# Evaluating the Effects of Fermentation, Sprouting and Roasting on the Chemical Composition of Local Raw Materials for Complementary Food Formulation

Perpetua Nwamalubia Izuakor, Patrice-Anthony Chudi Okoye, Uche Eunice

Ekpunobi, Kenneth Chukwugozie Nnaebue

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Perpetua Nwamalubia Izuakor, Patrice-Anthony Chudi Okoye, Uche Eunice Ekpunobi, Kenneth Chukwugozie Nnaebue. Evaluating the Effects of Fermentation, Sprouting and Roasting on the Chemical Composition of Local Raw Materials for Complementary Food Formulation. International Research Journal of Pure and Applied Chemistry, 2024, 25, pp.69 - 77. 10.9734/irjpac/2024/v25i6885. hal-05032564

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# Evaluating the Effects of Fermentation, Sprouting and Roasting on the Chemical Composition of Local Raw Materials for Complementary Food Formulation

Perpetua Nwamalubia Izuakor a*,
Patrice-Anthony Chudi Okoye a, Uche Eunice Ekpunobi a
and Kenneth Chukwugozie Nnaebue b

## Authors' contributions

This work was carried out in collaboration among all authors. Author PACO designed the study. Author UEE wrote the protocol. Author PNI wrote the first draft of the manuscript, managed the analyses and did literature searches. Author KCN performed the statistical analysis. All authors read and approved the final manuscript.

## Article Information

DOI: https://doi.org/10.9734/irjpac/2024/v25i6885

**Open Peer Review History:**
This journal follows the Advanced Open Peer Review policy. Identity of the Reviewers, Editor(s) and additional Reviewers, peer review comments, different versions of the manuscript, comments of the editors, etc are available here: https://www.sdiarticle5.com/review-history/126106

**Original Research Article**

Received: 18/09/2024

Accepted: 22/11/2024

Published: 28/11/2024

<footnote>a Department of Pure and Industrial Chemistry, Faculty of Physical Sciences, Nnamdi Azikiwe University Awka, Anambra State, Nigeria.</footnote>

<footnote>b Department of Applied Microbiology, Faculty of Biosciences, Nnamdi Azikiwe University Awka, Anambra State, Nigeria.</footnote>

<footnote>*Corresponding author: E-mail: pn.izuakor@unizik.edu.ng;</footnote>
ABSTRACT

This study evaluates the effects of processing techniques (fermentation, sprouting, and toasting) on the chemical composition of local raw materials (yellow maize, sorghum, millet, and soybeans) for complementary food formulation. The raw materials underwent fermentation, sprouting, and toasting processes before analysis. Both processed and unprocessed samples were assessed for their proximate, mineral, and vitamin composition using standardized analytical methods. Fermentation, sprouting, and toasting significantly (p<0.05) enhanced protein and mineral content while reducing carbohydrates. For instance, crude protein in millet increased from 7.90% to 8.23%, and iron in yellow maize rose from 15.76 mg/100g to 19.43 mg/100g post-processing. The samples showed nearly double their vitamin C content post-processing. Yellow maize increased from 7.50 mg/100g to 13.41 mg/100g. These results demonstrate that processing methods can significantly (p<0.05) enhance the nutritional profile of local raw materials, making them suitable for cost-effective, nutrient-dense complementary food formulations.

Keywords: Local raw materials; fermentation; sprouting; bioavailability; nutritional composition.

1. INTRODUCTION

Adequate nutrition during infancy and early
childhood is fundamental for a child's cognitive,
emotional, and overall development. Adequate
nourishment forms the basis for intellectual,
social, and emotional skills, as these develop
rapidly in the first few years of life. The World
Health Organization (2023) recommends
exclusive breastfeeding for the first six months,
followed by complementary foods alongside
breastfeeding up to two years or more.
Complementary feeding, introduced during the
critical window of 6-24 months of age, bridges
the nutritional gap between breast milk and the
dietary needs of a growing child (World Health
Organization, 2023). The nutritional status of
infants plays a fundamental role in their overall
health, growth, and development, making the
quality of complementary foods essential for the
cognitive and physical development of children
aged 1-3 years. Complementary foods should be
nutrient-dense, particularly rich in micronutrients
such as zinc, iodine, and vitamins, necessary for
a child's development (Dutta and Das, 2020). In
developing countries like Nigeria, infants face
high risks of illness and mortality during their
early years, especially after six months.
Commercial complementary foods are often
expensive or inaccessible, particularly in rural
areas. Formulating nutrient-dense
complementary foods from locally available and
culturally accepted raw materials is essential for
addressing malnutrition, boosting sustainable
agriculture, promoting food security, and
strengthening the local economy. Thus, there is a
need to explore affordable, locally sourced, and
nutritious alternatives to imported foods. Yellow
maize, sorghum, millet, and soybeans are
available, cheap, and accepted staples in

