Electronic Journal of Polish Agricultural Universities (EJPAU) founded by all Polish Agriculture Universities presents original papers and review articles relevant to all aspects of agricultural sciences. It is target for persons working both in science and industry,regulatory agencies or teaching in agricultural sector. Covered by IFIS Publishing (Food Science and Technology Abstracts), ELSEVIER Science - Food Science and Technology Program, CAS USA (Chemical Abstracts), CABI Publishing UK and ALPSP (Association of Learned and Professional Society Publisher - full membership). Presented in the Master List of Thomson ISI.
2005
Volume 8
Issue 3
Topic:
Food Science and Technology
ELECTRONIC
JOURNAL OF
POLISH
AGRICULTURAL
UNIVERSITIES
Abulude F. , Ojo M. 2005. DEVELOPMENT AND CHEMICAL EVALUATION OF “EGBO” FORTIFIED WITH LEGUME SEEDS, EJPAU 8(3), #34.
Available Online: http://www.ejpau.media.pl/volume8/issue3/art-34.html

DEVELOPMENT AND CHEMICAL EVALUATION OF “EGBO” FORTIFIED WITH LEGUME SEEDS

Francis Olawale Abulude, M. A. Ojo
Department of General Studies, Federal College of Agriculture, Akure, Nigeria

 

ABSTRACT

“Egbo” a popular Nigerian food made from maize grits was fortified with Vigna unguiculata L. Walp and Cajnus cajan in ratios 1:1 respectively to developed new “egbo” based recipes. The physico-chemical and functional properties, proximate composition, mineral content and organoleptic test were determined. Results showed that in all cases, the level of protein and mineral increased with the inclusion of the legumes. The values obtained for functional properties showed that “egbo” would be suitable for some food formulations. The fortified “egbo” samples were considered acceptable to panelists but the one with Vigna unguiculata L. Walp was preferred.

Key words: “Egbo”, fortification, Cajanus cajan, Vigna unguiculata L. Walp, chemical evaluation, organoleptic test.

INTRODUCTION

“Egbo” is a local food widely consumed in the South western part of Nigeria. The food is prepared from maize grains. The whole maize grains are dry milled and the hull removed. The dehulled seeds are cooked, eaten alone, served with vegetable or/stew or coconut. This can be eaten anytime of the day.

Food legumes are potential supplier of several important nutrients. They not only add to variety in human and animal diets, but also serve as an economical source of supplementary protein, especially in underdeveloped and developed third world countries [6].

Food specialists in Nigeria have advised that there should be legislation concerning food enrichment so that a particular food can be fortified so as to alleviate vitamin and protein deficiencies in the high-risk groups of the society [16].

The present tendency is the improvement of protein and vitamin status of food taken by the average population. Several workers in Nigeria have carried out many researches on food enrichment [5, 7, 16, 21], but there is no information on protein enrichment of “egbo” with legume seeds. Therefore the aim of this research was to extend knowledge on nutritional quality of “egbo” and the its fortification with legumes. First the development of high protenous “egbo”, chemical composition with reference to the contents of proximate and mineral has been determined, this study dealt with its physico-chemical and functional properties. Finally the organoleptic assessment was determined to assess the acceptability. It is hoped this will add to nutrition data.

MATERIALS AND METHODS

This research work was carried out at the Federal College of Agriculture, Akure, Ondo State Nigeria in May 2004. the materials, Zea mays, Cajanus cajan and Vigna unguiculata L. Walp were purchased at Ojba Oba, in Akure, Ondo State, Nigeria. They were screened to remove stone, dirt und unwanted seeds.

Preparation of “Egbo” samples

One kilogram of Zea mays was ground at local mill to separate the hull and germ fractions. The hulls were removed by winnowing leaving the maize grits. Five hundred grams of the dehylled seeds was cooked in a beakers using Bunsen flame for 80 min. Water (600 cm3) was used until cooked. The raw and half of the cooked (“Egbo”) samples were dried, ground in a Kenwood blender and kept in an air-tight container. The other half of “egbo” was fortified with Vigna unguiculata L. Walp (1:1) and Cajanus cajan (1:1).

