Quality Assessment of Bread Sold in Gombi Local Government Area, Adamawa State, Nigeria

The moisture, ash, crude fiber composition, vitamin (B2, B6 and B12) and mineral (Na, K, Ca Mg, Pb, Cd, Mn)contents as well as Sensory properties (color, taste, odour and texture)of ten brands of bread sold in Gombi Local Government Area, Adamawa State, Nigeria were determined using standard methods . Fresh loaves of ten most popular brands of bread namely:Trustee, Destiny, Ziranza, Royal and Zango, were randomly collected. Five of these brands were purchased from bakeries (coded: Aa –Ea), while others of the same brands were purchased from different points of sale (coded: Ab-Eb) within Gombi town. The results of the investigation revealed that Cd, Pb and potassium bromate were not detected in all the samples. Potassium and sodium were predominant among all the tested samples. The moisture, ash and crude fiber contents ranged from (20.00 to 34.49% and 13.96 to 19.49%), (0.49 to 1.95% and 0.50 to 2.49%), and (10.91 to 33.13 and 28.32 to 47.30%) of samples from bakeries and points of sales, respectively. Vitamins B2, B6 and B12 were non-significant differences (p>0.05) in the vitamin content among the bread samples. The concentrations of all the parameters studied were all within the standard specification given by Standard Organization of Nigeria (SON) except crude fiber that is higher. This study showed that the bread brands produced in Gombi town could be nutritious, free from pollutants and suitable for human consumption.

extensibility for molding and to increase the loaf volume and texture (Dooshima et al.,2014).
Several studies showed that many improvers such as potassium bromate used over the years have some deleterious effect to health, thereby necessitating their ban (Eriksson et al. 2014). Toxicological studies according to Olaoye et al. (2006), have shown that, with respect to human health, consumption of potassium bromate can lead to cancer effect, such as degrading vitamins A1,A2, B1,B2,E and niacin which are the main vitamins available in bread and causing significant differences in essential fatty acid content of flour treated with bromate, causing the development of cough, sore throat, abdominal pain, diarrhea, nausea etc (Oloyede et al., 2013). Several research studies have shown that potassium bromated is carcinogenic in nature, and have the potential to cause cancer by inducing oxidative stress in the tissues of both human and experimental animals (Olaoye et al. 2006;Dooshima et al. 2014;and Eshetu et al., 2018). The aim of this study is to assess the quality of bread,by determining the physicochemical parameters, vitamins, mineral contents and as well as sensory properties of bread sold in Gombi townin Gombi Local Government area of Adamawa State, Nigeria.

2.MATERIALS AND METHODS 2.1.Sample collection
Ten brands of bread samples most popular, commonly consumed and produced in Gombi town in Gombi Local Government area of Adamawa State, Nigeria were randomly collected within the study area. Five brands of bread samples were collected from five different bakeries namely Trustee, Destiny, Ziranza, Royal and Zango (codedAa -Ea) and five brands of the same brands of bread samples were purchase from different points of sales such as in the market, Motor Park, tea sellers, mechanic workshops and provision shops where major commercial activities take place (codedAb -Eb).These samples were analysed immediately after purchase.

2.1.Methods of analysis
Moisture and ash contents: Moisture and ash contents were determined according to AOAC (2005).

2.2.Determination of fiber content
Weende's method (James, 2013) was used for determination of fiber content. Two g of each sample was weighed using analytical balance and put in to a 250 ml round bottom flask. Then, 200 ml of 1.25% H2SO4 was added and the obtained mixture was then boiled under reflux for about 30 min. The solution was filtered with Whatman No. 52 filter paper, the residue was rinsed thoroughly with hot water until it was no more acidic when tested using universal pH indicator. The residue was transferred into a 250 ml beaker and 200 ml of 1.25% NaOH was added and boiled for 30 min in a digestion apparatus after which it was filtered and rinsed with distilled water until the filtrate was neutral when tested with universal pH indicator. The residue was transferred into a crucible and then placed in the electric oven at 100 o C for 8 h to dry. It was then removed and placed in desiccators to cool before weighing. The crude fiber content was determined using equation indicated below: Crude fiber (g/100g) = [ (W1 -W2) x 100] W3 Where: W1=weight of (crucible + sample) after drying; W2=weight of (crucible + sample) after ashing; W3=weight of fresh sample.