Nigeria. Maize and millet are rich sources of
carbohydrates and energy, while sorghum
contributes essential micronutrients, particularly
iron and zinc (Adebiyi et al., 2017). Legumes like
soybeans provide high-quality protein and
essential fatty acids for brain health. Processing
techniques like fermentation, sprouting, and
toasting are effective ways to improve nutritional
value and nutrient bioavailability of these
materials while reducing anti-nutritional
components. Research showed that fermenting
cereal grains for complementary foods, which
involves washing, sieving, and decanting,
changes their chemical composition and
nutritional value (Oyegoke et al., 2020, Tripathi et
al., 2021). Fermentation is a traditional food
processing technique that enhances nutrient
content and bioavailability through microbial
activity. It increases vitamin levels, particularly B-
complex vitamins and vitamin C, while degrading
anti-nutritional factors such as phytates and
tannins (Chaves et al., 2014). Likewise, sprouting
triggers the activation of natural enzymes in
grains and legumes, breaking down complex
compounds, enhancing the availability of
nutrients, improving protein digestibility, vitamin
levels, and mineral absorption. Toasting
enhances the taste and aroma of foods while
reducing enzyme inhibitors and microbial
contamination. Combining these processes could
create complementary foods that are nutritionally
dense, appealing, and safe for infants and young
children. However, the impact of such methods
on nutrients, particularly vitamins and minerals in
these raw materials that will be sourced from the
market needs further evaluation. The aim of this
research is to evaluate the chemical composition
of yellow maize, sorghum, millet, and soybeans
for complementary food formulation, focusing on
the effects of fermentation, sprouting, and
toasting. These insights will help create
affordable, nutritious, and culturally suitable
complementary foods to fight childhood
malnutrition in places like Nigeria.

**2. MATERIALS AND METHODS**

**2.1 Sources of Material**

The yellow maize, sorghum, millet, and soybeans
were acquired from the grain seed market
located in Onitsha, Anambra State. The
chemicals and reagents utilized in the study were
of analytical grade and procured from reputable
scientific chemical suppliers at Bridgehead
Market in Onitsha, Anambra State.

**2.2 Preparation of Samples**

**2.2.1 Preparation of untreated (UT) yellow maize, millet, sorghum, and soybeans**

Yellow maize, millet, sorghum and soybeans
were separately sorted, and any bad seeds were
removed. They were separately washed twice,
sprayed on metal trays and oven dried at 65°C
for 6 hours. They were ground into flour using an
electric milling machine and stored in airtight
containers before analysis.

**2.2.2 Preparation of fermented and sprouted (FS) yellow maize, millet, sorghum, and fermented, sprouted and toasted (FST) soybeans**

Yellow maize, millet, sorghum grains, and
soybean seeds were separately cleaned. The
grains and seeds were separately soaked for 24
hours at room temperature. The fermented
grains were drained, washed, poured into a
colander, and covered with a muslin cloth. The
colander was kept at room temperature. The
grains and seeds were rinsed under running
water every 12 hours for 3 days for the grains
and seeds to sprout. On the fourth day, they
were rinsed, sprayed on a metal tray, and dried
in an oven at 65°C for 12 hours. They were
ground into flour using an electric milling
machine and stored in airtight containers before
analysis. The soybeans after oven drying were
toasted at 175°C for 10 minutes, cracked and the
seed coat removed before grinding. It was stored
in an airtight container before analysis.

**2.3 Analysis**

**2.3.1 Proximate Analysis**

The crude fiber, crude fat, crude protein,
moisture, ash, carbohydrate, and energy

contents were determined by AOAC standard
methods as described by Tittikpina et al. (2021).

**2.3.2 Vitamin Analysis**

**2.3.2.1 Determination of Vitamin A**

The method described by Kesuma et al. (2020),
was modified. One gram of each sample was
mixed with 1.0 cm³ of saponification mixture (12
g potassium hydroxide dissolved in 88 cm³
ethanol) and refluxed for 20 minutes at 60°C in
the dark to avoid light interference. The
saponified mixtures were poured into boiling
tubes. The tubes were cooled, 20 cm³ of water
was added and mixed well. Vitamin A was
extracted twice with 10 cm³ of 40°C petroleum
ether. The samples were cooled and washed
thoroughly with water. Anhydrous sodium
sulphate was added to remove excess moisture.
An aliquot of the sample (1.0 cm³) was taken and
evaporated to dryness at 60°C. The residue was
dissolved in 1.0 cm³ chloroform. Standards
(vitamin A palmitate) of concentrations ranging
from 0 - 7.5 mg were pipetted into a series of test
tubes. The volume in all the tubes was made up
to 1.0 cm³ with chloroform. Tricarboxylic acid
(TCA) reagent (2.0 cm³) was added rapidly,
mixed and the absorbance was read immediately
at 620 nm in a spectrophotometer (Genesys
10UV). The same procedure was repeated
for the sample tubes. Vitamin A content
was obtained in mg/kg and converted to
µg/100g.

