White fonio (Digitaria exilis) is the main raw material used in the formulation of infant flours. This cereal was enriched with cream-colored bambara groundnut (Vigna subterranea) speckled with red, light gray cashew (Anacardium occidentale) speckled with black, and African locust bean fruit pulp (Parkia biglobosa). The variety of African locust bean used is the one with long pods and yellow pulp. The biological materials were purchased at the Abobo market and treated separately in lab.

The raw materials were treated according to the method described by [15] . They were sorted, winnowed, and cleaned to remove any physical impurities. Fonio was washed using the method described by [6] . One kilogram of each sample (fonio and Bambara groundnut) was fermented sequentially for 2 hours for fonio control, 8 hours for Bambara groundnut control, and 24, 36, and 48 hours for the other samples. After fermentation, the fonio and Bambara groundnut were dried and roasted at temperatures between 120˚C and 150˚C. The cashew nut was shelled, and the kernel was washed and dried in an oven at 50˚C to 60˚C. Grinding of the samples was separately done for each raw material using a multifunctional grinder (Gaone, Grinder 2500 rp/w, 36000 rpm). The African locust bean fruit pulp was obtained by drying the seeds surrounded by the pulp in an oven at 50˚C to 60˚C, crushing the dried seeds in an African wooden mortar with low handling force to detach the pulp from any cracked seeds, and sieving the resulting mixture through a mesh sieve ranking between 50 - 300 µm. For the germination process, one kilogram of fonio was soaked for 24 hours and spread on a polypropylene bag for 3 days to allow dark germination. The unsprouted grains were separated from the sprouted grains, and all the samples were dried in an oven at 50˚C to 60˚C. Degermination was performed, and the grains were ground using grinder (2500 rp/w, 36,000 rpm). The physicochemical parameters of the produced flours were determined.

The formulations used in this study were described according to the method described [16] . Different flour blends were prepared by combining 100 g of single flours of fonio, Bambara groundnut, cashew kernel, and African locust bean fruit pulp in various proportions. The flour formulations were developed using the matrix method of formulation supported by Excel software (2010). This method allows for finding a solution that satisfies two nutrient needs using at least two ingredients [17] . Macronutrient values, such as protein, carbohydrate, lipid (g/100 g), and energy (kcal/100 g), were computed using the following equation:

$a_{11}{X}_1+a_{12}{X}_2+\cdots +a_{1n}{X}_n=b1$

$a_{21}{X}_1+a_{22}{X}_2+\cdots +a_{2n}{X}_n=b2$

$a_{n1}{X}_1+a_{n2}{X}_2+\cdots +a_{nn}{X}_n=bn$

a = nutrient contents (carbohydrates, proteins, lipids and energy). X = proportions of ingredients to mix. b = needs to be satisfied and n = series of combination.

The dry matter, moisture, ash, protein, fiber, fat, and carbohydrate content were determined according to the method described by [18] . Mineral content was determined by the emission flame photometric method. The vitamin C and vitamin A (β-carotene) content were determined by the method of [19] . The swelling power and solubility index were determined using the method described by [20] .

The data were performed with a two-factor analysis of variance (ANOVA) using STATISTICA software (STAT 7.1 for Windows, USA). The results are the mean of three replications with standard deviations. Significant divergences are accounted at a statistical probability value of P < 0.05 using Duncan’s test for comparison of formulations.

