Proximate Composition and Nutritional Potential of Saba Senegalensis Fruit from Three Climatic Regions in Burkina Faso

Non-timber forest products such as lianas provide essential nutrients for human health and should be exploited in Burkina Faso. In order to better valorization, this study aimed to investigate the nutritional potential of Saba senegalensis fruit. The samples of fruit were obtained from three climatic regions then biochemical composition and nutritional content of it pulp were analyzed according to standard methods. The results showed that pulps were acidic with pH varying from 2.85±0.12 to 3.16±0.70 and titratable acidity 4.52±0.20% to 4.89±0.40%. Brix degree, moisture content, and ash were ranged respectively from 20.11±1.50% to 23.50±1.10%, 84.50±3.15% to 86.50±4.25%, 4.44±0.30 g/kg to 5.85±0.40 g/kg. Macronutrients contents were 3.89±0.10 to 3.89±0.10 g/kg, 4.65±0.70 to 7.78±0.50 g/kg, 19.44±1.80 to 23.80±1.40 g/kg, 146.40±11.25 to 155.70±14.50 g/kg respectively for lipids, proteins, total fibers and total carbohydrates. Vitamines rates of pulps were respectively 15.50 ± 1.91 to 17.14 ± 1.90 mg/kg, 0.25 ± 0.05 to 0.55 ± 0.08 mg/kg, and 22.6 ± 2.30 to 27.8 ± 2.90 mg/kg for vitamins B6, A and C. Pulp contain of phytonutrient and anti-nutritional factors were 105.18 ± 10.14 to 132.80 ± 15.00 mg/100g and 19.17 ± 1.16 to 39.60 ± 1.10 mg/100g for total polyphenols and flavonoids and yet ranged 105.25 ±5.15 to 121.80 ±2.20 mg/100g, 78.51 ±0.13 to 80.30 ±1.50 mg/100g, and 20.57 ±3.50 to 26.49 ±1.30 mg/100g respectively for phytates, tannins and oxalates. The mineral composition exhibited higher Mg, Ca, and P


Introduction
Burkina Faso's economy is predominantly agrarian, with agriculture contributing approximately 18.4% of the country's total gross domestic product (GDP) in 2020 and employing around 80% of the workforce (PNUD, 2022).The country's food policy prioritises a limited number of crops commonly referred to as "main crops," including cereals and legumes.Market garden crops are classified as secondary crops, whereas non-timber forest products are rarely considered food crops (Loubelo, 2015).Yet, their significance with regard to nutritional intake and their role in maintaining a balance of nutrients and achieving self-sufficiency in food cannot be overlooked (Loubelo, 2015).Consumption of non-timber forest food species in their natural state helps enhance the quality of food by adding micronutrients.
Non-timber forest products (NTFPs) play an important role in the lives of people, especially in rural areas.They are used by these populations to meet subsistence needs (food and health) or as sources of additional income and employment.Around 1.2 billion people in developing countries use the trees on their farms (fields) for food and income (FAO, 1996).The importance attached to these non-timber forest products (NTFPs) is linked above all to the major role they play in human nutrition as one of the main sources of micronutrients: vitamins and minerals (Sambou et al., 2016).
Adding value to non-timber forest products remains the most sustainable solution for combating malnutrition, the degradation of forest resources and the prevalence of certain diseases.forest resources and the prevalence of certain diseases.Despite the importance of forest fruits the nutritional quality of these fruits is poorly known by those involved in the sector (FAO, 2012).Semdé et al. (2019) have highlighted the variability in fat, total sugar, protein, and mineral contents of stump tubers harvested in different locations in Burkina Faso.These nutritional variations are similar to the research of Abalokoka et al. (2018), who discovered differences in the mineral values across three areas in Togo.According to Bourque (2000), ongoing global warming is resulting in climatic changes which may impact agriculture, specifically fruit production.As reported by Basson et al. (2020), Burkina Faso possesses three climatic zones -the Sudanian, Sahelo-Sudanian, and Sahelian zones -and climate variability has a detrimental effect on their agroforestry production.The research by Diouf et al. (2019) indicates that populations of goose liana display morphological variability in leaves, fruits, and seeds based on their respective climatic zones.The study by Bationo-Kando et al. (2009) further suggests that climate change can cause variations in the biochemical makeup of the species' fruits.
Most studies on of Saba senegalensis fruit in Burkina Faso focused only on its physicochemical characteristics (Parkouda et al., 2018;Tiendrebeogo et al., 2020) but not looking to climatic impact.For better valorisation of this Non-timber forest products (NTFPs) the influence of climatic factors on the fruit's potential needs to be checked.The main objective of this study was investigate the nutritional characteristics of S. senegalensis pulp according climactic zones of Burkina Faso.