**2.3.2.2 Determination of Vitamin E**

Vitamin E was estimated according to the
method described by Kesuma et al. (2020) with
little modification. Two and a half grams of each
sample was homogenized in 50 cm³ of 0.1M
sulphuric acid and allowed to stand overnight.
The flask contents were shaken vigorously and
filtered through the Whatman No.1 filter paper.
Aliquots of the filtrate were used for the
estimation. The sample filtrate (1.5 cm³), 1.5 cm³
of the standard, and 1.5 cm³ of water were
pipetted separately into 3 stoppered centrifuge
tubes. Ethanol (1.5 cm³) and 1.5 cm³ of xylene
were added to all the test tubes, mixed well, and
centrifuged. Xylene layer (1.0 cm³) was
transferred into another stoppered tube. Dipyridyl
reagent (1.0 cm³) was added to each tube. The
mixture (1.5 cm³) was pipetted into a cuvette and
the extinction was read at 460 nm. Vitamin D
content was obtained in µg/kg and converted to
µg/100g.
### 2.3.2.3 Determination of Vitamin C

The spectrophotometric method described by Shara et al. (2019), was used to analyse vitamin C with little modification. Ascorbate was extracted from 1.0 g of the sample using 4% TCA and the volume was made up to 10 cm³ with the same TCA. The supernatant obtained after centrifuging at 2000 rpm for 10 minutes was treated with a pinch of activated charcoal, shaken vigorously using a cyclomixer, and kept for 5 minutes. The charcoal particles were removed by centrifugation and aliquots were used for the estimation. Standard ascorbate ranging between 0.2 – 1.0 cm³ and 0.5 cm³ and 1.0 cm³ of the supernatant were taken in a test tube. The volume was made up to 2.0 cm³ with 4 % TCA. Dinitrophenyl hydrazine (DNPH) reagent (0.5 cm³) was added to all the tubes, followed by 2 drops of 10% thiourea solution. The contents in the tubes were mixed and incubated at 37°C for 3 hours. The result was the formation of osazane crystals. The crystals were dissolved in 2.5 cm³ of 85% sulphuric acid. To the blank alone, DNPH reagent and thiourea were added after the addition of sulphuric acid. The tubes were cooled in ice and the absorbance was read at 540 nm in a spectrophotometer. A standard graph was constructed using an electronic calculator set to the linear regression mode. The concentration of ascorbate in the samples was calculated using the formula (Y = mx + c) where Y= absorbance, x = concentration, m = 0.0135 and c = 0.0062. It was obtained in mg/kg and converted to mg/100g

### 2.3.2.4 Determination of Vitamins B1 and B2 (Thiamine and Riboflavin)

One gram of each sample was weighed into a conical flask and dissolved with 100 cm³ of deionized water. This was shaken thoroughly heated for 5 minutes and allowed to cool and filtered. The filtrate was poured into a cuvette and the respective wavelength for the vitamins (vitamin B₁ = 261nm and vitamin B₂ = 242nm) was set to read the absorbance using a spectrophotometer.

$$ \text{Concentration (mg \%)} = \frac{A \times D \times F \times \text{volume of cuvette}}{E} $$

where A = absorbance, E = extinction coefficient = 25 for B₁ and B₂, D.F = dilution factor.

### 2.3.2.5 Determination of vitamin B3 (Niacin)

Five grams of each sample was dissolved in 20 cm³ of anhydrous glacial acetic acid and warmed slightly. Acetic anhydride (5 cm³) was added and

mixed. Two drops of crystal violet solution were added as an indicator. The mixture was titrated with 0.1M perchloric acid to a greenish blue colour.

$$ \text{Vitamin B}_3 = \frac{\text{titre value} \times 0.0122}{0.1} $$

### 2.3.2.6 Determination of Vitamin B6 (Pyridoxine)

Five grams of each sample was dissolved in a mixture of 5 cm³ of anhydrous glacial acetic acid and 6 cm³ of 0.1M mercury II acetate solution. Two drops of crystal violet solution were added as an indicator. The mixture was titrated with 0.1M perchloric acid to a green colour endpoint. Calculation: each cm³ of 0.1M perchloric acid is equivalent to 0.02056g of C₈H₁₁NO₃HCL

### 2.3.2.7 Determination of Vitamin B12 (Cobalamin)

An equivalent of 0.1 g of each sample was weighed and taken into the separator. Water (5 cm³) was added, mixed well, and extracted with 5 cm³ chloroform. The water layer was discarded, and the chloroform layer was taken in a dry 50 cm³ volumetric flask after passing through anhydrous sodium sulphate. It was made up to 50 cm³ with chloroform. The extracted sample (2 cm³) and blank solution were taken into a test tube. In each test tube, 2 cm³ of 0.2 % solution of phenylhydrazine (in hydrochloric acid and alcohol in the ratio of 1:5 v/v) was added and mixed well. After that, it was heated in a water bath to almost dry and cooled at room temperature. A 2 cm³ solution mixture (ammonia and alcohol in a ratio of 1:1) was added to each test tube followed by 1 cm³ pyridine. Its absorbance was recorded at 635 nm against blank. Standard cobalamin was also analyzed and treated the same as the samples. The calibration curve was plotted, and the concentration of the samples was extrapolated.

