Effect of Stinging Nettle Leaf Flour Substitution on the Quality Characteristics of Fermented Corn Complementary Foods

Proper complementary feeding is required to provide essential nutrients to growing infants. However, most families in developing countries are severely food insecure, leading to constant child malnutrition. This study developed fermented corn complementary foods (pap) supplemented with abundantly available and affordable stinging nettles . Stinging nettle leaf flour was incorporated into pap at 5%, 10%, 15% and 20% and evaluated in relation to nutritional, functional, and sensory properties. Soybeans were used to compare the nutritional and health benefits of nettles in infant nutrition. A gradual incorporation of nettle leaf flour increased (p<0.05) the ash, protein

Consequently, there is an urgent need to develop low-cost high protein complementary foods using abundantly available and affordable nutritious plants such as stinging nettle.This study investigated the possibility of developing nutrient-rich fermented corn complementary foods supplemented with stinging nettle leaves.To achieve this objective: Four pap formulations containing 5%, 10%, 15% and 20% nettle leaf flour were prepared, and the nutritional (proximate analysis, total phenolic content, antioxidant activity, the predicted in vitro digestion and metabolic glycaemic response), functional, and sensory characteristics were examined.
In addition, soybeans, an essential source of food and a suitable ingredient in complementary foods (Codex Alimentarius, 2013;WHO, 2009), were used to compare the nutritional and health benefits of stinging nettle.

Plant Materials
Three plant materials; yellow corn (Zea mays L.), soybeans (Glycine max) and stinging nettles (Urtica dioica L.) were used.Yellow corn and soybeans seeds were obtained from the Institute of Agricultural Research for Development (IRAD), Yaounde, Cameroon.Stinging nettle leaves were harvested from three selected farms in Buea, located southwest of Cameroon, precisely at latitudes 4 0 12′N and longitudes 9 0 12′E.Buea is made up of tropical rainforest and stinging nettles are highly noticeable due to their stinging effects encountered on footpaths and arable land (Tanyitiku et al., 2022) (Note 1), especially during the rainy seasons (March to October) (Field observation, June 07-10, 2022).The consumption of nettles as food is unknown in the region.

Processing of Stinging Nettle Leaves and Soybean into Flour
Stinging nettle leaf flour was obtained using a freeze drying technique as described by Chakravartula et al. (2021).Compared with other methods such as blanching, and convectional drying, freeze drying was found suitable due to its ability to retain the plant pigments as well as its magnesium, phenolic, and antioxidant contents (Chakravartula et al., 2021).Fresh stinging nettle leaves were harvested locally and randomly among 4-week-old leafy vegetables (Note 2) in September 2022.The leaves were placed in sterile polythene bags, transported to the laboratory in ice packs, and processed within one hour.Here, the harvested leaves were gently washed with distilled water, drained, and crushed using an immersion blender (Breville, Australia).The crushed leaves were frozen at -80 0 C and freeze-dried at -48 to -55 0 C for 28 h in a domestic freeze-dryer (Harvest Right, USA).It was then milled and sieved using an ASTM E11 400µm stainless steel to obtained nettle leaf flour.
Toasted soybean flour was processed as described by Krička et al. (2003).1.5kg of soybeans were sorted, washed, and soaked (1part of the seeds in 10 parts of deionised water) in a 2 litre Sistema container (Sistema NZ) for 24 h.The soaked seeds were manually dehulled to reduce and/or eliminate fibre and antinutrients (Codex Alimentarius, 2013).It was then oven-dried at 55-60 0 C for 24 h and toasted at 135 0 C for 15 min in a fan-assisted 60cm pyrolytic oven (Miele, Germany).The toasted seeds were cooled for 30 min, milled, and sieved to obtain toasted soybeans flour.