Preparation of Vigna unguiculata L. Walp and Cajanus cajan

One kilogram each of the legume samples were weighted and divided into three portions. The first was ground in a Kenwood blender, sieved in a 2 mm wire mesh and kept prior to analysis (Raw). The second portion was cooked using the same methods for “egbo”. Cooking time, Vigna unguiculata L. Walp (80 min) and Cajanus cajan (90 min). the third was cooked and used for the fortifications.

All samples were labeled as follows:

Raw

Cooked

CC1 – Cajanus cajan

CC1C – Cajanus cajan

ZM2 – Zea mays

ZM2C – Zea mays

VU3 – Vigna unguiculata L. Walp

VU3C – Vigna unguiculata L. Walp

CZ4 – Cajanus cajan + Zea mays

CZ4C – Cajanus cajan + Zea mays

ZV5 – Vigna unguiculata + Zea mays

ZV5C – Vigna unguiculata + Zea mays

Proximate analysis

This was carried out AOAC standard methods. Nitrogen was determined micro-kiejdahl method and percentage nitrogen was converted to crude protein by multiplying by the factor of 6.25. Carobohydrates was calculated by difference. Energy values obtained using the Atwater formular [15]. Fat, protein and carbohydrate supplied 9, 4, and 3.75 Kcal/g respectively.

Mineral analysis

Mineral analysis was determined by first dry ashing the samples of 550°C in a muffle furnace and dissolving the ash in standard flask with distilled water containing a few drops of concentrated hydrochloric acid. Phosphorus was determined colorimetrically with spectronic 20 (Gallenkamp) using phosphovanadomolybdate method (AOAC) [17]. Iron was determined by the orthophenanthrone colorimetric method using Corning colorimeter 253. Sodium and potassium were done using flame photometer (Gallenkamp). All other mineral were determined by atomic absorption spectrophotometer.

Physico-chemical and functional properties

Bulk density of the samples was determined using AOAC [17] methods twenty-five gram of flour was weighted into a 100 cm3 graduated cylinder, tapping the cylinder ten times against the palm of the hand and expressing the final volume as g·cm-1. Specific gravity was measured as weight of sample divided by volume. Stirring 10 g sample in 100 cm3 hot deionized water and subjectively noting the ease of dispersion estimated hot water dispersability.

Water absorption capacity (WAC) was determined using the methods of Lin and Humbert [14]. Two gram of sample was mixed in 20 ml of distilled water. The samples was stirred with a magnetic electric stirrer and allowed to stand for 1 h at room temperature (25°C) before centrifuging at 2000 rpm for 25 min excess water decanted by inverting the tubes over filter paper placed in volumetric flask. The sample was allowed to drain dry for 35 min. The weight of water bound was determined by the difference. Least gelation capacity (LGC) was determined using Coffman and Garcia [8] methods. Sample suspencions of 5-14% were prepared in 5 cm3 of water. The LGC was determined and the concentration when the sample from the inverted test did not slip. Foaming capacity (FC) was determined according to the methods of Coffman and Garcia [8]. One gram sample was whipped with 50 cm3 water for 5 min in a Kenwood blinder at speed settings ‘fast’ and was poured into a 100 cm3 graduated cylinder. To obtain the FC, volume increase (%) was calculated according to the equation.

Volume increase =

Cooking time was determined by weighing 100 g of sample in a beaker fitted with condensers to avoid evaporation during boiling. Water was added in the ratio 1:4 (w/v). Sample was stirred at 2 min intervals. After 45 min, one seed was withdrawn without interrupting the boiling. Pressing the seed between finger and thumb tested degree of cooking. If seeds remained ‘uncooked’ one seed was again tested after 5 min. this procedure continued until five seeds were found to be cooked at this time, total cooking time (min) was recorded [6].

Sensory evaluation of “Egbo” samples

The was done by use of a taste panel (9 adults) who had earlier experience in sensory evaluation of other food products. They were requested to evaluate fortified and unfortified “egbo” samples in terms of flavour, texture, colour, taste and overall acceptability on a 9 point hedonic scale (9 = like extremely; 1 = dislike extremely). They were allowed to comment freely on the samples.

