Estimation of Mineral Content in Mango Fruit
CHAPTER ONE
Objectives
General objective
To quantify the levels of selected macro and micro minerals in residues of local and exotic mango varieties grown in Uyo Local Government Area, Akwa Ibom state, Nigeria.
Specific objectives
- To quantify the levels of macro (Na, K, Mg, Ca) and micro minerals (Zn, Cu, Fe, Mn) in the seeds of ngowe, apple and van dyke mango varieties from Urua Ikpa and Nwaniba areas, Uyo Local Government Area, Akwa Ibom state, Nigeria.
- To quantify the levels of macro (Na, K, Mg, Ca) and micro minerals (Zn, Cu, Fe, Mn) in the endocarps of ngowe, apple and van dyke mango varieties from Urua Ikpa and Nwaniba areas, Uyo Local Government Area, Akwa Ibom state, Nigeria.
- To quantify the levels of macro (Na, K, Mg, Ca),and micro minerals (Zn, Cu, Fe, Mn) in the epicarps of ngowe, apple and van dyke mango varieties from Urua Ikpa and Nwaniba areas, Uyo Local Government Area, Akwa Ibom state, Nigeria.
CHAPTER TWO
LITERATURE REVIEW
Uyo Local Government Area
Uyo is the state capital of Akwa Ibom, in South South Nigeria. The city became the capital of the state on September 23, 1987 following the creation of Akwa Ibom State from erstwhile Cross River State. The University of Uyo Main campus is located at Nwaniba, while the Town campus and Annex campus are located along Ikpa road. The population of Uyo, according to the 2006 Nigerian Census which comprises Uyo and Itu, is 427,873. While the urban area, including Uruan, is 554,906, with Ibibio language as it tribal language. The agro-ecological zones are directly linked with the major enterprises in the district, which include cotton and mangoes in the higher altitude, higher rainfall areas, and tobacco and livestock in the drier, lower altitude areas (Msabeni, 2010).
Mango varieties and maturity
Mango is successfully grown on a wide range of soils. The trees do well in sandy soils, loam, black cotton and even murram soils at other elevations (Griesbach, 2003). The mango fruit is a large, fleshy drupe, containing an edible mesocarp of varying thickness. Fruit color is genotype dependant and range from green, greenish-yellow, yellow and red bluish. The exocarp is thick and glandular. The mesocarp can be fibrous or fiber-free with flavor ranging from turpentine to sweet. The endocarp is woody, thick and fibrous (Slaughter, 2009). The picture showing different parts of a mango is shown in Appendix 10.
The apple mango fruits are medium to large, nearly round in shape and have a rich yellow or orange to red colour when ripe. Average length measures 9.7 cm by 11 cm in width, and the weight is 280-580 g (mean: 397 g). The skin is smooth and thin, and the juicy yellow flesh is of excellent flavour and of melting texture virtually free from fibre. This is not a polyembryonic cultivar and trees propagated by seed are very heterogeneous in fruit shape, colour and quality (Griesbach, 2003).
Ngowe is the most easily recognized of the local mango fruits. It is large, oblong and slender with a very prominent hook-like beak at the apex. From pale green, the fruit develops to a most attractive yellow to orange colour when ripe. The deep yellow flesh is of excellent quality, virtually free from fibre, melting and carries no turpentine taste. The average fruit length measures 14 cm with a width of 9.5 cm and a weight range of 425— 600 g (mean: 523 g). The seeds are polyembryonic which means progeny develops more or less true-to-type (Griesbach, 2003).
CHAPTER THREE
MATERIALS AND METHODS
Study Area
Uyo Local Government Area is found in Akwa Ibom state, Nigeria. Uyo is the state capital of Akwa Ibom, in South South Nigeria. The city became the capital of the state on September 23, 1987 following the creation of Akwa Ibom State from erstwhile Cross River State. The University of Uyo Main campus is located at Nwaniba, while the Town campus and Annex campus are located along Ikpa road. The population of Uyo, according to the 2006 Nigerian Census which comprises Uyo and Itu, is 427,873. While the urban area, including Uruan, is 554,906, with Ibibio language as it tribal language shown in Appendix 8.
Experimental research design
Mango fruit is a large freshy drupe containing an edible mesocarp of varying thickness and is widely grown in Nigeria. To quantify the levels of Na, K, Mg, Ca, Zn, Cu, Fe and Mn in mango residues, mature mangoes were sampled twice, flesh yellow in colour from Nwaniba and Urua Ikpa areas Uyo Local Government Area. The residues parts epicarp, endocarp and seeds were separated from the mesocarps (edible parts). The residues were then chopped to small pieces, oven dried, ground to powder, wet digested in a mixture of HNO3 and H2SO4 acids and finally analyzed using AAS and AES instruments.
CHAPTER FOUR
RESULTS AND DISCUSSION
Introduction
The levels of sodium, potassium, magnesium, calcium, zinc, copper, iron and manganese from the peel, endocarp and seeds of van dyke, ngowe and apple mango varieties was determined by AAS and AES. The results are presented and discussed in this chapter.
Method validation
The method validation of the various instruments that were used was done using regression analysis, recovery tests and reproducibility.
CHAPTER FIVE
CONCLUSIONS AND RECOMMENDATIONS
Conclusions
Based on the objectives and the results of this study which was to determine the levels of Na, K, Mg, Ca, Zn, Cu, Fe and Mn in residues of three mango varieties from Nwaniba and Urua Ikpa areas, the following conclusions can be drawn.
- The minerals K, Na, Mg, Ca, Zn, Cu, Fe and Mn were available in mango residues in levels that are potentially useful for health benefit.
- The levels of essential minerals in decreasing order were as follows Ca>K>Mg >Na> >Fe>Mn>Zn>Cu
- Sodium levels were significantly higher in apple with respect to peel and endocarp but seed of van dyke had significantly high sodium levels.
- Potassium levels were significantly higher in ngowe peels and endocarps but van dyke had significantly higher K in seeds.
- Magnesium levels were significantly higher in ngowe seeds, peels and endocarps.
- Zinc levels were significantly higher in ngowe peels and endocarps but for van dyke it was significantly higher in endocarps.
- Copper levels were significantly higher in apple peels and seeds but for van dyke it was higher in endocarps.
- Iron levels were significantly higher in van dyke seeds, peels and endocarps.
- Manganese levels were significantly higher in van dyke seeds and peels and high in ngowe endocarps
- Calcium levels were significantly higher in apple peels, van dyke endocarps and ngowe seeds. xii)There were variations in levels of minerals in residues with a general trend seed>peel> endocarp xiii) Variations of essential minerals in mango varieties were noted but generally ngowe and van dyke recorded significantly higher levels of most minerals than apple.
Recommendations from this study
- The residues analyzed in this study contain substantial levels of essential minerals with respect to the RDA in cattle and poultry and therefore can be explored for use in preparation of animal feeds and mineral supplements.
- The seeds had significantly higher level of most minerals among the three residues analyzed and therefore they can be explored for use as animal feeds to supply essential minerals sufficiently.
- Ngowe and Van dyke residues recorded the highest concentrations and therefore they can be used to supply with the eight minerals analyzed in this study adequately.
Recommendations for further work
- Other fruits like pineapples, bananas, avocadoes and paw paws residues in Nigeria should to be analyzed for essential macro and micro minerals. ii) The levels of proteins, vitamins and carbohydrates in mango fruit residues need to be investigated as they play important role in the body of animals.
- The varieties of mangoes grown and consumed in other parts of Nigeria need to be analyzed for the same minerals as in this study.
- The Bio availability of minerals in mango residues in animal’s body need to be investigated.
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