### 2.3.2.8 Determination of Vitamin D

Vitamin D was assayed according to the method of Vinhas et al. (2017), with little modification. Vitamin D working standard (25 mg) was weighed and put into a 25 cm³ volumetric flask. It was dissolved with a solution mixture (chloroform and methanol in a ratio of 1:9), diluted with the same solution mixture, and made up to the mark. It was thoroughly mixed. An equivalent 0.1 g sample was weighed into a 25 cm³ volumetric flask. It was dissolved with a solution mixture (chloroform and methanol in a ratio of 1:9), diluted with the same solution
mixture, and made up to the mark. It was mixed thoroughly, 1.6 cm³ of 0.25 M HCl, 0.5 cm³ of 15.0 % trichloroacetic acid, and 0.5 cm³ of 0.375% thiobarbituric acid (TBA) were added. Its absorbance was recorded at 464 nm against blank.

## 2.4 Mineral Analysis

The mineral analysis was conducted using Varian AA240 Atomic Absorption Spectrophotometer according to the method of Yitayal et al., (2017). The samples were weighed into porcelain crucibles and heated at 400°C for 4 hours in a muffle furnace. After 4 hours, they were removed and cooled in a desiccator. After that, 0.5 cm³ of 1M trixonitrate (V) acid (HNO₃) solution was added to the left-over ash and evaporated to dryness on a hot plate. They were returned to the furnace for heating again at 400°C for 20 minutes until perfect grayish-white ash was obtained. The samples were allowed to cool in a desiccator for 20 minutes. The ash was dissolved with 15 cm³ of hydrochloric acid in a 100 cm³ volumetric flask. The volume was made up to the mark with distilled water. The solution was filtered into a 100 cm³ volumetric flask and the volume was made to 100 cm³ with distilled water. A series of standard metal solutions in the optimum concentration range were prepared. The reference solutions were prepared daily by diluting the single stock element solutions with water containing 1.5 cm³ concentrated nitric acid. A calibration blank was prepared using all the reagents except the mineral stock solutions. A calibration curve for each mineral was prepared by plotting the absorbance of standards versus their concentrations.

## 2.5 Statistical Analysis

The results were expressed as mean ± standard deviation of duplicate result and the test for statistical significance was carried out using one-way analysis of variance (ANOVA). The OriginPro 2024 statistical software was used to determine significant differences. Significant means was separated using Tukey test and differences was considered significant at (*p*<0.05).

# 3. RESULTS AND DISCUSSION

Table 1 shows the proximate composition of the local raw materials. Fermentation, sprouting and toasting processes significantly (p<0.05) alter the

proximate composition of yellow corn, sorghum, millet, and soybeans. Crude fiber decreased from (0.42, 4.21, and 2.57) % in untreated (UT) yellow maize, sorghum and millet respectively to (0.40, 4.06, and 2.42) % in fermented and sprouted (FS) yellow corn, sorghum, and millet. This reduction aligns with observed trends in earlier studies, where fiber reduction improves digestibility (Akinola et al., 2020). Similarly, crude fat content decreased across all samples from the UT to FS samples. There is an increase in the crude protein content of soybeans from 36.61% in UT soybeans to 38.23% in FST soybeans. This is consistent with findings by Igbabul et al. (2014) and Ogodo et al. (2018), who documented enhanced protein levels in various legumes post-fermentation and sprouting, suggesting increased nutrient density and digestibility. The 36.61% obtained for UT soybeans aligns with 35.53% obtained by Ikese et al. (2017), for soybean flour. Also, protein level increased from 7.90% in UT millet to 8.23% in FS millet. Aande et al. (2020), observed similar trends in pearl millet, with protein content rising from 12.58% in unprocessed millet to 18.35% in roasted millet. No significant (p<0.05) difference exists between the moisture level of each untreated sample and the FS sample. Ash content, represents mineral density, enhancing mineral bioavailability. Ash level, 2.50% of UT sorghum, significantly (p<0.05) increased to 3.88% in FS sorghum. Carbohydrate and energy content showed minimal decrease from UT samples to FS samples, except in soybeans where carbohydrate reduced from 36.56% in UT soybeans to 29.49% in FST soybeans. This reduction may indicate carbohydrate utilization by fermentative microbes. Also, toasting might have caused some nutrient losses due to thermal degradation. Similar declines in carbohydrates and energy have been observed in post-fermentation, attributed to the partial breakdown of complex sugars (Mohapatra et al., 2019).