RESULTS AND DISSCUSION

The data in Tables 1a and 1b shown the proximate composition of the samples. The mean protein and fat content of the samples ranged from 16.10-24.43% and 8.86-11.08% respectively and energy and ash contents ranged from 372.65 to 468.81% and 2.30-4.40% respectively. The raw samples were therefore high in protein and fat compared with cooked samples. The protein content of the unfortified “egbo” was below 9.21-12.99% but these values increased to 21.58-31.53% when the “egbo” was fortified with equal amount of legume seeds. The values decreased when the samples were subjected to heat when cooked. This might be due to denaturation during cooking. There were marked differences between fortified and unfortified “egbo” samples. Moisture and fibre contents of the samples ranged between 10.58-11.94% and 3.67-4.159 respectively. In general, the lower the moisture contents of a product the longer potential storage time. The moisture levels of the raw and cooked, ay by high for product storage since growth of microorganisms, food spoiling agents may by assisted at such moisture levels. From the results, it was observed that cooked fortified “egbo” had lower moisture contents compared with unfortified. This could be attributed to the lower starch contents of the legume seeds. The mark differences between the fibre contents was also observed. This might be due to the removal of the hull, this in turn made the protein contents higher in the fortified “egbo”. All the results obtained in this work were in close agreement with the values obtained for fortified ‘adun’ [16], fortified ‘amala’ [21] and fortified snacks and weaning foods [7]. Carbohydrate and energy values ranged from 45.75-57.13 and 372.65-468.81 Kcal per 100 g of products with low coefficient of variation (%).

Table 1a. Proximate composition (% DM) of raw samples analyzed

Sample code a

Moisture

ash

protein

fibre

fat

carbohydrate

energy (Kcal)

CC1

9.93

4.63

28.62

4.00

12.12

40.70

386.36

ZM2

10.05

2.77

12.99

5.12

8.32

60.75

821.28

VU3

11.83

5.92

17.50

3.78

13.03

67.94

379.03

CZ4

9.82

3.34

31.53

3.88

11.26

40.17

388.14

ZV5

11.27

3.53

31.53

3.96

10.65

39.06

378.21

Mean

10.58

4.04

24.43

4.15

11.08

45.72

468.81

±Std. dev.

0.90

1.50

8.62

0.55

1.78

9.10

192.06

CV (%)

8.60

30.94

35.28

13.26

16.10

19.90

40.97

a CC1 – Cajanus cajan, ZM2 – Zea mays, VU3 – Vigna unguiculata L. Walp
CZ4-mixture of Cajanus cajan and Zea mays (1:1), ZV5-mixture of Vigna unguiculata L. Walp and Zea mays (1:1).

Table 1b. Proximate composition (%DM) of cooked samples analyzed

Sample code a

Moisture

ash

protein

fibre

fat

carbohydrate

energy (Kcal)

CC1C

11.42

2.38

15.89

3.25

8.21

58.85

372.85

ZM2C*

11.64

1.70

9.21

4.88

7.25

65.32

363.37

VU3C

13.24

3.32

10.21

3.50

10.25

59.48

371.01

CZ4+

10.85

2.00

23.62

3.20

9.36

50.97

383.42

ZV5++

12.55

2.10

21.58

3.52

9.22

51.03

373.42

Mean

11.94

2.30

16.10

3.67

8.86

57.13

372.65

±Std. dev.

1.00

0.06

6.50

0.69

11.54

61.38

6.86

CV (%)

8.00

27.0

40.34

18.84

13.03

10.74

1.84

a – see footnote Table 1a, * – unfortified “egbo”, + – fortified “egbo” (Zea mays + Cajanus cajan), ++ fortified “egbo” (Zea mays + Vigna unguiculata L. Walp).

Elemental analysis of the raw and cooked samples showed substantial difference between the mineral contents of all the samples (Table 2a and 2b) of the two samples, the raw displayed a greater mineral content, which suggested that substantial elements have been volatilized after cooking. Minerals, which appeared to be the least soluble, were Na, Ca and Zn. These were present in the cooked samples of levels at of (mean) 53.4, 33.1 and 1.26 mg × 100 g-1 of the original value found in the raw samples. The cooked samples appeared to be good sources of Mg, K and P and fair sources of Ca and Fe. The recommended dietary allowance (RDA) of K, P, Fe and Mg were 350, 3750, 800 and 100 mg per day respectively [22], a 100 g serving of the “egbo” samples would provide 75.6, 16.0, 34.0 and 44.0% (unfortified) and 88.6-82.9%, 13.9-16.7%, 35.6-9% and 40-45% (fortified) of the adult daily requirement for the minerals. Also the legumes are good sources of Mg, K, P and Fe, providing: Cajanus cajan (CC1C) 55.6, 5.3, 39.0 and 34%, Vigna unguiculata (VU3C) 88.0, 19.1, 25.9 and 41% of RDA intake of these elements per 100 g respectively. The results of the minerals obtained in this report were approximately similar to other quoted values [1, 2, 19].