Table 1 presents the biochemical and energy composition of the raw materials, namely fonio, Bambara groundnut, cashew kernel, and African locust bean fruit pulp. Fonio has a high carbohydrate content (80.4%), Bambara groundnut and African locust bean fruit pulp (61.6% and 64.4%, respectively). Cashew kernel has the lowest carbohydrate content (23.4%). The protein analysis revealed that Bambara groundnut and cashew kernel are very rich in protein (22.1% and 20.8%, respectively), while low protein contents were observed in African locust bean fruit pulp (6.3%) and fonio (7.8%). Cashew kernel has the highest lipid content of 48.5%, which is higher than the contents of fonio, Bambara groundnut, and African locust bean fruit pulp (1.3%, 6.5%, and 2%, respectively). This content is higher than that of unfermented cashew flour reported by [21] . African locust bean fruit pulp had higher amounts of fiber (11.5%) and Vitamin C (640 µg/g) compared to fonio (1.3% and 119 µg/g), Bambara groundnut (3.8% and 160 µg/g) and cashew kernel (2% and 488 µg/g), respectively. Additionally, African locust bean fruit pulp had a high β-carotene value (88.7 µg/g) compared to fonio (6.3 µg/g), Bambara groundnut (5.7 µg/g) and cashew kernel (16.1 µg/g). Cashew kernel had the highest energy value (612.7 Kcal) and the lowest was observed in African locust bean fruit pulp (300.8 Kcal). The composition of the control Bambara groundnut was like that mentioned by [22] . Fonio had a composition like the two ecotypes studied by [4] , and the cashew kernel had a similar composition to the study by [23] . The analyzed African locust bean fruit pulp had a composition like the work of [24] .

Mean values _ standard deviations from three replicate analyses. Mean values followed by the same letter in the same column are not significantly different at P < 0.05. * mean % not applicable the component.

Table 2 presents the mineral composition of the raw materials (fonio, Bambara groundnut, cashew kernel and African locust bean fruit pulp). African locust bean fruit pulp had the highest potassium content (1392 mg/100 g) compared to Bambara groundnut, cashew kernel, and fonio, whose contents were respectively 1105, 600.8, and 91.2 mg/100 g. Bambara groundnut and African locust bean fruit pulp had the highest sodium contents, but their values were not significantly different at the 5% threshold, at 617.1 and 704.1 mg/100 g, respectively. Fonio had the lowest sodium content with 61.9 mg/100 g. Cashew kernel and fonio were rich in iron content with 12.2 and 11 mg/100g, respectively. However, Bambara groundnut and African locust bean fruit pulp had the lowest iron content, with 4.5 and 3.7 mg/100g, respectively. Bambara groundnut was richer in copper content, with 52.2 mg/100 g, than fonio, African locust bean fruit pulp, and cashew kernel, whose contents were 31.3, 30, and 4.5 mg/100 g, respectively. Phosphorus content was more abundant in cashew kernel (494.8 mg/100 g) than those of Bambara groundnut, fonio, and African locust bean fruit pulp, which were 283.9, 136.7, and 101.7 mg/100 g, respectively. Bambara groundnut was richer in zinc content with 22.2 mg/100 g than that of African locust bean fruit pulp, fonio, and cashew kernel, whose compositions were 13.1, 1, and 9.4 mg/100 g, respectively. Cashew kernel and fonio had the highest calcium contents but were not significantly different at the 5% threshold (1168 and 1100 mg/100 g). The cashew kernel was richer in magnesium content (279.6 mg/100 g). African locust bean fruit pulp and Bambara groundnut had the lowest magnesium contents, which were 178 and 170.6 mg/100 g, respectively. These values were not significantly different at the 5% level. The mineral composition of the control African locust bean fruit pulp was like that of the [22] study. Fonio had a mineral composition like the two (2) ecotypes studied by [4] . The cashew kernel had a composition like that obtained by [23] .

Mean values _ standard deviations from three replicate analyses. Mean values followed by the same letter (a, b, c, d) in the same column are not significantly different at P < 0.05.

Fermentation has a significant effect on the biochemical composition of fonio and Bambara groundnut flours (as shown in Table 3 ). During fermentation, there was a noticeable increase in the dry matter content of fonio and Bambara groundnut, with an increase from 94.7% to 97.5% for fonio and from 97.5% to 99% for Bambara groundnut. Moreover, there was a significant increase in the protein content of both flours. After 48 hours of soaking, the protein content of fonio increased from 7.8% to 8.7%, while that of Bambara groundnut increased from 22.1% to 25.4%. Bambara groundnut had the highest protein content (25.4%), which is like the protein content of Bambara groundnut flours soaked for 0 - 72 hours, as reported by [25] . The increase in protein content could be attributed to the optimal time of 48 hours for fermentation, which allowed for the release of more free amino acids and reduced the metabolism use of microflora proteins. This finding is consistent with previous research on fermented cereals and legumes, where dormant proteolytic enzymes were activated during fermentation, leading to the hydrolysis of proteins and the release of more free amino acids [26] .

