Physicochemical properties, vitamins, antioxidant activities and amino acid composition of ginger spiced maize snack ‘kokoro’ enriched with soy flour (a Nigeria based snack)

doi:10.4236/as.2013.45B014

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Vol.4, No.5B, 73-77 (2013) Agricultural Sciences

doi:10.4236/as.2013.45B014

Physicochemical properties, vitamins, antioxidant

activities and amino acid composition of ginger

spiced maize snack ‘kokoro’ enriched with soy

flour (a Nigeria based snack)

Fasasi Olufunmilayo Sade*, Alokun Omot ayo Aderonke

Department of Food science and Technology, Federal University of Technology, Akure, Nigeria; *Corresponding Author:

sadefunmi71@gmail.com

Received 2013

ABSTRACT

Blends of white maize, ginger po wder (white and

yellow) and soy flour were prepared at the fol-

lowing ratio of white maize 97%: yellow ginger

3% (WM /YG); white maize 97%: white ginger 3%

(WM/WG); white maize 87%: soy bean 10%: yel-

low ginger 3% (WM/S/YG); white maize 87%: soy

bean 10%: white ginger 3% (WM/S/WG), white

maize 90%: soybean 10% (WM/S), white maize

100% (WM) control. As result revealed protein

content, energy value, ash contents of ginger

spiced ‘kokoro’ improved significantly with the

addition of ginger spice and or soy flour com-

pared with the control. The mineral composition

of ginger spiced ‘kokoro’, increased signifi-

cantly at p < 0.05 especially with WM/S. Addition

of ginger and or soy improves the vitamin A and

C content of ginger spiced ‘kokoro’, WM/S/YG

had the highest vitamin A. while WM/S/WG had

the highest Vitamin C content as compared with

the control (WM). Result revealed that WM/S/YG

displayed the highest DPPH radical scavenging

actives. Significant (p < 0.05) improvement was

observed in the amino acid content of the ginger

spiced ‘kokoro’. The addition of ginger powder

and or soy flour decreases the load at break (N),

compressed Extension at Break (mm), and the

energy at break (J) of th e ginger spic ed ‘kokoro’.

Keywords: Maize; Ginger Powder; Soy Flour;

Snacks

1. INTRODUCTION

Snacks are becoming popular most especially in the

urban cities due to the fact that most people now work

far away from their homes. The annual production of

maize in Nigeria is about 5.6 million tones [1]. It is pre-

pared and consumed in a multitude of ways which vary

from region to region or from one ethnic group to the

other. They are also used for the production of different

convenience snack foods which are eaten to prevent

hunger before the main meals or just (as relish) for the

fun of eating them. Maize are deficient in sulphur amino

acids such as lysine hence the need to compliment maize

with legumes such as groundnuts and soybeans which

are better sources of the sulphur amino acids [2];

Ameida-Dominguez et al,[3] reported an improved bal-

ance of amino acids in the products made from such

combination. Omueti and Morton [4] reported that snack

does not provide nutrients in adequate quantities needed

by the body, which is due to their composition or due to

the production process. Whatever might have been re-

sponsible for their poor nutritional content, it is neces-

sary to ensure that food consumed as main meal or snack

contain required nutrients in adequate amounts, this is

important because many people now work outside their

homes due to urbanization and are becoming more de-

pendent on snacks for the supply of part of their daily

nutritional requirements. It is therefore necessary to pro-

duce a highly acceptable snack with high nutritional

quality that could be useful in nutritional programmes to

combat malnutrition and nutrient deficiencies [5]. Ginger

(Zingiber officinale) is a spice believed to be indigenous

to South East Asia, from where it has spread to other

tropical regions of the world [6]. Other major producers

include India, Nigeria, Sierra Leone, Jamaica, China and

Haiti [7]. The extracts of ginger have multiple pharma-

cological effects, cardiotonic effects, gastro-intestinal

actions thermogenic, and antibiotic activities they are

also important as digestive stimulants [8]; Ginger is used

in food, beverages and confectionary [9]. Kokoro’ is a

popular local snack in South Western Nigeria made from

maize flour. It is widely accepted in Southwestern Nige-

F. O. Sade, A. O. Aderonke / Agricultural Sciences 4 (2013) 73-77

ria; it is inexpensive compared to other snacks because of

its relatively low cost of production. It is widely accepted

among children and adults as a product that is consumed

on such a wide scale; it could be a convenient vehicle for

the desired nutritional and antioxidant properties. The

study aims at investigating the physicochemical proper-

ties, amino acid composition and antioxidant properties

of ‘kokoro’ substituted with soy flour and ginger spice.