Table 2a. Mineral composition (mg/100g DM) of raw samples analyzed

Sample code a

Na

Mg

Fe

K

Zn

Ca

P

CC1

62.0

325.0

4.43

220.0

2.10

60.5

325

ZM2

50.0

300.0

5.43

620.0

1.20

10.5

305

VU3

68.0

362.0

4.32

840.0

2.44

58.2

297

CZ4

58.0

328.0

4.44

524.0

2.10

58.2

294

ZV5

60.0

315.0

5.10

680.0

2.40

43.0

305

Mean

59.6

326.0

4.74

576.8

2.07

46.1

305.3

±Std. dev.

6.5

22.9

0.49

230.2

0.51

21.1

12.1

CV (%)

11.0

7.0

10.39

39.9

24.42

45.7

3.99

a see footnote Table 1a.

Table 2b. Mineral composition (mg/100g DM) of cooked samples

Sample code a

Na

Mg

Fe

K

Zn

Ca

P

CC1C

60.0

310.0

3.4

200.0

1.10

42.0

280.0

ZM2C*

39.0

286.0

4.4

605.0

0.92

7.5

278.0

VU3C

58.0

308.0

4.1

715.0

1.84

47.9

207.0

CZ4+

52.0

310.0

4.0

520.0

1.22

35.6

285.0

ZV5++

58.0

290.0

4.5

625.0

1.23

32.6

287.0

Mean

53.4

310.8

4.1

533.0

1.26

33.1

267.0

±Std. dev.

8.59

28.6

0.4

198.0

0.35

15.5

34.0

CV (%)

16.09

9.2

10.6

37.3

27.45

46.8

13.7

a – see footnote Table 1a, *, +, ++ – see footnote Table 1b.

The bulk density of the samples was determined by the puffing properties. The puffing ability or the of expansion affects product density, fragility and crispness. The data in Table 3b shows that all the cooked samples had high specific gravity and bulk density products in the expanded form. This was due to their absorption of water during the time of cooking. The “egbo” prepared from 100% maize was denser that from the fortified maize. This was considered to be due to lower fiber in legumes than maize. Fiber does not expand and merely acts as solid filter, thus affecting the structure of “egbo” by making it more dense and dry [10]. The water absorption capacity (WAC), foaming capacity (FC) and least gelation (LGC) values are shown Table 3a and 3b the WAC mean results were 212 (raw) and 208 (cooked). All these results were significant at P = 0.05. the values obtained for cooked samples were lower that of raw sample. The results compared with values reported by Ige et al. [11] for three varieties of melon, Abulude [1] for cowpea and Abulude [3] for Cola nitida and Cola acuminata, but higher than African yam bean (AYB) [4] and raw and processed taro [9]. The above trends showed that the samples used for this work were more hydrophilic than AYB and taro flours. WAC is considered a critical function of protein in viscous foods like soup, gravies, dough, baked products. Hence, fortified “egbo” may be useful in these food formulations. The LGC values raged between 8 and 10. they were in the range reported in the literatures cited. The cooked fortified “egbo” samples were less viscous than the war samples. This may be due to the water absorbed by them during cooking. Gelation is an index of WAC. This is important for some foods like weaning foods. FC varied between 36-52%. These values were higher than values for variegated grasshoppers (12%) [18]. The FC for all the samples did not shown marked difference (CV 12.9-13.5%). The relatively high FC of the fortified “egbo” may enhance the functionality in their uses for the production of cakes [13].