Pulp Extraction and Preparation
The fruit batches were washed using potable water and soap before being disinfected in a water solution containing a few drops of sodium hypochlorite.The pulps were extracted using a knife and spoon method and then blended using a Nasco 500 W5 blender (refer to Figure 3: A, B, C).For analysis, samples of 500g mixed pulp, without seeds per locality in the climatic zones, were taken and then dried in an oven at 40°C for 14 days.A part of pulp obtained was stored at + 4°C in freezer bags and kept frozen for analysis.The dried pulp was powdered using a MINA MIQABO electric grinder (Figure 3D).A composite sample of pulp extracted from each area was monitored.

Determination Physicochemical Parameters of Pulp
The pH and titratable acidity were measured using a pH Metro Digital pH-2005.4120500model pH meter and titrimetry, respectively, at a ratio of 1/10 (m/v) following the AOAC (1990) method.The results of tritratable acidity were expressed as the percentage (%) of citric acid in the juice.The Brix level was measured using the ATAGO PACKET refractometer according to the AOAC (1990) method.Moisture was determined according to the method of AOAC (1990).A quantity of 0.5 g of pulp was dried oven at 105°C for 24 hours, and the dry matter was determined.Ash content was determined by calcining samples in a muffle furnace (JP Selecta SA 313066) at 550°C for 6 hours, as per the AOAC (1990) method.

Determination of Macronutrients
The pulp proximate macronutrients were determined using the methods of AOAC.
Carbohydrates were determined using the liquid chromatographic sugar separation method as outlined in (A.O.A.C, 1984).A sample (10 g) was used to determine lipids by extracting with n-hexane (40-60°C) in a Soxhlet apparatus (A.O.A.C, 1995).
Protein was estimated using the macro-Kjeldahl method, then calculated by multiplying the measured nitrogen by a factor of 6.25.The crude fiber was evaluated by digesting the defatted sample (2 g) in 1.25% HCl and 1.25% NaOH (A.O.A.C, 1990).

Determination of Phytonutrients and Anti-nutritional Components
Total polyphenols content was evaluated by method using Folin-Ciocalteu (Joshi et al. 2015).
Phenolic content was measured using Folin-Ciocalteu according to Joshi et al. (2015) method.The pulp extracted by ethanolic solution were treated with Folin-Ciocalteureagent (500 µL, 1 N) followed by saturated sodium bicarbonate (100 µL).The final volume was made up to 25 mL using distilled water.The reaction mixture was then incubated at room temperature for half hour.Absorbance was readed at 730 nm against blank using UV-Vis spectrophotometer (Eppendorf).Gallic acid was used as the standard and expressed in mg gallic acid equivalents (GAE) per g extract.
Flavonoids were are determined at 415 nm using the method described by (Meda et al., 2005).Flavonoids react with aluminum chloride in the presence of potassium acetate to give a yellow complex whose intensity is proportional to the amount of flavonoid present in the medium.
Phytate quantification was based on an indirect method that involves complexing phytates with iron (phytates-ferric), followed by spectrophotometric determination of the iron.(Mohamed et al., 1986).The concentration of tannins in pulp was measured using the method described by Bainbridge et al. (1996).The oxalic acid content was evaluated following to the AOAC (1995) as adapted by Sotomayor et al. (2001).

