proximate composition and organoleptic properties of cookies produced from the flour blends
Wheat (Triticum aestivum L)
Wheat (Triticum aestivum L) is the most extensively grown cereal crop in the world, covering about 237 million hectares annually, accounting for a total of 420 million tonnes (Isitor et al., 2000; Langer and Hill, 2001; Olabanji et al., 2004), and for at least one-fifth of man’s calorie intake (Ohiagu et al., 2007). Wheat is an annual grass growing to between ½ to 1 ¼ meters in height, with a long stalk that terminates in a tightly formed cluster of plump kernels enclosed by a beard of bristly spikes (Smith, 2010). It is grown all over the world for its highly nutritious and useful grain, as one of the top three most produced crops, along with corn and rice. It is used in the production of bread, biscuits, feeds, confectionary, amongst many, utilization.
The crop, which has been cultivated for over 10,000 years probably, originates in the Fertile Crescent, along with other staple crops. However, ancestral wheat may have looked very different from what we presently have today, with much smaller kernels. Early domesticators of wheat obviously wanted to select for plants with particularly large kernels, since more nutrient could be eked out from each stalk. Wheat has been cultivated in Nigeria for centuries (Olugbemi et al., 2009; Ohiagu et al., 2007). Ample evidence exists to show that wheat has been cultivated in Nigeria as early as 200BC, although the currently cultivated varieties are relatively recent introduction (Olabanji et al., 2004). However, Nigeria’s domestic wheat production has remained at a very low level in spite of the ever – rising demand for the crop. The constraints to the cultivation of wheat in most wheat growing areas in Nigeria include climatic requirements, appropriate agronomic practices and preference for the cultivation of vegetables (Ohiagu et al., 2007). Development of improved agronomic practices in respect of land preparation, planting, nutrition, water management, crop protection, harvest and postharvest technology have been the major areas where researchers have concentrated their efforts.
With a projected population of 137.86 million people in 1997 (Ohiagu et al., 2007), wheat consumption in Nigeria was projected to reach 1.5 million metric tonnes, with domestic production lagging behind demands. Decades later, the prospect of meeting local wheat demands seem unlikely, particularly with the demise of most River Basin Development Projects (Olabanji et al., 2004). To complicate issues, yields obtained on farmers’ plots have often lagged behind world average. Wheat cultivation in Nigeria up to 1985 was about 66, 000 tonnes (Anon, 2009), but rose to about 400, 000 to 600, 000 tonnes from a total land area of 215, 000 hectares between 2008 and 1989 with an average field yield of 2t ha-1 after ban was imposed on wheat importation. Average farm yield is still quite below what exist in the UK or the world average.
Wheat as an important industrial crop is the main raw material in feed mills, with bread, cake, biscuit, pasta, spaghetti, semovita, macaroni, containing reasonable amounts of wheat. The offal is used in compounding life stock feeds. After wheat harvest, the grain is separated from the stalks and chaff. The wheat stalks are used in a variety of applications: mulch, construction material, and as animal bedding. As food, wheat contributes more protein and calories to the diet than any other crop and world trade in wheat far exceeds the contributions of other grains put together.
Classification of wheat
Wheat is classified based on species, commercial types, and growth habit. Based on these, there are sixteen species, two commercial types: bread (Triticum aestivum) and macaroni or Duran wheat (Triticum durun); and three growth habits (winter habit wheat, spring wheat and facultative wheat). Winter wheat lies dormant during a winter freeze.
MATERIALS AND METHODS
Collection of Materials
Wheat, sweet potato and soybean were all purchased from the main market (Oja-oba) in Owo, Ondo State. The raw materials (wheat, sweet potato and soybean) were all processed into flour in the processing laboratory of Food Science and Technology, Rufus Giwa Polytechnic, Owo, Ondo State.
Preparation of fermented sweet potato
Fresh sweet potato root were washed, peeled, sliced, the cleaned sliced sweet potato root was soaked i.e. fermented for 24 hours. After 24 hours the fermented sample was washed, drained, sun dried and dry milled into powder, sieved and packaged in airtight container for further analysis (Fig. 1).
RESULTS AND DISCUSSION
Table 2: Proximate composition of biscuits produced from fermented and unfermented flour blends
CONCLUSION AND RECOMMENDATIONS
The present study demonstrated that fermentation significantly improves the protein quality of the cookies. Specifically, the findings of this study suggest that relative to unfermented cookies the fermented cookies with 70:20:10% ratio are richer in nutritional component. The findings of this research revealed that the cookies produced with soybean flour substitution up to 10% warnut nutritionally superior to other different blends of the cookies produced from wheat, sweet potato, soybean. The high protein content in the wheat, sweet potato, soybean supplemented food would be of nutritional importance in most developing countries like Nigeria where many people can hardly afford high proteineous food because of their high cost. Therefore it can be concluded that addition of 10% soybean flour, 20% sweet potato flour to cereal flour (wheat) enhance the nutritional composition of the cookies.
The economic impact of utilization of flour produced from indigenous crop ( sweet potato, soybean flour) to complement wheat flour will enhance gross domestic products in Nigeria and bring about reduction in foreign exchange on wheat importation and also improves the nutritional composition of whole wheat cookies. It can also be recommended in the snacking pattern of children and adults in Nigeria.
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