2. MATERIALS AND METHODS

2.1. Materials

Maize, ginger (white and yellow Zingiber officinale);

soybean (Glycine max); refined vegetable oil; onions and

salt used in this study were purchased, from a local mar-

ket in, Akure, Nigeria.

All chemical used were of analytical grades.

2.2. Methods

Production of Soybean flou r

Soybeans flour was produced using the method de-

scribed by [10], with little modification. Soy bean were

sorted cleaned manually. The clean seeds were soaked in

water for 2hrs and boiled in water at (100 ± 2)℃ for 20

mins. The blanched soybeans were dehulled manually and

drained. The decorticated seeds were oven (Model

DHG-9101.I SA) dried at (60 ± 5)℃ for 8 hrs. The

dried cotyledons were dry milled using an attrition mill.

Flour obtained was sieved using sieve of 150 µm.

Processing of ginger powder

Ginger roots used were cleaned, peeled, cut, wash and

dried at (60 ± 2) ℃ for 10 hrs in an oven (Model DHG-

9101.ISA). Dried ginger was milled and sieved using

150µm to obtain a powdery form.

Production of Ginger Spiced ‘Kokor’

A preliminary study on the traditional production of

‘kokoro’ was carried out in Imasayi Yewa South Local

government area of Ogun-State where ‘kokoro’ produc-

tion is their major source of income. The traditional

method of ‘kokoro’ production was used with a slight

modification. The maize grains were manually cleaned

and were cooked (boiled) till soft and dewatered. The

cooked grains were cooled over night and wet milled. 40

g of milled onions (the onions were peeled, cut and wet

milled) were added immediately after milling. 2 g of salt

was added to the dough (common salt was added to the

control ‘kokoro’ while rock salt was added to the re-

maining dough). Dough was gently mixed into a stainless

steel pot, depending on the ratios. Soybean flour and

ginger were added as appropriate the mixture was con-

tinuously mixed until stiff dough is formed. The mixed

dough was kneaded, rolled for 5 min on a chopping

board; cut out into pieces and rolled into ring shape on a

chopping board; the rings were deep fried in hot vegeta-

ble oil at (150 ± 2)℃ for 10min. It was kept overnight to

cool and fried again the next day at (150 ± 2)℃ for 3

min till a white crispy color was obtained. It was cooled

and packed into a sealed polyethylene bags and kept at 4

℃ before use.

The formulations were prepared using the following

blend ratio.

Proximate composition of the ‘kokoro’ was deter-

mined as described by AOAC [11]. Carbohydrate was

calculated by difference. Energy was calculated using

Atwater factor. The Calcium, Sodium, Magnesium and

Potassium contents were determined by flame photome-

try [11]. The concentration of Iron was determined after

wet digestion with a mixture of perchloric and nitric acid

using Atomic Absorption Spectrophotometry (AAS, Model

SP9, pye Unicam, UK). Phosphorus was estimated col-

orimetrically by ammonium molybdate method. Vitamin

A (β – carotene) was determined using acetone – petro-

leum ether (40 - 60℃) in the ratio 1 : 3 as a solvent as

described by [11]. Ascorbic acid (Vitamin C) was deter-

mined by titration against 2, 6 – dichlorophenol indo-

phenols as described by [12]. Determination of the amino

acid profile consists of two steps: Hydrolysis of the pro-

tein to constituent’s amino acids and the quantitative

estimation of the amino acids in the hydrolysate,

using the Technicon Sequential Analyzer Union Carbide

Corp., New York, N.Y. (TSM). The DPPH radical scav-

enging activity of the samples was determined according

to the method of Mensor et al. [13]. The breaking strength

(load at break), hardness (energy at break) and toughness

(extension at break) of the ‘kokoro’ was measured using

Universal Testing Machine (model M500-50KN, Tes-

tometric, England) according to the method described by

[14].