Determination of Micronutrients
Vitamines (A, B6 and C) contents were determined in accordance with standard method EN 12823-1: 2014 using high-performance liquid chromatography (HPLC) with fluorometric detection (F).This method was described by Albalà -Hurtado et al (1997).The retinol molecule was used as the standard for vitamin A. Vitamin B6 is the mass fraction of the sum of pyridoxine, pyridoxal, pyridoxamine including their phosphorylated derivatives determined as pyridoxine.Minerals content were carried out according the method of AOAC (2005).using inductively coupled plasma atomic emission spectrometer (ICPE 9000, Shimadzu, Japan).Sample The concentrations of Calcium (Ca), potassium (K), magnesium (Mg), phosphorus (P), iron (Fe), zinc (Zn), and manganese (Mn) were determined by comparing their absorbance to a standard linear regression curve from standard solutions.Minerals content were carried out according the method of AOAC (2005).using inductively coupled plasma atomic emission spectrometer (ICPE 9000, Shimadzu, Japan).Sample The concentrations of Calcium (Ca), potassium (K), magnesium (Mg), phosphorus (P), iron (Fe), zinc (Zn), and manganese (Mn) were determined by comparing their absorbance to a standard linear regression curve from standard solutions.

Statistical Analysis
The data obtained after analysis were subjected to an analysis of variance (ANOVA) at the 0.05 significance level using XLSTAT software (Version 2016).The Fischer LSD test was used to determine significant differences between samples.Principal Component Analysis (PCA) was performed to explicitly determine parameter variations between climatic zones.

Proximate Biochemical Composition of Pulp Related To the Region
3.1.1pH, Titratable Acidity, Brix degree, Moisture, Ash The physico-chemical parameters of fruit pulp from three regions were presented in the the table 1. Results showed no statistically significant differences (p>0.05) in the pulp among the regions concerning pH, Titratable acidity, Brix degree, moisture.However, a significant difference was observed for Ash.The pH values of liana fruit pulp ranged 2.85±0.12,3.1±0.25 and 3.16±0.70while tritratable acidity ranged 4.52±0.2%,4.64±0.15%and 4.89±0.40%respectively for Sudanian zone, Sudanian, Sahelo-Sudanian and Sahelian zone.The pH values indicated that S. Senegalensis fruit is acidic.These values were closed to those of Parkouda et al. (2015) in Burkina Faso, who obtained pH values of 2.76 ± 0.1.Similarly, Kouakoua et al. (2019) and Diabagaté et al. (2019) in Côte d'Ivoire found similar pH values of 2.85 ± 0.21 and 3.03 ± 0.01 respectively.In Senegal, Gaye et al. (2022) also obtained similar results with a pH of 2.79 ± 0.05.
The acidic pH in the fruit may be attributed to the existence of organic acids as citric acid, tartaric acid, malic acid and succinic acid, which are commonly present in fruits such as oranges and lemons (Ouchemoukh et al., 2007).According to Vondruskova et al. (2010), organic acids have the ability to lower pH and thereby reduce the growth of certain pathogenic bacteria.Only acidophilic microorganisms can survive in such an environment (Yeo et al., 2021).Titratable acidity values exceed those reported by Parkouda et al. (2015) in Burkina Faso, Kouakoua et al. (2019) and Diabagaté et al. (2019)in Côte d'Ivoire, with values of 1.35%, 2.2% and 0.28% respectively.Acidity is crucial in prolonging the shelf life of food (Li et al., 2022).
The Brix values obtained for the Sudanian, Sahelian, and Sahelo-Sudanian zones were gradually 20.11±1.50%,22.20±1.50%,and 23.50±1.10%,respectively.Statistical analysis revealed no significant difference (p>0.05) in Brix values between the three climatic zones of Burkina Faso.Brix degree was higher than those obtained by Tiendrebeogo et al.(2020) in liana pulp (18.74±0.00%) in Burkina Faso, and Kouakoua et al. (2019) in Cote d"Ivoire (19.60±0.1%)then to those of Boamponsem et al. ( 2013) in Ghanaian goï ne liana fruit pulps (14.1%).In contrast, Parkouda et al. (2015) in Burkina Faso found higher values (26.62±1.08%).The Brix level depends on the sugar content of the fruit.According to Piard et al. (2014), the sweetness of a sample increases with its Brix level.The composition of fruit sugar varies considerably during the development stage based on crop management and climatic factors (Taghavi et al., 2019).
The variable moisture content in the pulp of three zones can be attributed to agromorphologic conditions and other factors such as sunlight and wind exposure contributing to fruit pulp dryness (Ruiz-Rodrí guez et al., 2011).On the other hand, Ash values ranged gradually 4.44±0.30g/kg, 5.85±0.40g/kg and 5.30±0.60g/kg for Sudanian, Sahelian, Sahelo-Sudanian zone.The ash was found to be significantly different between the three climatic regions (p<0.05).
The mean value obtained of 5.19±0.71g/kg was similar to those of Tiendrebeogo et al. (2020), who reported 5.9 ± 3.1 g/kg for fruit pulps sourced in Burkina Faso, moreover was higher to those reported by Diabagaté et al. (2019) in Côte d'Ivoire (0.46 ± 0.01%) and Boamponsem et al. (2013) in Ghana (2.8%).The difference of ash contents obtained in this study and those of the literature could be explained either by the different varieties, the geographical locations of the plant studied.According to Diabagaté et al ( 2019) difference could provide to the nature of the climate and the property of the soil on which the plant grows and technological treatments applied.The ash content is a reflection of the inorganic matter and of minerals of the pulp (Muthai et al., 2017).