During the fermentation of fonio, the fiber content decreased significantly from 2% to 0.7% after 48 hours in the control group. This reduction in total fiber content is a common trend observed in the fermentation of cereals, as reported by [27] and [28] during the fermentation of barley. The decrease in fiber content can be attributed to enzymatic fiber degradation by microorganisms which produce extracellular enzymes that hydrolyze and metabolize insoluble polysaccharides [29] . However, there is an increase in fiber content during the fermentation of voandzou, which increases from 3.8% to 4.7%. During the fermentation of fonio, a significant increase in carbohydrate content was observed, with the carbohydrate level increasing from 82.7% to 86.3% in the control group after 48 hours soaking. [30] reported a similar increase in carbohydrate content in fermented millet between 16 and 20 hours. This increase in carbohydrate content could be due to the low pH, which inhibits amylase activity and reduces starch degradation [31] , or the presence of inhibiting amylotic enzymes such as tannins.

Mean values _ standard deviations from three replicate analyses. Mean values followed by the same letter (a, b, c, d) in the same column are not significantly different at P < 0.05. * mean % not applicable the component.

Fermentation, on the other hand, led to a reduction in the level of carbohydrates in the voandzou, which fell from 61.6% to 58.4%. Xiao et al., 2018 found similar results when fermenting kidney beans (Phaseolus angularis). [32] also found a drop in carbohydrate levels during the fermentation of Phaseolus vulgaris. This decrease could be attributed to the fact that the microorganisms use carbohydrates as an energy source during fermentation. Fermentation caused a significant increase in the lipid level in both voandzou and fonio. In fact, the lipid rate went from 0.9% to 1.4% for fonio and from 6.5% to 7.1% for voandzou. [33] and [34] obtained similar results during the fermentation of sweet potatoes for some and red beans for others.

Similarly, the energy value of fonio and Bambara groundnut increases during fermentation, as reported by [32] in their study on Moringa oleifera seeds. The increase in energy value in both fonio and voandzou could be because there is an increase in the lipid level during the fermentation of fonio and voandzou. Fermentation also leads to an increase in vitamin C content, with the highest levels found at 48 hours of fonio’s fermentation (737.6 μg/g) and the lowest at 119.5 μg/g. Bambara groundnut fermentation leads to an increase in vitamin C. This increase in vitamin C content is consistent with the results of studies on the fermentation of hybrid amaranth leaves [35] .

The β-carotene content remains stable during fonio fermentation whereas it decreases during voandzou fermentation. [36] and [37] also obtained a reduction in β-carotene during fermentation.

The germination of fonio seeds results in a significant reduction in dry matter from 94.7% to 90.8%. Additionally, with a water content of 9.2%, sprouted fonio flour has a higher moisture content than all compared fermented fonio flours. This significant increase in moisture content could be attributed to the activation of a wide range of enzyme systems during the hydration process, which hydrolyzed and solubilized food reserves [38] . Moreover, germination leads to a significant increase in lipid content in fonio seeds, as observed in previous studies [39] . This increase could be explained by the early stages of seed development, during which lipids were practically devoid of triglycerides. Seeds develop with a rapid increase in triglyceride synthesis, leading to an increase in lipid content. In contrast, germination significantly reduces the protein content of fonio flour from 7.8% to 6.2% in the control compared to germinated fonio, as reported by [35] and [40] . These researchers found that germination led to pronounced metabolic changes in seeds, resulting in the modification of the structural profile of various organic components. [41] explained that protein is one of the major sources of energy for germ development. During germination, proteins are hydrolyzed into simple peptides and amino acids by protease activity and transported to the developmental axis [42] . Lastly, a significant drop in carbohydrate content was observed in sprouted fonio flour due to metabolism. During germination, carbohydrates in fonio seeds may have been digested into simple sugars by amylolytic enzymes, which were then absorbed by the growing germ as an energy source [43] . Germination also leads to a significant increase in vitamin C content, which increases from 111 μg/g in the control to 214.3 μg/g.

