Physicochemical and nutritional characteristics of bee pollen from Burkina Faso

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INTRODUCTION
Bee products are nowadays used as food, food supplements, additives in cosmetic products and therapeutic API drugs.Pollen is one of these hive products presented in the form of microscopic grains contained in the anthers of the stamens of flowering plants (Prost and Le Conte, 2005).It is also the most important source of protein for the survival of bees (Almeida et al., 2005).Indeed, for food needs, beekeepers can collect bee pollen, in the form of pellets, by installing a trap or pollen trap at the entrance of the hive (Almeida et al., 2005).
Pollen can be used and consumed as a dietary supplement for its high dietary and dietary values.It is also rich in nutrients and biologically active substances (Silva et al., 2004).Its physicochemical and nutritive composition depends mainly on the bee species and the *Corresponding author.E-mail: kaborejeanaxeltegwende@gmail.com.Tel: +22663304340, +22664868368.
Author(s) agree that this article remain permanently open access under the terms of the Creative Commons Attribution License 4.0 International License climatic conditions of the production region.
The beekeeping sector is growing in Burkina Faso due to the growing demand for hive products (Bambio, 2020).The production of bee products has increased from around 500 tonnes over the period 2011-2015 (Bambio, 2020) to 1500 tonnes in 2022 (MEDIAPROD and CTA, 2022).One of the major constraints in this sector is the lack of knowledge of modern production techniques inherent in the lack of actor training (Bambio, 2020).Pollen production in Burkina Faso remains embryonic and its biochemical composition remains unknown.This may limit its use and consumption.
To date, practically no study to our knowledge has focused on the physicochemical and nutritional characterization of pollen from Burkina Faso.This characterization would be very important for the use of pollen in food and nutritional technology.The aim of this work is to constitute a database on the physicochemical and characteristics of the pollen produced in Burkina Faso.This database could be used in the formulation of pollen-based foods.

Biological material
The biological material is made up of the samples of bee pollen.These pollen samples were collected based on availability and accessibility to beekeepers.

Sampling
Bee pollen was collected in Kenyann type hives in the following localities in Burkina Faso: Fada N'Gourma, Banfora, Tenkodogo, Koudougou, Sapouy and Bobo Dioulasso.These different localities are distributed in two different climatic domains characterizing each of the domains by different vegetation.The localities of Tenkodogo, Fada, Koudougou, and Sapouy are located in the northern Sudanese domain characterized by vegetation composed of shrubby savannah, while the localities of Bobo Dioulasso and Banfora are located in the southern Sudanese domain characterized by vegetation composed of wooded to shrubby savannah.Two samples per locality were taken, packaged in jars and kept in the refrigerator.

Method for determining the biochemical composition
The pH was measured using a pH meter according to the method of Doukani et al. (2013).The titratable acidity was determined by titration of 5 g of bee pollen according NF V 05-101, 1974 and the results are expressed as a percentage (%) of bee pollen.The total ashes were determined by incineration at 550°C for 4 h in a muffle furnace according to the ISO standard 2171ISO standard (2007)).
The soluble dry extract or the Brix degree of the samples was determined using a digital refractometer.Moisture and dry matter were determined by oven drying (Gacem et al., 2011).The protein content was determined according to the ISO 16634 method, 2008.The fat content was made by Soxhlet extraction according to the method of AOAC 960.39 (1999) using hexane as solvent.Carbohydrates were assayed by the spectrophotometric method of Montreuil and Spik, 1969.The mineral content (calcium, magnesium, sodium, zinc, iron, copper) of the pollen samples was determined by flame atomic absorption spectrophotometry after mineralization of the samples according to the ISO 1762 standard, 2019.The theoretical energy value was calculated using the Merrill coefficients (Merill and Watt, 1955) adopted by the FAO in 1970.

Statistical analyzes
The results of the analysis are presented as mean ± standard deviation.The processing of the results was done by analysis of variance (ANOVA) at the significance level of 5%.These analyses were carried out with the software "XLSTAT version 2022.1."
This moisture content was higher compared to the maximum threshold value in Argentina and Brazil (3 g/100 g and 4 g/100 g).This content was close to the content obtained by Souza et al. (2018) (6.73 g/100 g).It was lower than that obtained by Heldt et al. (2019) (7.44 g/100 g), El Ghouizi et al. (2021) (10.7 g/100 g).However, this moisture content was higher than that obtained by Aličić et al. (2020) (6.07 g/100 g).High humidity of pollen can make spoilage possible particularly by moulds.This requires a conservation technique to obtain pollen with a humidity of less than or equal to 6% in order to facilitate conservation.
The pH values obtained from pollen samples from the localities of Tenkodogo, Fada N'Gourma and Koudougou were similar to those obtained by Souza et al. (2018) (4.0-6.0) and El Ghouizi et al. (2021) (4.19-4.82).The analysis of the titratable acidity showed us a fluctuation of the values.These results corroborated the values of Younsi and Lazizi, 2016) (6 g/L to 19 g/L).This fluctuation can be explained by the free acidity of fresh pollen due to the action of the natural lactic flora which is found in fresh pollen to hydrolyze organic compounds, particularly carbohydrates, to release organic acids.
The micronutrient contents of pollen from Fada N'Gourma were highest in Calcium, Magnesium and Zinc.(2021) (39.722 mg/100 g) but higher than the content (6.465 mg/100 g) obtained by Veysel et al. (2021).The botanical origin and the nature of the species foraged may be the cause of this difference in results (Younsi and Lazizi, 2016).

Conclusion
This study shows the nutritional richness of the pollen produced in Burkina Faso.Indeed, it is rich in carbohydrates, proteins and fats.It is also rich in micronutrients such as calcium (57.12 mg/100 g), magnesium (108.88 mg/100 g), zinc (59.33 mg/100 g), potassium (33.46 mg/100g) and iron (17.34 mg/100 g).The study shows that the biochemical composition of pollen produced in Burkina Faso varies depending on the region of origin but also is different from pollen from other countries.This difference could be explained by the floral diversity and the action of the natural lactic flora.
The results of this study could contribute to the popularization of pollen and to promote its technological and nutritional use.
Security of Environment, Nutrition, Labor and Health Products (ANSSEAT) are thanked for collaboration under analytics.The ISP/IPICS/RABIOTECH project is thanked for financial support.

Table 1 .
Biochemical composition and energy value of pollen from different localities in Burkina Faso.

Table 2 .
Biochemical composition of pollen from different localities in Burkina Faso.
bThe values reported in the same column and bearing the different superscript letters are significantly different at the 5% level.Source: Authors

Table 1 .
Mineral salt content of pollen from different localities in Burkina Faso.