The mineral composition of the local raw materials for complementary food formulation was recorded in Table 2. The effects of fermentation, sprouting and toasting on mineral composition across all samples reveal significant (p<0.05) differences, indicating that these processes enhance specific mineral bioavailability. There was an increase in sodium and calcium contents across all samples from UT samples to FST samples confirming the role of these processes in enhancing nutrient profiles. Sodium is required for acid-base balance and
<table><caption>Table 1. Proximate composition of local raw materials for complementary food formulation</caption><thead><tr><th>Parameters (%)</th><th>UT Yellow maize</th><th>FS Yellow maize</th><th>UT Sorghum</th><th>FS Sorghum</th><th>UT Millet</th><th>FS Millet</th><th>UT Soybeans</th><th>FST Soybeans</th></tr></thead><tbody><tr><td>Crude fibre</td><td>0.42<sup>c</sup> ± 0.06</td><td>0.40<sup>e</sup> ± 0.07</td><td>4.21<sup>a</sup> ± 0.27</td><td>4.06<sup>a</sup> ± 0.24</td><td>2.57<sup>b</sup> ± 0.25</td><td>2.42<sup>b</sup> ± 0.22</td><td>2.43<sup>b</sup> ± 0.15</td><td>2.73<sup>b</sup> ± 0.23</td></tr><tr><td>Crude fat</td><td>6.29<sup>c</sup> ± 0.43</td><td>5.22<sup>d</sup> ± 0.07</td><td>8.28<sup>b</sup> ± 0.34</td><td>7.97<sup>b</sup> ± 0.03</td><td>6.29<sup>c</sup> ± 0.09</td><td>6.31<sup>c</sup> ± 0.07</td><td>17.08<sup>a</sup> ± 0.06</td><td>16.92<sup>a</sup> ± 0.07</td></tr><tr><td>Crude protein</td><td>9.39<sup>c</sup> ± 0.53</td><td>9.98<sup>c</sup> ± 0.25</td><td>8.9<sup>e</sup> ± 0.63</td><td>9.28<sup>c</sup> ± 0.25</td><td>7.90<sup>e</sup> ± 0.08</td><td>8.23<sup>de</sup> ± 0.25</td><td>36.61<sup>b</sup> ± 2.64</td><td>38.23<sup>a</sup> ± 0.25</td></tr><tr><td>Moisture</td><td>10.18<sup>ab</sup> ± 0.11</td><td>10.18<sup>a</sup> ± 0.11</td><td>8.23<sup>c</sup> ± 0.14</td><td>8.29<sup>c</sup> ± 0.10</td><td>9.56<sup>b</sup> ± 0.34</td><td>9.64<sup>b</sup> ± 0.26</td><td>10.32<sup>ab</sup> ± 0.19</td><td>10.44<sup>a</sup> ± 0.18</td></tr><tr><td>Ash</td><td>2.02<sup>c</sup> ± 0.16</td><td>2.33<sup>b</sup> ± 0.17</td><td>2.50<sup>bc</sup> ± 0.04</td><td>3.88<sup>a</sup> ± 0.09</td><td>2.71<sup>b</sup> ± 0.21</td><td>3.50<sup>a</sup> ± 1.40</td><td>2.00<sup>c</sup> ± 0.02</td><td>2.21<sup>b</sup> ± 0.08</td></tr><tr><td>Carbohydrate</td><td>73.22<sup>a</sup> ± 0.26</td><td>71.90<sup>a</sup> ± 0.19</td><td>69.19<sup>c</sup> ± 0.10</td><td>66.54<sup>d</sup> ± 0.23</td><td>71.48<sup>abc</sup> ± 0.23</td><td>69.91<sup>bc</sup> ± 0.14</td><td>31.56<sup>e</sup> ± 1.63</td><td>29.49<sup>f</sup> ± 0.20</td></tr><tr><td>Energy (kcal)</td><td>379.00<sup>b</sup> ± 4.95</td><td>374.46<sup>bcd</sup> ± 0.40</td><td>377.66<sup>bc</sup> ± 1.16</td><td>374.98<sup>bcd</sup> ± 0.34</td><td>370.16<sup>cd</sup> ± 2.06</td><td>369.31<sup>d</sup> ± 1.07</td><td>426.42<sup>a</sup> ± 0.54</td><td>423.08<sup>a</sup> ± 0.46</td></tr></tbody></table>