The mineral composition of raw materials was evaluated after pretreatments, and the results are presented in Table 4 . The highest zinc rate was found in the control Bambara groundnut with 22.2 mg/100g, while the flours from fonio grains soaked for 48 h and 36 h had the lowest rate at 0.7 mg/100g. The highest levels of calcium (1233 mg/100g) and magnesium (264 mg/100g) were found in sprouted fonio, whereas the control Bambara groundnut had the lowest rate of calcium (865 mg/100g) and magnesium (170.6 mg/100g). Fermentation of Bambara groundnut led to a significant increase in iron (45.5 - 61.1 mg/100g), copper (52.6 - 63.5 mg/100g), magnesium (170.6 - 229.1 mg/100g), and calcium (865 - 913 mg/100g). However, during the fermentation of the African locust bean fruit pulp, there was a decrease in the sodium level (617.1 - 506.9 mg/100g). Like [44] , a drop in sodium level was observed during the fermentation of three varieties of sorghum. Fermentation of Bambara groundnut had no significant effect on potassium. The fermentation of fonio led to an increase in the rate of sodium and phosphorus. The increase in certain minerals in fermented samples may be due to the release of minerals bound to other compounds such as anti-nutrients by the microorganisms responsible for fermentation [45] . The mineral contents of fonio grain flours soaked for 24 and 48 hours were higher than those reported by [46] . Germination significantly increased the content of sodium, phosphorus, calcium, and magnesium. This increase could be explained by the fact that germination enhances the retention of these minerals [47] [48] . However, germination induced a drop in iron levels. The reduction of other minerals could be due to their leaching in the steeping water during the germination process [49] .

Mean values _ standard deviations from three replicate analyses. Mean values followed by the same letter (a, b, c, d) in the same column are not significantly different at P < 0.05.

The different combinations of the raw materials, along with their respective soaking times, are presented in Table 5 . The control fonio and Bambara groundnut were combined with African locust bean fruit pulp and cashew kernel to produce F0 flour. Subsequently, each fonio flour obtained at different soaking times was mixed with each Bambara groundnut flour obtained at different soaking times. Finally, the mixture was supplemented with African locust bean fruit pulp and cashew kernel. The best-performing combinations are listed in Table 5 .