Pap Preparation
Pap was prepared as described by Baningo and Akpapunam (1999) with slight modification of the natural fermentation time.1.5kg of yellow corn was manually sorted for soil and splits.Seeds were soaked as for soybeans above, drained and re-soaked to ferment at room temperature for another 48 h.Subsequently, the fermented seeds were drained and ground into a paste using a tabletop stone wet grinder (Ultra Grind + Gold, USA).The paste was pressed through a 0.5µm stainless steel sieve to remove any coarse particles and then squeezed using a clean porcelain cloth to obtain a thicker cake (pap).It was then oven dried at 55-60 0 C for 24 h, milled, and sieved using an ASTM E11 400µm sieve.
To prepare the different complementary foods, pap (initially 350g) was weighed and gradually replaced with nettle leaf flour or soybean flour at 5%, 10%, 15% and 20%.For example, considering nettle-enriched pap: 5% nettle-enriched flour contained 332.5g of pap + 17.5g of nettle leaf flour; 10% nettle-enriched pap contained 315g of pap + 35g of nettle leaf flour; 15% nettle-enriched pap contained 297.5 of pap + 52.5g of nettle leaf flour and 20% nettle-enriched flour contained 280g of pap + 70g of nettle leaf flour.Each complementary food was mixed for 3 min using an electric mixer (Breville, Australia), set at speed 1, and stored at 4 0 C in labelled airtight polyethylene bags for further analyses.100% fermented corn flour (pap) served as a control in all experiments.

Sample Extraction
Sample extraction was carried out according to Chakravartula et al. (2021) with slight modifications.2g of each formulation was added to a 100ml volumetric flask containing 40ml of methanol/water (95:5v/v).In dark conditions, it was incubated in a shaker incubator (ThermoScientific, NZ) at 25 0 C for 24 h and then filtered using a Whatman No. 4 filter paper.5ml of each filtered solution was then centrifuged at 8000 g for 5 min and the supernatant (methanolic extract) was obtained for the determination of total phenolic content and antioxidant activity, described in 2.3.6 and 2.3.7 below.

Proximate Composition
The moisture, ash, crude protein, fat and total dietary fibre were determined according to AOAC (2000).Moisture content was measured by drying 3g of each sample at 105 0 C for 24 h in a hot-air oven (Stanhope-Seta, UK).Ash content was obtained by calcinating 10g of each sample in a muffle furnace (Stanhope-Seta, UK) at 550 0 C for 6 h.Calcinated samples were then used to determine the mineral content of each formulation.Total crude fat was extracted from 1.5g of the sample in a Soxhlet extractor (ThermoFisher Scientific, USA) using petroleum ether as solvent.Crude protein was estimated by multiplying the crude nitrogen content by a factor of 6.25, that is, % crude protein = % Nitrogen × 6.25.Crude nitrogen was obtained using the Kjeldahl method.Total dietary fibre was measured using Megazyme enzymes (Megazyme International Ireland Ltd., Wicklow, Ireland).The caloric values were obtained using the Atwater general factor system by multiplying the crude protein, fat, and carbohydrate values by their physiological fuel values of 4, 9, and 4 respectively.Carbohydrate content was obtained by difference, that is, % carbohydrate = 100 -% protein + %fat + %crude fibre + %ash + %moisture.

Mineral Composition
Na, K, Ca, Fe, Zn, P and Mg was measured using the atomic absorption spectrophotometry according to AOAC (1997) method 985.35.5ml of 6N HCl solution was added to 5g of each calcinated sample mentioned above.It was dried on a hot plate followed by the addition of 7ml of 3N HCL solution.Distilled water was added dropwise to dilute the solution to the 50ml mark on the flask.Mg, Ca, and Fe were determined using air/acetylene as a source of flame energy for atomisation.A flame photometer was used to estimate Na and K concentrations at 589 nm and 767 nm, respectively.P was determined using the ammonium molybdovanadate colorimetric method.Each mineral content was obtained by comparing its concentration with known standards and then expressed in mg/100g of each formulation.

Total Carotenoids
Total carotenoids were measured spectrophotometrically according to Lichtenthaler and Buschmann (2001).Each formulation (1g) was mixed with 200mg of MgCO 3 , 3ml of 100% acetone, and centrifuge at 8000g for 3 min.The absorbance of the clear supernatant was measured at 470 nm and expressed in mg/100g of each formulation.

Vitamin C
Vitamin C was measured as described by Rahman et al. (2006).In a coupling reaction involving 2,4-dinitrophenyl hydrazine (DNPH) dye and vitamin C, 10g of each sample were thoroughly mixed in 50 ml of 5% metaphosphoric acid/10% acetic acid solution.The solution was diluted to 100 ml in a volumetric flask and then filtered using a Whatman No. 4 filter paper.Few drops of bromine and 10% Thiourea solution (2,4-Dinitrophenyl-hydrazine solution and 85% Sulphuric acid) were added and the absorbance was read and expressed in mg/100g of each formulation.