2.3.Determination of mineral content
Mineral contents of bread were determined after digestion using dry ashing method following the method reported by AOAC (2005). To the digested filtrate, 2ml of concentrated HCl, 10mL of 20% HNO3 were added, evaporated on the hot plate. 50ml of distilled water was added and was filtered through WhatmanNo.1 filter paper into 50ml volumetric flask. The mineral elements and the heavy metals were determined by atomic absorption spectroscopy (Buck Scientific 210 model, (Scotland), while sodium and potassium was determined using flame photometer (Sherwood Scientific 410 Model, (UK). For each element, calibration curves were constructed using standard concentrations of each element.

2.4.Physical Determination
The sensory evaluation of the breads for texture, taste, aroma, and colour, were determined according to (Ihekoronye and Ngoddy, 1985).1g of the bread sample was heated on a hot plate and the aroma was perceived. The texture of each sample was determined by hand feel using the thumb and fore-finger (Ihekoronye and Ngoddy, 1985).

2.6.Detection of potassium bromate in bread samples
Potassium Bromate was determined by qualitative method as described by AOAC (2005). 7 cm 3 of 1% KI solution was pipette into a beaker and 1 cm 3 of HCl was added to it, then 4g of the sieved powdered sample was evenly distributed into it until all the powdered bread sample was wetted by the reagent. The presence of black specks or purple spots indicated the presence of potassium bromated, otherwise, it was absent.

2.7.Statistical analysis
All analysis was conducted in triplicate determinations and results were presented as mean and standard deviation.

3.RESULTS AND DISCUSSION
All the bread samples were white in colour except sample coded "Db" which had chocolate colour, they all have sweet aroma and taste. The white colour of the bread may be due to the wheat used and the efficiency of the milling system and also may be attributed to the use of bleaching agents. Bleaching, changes the colour of the wheat flour by oxidizing the caroteniod pigments in the endosperm, and the colouring matter from the ban (Alexander and Ndukwe, 2010). All the bread samples has sweet aroma on heating, possibly due to the released of volatile flavouring compounds or maillard reaction (Ihekoronye and Ngoddy (1985).
However, presence of sugars in flour is very important for the growth of yeast during fermentation and also their presence determined the gassing property of the flour. Samples coded "Ab", "Cb", "Db", "Aa", "Ca", and "Da" were soft and consistent while samples coded "Bb", "Eb", "Ba" and "Ea" were soft and crumbly (crisp) Begum et al. (2014). The addition of small quantity of sodium chloride during mixing gives taste and imparts flavour Eriksson et al. (2014).

3.1.Moisture, Ash, crude fiber and Mineralprofiles
The results of moisture, ash, and crude fiber contents, as well as mineral profiles of the selected bread samples from the bakeries and points of sales are as presented in Tables 1 and 2.There were significant differences (p<0.05) in the moisture, crude fibre, and ash contents of the bread samples.These values fall within the ranges permitted by SON (2004) except for crude fiber which was higher .The moisture content of (20.00 to 34.49% and 13.96 to 19.49%), compared to the maximum value of 40.00% specified by SON and this is comparable to the amount in bread flour 13.9 to 15.0% and also is in agreement with the findings of Olaoye and Onilude (2011); Adebayo-Oyetoro et al. (2016). However, all the samples falls within the standard limit range of Standard Organization of Nigeria (SON, 2004) 10 -40% for white bread. The moisture content of foods is usually used as an indicator of food quality. It is important to measure the moisture content in breads because of its potential impact on the sensory, physical and microbial properties of the bread Olaoyeet al. (2006); Adebayo-Oyetoro et al. (2016). It was noted that as the substitution level increases the moisture content also increases (Ayub et al., 2003).
The ash contents of the samples from the bakeries and points of sale ranged from 0.49 to 1.95% and 0.5 to 2.49% respectively, this was in agreement to the findings of Olaoye et al. (2006); Mongi et al. (2011);Eshetu et al. (2018).These values were within the standard specification of (SON, 2004) for ash content of wheat flour (0.60 to 1.10%) and wheat grain (0.4 to 1.0%).The result showed no significant difference between the ash content of the samples from the bakeries and those from points of sale.