Table 6 presents the biochemical and energy composition of the formulated infant flour. The dry matter content in the flour ranges from 92.4% to 97.3%, with the lowest dry matter content observed in F3 and the highest in F1. The moisture content in the fermented composite flours and sprouted flour varies from 2.7% to 7.5%. These moisture contents are lower than those found in the fermented infant flours of [50] , whose moisture contents range from 10% to 10.70%. Of the flours studied, those produced from fermented seeds F0 and F1, as well as the sprouted compound flour F5, have water contents of 4.5%, 2.7%, and 5.2%, respectively, which meet the standard of 5% or less in infant flour established by [35] . F2 and F4 have the highest water contents, which are not significantly different (7% and 7.1%). Flours F0, F1, and F5 are expected to have a longer shelf life than the others because a large amount of water in the flour can compromise its shelf life. In fact, water promotes the growth of microorganisms that produce amylase, which is necessary for starch hydrolysis in flours, and this facilitates the acidification of the flours [51] . The ash content of the infant flour varies from 1.7% to 2.5%. Fermented composite flours F2, F3, and F4, as well as germinated composite flour F5, have the highest ash content and are not significantly different from each other. F1 has the lowest ash content (1.7%). The analyzed formulations of infant flours showed a lipid content ranging from 7.2% to 8.1%, with F4 having the lowest and F1 having the highest lipid content. These levels fall within the range of 7% - 9% recommended by [52] for infant flours. The lipid content in this study is lower than that reported by [53] , whose values ranged from 12.76 to 14.59%. Although high-fat flours provide high energy, they are prone to hydrolytic and oxidative rancidity, which affects both the taste and storage stability of the product [54] . The low fat content in the flours analyzed may enhance their storage stability, if they are packaged properly. The protein content of the compound flours ranged from 12.7% to 13.4%, with the highest content found in the control formulation. These values are lower than those reported by [55] , whose protein levels of fermented and roasted flours varied from 18.58% to 25.74%. However, the protein levels in the current study fall within the [52] recommended range of 12% - 15% for infant flour. The higher protein content observed in the sprouted compound flour may be attributed to the combined contribution of the soaked bambara groundnut and cashew almond. The fiber content of the formulations ranged from 3.1% to 4.7%, with the lowest content found in fermented compound flour F1 and the highest in fermented compound flour F2. These values are higher than those reported by [55] , ranging from 0.54% to 0.86%. The fiber levels observed in this study are consistent with [56] recommendations of less than 5%. A low fiber content in complementary diets reduces food bulk and promotes the high digestibility and absorption of nutrients such as proteins and minerals. This encourages children to consume the food samples to meet their daily energy and essential nutrient requirements [57] . The carbohydrate flour composition in the formulations varied from 65.9% to 72.7%. The rates of the various flours tested in this study are like those found in a previous study by [55] which reported rates of 57.14% - 71.4%. The F0 flours and compound flour that were germinated had carbohydrate content percentages of 68.5% and 68.1%, respectively, which comply with [52] standards of [68% - 70%] for infant flours. The energy content of the formulated flours ranged from 382.8 to 410.7 kcal. Except for fermented mixed flour F1, the other fermented composite flours had lower energy values than the germinated composite flour F5. The flours F1 with an energy value of 410.7 kcal meet [56] standards of [400 - 425 kcal]. The vitamin C content of the flours varied from 149 to 973.6 µg/g, with the control having the lowest level and the fermented composite flour F1 having the highest. The germinated composite flour had a vitamin C content of 509.9%. Vitamin C is a reducing agent and a powerful antioxidant that can limit the harmful effects of free radicals. It also facilitates the absorption of non-heme iron from plant foods [58] . The β-carotene content of the flours ranged from 10.1 to 30.5 µg/g. Carotenoids are involved in many biological processes, including photosynthesis, vision, and free radical scavenging, due to their ability to dissolve in fat [59] [60] .

Mean values _ standard deviations from three replicate analyses. Mean values followed by the same letter (a, b, c, d, e) in the same column are not significantly different at P < 0.05. * mean % not applicable to the component. with; F0: Fonio 2 h (54%) + Bambara groundnut 8h (28%) + African locust bean fruit pulp (8%) + cashew kernel (10%); F1: Fonio 24 h (59%) + Bambara groundnut 24 h (20%) + African locust bean fruit pulp (6%) + cashew kernel (15%); F2: Fonio 36 h (44%) +Bambara groundnut 48 h (23%) + African locust bean fruit pulp (23%) + cashew kernel (10%); F3: Fonio 48h (42%) +Bambara groundnut 24 h (25%) + African locust bean fruit pulp (23%) + cashew kernel (10%); F4: Fonio 48 h (42%) +Bambara groundnut 36 h (25%) + African locust bean fruit pulp (23%) + cashew kernel (10%); F5: Fonio 24 h (41%) + Bambara groundnut 24 h (25%) + African locust bean fruit pulp (11%) + cashew kernel (15%) + sprouted fonio (8%).

Table 7 displays the mineral composition of the mixed flours. The potassium levels range between 199.1 and 552.1 mg/100 g, with the fermented flour composed of F2 having the lowest content, and the germinated flour mixed F5 having the highest. However, the potassium level of the germinated composite flour is lower than that of [11] . Only flour F0, with a value of 514.4 mg/100 g, has a potassium content substantially equal to the recommended standard of 516 mg/100 g according to [56] . The sodium content ranges from 175 to 250.9 mg/100 g, with F0 having the lowest content and F4 having the highest. The sodium contents of the fermented F1 and germinated F5 composite flours are not significantly different from the control, while fermented flours F3 and F4 have significantly higher sodium levels than the control. The sodium levels of the whole flours are higher than those of [11] , but all flours have sodium levels below the standard of 296 mg/100 g, according to [56] . The iron content of the flours ranges between 62.2 and 76.3 mg/100 g. The germinated composite flour has about the same amount of iron as the unmodified flour, but all fermented compound flours have more iron than the unmodified flour. All the flours have more iron than the WHO standard of 16 mg/100 g [56] . The copper content ranges from 33.9 to 70.7 mg/100 g. The flour with the lowest copper content is F0 and the flour with the highest copper content is F5. F3 and F4 have more copper than the unmodified flour, but all the copper levels are below the WHO standard of 160 mg/100 g [56] . The phosphorus content ranges from 195.1 to 242.5 mg/100 g, with the lowest content in F3 and the highest in F0. The fermented and sprouted composite flours have less phosphorus than the unmodified flour and the WHO standard of 456 mg/100 g [56] . However, these levels are similar to the phosphorus content in some artisanal infant flours from Cameroon [61] which have between 177.7 and