Macronutrient Content
The results of macronutrient content were mentioned in the table 2. Results showed statistically significant difference (p<0.05) for fat, protein and total fiber according the three regions.And yet no significant difference was found for total carbohydrates content.The mean crude protein content ranged gradually 4.65±0.70g/kg, 5.65±0.30g/kg, 7.78±0.50g/kg for Sudanian, Sahelian, Sudano-Sahelian zones.There was specific regional trend across the regions.The results showed that there were statistically significant differences (p < 0.05) among the regions for protein content.
The mean value recorded in this study was comparable to results of previous studies on S. senegalensis fruit pulp conducted by Tiendrebeogo et al. (2020) in Burkina Faso (5.9 ± 1.2 g/kg), Boamponsem et al. (2013) in Ghana (5.3 g/kg).However, it was lower than those obtained by Diabagaté et al. (2019) in Côte d'Ivoire (29.1± 5.1 g/kg).
The Sudanian zone exhibited a crude fiber content of 19.44±1.80g/kg,while the Sahelo-Sudanian zone and Sahelian zones displayed 23.80±1.40g/kgand 20.17±1.32g/kg,respectively.Notably, the Sahelo-Sudanian zone recorded the highest content levels in comparison to the other two zones.Mean pulp crude fiber content showed lower value than those of Boamponsem et al. (2013) in Ghana 13.52g/kg.This finding showed that the influence of environment on pulp crude fiber content was very minimal.This experiment demonstrated for the first time that the pulp fiber content of liana was influenced by the provenance of origin.
These variations according of the climatic regions could potentially be explained by the effects of soil and climatic conditions within the particular zones (Dabbou et al., 2010).
Total carbohydrate levels for the three climatic zones exhibited no significant differences.The Sudanian, Sahelo-Sudanian, and Sahelian zones recorded contents of 146.400 g/kg, 155.7 g/kg, and 151.180 g/kg, respectively.These values were closed to those obtained by Tiendrebeogo et al. ( 2020) (144.2 ± 4.7 g/kg) in Burkina Faso.
Other authors as Diabagaté et al.(2019) in Côte d'Ivoire, reported a lower mean of 84.2±7.4 g/kg.These differences could be attributed to the climatic conditions existing in the countries and the level of ripeness of the fruits at the time of harvest alongside fruit storage circumstances (Gaye et al., 2022).