Values are mean of duplicate determinations ± standard deviation. Means with different superscripts in the same row are significantly (p<0.05) different. UT means untreated, FS means fermented and sprouted and FST means fermented, sprouted and toasted

<table><caption>Table 2. Mineral composition of local raw materials for complementary food formulation</caption><thead><tr><th>Parameters (mg/100g)</th><th>UT Yellow maize</th><th>FS Yellow maize</th><th>UT Sorghum</th><th>FS Sorghum</th><th>UT Millet</th><th>FS Millet</th><th>UT Soybean</th><th>FST Soybean</th></tr></thead><tbody><tr><td>Sodium</td><td>176.38<sup>a</sup> ± 0.07</td><td>177.74<sup>a</sup> ± 0.49</td><td>180.35<sup>a</sup> ± 7.07</td><td>186.93<sup>a</sup> ± 2.49</td><td>155.69<sup>b</sup> ± 6.64</td><td>178.74<sup>bc</sup> ± 0.42</td><td>154.23<sup>b</sup> ± 0.77</td><td>178.05<sup>c</sup> ± 0.59</td></tr><tr><td>Calcium</td><td>50.64<sup>ab</sup> ± 0.25</td><td>56.88<sup>ab</sup> ± 5.9</td><td>62.39<sup>ab</sup> ± 5.65</td><td>68.61<sup>a</sup> ± 1.56</td><td>46.96<sup>b</sup> ± 2.79</td><td>48.76<sup>b</sup> ± 1.20</td><td>61.44<sup>ab</sup> ± 1.09</td><td>61.70<sup>ab</sup> ± 0.03</td></tr><tr><td>Potassium</td><td>51.30<sup>a</sup> ± 3.64</td><td>65.31<sup>a</sup> ± 14.95</td><td>60.75<sup>a</sup> ± 9.72</td><td>70.25<sup>a</sup> ± 4.81</td><td>60.25<sup>a</sup> ± 0.69</td><td>63.73<sup>a</sup> ± 2.11</td><td>58.23<sup>a</sup> ± 2.14</td><td>63.73<sup>a</sup> ± 2.11</td></tr><tr><td>Magnesium</td><td>161.86<sup>ab</sup> ± 3.58</td><td>174.16<sup>a</sup> ± 0.27</td><td>153.94<sup>ab</sup> ± 0.06</td><td>169.16<sup>a</sup> ± 0.45</td><td>140.13<sup>b</sup> ± 5.78</td><td>161.48<sup>ab</sup> ± 1.32</td><td>155.55<sup>ab</sup> ± 6.46</td><td>172.84<sup>a</sup> ± 14.03</td></tr><tr><td>Phosphorus</td><td>408.87<sup>a</sup> ± 0.64</td><td>403.77<sup>a</sup> ± 0.83</td><td>350.12<sup>c</sup> ± 1.03</td><td>344.08<sup>c</sup> ± 2.72</td><td>368.85<sup>b</sup> ± 2.02</td><td>365.64<sup>b</sup> ± 3.34</td><td>370.2<sup>b</sup> ± 0.31</td><td>369.06<sup>d</sup> ± 0.83</td></tr><tr><td>Iron</td><td>15.76<sup>a</sup> ± 1.30</td><td>19.43<sup>a</sup> ± 0.45</td><td>3.51<sup>b</sup> ± 1.17</td><td>5.51<sup>b</sup> ± 2.53</td><td>2.77<sup>b</sup> ± 0.26</td><td>5.25<sup>b</sup> ± 0.35</td><td>3.07<sup>b</sup> ± 0.04</td><td>7.17<sup>b</sup> ± 1.70</td></tr><tr><td>Zinc</td><td>2.61<sup>b</sup> ± 0.67</td><td>5.60<sup>ab</sup> ± 0.93</td><td>3.66<sup>b</sup> ± 1.27</td><td>5.76<sup>ab</sup> ± 0.62</td><td>3.72<sup>b</sup> ± 0.04</td><td>7.69<sup>a</sup> ± 0.30</td><td>2.81<sup>b</sup> ± 0.93</td><td>7.91<sup>a</sup> ± 1.13</td></tr><tr><td>Manganese</td><td>2.22<sup>a</sup> ± 0.01</td><td>2.92<sup>a</sup> ± 0.06</td><td>2.57<sup>a</sup> ± 0.57</td><td>2.88<sup>a</sup> ± 0.18</td><td>2.36<sup>a</sup> ± 0.25</td><td>2.44<sup>a</sup> ± 0.35</td><td>2.84<sup>a</sup> ± 0.07</td><td>2.93<sup>a</sup> ± 0.85</td></tr><tr><td>Iodine</td><td>87.54<sup>a</sup> ± 4.13</td><td>87.61<sup>a</sup> ± 3.87</td><td>85.35<sup>a</sup> ± 4.73</td><td>85.41<sup>a</sup> ± 4.72</td><td>87.95<sup>a</sup> ± 0.91</td><td>88.08<sup>a</sup> ± 0.80</td><td>75.76<sup>a</sup> ± 0.60</td><td>75.82<sup>a</sup> ± 0.92</td></tr></tbody></table>