Total Phenolic Content (TPC)
TPC was measured by colorimetry using Folin-Ciocalteau reagent (FC) as described by Kupina et al. (2018) with slight modifications.1ml of each methanolic extract was mixed with 1ml of Folin & Ciocalteu's phenol reagent and allowed to sit for 6 min.To neutralise the mixture, 3.0ml of sodium carbonate (20% Na 2 CO 3 ) solution was added followed by 15ml of water after 15 min.It was then heated on a heating block for 120 min, and the precipitate formed was removed by centrifugation at 4000 g for 5 min.TPC was determined by measuring the absorbance of each sample at 765 nm using gallic acid, ranging from 40-200mg/l gallic acid as standard.Results were expressed as mg of gallic acid equivalents (GAE) per gram of each formulation.

Antioxidant Activity (AA)
AA was estimated using a DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging assay according to Khare et al. (2012).2ml of each 10mg/ml DPPH solution was mixed with 2ml of each methanolic extract and stored in the dark for 30 min.The free radical scavenging activity was measured spectrophotometrically at 520 nm using vitamin C as a standard.The AA of each extract was calculated using the following equation.
The concentration required to obtain a 50% antioxidant capacity termed IC 50 , was determined from the graph of antioxidant capacity (%) against extract concentration (mg/g).Additionally, the antioxidant activity index (AAI) was calculated based on Scherer & Godoy (2009).

Assessing the Functional Properties of Each Formulation
Three function properties: bulk density, water absorption capacity (WAC), and swelling capacity were determined as described by Appiah et al. (2011).Dispersibility was measured based on Kulkarni et al. (1991).
The bulk density (g/ml) was calculated by the ratio of the weight (g) of each flour to its volume (ml) when 50g of each sample was gently tapped to a constant volume in a 100ml graduated cylinder.WAC (g/g) was calculated as grams of water absorbed per gram of each sample.1g of each sample was mixed with 10ml of distilled water in a preweighed tube.The paste-like suspension was vortexed for 2 min, allowed to stand at 28 0 C for 30 min, and then centrifuged at 8000 g for 15 min.The clear supernatant was discarded and the centrifuge tube containing the paste was reweighed and recorded as the amount of water absorbed per gram of sample.The volume of water absorbed was multiplied by the density of the sample to convert into grams.For the swelling capacity, 1g of each sample was mixed with 10ml of distilled water and heated at 80 0 C for 30 min in a shaking water bath (ThomasScientific, USA).The suspension was then centrifuged at 8000 g for 20 min, and the supernatant was decarded.The swelling capacity (g/g) was calculated as a ratio of the weight of the paste to the weight of each formulation.Finally, 10g of each formulation was vigorously stirred in distilled water placed in a 100ml measuring cylinder.The suspension was then allowed to settle for 3h. and dispersibility (%) was obtained by subtracting the volume of settled flour from 100.

Estimation of in vitro Digestion and Glycaemic Index (GI)
In vitro starch digestion and glycaemic index was estimated according to Goñi et al. (1997), slightly modified by Leoro et al. (2010), 50mg of each sample was boiled in 15ml of distilled water for 3 min, then 10ml of HCI-KCI buffer was added to adjust the pH to l.5.To initiate gastric digestion, 0.2ml of pepsin solution (1g of Pepsin in 10ml of HCI-KCI buffer) was added, incubated at 40 0 C for 1 h in a shaker incubator (ThermoScientific, NZ) and completed to 25ml with Tris-Maleate buffer (pH=6.9).5ml α-amylase in Tris-Maleate buffer (2.6 UI/ml) was then added and incubated at 37 0 C in a shaker incubator (ThermoScientific, NZ).Subsequently, 1ml aliquots were taken at different times (0, 30, 60, 90, and 120 min) and placed in a tube at 100 0 C. It was briefly vortex for 5 min to inactivate the enzyme and then refrigerated until the end of the incubation time.To hydrolyse the digested starch into glucose, 3ml of 0.4M sodium acetate buffer (pH=4.75)and 60µl of amyloglucosidase enzyme (3000 U/ml) was added at 60 0 C. Glucose concentration was measured using the glucose oxidase-peroxidase (GOD-POD) enzymatic colorimetric kit (NZYTech, NZ).Hydrolysis curves were plotted and the areas under the hydrolysis curves (AUC, at 0-120 min) were calculated using a non-linear model described by Goñi et al. (1997).
The rate of starch digestion was expressed as a percentage of total starch hydrolysed during these times (30, 60, 90, and 120 min).The Hydrolysis Index (HI) was calculated as the ratio of the AUC of each sample to the AUC of a reference sample (glucoses) and expressed as a percentage.Glycaemic index (GI) was then estimated according to Leoro et al. (2010) as:

Sensory Evaluation
Twenty-five (25) breastfeeding mothers (aged 25 to 38 years) were recruited during routine infant immunisation and semi-trained to serve as sensory panelists.Each formulation was coded (N5, N10, N15, N20, S5, S10, S15, and S20) and prepared according to the nutritional guidelines of the World Food Programme for processed foods aged 6-23 months (WFP, 2018).A 'rule of thumb' was used where 50g of each formula was cooked in 250ml of boiling water for 3 min.The cooked gruels, corresponding to 0.8kcal/g of energy (WFP, 2018), were allowed to cool and served warm to the individual panelists.A nine-point hedonic scale ranging from 1 = Dislike extremely to 9 = Like extremely was used and the gruels were rated for colour, taste, flavour, smoothness, and overall acceptability.In addition, breastfeeding mothers were served with 100% nettle leaf flour (coded N) and using yes or no responses, they were asked if they would feed their babies with the ingredient (N) if revealed to them.

Statistical Analysis
All experiments were carried out in triplicate and are expressed as mean ± standard deviation.Using the Statistical Package for Social Sciences (SPSS, Version 21), analysis of variance (ANOVA) was used to test the differences in means between samples, and Duncan's multiple range test was used for mean separation at the probability level of 5%.
On the other hand, the fat, carbohydrate, and energy values of nettle-enriched pap significantly (p<0.05)decreased with increasing incorporation of nettle leaf flour (Table 1).Fat content ranged from 3.32 to 3.98% and was significantly (p<0.05)not different from the control (3.50%), but lower (p<0.05)than soybean-enriched pap (6.45 to 10.46%).Maietti et al. (2021) reported a similar lower fat content of 2.13g/100g in nettle-enriched bread.
Fat is a source of energy and fatty acids are essential in the diets of growing infants.Its recommended intake in complementary foods increases from 0% at 6-8 months to 5-8% at 9-11 months, and then 15-20% at 12-23 months (Abeshu et al., 2016).

Functional Composition
The results of the bulk density, swelling capacity, water absorption capacity and dispersibility of the complementary foods are presented in Table 3. Bulk density of nettle-enriched pap was within 0.51 to 0.53g/ml, the control was 0.52g/ml and soybean-enriched pap ranged from 0.50 to 0.53g/ml.The bulk density indicates the particle size of a flour and measures the weight per unit volume occupied by a given product.The smaller the particle size, the more surface area is available for water absorption (Kulkarni et al., 1991).Also, the higher the fibre content, the bulkier the product and the higher the protein content, the lesser the bulk density (Codex Alimentarius, 2013).This research nettle-enriched pap had a low bulk density that could be attributed to its high protein and low fibre contents, and this was found suitable for complementary foods (Appiah et al., 2011).
The water absorption capacity of nettle-enriched pap was significantly (p<0.05)different and was within the same range (1.12-1.54g/g)as the control (1.14g/g) and soybean-enriched pap (1.00-1.89g/g).Infant formulations with low water absorption are desirable for thin gruels formed during reconstitution or cooking.This differences in water absorption could be mainly due to slight increases in soluble sugars and hydrophilic proteins that enabled the binding of water and fats in the flours (Appiah et al., 2011;Tanyitiku & Njombissie Petcheu, 2022).
The swelling capacity was highest (0.96g/g) in 20% nettle-enriched pap and lowest (0.89g/g) in 10% nettle-enriched pap.20% nettle-enriched pap and 5% soybean-enriched pap were not significantly (p<0.05)different and were higher than the control (0.94g/g).Swelling capacity is the ability of flours to absorb moisture from their surroundings, and this research varying results could be linked to the molecular structure of the formulation's starch granules.
Furthermore, the dispersibility of nettle-enriched pap was high between 72.13% (15% nettle-enriched pap) and 79.65% (5% nettle-enriched pap) and was not different (p<0.05) from the control (79.56%) and soybean-enriched pap (74.25 to 79.50%).Kulkarni et al. (1991) reported a similar acceptable dispersibility value of 63 to 79% in weaning food formulations produced from malted sorghum and sesame flour.Dispersibility indicates the ease of reconstitution when a flour is mixed with water (Tanyitiku & Njombissie Petcheu, 2022), thus, the results showed that nettle-enriched pap could be easily cooked into gruels

