Comparative Study of the Nutritional Composition of Varieties of Potato (Sweet and Irish Potato) Flour
The Objective of the Study
Therefore the aim of this study is to determine the nutritional composition of two varieties of potatoes (sweet and Irish potatoes) flour.
Origin of Potato Crop
Sweet Potato (Ipomoea batatas (L) Lam.)
Sweet potato (Ipomoea batatas (L) Lam.) is a member of the Convolvulaceae family (Purseglove, 2002). Approximately 900 different species of Convolvulaceae in 400 genera have been identified around the world. Yen (2004) and Austin (2008) recognized 11 species in the section batatas, which includes sweet potato. The closest relative of the sweet potato appears to be Ipomoea trifida that is found wild in Mexico, and Ipomoea tabascana. Sweet potato has a chromosome number of 2n = 90. Since the basic chromosome number for the genus Ipomoea is 15, sweet potato is considered to be a hexaploid. Most sweet potato cultivars are self-incompatible, which means that when self-pollinated, they cannot produce viable seed. It is accepted that cultivated sweet potato originated in Central America or tropical South America. Nishiyama (2001) and Martin and Jones (2002) suggested Mexico as a centre of diversity of the batatas section of Ipomoea.
Irish Potato (Solanum tuberosum L.)
Potato is generally considered to have originated from the region between latitude 10°N and 20°S at an altitude of 2000 meters but to be precise in Bolivia (Okonkwo, 2001). FAO (2008) identified the centre of origin to be between Mexico and Chile but specifically suspected the Andean highland of Bolivia or peru, where the presence of wild species of the crop serves as clues. The neighborhood of laketitican located at an altitude of 3512 meters above sea level in the peru-Bolivia Plateau area is more definite. Potatoes were introduced outside the Andes region four centuries ago, and have become an integral part of much of the world’s cuisine. It is the world’s fourth-largest food crops, following rice, wheat and maize (Hawkes, 2000). Long term storage of potato requires specialized care in cold warehouse (Lang, 2001).
Wild potato species occur throughout the Americas, from the United States to Southern Chile (Langar, 2005). The potato was originally believed to have been domesticated independently in multiple location (McNeill, 2009), but later genetic testing of the wide variety of cultivars and wild mild species proved a single origin for potatoes in the area of present-day southern and extreme north western Bolivia (from a species in the Solanumberevicaulecomplex) where they were domesticated 7,000-10,000 years ago (McNeill, 2009). Following centuries of selective breeding, there are now over a thousand different types of potatoes of these sub-species, a variety that at one point grew in the Chile Archipelago (the potato’s south central Chilean sub-center of origin) left its garn plasum on over 99% of the activated potatoes world-wide (Salaman, 2009).
The crop moved out of the south America (center of origin) by deliberate introduction to spain in 1570, to England in 1586, then to Ireland by Spanish explorers from 1663, the crop was grown on a large scale in Ireland and becomes so popular such that it is not too surprising that it acquired the name “Irish Potato” (Randel,2003) indicated that the English introduce potato into Virginia in 1621 and into Bermuda island in 1913. The years 2007-2008 saw dramatic increase in the world food prices, creating global crises that led to political and economic instability in both the developed and developing nations.
The initial causes of the late 2006 price increase were due to draught in grain producing nations and the rising oil prices, the increase in oil prices also cause general escalation in the cost of fertilizers, food transportation, industrial and agricultural products. This factors coupled with the following world food stock pilled contributed to the global rise in food prices (Global and Mail, 2008) in response to the severity of the food crises and the need for prompt action, the world bank set up the global food crises response program (GFRP) in May 2008 to provide immediate relief to countries hard hit by food high prices. The bank’s response has been articulated in collaboration with united nations “High task force” on food security “HLTF” (World Bank,2009) highlighted potato’s role in world food production, they cited it’s enormous potentials for boosting food production, being a cheap and abundant crop that grows in a wide variety of climates and locality due to its perishability however, only about 5% of the world potato production is traded internationally. This contributes to its stable pricing during the 2007-2008 world food crises (FAO, 2008). It is a source of starch and alcohol, in addition to its food and feed supply value to both human and animals, respectively (Uniferm, 2009). Its production is lopsided to the predominant small scale farmers. This category of farmers suffers from a crippling technical inefficiency in the use of their production inputs (Hamidu, 2000).
MATERIALS AND METHODS
Sweet potato (Ipomoea batatas L) andIrish Potato (Solanumtuberosum L) was obtained from the local market in Owo, Ondo state. The two potato varieties processed in food processing laboratory in the department of Food Science and Technology, Rufus Giwa Polytechnic Owo, Ondo State.
RESULTS AND DISCUSSION
Table 4.1: Results for Proximate Analysis of Sweet Potato Flour and Irish Potato Flour
CONCLUSION AND RECOMMENDATIONS
Sweet potato and Irish potato is an important nutritious staple crop cultivated in Nigeria, though people in Nigeria are yet utilized it to its full potential. As reveal in this study both sweet potato and Irish potato flour have proven to be a very nutritious crop which can be used in many ways, the moisture content of both samples especially SPF makes it more durable with longer shelf life, though not too rich in mineral its protein quantities makes it more nutritious for consumption, the results also reveals the carbohydrates content of both samples which is above 30%, this makes it an energy given food. In conclusion both sweet potato and Irish potato flourare nutritious flour which can be used in many ways, both in food industrial and at home.
Based on the research study above it is therefore recommended that utilization of potato (sweet and Irish potato) should be encourage by food industries and enlightenment of these crop should be given to farmers in Nigeria. And also, further studies are however required on the bioavailability of nutrients and acceptability of various added products produced from these flour.
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