Values are mean of duplicate determinations ± standard deviation. Means with different superscripts in the same row are significantly (p<0.05) different. UT means untreated. FS means fermented and sprouted. FST means fermented, sprouted and toasted

<table><caption>Table 3. Vitamin composition of local raw materials for complementary food formulation</caption><thead><tr><th>Parameters</th><th>UT Yellow maize</th><th>FS Yellow maize</th><th>UT Sorghum</th><th>FS Sorghum</th><th>UT Millet</th><th>FS Millet</th><th>UT Soybean</th><th>FST Soybean</th></tr></thead><tbody><tr><td>Vitamin A (µg/100g)</td><td>502.83<sup>b</sup> ± 3.56</td><td>506.38<sup>b</sup> ± 1.16</td><td>499.73<sup>b</sup> ± 7.47</td><td>495.09<sup>b</sup> ± 1.29</td><td>503.28<sup>b</sup> ± 2.57</td><td>505.21<sup>b</sup> ± 1.12</td><td>520.63<sup>a</sup> ± 0.46</td><td>520.39<sup>a</sup> ± 0.86</td></tr><tr><td>Vitamin D (µg/100g)</td><td>4.55<sup>a</sup> ± 0.08</td><td>4.57<sup>a</sup> ± 0.07</td><td>4.76<sup>a</sup> ± 0.16</td><td>4.77<sup>a</sup> ± 0.16</td><td>4.63<sup>a</sup> ± 0.06</td><td>4.64<sup>a</sup> ± 0.04</td><td>3.86<sup>b</sup> ± 0.13</td><td>3.87<sup>b</sup> ± 0.13</td></tr><tr><td>Vitamin E (mg/100g)</td><td>10.11<sup>ab</sup> ± 0.01</td><td>10.22<sup>a</sup> ± 0.07</td><td>9.39<sup>c</sup> ± 0.10</td><td>9.69<sup>bc</sup> ± 0.23</td><td>8.23<sup>ef</sup> ± 0.06</td><td>8.78<sup>d</sup> ± 0.23</td><td>7.85<sup>f</sup> ± 0.12</td><td>8.60<sup>de</sup> ± 0.06</td></tr><tr><td>Vitamin C (mg/100g)</td><td>7.50<sup>b</sup> ± 0.25</td><td>13.41<sup>a</sup> ± 0.14</td><td>6.39<sup>c</sup> ± 0.15</td><td>13.60<sup>a</sup> ± 0.07</td><td>6.62<sup>c</sup> ± 0.30</td><td>13.65<sup>a</sup> ± 0.04</td><td>6.46<sup>c</sup> ± 0.31</td><td>13.38<sup>a</sup> ± 0.03</td></tr><tr><td>Vitamin B1 (mg/100g)</td><td>0.01<sup>a</sup> ± 0.06</td><td>0.12<sup>a</sup> ± 0.01</td><td>0.01<sup>a</sup> ± 0.06</td><td>0.12<sup>a</sup> ± 0.01</td><td>0.11<sup>a</sup> ± 0.01</td><td>0.13<sup>a</sup> ± 0.01</td><td>0.01<sup>a</sup> ± 0.06</td><td>0.20<sup>a</sup> ± 0.01</td></tr><tr><td>Vitamin B2 (mg/100g)</td><td>0.12<sup>bc</sup> ± 0.01</td><td>0.15<sup>abc</sup> ± 0.01</td><td>0.11<sup>bc</sup> ± 0.01</td><td>0.16<sup>ab</sup> ± 0.01</td><td>0.11<sup>bc</sup> ± 0.01</td><td>0.15<sup>abc</sup> ± 0.01</td><td>0.11<sup>c</sup> ± 0.02</td><td>0.18<sup>a</sup> ± 0.01</td></tr><tr><td>Vitamin B3 (mg/100g)</td><td>1.35<sup>e</sup> ± 0.04</td><td>1.45<sup>de</sup> ± 0.05</td><td>1.59<sup>bcd</sup> ± 0.02</td><td>1.64<sup>abc</sup> ± 0.04</td><td>1.50<sup>cde</sup> ± 0.01</td><td>1.52<sup>bcd</sup> ± 0.01</td><td>1.66<sup>ab</sup> ± 0.06</td><td>1.75<sup>a</sup> ± 0.05</td></tr><tr><td>Vitamin B6 (mg/100g)</td><td>0.15<sup>c</sup> ± 0.02</td><td>0.24<sup>a</sup> ± 0.01</td><td>0.15<sup>c</sup> ± 0.01</td><td>0.23<sup>ab</sup> ± 0</td><td>0.19<sup>bc</sup> ± 0.01</td><td>0.27<sup>a</sup> ± 0.01</td><td>0.16<sup>c</sup> ± 0.01</td><td>0.26<sup>a</sup> ± 0.01</td></tr><tr><td>Vitamin B12 (µg/100g)</td><td>3.29<sup>a</sup> ± 0.03</td><td>3.39<sup>a</sup> ± 0.02</td><td>1.48<sup>c</sup> ± 0.12</td><td>2.11<sup>d</sup> ± 0.01</td><td>2.00<sup>c</sup> ± 0.15</td><td>2.70<sup>b</sup> ± 0.06</td><td>1.93<sup>c</sup> ± 0.08</td><td>2.74<sup>b</sup> ± 0.06</td></tr></tbody></table>