Phytonutrients and Anti-nutritional Factors
The phytonutrients and antinutritionals factors content, were examined in the fruit pulps of S. senegalensis and the results were mentioned in table 3. Results were significantly different (p<0.05) for flavonoids, phytates and oxalates according to the climatic regions.In addition, no significant difference was observed for polyphenols and tannins.The polyphenol content values in this study ranged gradually 105.18 mg/100g, 117.35 mg/100g and 132.8 mg/100g for Sudanian, Sahelian and Sudano-Sahelian respectively.Statistical analysis indicated (p > 0.05) that there was no significant difference in polyphenol levels between the three climatic zones.Statistical analysis reveals that climatic zone does not impact tannin content, while phytate and oxalate content exhibit considerable variations based on the zone (p < 0.05).
The variations in polyphenol and flavonoid concentration across climatic zones may be attributed to the weather conditions in the areas where Saba senegalensis fruits were harvested (Baiyeri et al., 2019).
Polyphenols play a significant role in nutrition.Indeed, there is significant epidemiological evidence that a diet abundant in fruits, vegetables, cocoa, and beverages rich in polyphenols protects against the development of cardiovascular disease and type 2 diabetes (Williamson, 2017).Flavonoids are polyphenolic substances of plant origin with significant biological, antioxidant, vasculoprotective, anti-hepatotoxic, anti-allergic, anti-inflammatory, anti-ulcer, and anti-tumor properties (Lahouel et al., 2004;Ghedira, 2005).
Analysis of goï ne liana pulps revealed the presence of anti-nutritional factors, including tannins, phytates, and oxalates.Tannin levels were found to be 78.51±0.13 mg/100g in the Sudanian zone, 80.30 ±1.50 mg/100g in the Sudano-Sahelian zone, and 80.10 ±4.60 mg/100g in the Sahelian zone.These measurements are lower than those reported by Diabagaté et al.(2019), who found tannin content in fruit pulp harvested in Côte d'Ivoire to be 198.94± 1.19 mg/100g.These findings closely match those reported by Diabagaté et al. (2019) for Saba senegalensis fruit jams made in Côte d'Ivoire at 78.51 ± 0.14 mg/100g.These lower values can be attributed to the dilution effect in the jam's formulation.Tannins have an essential role in nutrition as they hinder the bacterial metabolism by inhibiting their growth Larwence et al.(1984).This process increases the food's shelf life.Tannins are responsible for the therapeutic properties of some plants.The leaves and fruits contain tannins in the range of 6 to 8% (Sereme et al., 2008).Tannins may exhibit antimicrobial effects by binding to cell wall pore proteins, which can alter molecule transport mechanisms, thereby reducing nutrient bioavailability (Mebirouk-Boudechiche et al., 2015).
Oxalates, which can hinder the uptake of micronutrients and reduce their bio-availability, are found in the product.It must be elucidated that not all oxalates are eliminated through cooking (Ngombo-nzokwani et al., 2021).

Vitamins and Minerals Contents
The vitamins and minerals content in the fruit pulps of S. senegalensis were shown in table 4 and table 5. Results were significantly different (p<0.05) for vitamin A and minerals as Zn and Mn according to the climatic regions.In addition, no significant difference was observed for Vitamins B6, C and minerals as Mg, Ca, P, K, and Fe.2020) of 15.11± 0.025 mg/kg in pulps from Burkina Faso.Vitamin C is vital for collagen production and is crucial in the immune system's response to infections (Buxeraud and Faure, 2021).Vitamin C has several biochemical functions such as activating hormones, antioxidants, and histamine detoxification, while also stimulating certain enzymes, collagen biosynthesis, phagocyte and leukocyte functions, nitrosamine formation, and proline hydroxylation, among others (Walingo, 2005).
The variations in levels across countries can be explained by variances in climatic factors and soil types as documented by Bourque (2000); Amiot and George (2017); Tajini et al. (2020).All of these specific minerals have a crucial function in constructing the body.Magnesium is a vital component in a broad range of primary cellular reactions, and its absence has been linked to pathological conditions in humans (Mazur et al., 2007).The nutritional significance of magnesium's presence in fruit contributes to a well-balanced diet.
Calcium, on the other hand, is an essential element in skeletal development.It is involved in several biological functions, including muscle contraction, blood coagulation, hormone release, and enzyme activation (Katz and Miledi, 1967).Determining its presence in Saba senegalensis fruit pulp offers valuable information for nutrition and could aid in balancing the diets of populations.Phosphorus is a crucial element for organisms.It plays a role in various cellular reactions, such as glycolysis and oxidative phosphorylation, which are the primary sources of ATP (Delanaye and Krzesinski, 2005).Its presence in Saba senegalensis fruit is nutritionally interesting and can aid in maintaining a balanced diet.Manganese contributes to normal energy metabolism, protects cells against oxidative stress, and participates in skeletal formation within the body (Li and Yang, 2018).Potassium is a crucial mineral in the body, playing a significant role in the normal functioning of the nervous system, proper muscle activity, and the maintenance of normal blood pressure (Turck et al., 2016).Zinc is fundamental to the structure and function of various macromolecules within the body.It is involved in gene expression and stabilises protein structure, and also plays a prominent role in over 300 enzymatic reactions, including spermatogenesis, free radical detoxification via superoxide dismutase, alcohol metabolism via alcohol dehydrogenase (Fallah et al., 2018).Its determination in fruit is also of interest for food.Saba senegalensis fruit could be used as a mineral supplement to compensate for certain zinc deficiencies.Iron is crucial for the growth and survival of organisms.It is crucial for several biological processes, particularly the transportation of oxygen by hemoglobin, DNA synthesis (as a ribonucleotide reductase coenzyme) and the redox activity of many mitochondrial enzymes (Cadet et al., 2005).