Nettle leaf flour increased TPC and Antioxidant activity of pap
TPC values of nettle-enriched pap were significantly (p<0.05)different and increased from 51.78mgGAE/g to 125.45mg GAE/g (Table 4).These results were significantly (p<0.05)doubled compared to soybean-enriched pap: 27.94mgGAE/g (5% soybean-enriched pap) to 58.12mgGAE/g (20% soybean-enriched pap).In particular, 15% nettle-enriched pap (102.09mgGAE/g) and 20% nettle-enriched pap (125.45mgGAE/g) were 100 times higher than the control (1.23mgGAE/g).Kukrić et al. (2012) recorded a higher TPC value (208.37±4.39mgGAE/g)for nettles and further highlighted that environmental, climatic, or geographic factors may influence the quality and the quantity of phenolic components in nettles.This research TPC values indicated that stinging nettles harvested in the tropical rainforest belt (Cameroon) are good sources of phenolic compounds and could provide various biological functions, including antioxidant and antimicrobial activities in infants.

Nettle Leaf Flour Decreased Metabolic Glycaemic Response of Pap
The rate of starch hydrolysis during 120-min in vitro digestion of the complementary foods are presented in Figure 1.From the hydrolysis curves, nettle-enriched formulations had slightly lower hydrolysis values than the control and soybean-enriched pap.A sharp increase was observed during the first 30 minutes of digestion in all formulations.This slightly increased to 60 min and then slowly flattened at 120 min.Leoro et al. (2010) observed similar starch hydrolysis trends when organic passion fruit fibre was added to corn flour.
In Table 5, reducing the quantity of pap in each formulation following the gradual incorporation of nettle leaf flour or soybean flour significantly (p<0.05)decreased the hydrolysis of starch into sugars, and subsequently, the metabolic glycaemic response.For the nettle-enriched pap, the highest GI value (48.12) was obtained in 5% nettle-enriched pap and the GI of 20% nettle-enriched pap (35.60) was approximately 30-times lower than the control (68.53) and four-times lower than 20% soybean-enriched pap (40.24).Krawęcka et al. (2021) recorded lower GI values of 49.64, 49.38, and 49.31% when durum wheat pasta was enriched with 1, 2, and 3% stinging nettle leaves.Likewise, Leoro et al. (2010) reported GI values of 47.93 to 49.74% in passion fruit fibre-enriched corn flour extruded breakfast.Starch is the major constituent of many formulated complementary foods and should be provided in a digestible form (Codex Alimentarius, 2013).The glycaemic index (GI) describes the rate of absorption of blood glucose after the consumption of starchy foods and is considered low when it <55%.In this research, the high GI value of fermented corn flour (pap) could be related to the structure of its non-gelatinized starch which is commonly known to resist enzymatic digestion (Goñi et al., 1997;Leoro et al., 2010).On the other hand, a decrease in nettle-and soybean-enriched pap could be due to 1) added protein and dietary fibre that formed polymeric complexes leading to incomplete gelatinization and starch retrogradation (Leoro et al., 2010), or 2) the high phenolic compounds recorded in nettle-enriched pap that could have inhibited amylolytic enzymes and delayed glucose absorption, (Krawęcka et al., 2021).Above all, nettle-enriched pap could be classified as a 'low glycaemic index complementary food', which could provide essential nutritional and health benefits to a growing infant.

Sensory Evaluation of Prepared Gruels
The results of the sensory analysis are presented in Table 6.Colour, smoothness, taste, flavour, and overall acceptability met the "targeted" sensory qualities of breastfeeding mothers.Colour for nettle-enriched pap was within 6.11 and 7.77.The scores for 10-and 15% nettle-enriched pap were higher than the control (7.02) and 100% nettle flour (4.52).Soybean-enriched pap was within 7.32 and 8.00 with no significant (p<0.05)difference between 5-and 10% soybean-enriched pap and 15-and 20% nettle-enriched pap.The colour was dependent on the ingredients used, that is, green for nettle-enriched pap and yellow for soybean-enriched pap.Smoothness for all formulations was within 7 and 8 except for 15% nettle -enriched pap that was lower (6.21).100% nettle flour was rated lowest (4.70) for taste; otherwise, all formulations were within 6 and 8.In particular, 15% soybean-enriched pap was scored 8.54 for taste and this value was significantly (p<0.05)higher than the control (6.45) and all nettle-enriched formulations.Taste could be attributed to the presence of simple sugars arising from the fermentation of corn and the toasting of soybeans.Flavour for nettle-enriched pap was between 5.86 and 6.30 and was significantly (p<0.05)lower than the control (7.64) and soybean-enriched pap (7.20 and 8.55).Furthermore, toasting has been found to improve the taste and taste of foods through starch dextrination (Codex Alimentarius, 2013).In terms of overall acceptability, nettle-enriched pap ranged between 6.23 (20% nettle-enriched pap) and 7.66 (15% nettle-enriched pap).These scores were within the control (7.12) but slightly lower than soybean-enriched pap (7.23 and 8.76).Throughout the sensory analysis, soybean-enriched pap was highly preferred over nettle-enriched pap.Couple with the fact that stinging nettle was entirely unknown to panelists, there was this tendency to generally accept familiar soybean products.However, 12 of the 20 breastfeeding mothers accepted that they could feed their babies with nettle leaf flour, thus indicating could be confidently used in complementary feeding following sensitisation of its nutritional and health benefits.