Mean values _ standard deviations from three replicate analyses. Mean values followed by the same letter in the same column are not significantly different at P < 0.05. with; F0: Fonio 2 h (54%) + Bambara groundnut 8 h (28%) + African locust bean fruit pulp (8%) + cashew kernel (10%); F1: Fonio 24 h (59%) + Bambara groundnut 24 h (20%) + African locust bean fruit pulp (6%) + cashew kernel (15%); F2: Fonio 36 h (44%) + Bambara groundnut 48 h (23%) + African locust bean fruit pulp (23%) + cashew kernel (10%); F3: Fonio 48 h (42%) + Bambara groundnut 24 h (25%) + African locust bean fruit pulp (23%) + cashew kernel (10%); F4: Fonio 48 h (42%) + Bambara groundnut 36 h (25%) + African locust bean fruit pulp (23%) + cashew kernel (10%); F5: Fonio 24 h (41%) + Bambara groundnut 24 h (25%) + African locust bean fruit pulp (11%) + cashew kernel (15%) + sprouted fonio (8%).

281.6 mg/100 g. Phosphorus is important for energy production, bone and tooth health, and forms calcium phosphate, which is important for bone strength [62] . The zinc content ranges from 2.7 to 5.2 mg/100 g. The composite flours from fermented seeds have less zinc than the unmodified flour but more than the WHO standard of 3.2 mg/100 g [56] . Zinc, along with iron, is one of the most concentrated minerals in the brain, which is important for infant brain growth. Zinc is also important for immunity and can reduce the incidence and severity of children’s diarrhea [63] . The calcium content of the flours ranges from 784.5 to 978.6 mg/100 g. The fermented and sprouted composite flours have less calcium than the unmodified flour but more than the WHO standard of 500 mg/100 g [56] . The control and fermented and germinated mixed flours have higher magnesium contents than the WHO standard of 76 mg/100 g [64] .

Table 8 presents the swelling power and solubility of the different formulations. The swelling power of the composite flours ranges from 7.1 to 12.7 ge/gMS. F5, which is the germinated composite flour, has the lowest swelling power, while the fermented flour F3 has the strongest power. It is worth noting that all these flours have greater swelling powers than infant flours made of plantain banana and cashew kernel, whether fermented or not [21] . On the other hand, the solubility index ranges from 14.5 to 25.2%, with the lowest index observed for the control flour and the highest index for the fermented compound flour F3. These solubility indices are like those reported in previous works [21] .

Mean values _ standard deviations from three replicate analyses. Mean values followed by the same letter in the same column are not significantly different at P < 0.05. with; F0: Fonio 2 h (54%) + Bambara groundnut 8 h (28%) + African locust bean fruit pulp (8%) + cashew kernel (10%); F1: Fonio 24 h (59%) + Bambara groundnut 24 h (20%) + African locust bean fruit pulp (6%) + cashew kernel (15%);F2: Fonio 36 h (44%) + Bambara groundnut 48 h (23%) + African locust bean fruit pulp (23%) + cashew kernel (10%); F3: Fonio 48 h (42%) + Bambara groundnut 24 h (25%) + African locust bean fruit pulp (23%) + cashew kernel (10%); F4: Fonio 48 h (42%) + Bambara groundnut 36 h (25%) + African locust bean fruit pulp (23%) + cashew kernel (10%); F5: Fonio 24 h (41%) + Bambara groundnut 24 h (25%) + African locust bean fruit pulp (11%) + cashew kernel (15%) +sprouted fonio (8%).