Table 3a. Physical and functional properties of raw samples (%, DM)

Sample
code a

Bulk density

specific gravity

LGC

WAC

FC

Dispersability (Hot water)

Cooking time

CC1

1.5

1.00

10

210

40

Good

90 min

ZM2

2.0

1.00

10

206

38

Good

65 min

VU3

1.8

0.98

10

225

45

Good

80 min

CZ4

1.8

0.97

10

205

50

Good

90 min

ZV5

1.8

0.99

10

215

52

Good

90 min

Mean

1.8

0.99

10

212

45

-

83 min

±Std. dev.

0.2

0.01

0

8.17

6.1

-

11 min

CV (%)

11.6

1.36

0

8.85

13.5

-

13.2 min

a see footnote Table 1a.

Table 3b. Physical and functional properties of cooked samples analyzed (%, DM)

Sample code a

Bulk density

specific gravity

LGC

WAC

FC

Dispersability (Hot water)

Cooking time

CC1C

1.7

1.10

8.0

208

38

Fair

-

ZM2C*

2.1

1.20

8.0

200

36

Fair

-

VU3C

1.9

1.00

8.0

220

40

Fair

-

CZ4+

2.0

1.00

8.0

200

48

Fair

-

ZV5++

2.0

1.00

8.0

210

47

Fair

-

Mean

1.9

1.1

8.0

20

41.8

-

-

±Std. dev.

0.2

0.1

-

6.8

5.4

-

-

CV (%)

7.8

8.4

-

4.1

12.9

-

-

a – see footnote Table 1a, *, +, ++ – see footnote Table 1b.

Table 4 shows the hedonic rating of taste, colour, texture, flavour and overall acceptability of the fortified and unfortified “egbo” samples. The score for the taste of “egbo” ranged from 6.5 to 7.3. there were no significant differences (P < 0.05) in taste among the samples fortified with Vigna unguiculata L. Walp rated the highest while the one fortified with Cajanus cajan was rated the lowest. Almost the same trend was reported for colour, texture and flavour among the “egbo” samples tested, sample fortified with Vigna unguiculata L. Walp was preferred in overall acceptability among the panelists. The reaseon was considered to be due to its taste, colour and flavour. The other fortified sample was less preferred (P < 0.05). the major complaints were flavour and colour. Taste, colour and flavour hard a prominent effect in sensory scores of the “egbo” samples (Table 5).

Table 4. Organoleptic evaluation of cooked samples analyzed

Sample code

Taste

Colour

Texture

Flavour

Overall acceptability

CC1C

6.5

6.5

6.5

6.8

6.8

ZM2C*

7.0

7.0

6.8

7.0

7.0

VU3C

7.0

6.9

6.8

7.0

6.9

CZ4C+

6.5

6.3

6.5

6.2

6.3

ZV5C++

7.3

7.2

6.8

7.1

7.4

Mean

6.9

6.8

6.7

6.8

6.9

Std dev.

0.4

0.4

0.2

0.4

0.4

CV (%)

5.1

5.5

24.6

5.3

5.8

LSD (0.05)

2.8

2.8

1.6

2.8

2.8

a see footnote Table 1b.

Table 5. P-value of the quality attributes of “egbo” samples

Attributes

P-Value

Error

Colour

0.02**

0.2

Flavour

0.006*

0.3

Taste

0.006*

0.3

Acceptability

0.001***

0.3

Texture

0.001***

0.5

*significant at 10.0% level
** significant at 5.0% level
*** significant at 1.0% level.

CONCLUSIONS

From the analytical results, it was observed that fortification of “egbo” with legumes increased the nutritive values and cooking did not harm the nutritional quality. It was also observed that fortified “egbo” would be very useful in some food formulations. The addition of Vigna unguiculata L. Walp improved the flavour, taxture, taste and colour, but panelists complained about the flavour and colour of the “egbo” fortified with Cajanus cajan.

ACKNOWLEDGEMENTS

The authors are grateful to M. Oladimeji, M. Gabriel and B. Adeyeye of Department of General Studies, Federal College of Agriculture, Akure, Nigeria for providing the technical assistance.

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Francis Olawale Abulude
Department of General Studies,
Federal College of Agriculture, Akure, Nigeria
Akure 340001, Ondo State, Nigeria

M. A. Ojo
Department of General Studies,
Federal College of Agriculture, Akure, Nigeria
Akure 340001, Ondo State, Nigeria

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