Values are mean of duplicate determinations ± standard deviation. Means with different superscripts in the same row are significantly (p<0.05) different. UT means untreated, FS means fermented and sprouted and FST means fermented, sprouted and toasted
osmoregulation (Izuakor et al., 2024) There is no significant (p<0.05) difference in the potassium content across all samples. The magnesium content of all samples significantly (p<0.05) increased from UT samples to FST samples. The phosphorous content decreased from 408.87 mg/100g in UT yellow maize to 403.77mg/100g in FS yellow maize. Similar trend was observed across all samples. This may be attributed to metabolic consumption during sprouting (Khattak et al., 2013). There is a notable increase in iron level from 15.76 mg/100g in UT yellow maize to 19.43 mg/100g in FS yellow maize and from 3.07 mg/100g in UT soybeans to 7.17 mg/100g in FST soybeans. This alligns with the finding that fermentation was proved to improve the nutritional value of soybeans by increasing nutrient bioavailability and reducing antinutritional factors (Sukhikh et al., 2022). The 2.61 mg/100g zinc content of UT yellow maize obtained in this study is close to 2.01 mg/100g reported by Liomba et al. (2018), for unprocessed maize flour. No significant (p<0.05) difference exists between the manganese level across all samples. Iodine content remained stable across all samples, supporting previous reports that iodine retention is largely unaffected by these processes (Ademulegun et al., 2021).

Fermentation, sprouting and toasting processes significantly (p<0.05) impact the vitamin concentration of the samples as shown in Table 3. The vitamin A content increased from 502.83 µg/100g in UT yellow maize to 506.38 µg/100g in FS yellow maize while it increased from 503.28 µg/100g in UT millet to 505.21 µg/100g in FS millet. The vitamin D content remained relatively stable across all samples, with minor increases. This stability is consistent with findings from Nkhata et al. (2018), which indicated that fermentation and sprouting processes do not significantly affect vitamin D levels due to its fat-soluble nature. There is a remarkable increase in vitamin C contents of all FS samples. The FS variants showed nearly double the vitamin C content compared to their UT counterparts (e.g., yellow maize increased from 7.50 mg/100g to 13.41 mg/100g). This finding aligns with that of Chaves-López et al. (2024) where fermentation was shown to increase vitamin C levels through microbial metabolism, which generates ascorbic acid. The water-soluble B vitamins showed significant (p<0.05) increases probably due to fermentation and sprouting treatments, particularly in vitamin B6 and B12 content in soybeans, where levels increased by over 50%. These results are consistent with studies which

observed that enzymatic action during sprouting enhances bioavailability and concentration of B vitamins in legumes and cereals (Mohapatra et al., 2019, World Health Organization, 2020).

## 4. CONCLUSION

The findings from this study showed the effects of processing techniques (fermentation, sprouting, and toasting) on the chemical composition of local raw materials (yellow maize, sorghum, millet, and soybeans) for complementary food formulation. These processing techniques enriched protein, iron, zinc, and vitamin contents particularly vitamins C, B1, B6, and B12 while slightly reducing carbohydrate and fiber content. These results revealed that the processing methods significantly (p<0.05) enhanced the nutritional profile of local raw materials, making them suitable for cost-effective, nutrient-dense complementary food formulations. However, incorporating ingredients like walnuts, pumpkin seeds, and date palm fruits can further improve nutrient bioavailability. It is recommended that further research to formulate complementary foods using the optimized ratios of these raw materials and adding the suggested diverse materials needs to be embarked on. Further analysis to determine proximate, mineral, vitamin, and anti-nutritional factors of the formulated foods would confirm the findings from this study.

## DISCLAIMER (ARTIFICIAL INTELLIGENCE)

Author(s) hereby declare that NO generative AI technologies such as Large Language Models (ChatGPT, COPILOT, etc.) and text-to-image generators have been used during the writing or editing of this manuscript.

## COMPETING INTERESTS

Authors have declared that no competing interests exist.

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