2.3. Statistical Analysis

All determinations were performed in triplicate and

the results are expressed as means values ± standard de-

viations (SD). The data were subjected to statistical analysis

using statistical program package STATISTICA. The

one-way analysis of variance (ANOVA) followed by

Duncan multiple range test were employed and the dif-

ferences between individual means were deemed to be

significant at P < 0.05.

3. RESULTS AND DISCUSSION

The proximate composition (dry matter basis) of gin-

ger spiced ‘kokoro’ is shown in Table 1 Moisture content

(%) of ginger spiced ‘kokoro’ varied significantly, values

fell within the recommended moisture content of snack

pellets 10 and 14% [15]. Low moisture content is desir-

able in such snacks, as high moisture content could result

in crispiness of the snack, and accelerate other biochemi-

F. O. Sade, A. O. Aderonke / Agricultural Sciences 4 (2013) 73-77

cal changes such as oxidative rancidity. Addition of gin-

ger and or soy flour resulted in significant increase in-

crease in the crude fiber, crude fat and protein content of

‘kokoro’. The increase in the fat content might be attrib-

uted for the fact that soy flour is rich in oil. Values ob-

tained for the protein content were fairly comparable to

the recommended protein level of 18% - 20% [16]. Addi-

tion of soy resulted in significant increase in the calcu-

lated energy content of ‘kokoro’ this might be attributed

to the oil in the snack which is a good source of energy.

As indicated in Tab le 2 , Addition of soy and or ginger

powder resulted in significant increase in the Ca, Mg, P,

Na and K, of ‘kokoro’ The Na/K ratio in the body is im-

portant because it helps in controlling high blood pres-

sure Na/K ratio values compares favourably with the

recommended value of less than one [17]. Nieman et al.,

[18] considered a food source good if the Ca/P ratio is

above 1 and poor if the ratio is less than 0.5. The maize

snack ‘kokoro’ happen to be good food source (Ca/P ra-

tio ranged from 0.5 -1.5) for minerals used in bone for-

mation. The presence of soy flour and ginger increased

the vitamin C and A contents of ginger spiced ‘kokoro’ in

comparison with the control (Figures 1 and 2). The

Table 1. Proximate composition of ‘kokoro’ substituted with soy flour and ginger spice (% dry matter basis).

SAMPLES MOISTURE

(%) ASH

(%) CRUDE FAT

(%) CRUDE

FIBRE (%)CRUDE

PROTEIN (%)CARBOHYDRATE

(%) CALCULATED ENERGY

VALUE (KJ/g)

WM 10.71 ± 0.01d 1.88 ± 0.00d 20.92 ± 0.01f1.04 ± 0.00f8.32 ± 0.00 f 57.13 ± 0.00a 1887 ± 0.00 d

WM/WG 12.19 ± 0.01b 1.74 ± 0.01e 27.01 ± 0.01d1.09e ± 0.00 10.05 ± 0.00e 47.92 ± 0.02c 1985 ± 0.33bc

WM/YG 11.04 ± 0.01c 2.14 ± 0.01b 23.05 ± 0.01e1.15 ± 0.01d10.96 ± 0.01d 51.65 ± 0.03b 1917 ± 0.33d

WM/S/WG 10.15 ± 0.01e 1.94 ± 0.01c 29.98 ± 0.01b1.23 ±0.01b 13.11 ± 0.03c 43.59 ± 0.04d 2000 ± 73.17bc

WM/S/YG 12.47 ± 0.01a 2.19 ± 0.00a 29.86 ± 0.01c1.25 ± 0.01a13.60 ± 0.00b 40.63 ± 0.02e 2027 ± 0.00 b

WM/S 9.25 ± 0.01f 1.36 ± 0.01f 31.72 ± 0.03a1.21 ± 0.00c15.91 ± 0.01a 40.54 ± 0.04e 2135 ± 0.88a

Values represent means of triplicates. Values in a column with same superscript are not significantly different at p ≤ 0.05. NOTE: WM = White Maize; WM/WG

= White Maize: White Ginger; WM/YG = White Maize: Yellow Ginger; WM/S/WG = White Maize: Soy bean: Yellow Ginger; WM/S/YG = White Maize: Soy

bean: Yellow Ginger; WM/S = White Maize: Soy bean.