3.2.Mineral profile:
Results of the mineral composition of the ten selected bread samples are as presented in Tables 1 and 2. Calcium, magnesium, sodium, and potassium were found in all the bread brands. There were no significant differences in the mineral values among the bread samples. This is contrary to the reports of Ebuehi et al. (2007) and Dooshima et al. (2014) with bread samples in Lagos, Benue and Nassrawa metropolis in Nigeria.
The metabolic functions of minerals for life cannot be overemphasized and has been extensively reported in literature Eke et al. (2013).The calcium content of breads from different bakeries and points of sales ranged from 5.10 to 5.70%. Compared with the (WHO/FAO, 2011) (18mg/kg), the breads investigated in this study were found to contain lower calcium content and hence did not meet the bread quality standards in this respect. Calcium is an important constituent of body fluids and bone formation in conjunction with phosphorus (Olaoye et al., 2006). Calcium also plays a major role in nutrition including bone formation, maintenance and growth, tooth formation, blood clot formation, absorption of vitamin B12 and contraction of muscles. Calcium is necessary for supporting bone formation and growth (Eriksson et al., 2014). Generally the entire bread samples studied, had their calcium values lower compare to WHO/FAO standard limits (18mg/100g). The results revealed that there is no significance difference (p>0.05) in the calcium contents of the bread samples from bakeries and those from points of sales.
The values of magnesium in all the studied bread samples ranged from 0.60 to 1.20% and 0.03 to 1.20% of breads from bakeries and point of sales respectively. These values were very low compared to the standard values recommended by WHO/FAO (2011) (31mg/kg). The results also revealed that the magnesium contents were less than those of calcium in all the studied bread samples. The fortification of flour contributes 14% of the total calcium intake for adults and almost 20% for children (O'Connor, 2012).
The concentration of sodium recorded in this study ranges from 31.50 to 62 .70% and 61.50 to 75.30% of the bread samples from bakeries and points of sales, respectively. An adult needs about 3g per day of Na but modern dietary habits can take in 5-20g per day (Odedeji et al., 2014).These values fall within the standard values recommended by WHO/FAO The potassium content in this investigation ranged from 45.00 to 60.00% in bread samples from bakeries and 61.50 to 75.30% in samples from other points of sales. This result is in agreement with the findings of Odedeji et al.(2014); Adebayo-Oyetoro et al.(2016) and Eshetu et al.(2018). Tables 3 and 4 presented the vitamins (B2, B6 and B12) contents of the selected bread samples. There was no significant differences (p>0.05) in the vitamin contents among the bread samples from the bakeries and points of sales, and this results are in agreement to the findings of Eke et al.(2014) and also are within the standard specification of (SON, 2004).

3.4.Pollutants or Hazardous materials:
The results of heavy metals and potassium bromate are presented in Tables 5 and 6. The results of the investigation carried out showed that all the bread samples studied were free of potassium bromate.
Cadmium and Lead were not detected in all the bread samples analyzed and this is very commendable. All the bread samples studied have their manganese values within WHO/FAO standard values (1 -3%).

4.CONCLUSION
This study has shown that calcium, potassium, sodium, magnesium and vitamins B2, B6 and B12 were present in the studied bread samples. The study also revealed that there was free potassium bromate in all the studied bread samples. Heavy metals were also determined; Pb and Cd were not detected, which is a very good development. Bakers are therefore advised to fortify their products in order to meet the expected standard. It has been observed that the bread samples studied from the bakeries contained more moisture than the bread obtained from different points of sales. This might be as a result of long time exposure of bread at the points of sales. This study showed that the bread brands sold in Gombi town could be nutritious, free from pollutants and suitable for human consumption.