Conclusion
In this study, stinging nettle leaf flour was gradually incorporated into fermented corn flour (pap) to improve its nutritional, functional, and sensory properties.In particular, the study observed a significant (p<0.05)increase in ash, protein, dietary fibre, total phenolic content, and antioxidants.The metabolic glycaemic response significantly decreased from 68.53% (pap) to 35.60 (20% nettle-enriched pap), indicating 'low glycaemic index complementary foods' could be produced when nettles are substituted in infant formulations.A consumption of such low-cost nutrient-rich nettle-enriched complementary foods could reduce and/or combat malnutrition especially in poorer developing countries where stinging nettle is growing abundantly as a 'weed'.However, nutritional sensitization and awareness campaigns are required to initiate stinging nettle into complementary feeding in these communities.Further research is required to understand the health and food safety as well as the consumption limits of stinging nettles.

Figure 1 .
Figure 1.Starch hydrolysis of complementary foods during 120 min of in vitro digestion

Table 1 .
(Ullah et al., 2010)1) 74.10 (5% soybean-enriched pap) and 70.02% (20% soybean-enriched pap).Krawęcka et al. (2021)reported a similar decreased (78.40 to 72.34g/100g) in nettle-enriched durum wheat pasta.Yellow corn seeds are rich sources (69.659 to 74.549%) of carbohydrates(Ullah et al., 2010), and this could have contributed to the high carbohydrate content in the nettle and soybean formulations.Likewise, energy values significantly (p<0.05)Proximate composition of complementary foods Values are expressed as mean ± standard deviation of three replications.Means with different superscripts within the same column are significantly different at p <0.05.
Adhikari et al. (2015) this research formulated diets could meet the energy needs of a growing breast-fed child with several proportions consumed per day.Carbohydrates are responsible for the bulk of calories in infant foods.In this research, its value significantly (p<0.05)decreasedfrom the control (87.87%) and ranged from 71.45 (5% nettle-enriched pap) to 57.01%(20% nettle enriched pap) in nettle-enriched pap.Total carotenoids were significantly (p<0.05)higher in nettle-enriched pap (3.97 to 4.99mg/g) than in the control (0.18mg/g) and soybean-enriched pap (0.19 to 0.96mg/g).Apart from 15-and 20% nettle-enriched pap that were significantly (p<0.05)notdifferentfrom each other, all formulations were significantly (p<0.05)different(Table2).Krawęcka et al. (2021)recorded lower carotenoids values (2.52 and 13.35µg/g) in nettle-enriched durum wheat pasta.However,Adhikari et al. (2015)reported high total carotenoids values (3496.67µg/100g) in 100% nettle leaf flour, which might have contributed to carotenoids increase in nettle-enriched pap.An important carotenoid in nettle is β carotene which could function as a potent antioxidant and dietary factor in infant growth when nettle-enriched pap is consumed.Also, carotenoids are precursors of vitamin A. Vitamin A deficiency is a major public health problem that affects infant vision and the formation of healthy skin and hairs (UNICEF, (2021, December 12)).As such, the introduction of carotenoids-rich nettles in complementary feeding could help combat such public health concerns.

Table 2 .
Carotenoids, vitamin C and some mineral composition of complementary foods Values are expressed as mean ± standard deviation of three replications.Means with different superscripts within the same column are significantly different at p <0.05.

Table 3 .
Functional Properties of Complementary Foods

Table 4 .
The TPC values and antioxidant activity of complementary foods

Table 5 .
In vitro glycaemic response of complementary foods Values are mean ± standard deviation of triplicate.Means with different superscripts in the same column are significantly different (p<0.05).