Table 2. Mineral composition of ginger spiced ‘kokoro’.

Samples Ca

(mg/100 g) Mg

(mg/100 g) P

(mg/100 g) Na

(mg/100 g K

(mg/100 g) Na/K Ca/p

WM 352 191 272 293 380 0.8 1.3

WM/WG 410 205 277 298 605 0.5 1.5

WM/YG 438 297 318 345 412 0.8 1.4

WM/S/WG 309 299 625 1517 1882 0.8 0.5

WM/S/YG 492 394 811 1610 1904 0.8 0.6

WM/S 488 366 713 1500 1978 0.8 0.7

Values represent means of triplicates. KEYS: WM = White Maize; WM/WG = White Maize: White Ginger; WM/YG = White Maize: Yellow Ginger;

WM/S/WG = White Maize: Soy bean: Yellow Ginger; WM/S/YG = White Maize: Soy bean: Yellow Ginger; WM/S = White Maize: Soy bean.

Figure 1. Vitamin C content of Ginger spiced ‘kokoro’. Figure 2. Vitamin A content of Ginger spiced ‘kokoro’.

Openly accessible at

F. O. Sade, A. O. Aderonke / Agricultural Sciences 4 (2013) 73-77

presence of white ginger increases vitamin C signifi-

cantly while the presence of yellow ginger increases the

vitamin A content. Vitamin C provides a protective func-

tion against free radicals. Average daily intake level that

is sufficient to meet the nutritional requirement of ascor-

bic acid or recommended dietary allowances (RDA) for

adults (> 19 yr) are 90 mg/day for men and 75 mg/day

for women [19]. Ginger spiced ‘kokoro therefore could

not be referred to as a good source of vitamin C. The

presence of yellow ginger increases the vitamin A con-

tent of ginger spiced ‘kokoro. The obtained results on the

DPPH radical scavenging activities of ginger spiced

‘kokoro’ are shown in Figure 3. The extract of ginger

spiced ‘kokoro showed a significant effect in inhibiting

DPPH. Increase of 11% had been observed in DPPH

scavenging activities of WM/S/YG, when compared with

WM. The antioxidant activity of plant extracts containing

polyphenol components is due to their capacity to be

donors of hydrogen atoms or electrons and to capture the

free radicals.

DPPH analysis is one of the tests used to prove the

ability of the components of the ginger spiced ‘kokoro’

extract to act as donors of hydrogen atoms and to capture

free radicals.

The amino acid composition of ginger spiced ‘Kokoro

is shown on Table 3.

Leucine is the most predominant essential amino acid

in the ginger spiced ‘kokoro’. These observation are in

agreement with the observations made earlier by Aremu

et al., [20] and Olaofe, et al., [21], suggesting Leucine as

the most concentrated essential amino acid in Nigerian

plant foods. Glutamic is the most concentrated non –

essential amino acid. Total essential amino acid in the

ginger spiced ‘kokoro’ ranged from 18.40 to 29.57

g/100 g protein; the highest was observed in WM/S/YG.

This implies that yellow ginger (YG) has higher total

essential amino acid than the white ginger (WG). The

nutritive value of a protein depends primarily on the ca-

pacity to

Figure 3. DPPH radical scavenging activities of ginger spiced

‘Kokoro’.

satisfy the needs for nitrogen and essential amino acids

[21]. TSAA for the ginger spiced ‘kokoro’ is higher than

the 5.8 g/100 g crude protein recommended for infants

[22], which makes ginger spiced ‘kokoro’ an ideal snack

for infants.

The textural profile of ginger spiced ‘kokoro’ is shown

in Table 4. Texture is a very important quality character-

istic which makes a significant contribution to the overall

quality acceptance of food products.

Table 3. Amino acid composition of Ginger spiced ‘kokoro’.