Principal Component Analysis (PCA) of Physicochemical and Nutritional Parameters According to Climatic Zones
The collected data underwent PCA analysis to investigate discriminative qualities between the three climatic zones and to determine the impact of indicators such as the physico-chemical and nutritional analysis results, as well as the production origin of the samples analysed from Zones 1, Zone 2 and Zone 3. The eigenvalues of the correlation matrix were employed to quantify the percentage of variance explained by each factor.In the PCA, the F1 component accounts for 75.10 % of the total variable variation, while the F2 component represents 24.90 %.The histogram of eigenvalues indicates that the F1 and F2 axes constitute the first factorial plane, which explains the entire inertia with a total of 100 %.This adequately explains most of the inertia.Under the given conditions of the three climatic zones, it can be observed that the two main components account for the complete variance.Furthermore, the parameters investigated have a strong correlation with the principal axis (F1 = 75.10% of the total variance).The screen plot depicted in Figure 3(B) displays the physico-chemical indices such as pH, acidity, brix, water content (H), ash content, lipids, proteins, total carbohydrates and crude fibre, alongside phytonutrients and anti-nutrients, including total polyphenols.Flavonoids, tannins, phytates, and oxalates, along with vitamins B6, A, and C, and mineral composition including Mg, Ca, P, Mn, K, Zn, and Fe, exhibit positive correlation with the principal axis F1, which explains 75.10 % of the variability.The physicochemical and nutritional parameters analyzed are highly correlated with the Sudano-Sahelian zone (Z2) (see Figure 3B).Some authors affirm that this zone is favourable for the development of Saba senegalensis species.According to Kabré et al (2020), the Sahelian and Sudanian zones exhibit the highest densities of adult S. senegalensis.The nutritional and physicochemical profile obtained may be attributed to the young population in the Sudano-Sahelian zone.

Conclusion
The study provides insight into the possible nutritional and biochemical content of the pulp of the goï ne liana fruit in the three primary climates of Burkina Faso.Based on the nutritional value of the pulp, it is evident that the fruit of Saba senegalensis could offer a positive contribution to the dietary balance of populations and serve as a remedy for specific nutritional deficiencies in individuals with a deficiency.The studied parameters reveal that the composite sample from the Sudano-Sahelian zone displays the most optimal biochemical and nutritional profile.

Figure 1 .
Figure 1.Saba senegalensis: a) Saba Senegalensis fruit species b) Saba senegalensis fruits c) Pulp-coated seeds . Each sample weighed 1 kg, and a total of 225 samples were transported to the laboratory.

Figure 3 .
Figure 3. Preparation steps of dried pulp powders: A) fruit, B) fruit hulls and C) pulp extraction D) dried pulp

Figure 4 .
Figure 4. PCA of physico-chemical and nutritional parameters as a function of climatic zone according to the (F1xF2) design: A) factorial map of variables; B) factorial map of variables as a function of climatic zone

Table 1 .
Physico-chemical parameters of fruit pulp of S. senegalensis For the same column, values (means ± SEM) followed by the same letter are not significantly different.