Amino acid WM/S/WG

(g/100 g

protein)

WM/S/YG

(g/100 g

protein)

WM/S

(g/100 g

protein)

Tyrosine 2.86 3.02 3.02

Methionine 0.68 0.89 1.12

Threonine 2.48 2.71 3.04

Valine 2.86 3.29 3.41

Phenylalanine 3.23 4.02 3.93

Isoleucine 2.06 2.95 2.89

Leucine 7.15 8.60 9.15

Lysine 3.13 3.16 3.24

Cystine 0.79 0.93 0.99

Tryp ND ND ND

Total Ess. AA 25.24 29.57 18.40

Histidine 1.89 2.21 2.30

Arginne 3.54 3.88 3.97

Aspartic Acid 5.12 6.11 6.14

Serine 2.20 2.79 2.82

Glutamic Acid 6.59 7.50 8.18

Proline 2.85 3.36 3.36

Glycine 2.79 2.91 3.15

Alanine 3.00 3.19 3.38

Isoleucine 2.06 2.95 2.89

Total Non Ess. AA 30.04 34.9 36.19

Total (TEAA + TNEAA)55.28 64.47 54.59

TEAA/TNAA% 0.84 0.85 0.51

TEAA/TAA % 0.46 0.46 0.34

TSAA (Meth +Cys) 1.47 1.82 2.11

Ar EAA (Phe + Tyr) 6.09 7.04 6.95

Table 4. Textural profile of ginger spiced ‘kokoro’.

Samples Load at

Break (N)Compressed Extension

at Break (mm ) Energy at

break (J)

WM 8.11 5.12 0.04

WM/S/WG 2.60 3.0 0.01

WM/S/YG 5.09 2.8 0.01

WM/S 3.60 4.7 0.03

F. O. Sade, A. O. Aderonke / Agricultural Sciences 4 (2013) 73-77

[9] Rodriquez, D.W. (1991) A Short economics history of

ginger commodity, Bulletin No. 4, Agricultural planning

unit, Ministry of Agriculture and Fisheries, Jamaica.

It was one of the three main acceptability factors used

by consumers to evaluate food, the other two being ap-

pearance and flavor [23]. The load at break (N) is the

maximum or peak compressive force experienced by the

food sample during a compression test. The values ob-

tained, for load at break (N), Compressed Extension at

Break (mm), and the energy at break (J) decreases with

the addition of soy and or ginger powder. The implica-

tion of this observation is that a lower force, lower en-

ergy would be required to break the ginger spiced

‘kokoro’. The fragilility of the ginger – spiced ‘kokoro’

will be a desirable textural quality.

[10] Ibanga, U.I. and Oladele, A.K. (2008) Production and

determination of the proximate composition and con-

sumer acceptability of an enriched dumpling (masovita)

made of maize, soybeans and cassava. Journal of Applied

Biosciences, 6, 180-183.

[11] AOAC. (2000). Official Methods of Analysis. 17th Edn.,

Association of Official Analytical Chemists, Washington,

DC.

[12] Robinson, W.B. and Stotz, E. (1945) The indeophenolxy-

lene extraction method for ascorbic acid and modifica-

tions for interfering substances. The Journal of Biological

Chemisty, 160, 217-225.

The research had successfully provided infornation on

the nutritional and textural properties of ginger spiced

maize snack ‘kokoro. [13] Mensor, L.L., Menezes, F.S., Leitao, G.G., Reis, A.S., dos

Santos, T.C., Coube, C.S. and Leitao, S.G. (2001)

Screening of brazilian plant extracts for antioxidant activ-

ity by the use of DPPH free radical method. Phytotherapy

Research, 15, 127-130. doi:10.1002/ptr.687

4. ACKNOWLEDGEMENTS

This study was funded under the auspices of STEP B., Centre For

Excellence in Food Security Research grant of the Federal University

of Technology, Akure, Nigeria.

[14] Bajaj, S. (2004) Antioxidative properties of mint (Mentha

spicata L.) and its application in biscuits. MScdissertation,

University of Mysore (2004).

[15] Guzman, A.Q. (2012) GMPs in the snack food industry in

Latin America. Food Safety Magazine. April/ May.

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