Physical characterization of the fruit and nutritional value and microbiology quality of the Pentadesma butyracea fruit pulp collected from various parks in Benin


 In Benin, Pentadesma butyracea fruit pulp undergoes significant post-harvest loss due to its low valorization. The collected fruits in five parklands from a survey of transformer's perception were characterized through their visual observations, the determination of their dimensions and pulp proportions. The nutritional value of pulp was evaluated through its chemical characterization. The results of this study revealed that four shapes (ellipsoid, globular, ovoid, ellipsoid twisted) identify the physical aspect of P. butyracea fruits in the P. butyracea parklands. The average length, diameter at the equator, mass and pulp proportion of fruits were 130.93 mm, 86.98 mm, 125.63 g and 35.79%, respectively. The physicochemical characterization showed that the P. butyracea fruit pulp contained 3.37-3.41 pH, 3.33-4.61% protein, 20.37 – 20.78% fiber, 2.78-3.57% ash, 6.31-6.51% crude lipid, 85.77-86.47% moisture, 21.54-23.22 mg/ml total phenolics, 0.73-1.03% acidity titratable, 65.10 – 66.94% carbohydrates, 335.75-338.99 kcal calorie and minerals (Ca, Fe, Zn, Mn). The antioxidant activity result showed that the P. butyracea fruit pulp is a valuable source of antioxidant pigments. Faecal coliforms are not detected in pulps and the aerobic mesophilic bacteria, yeasts and moulds, and Staphylococcus aureus were below detection level in P. butyracea fruit pulps.


Introduction
P. butyracea Sabine (Clusiaceae) is a ligneous forest species with multipurpose uses. It is widely distributed in Africa fromGuinea-Bissau to thewest of the Democratic Republic of Congo 1 . P. butyracea is found in the centre and northern part of Benin in forest galleries and along waterways 2,3 . The P. butyracea tree gives a fruit, made up of pulp and seeds. The seeds are the element of the fruit more nowadays exploited because it contains an almond rich in butter. The rural population used P. butyracea butter in cosmetic and in the manufacturing of soap 4 . This butter is mostly used for food preparation, cosmetic and therapeutic applications because of its yellow colour, hard texture, relatively sweet taste, softening, lubricating and healing qualities 5 . Comparative studies carried out by 5 on P. butyracea and shea butters, showed that P. butyracea butter is clearly better than shea butter mostly on the organoleptic level. 6 evaluated the physicochemical characteristics of P. butyracea butter and reported that the oil content was 419.0 g kg−1, crude protein content was 44.0 g kg−1, lysine content was 3.2 g kg−1 dry matter, methionine content was 1.6 g kg−1 and cysteine was 1.5 g kg−1.
In spite of the strong knowledge of the biochemical composition of the P. butyracea kernels and potential application of its butter in food, in cosmeic and therapeutic field, there is no information on the physicochemical and biactive properties, microbiological and sensorial characteristics of P. butyracea fruit pulp. During P. butyracea butter extraction, the fruit pulp undergoes significant loss because of the ignorance of the nutritional value and bioactive properties of this part of the fruit. This pulp is almost unutilised, unexploited for several reasons.
One of the reasons is the ignorance by the populations of the nutritional value of pulp. More than 99% of this pulp are thrown by the gatherers in spite of its potentialities. Studies carried out on the pulp of the shea fruit from Chad 7 , Nigeria 8 and Uganda 9 , showed that it contains a significant quantity of nutritive elements such as the glucides, the proteins, the fibres, minerals and the vitamins. It is then necessary to develop technologies of valorization of P. butyracea fruit pulp in Benin. For this reason, it is important to study the nutritional quality of the fruits pulp in Benin. The present study evaluated the nutritional value and microbiology quality of the Pentadesma butyracea fruit pulp collected from various parks in Benin and determined the various uses of fruit pulp using a quantitative survey approach and the Physical characterization of the fruit.

Survey and data collection
The study was undertaken in five municipalities of nord Benin, namely Bassila, Tchaourou, Toucountouna, Natitingou and Kandi. An investigation was conducted between May and June 2020 in villages having a tradition of P. butyracea fruits processing. All participans were more than 18 years, selected from the study sites. The study interest and procedure were explained to the community through village leaders. Therefore, all subjects approved the activity because they understood that it will allow them to valorize the P. butyracea fruit pulp. Each participant provided informed consent prior to responding to the survey. Individuals who did not provide informed consent could not proceed with the survey. This survey was approved by the Institution Ethics Board and the School of Nutrition and Food Sciences and Technologies (SNFST) of Abomey-Calavi University (UAC), approval N° F-025-2020-SNFST. To determine adequate number of respondents for our survey among the P. butyracea actors per parkland, the following formula was used: Ni = 4Pi(1−Pi)/d2 where Ni is the total number of P. butyracea actors to be surveyed in parkland i, Pi is the proportion of P. butyracea actors found in previous studies in parkland i, and d is the expected error margin in the conclusion, which was fixed at 0.1 10 . Based on this method, a total of 260 subjects distributed in twelve villages of aforementionned municipalities was obtained. Data were collected by administering questionnaires to randomly selected and willing respondents. The questionnaires included the following aspects: P. butyracea actor's perception on fruit pulp, various uses, collection state and various methods of collection of the fruits of P. butyrace. In addition, the various fruit shapes available in each commune was determined.

Subjects
The socio-demographic characteristics of the participants in the quantitative survey were as follows. Subjects were 180 females and 80 males. They were processors of P. butyracea butter.

Physical charecterization of the P. butyracea fruits
The fruits evaluation has been done immediately after the sample collection. The characteristics analysed were: diameter, length, fruit mass and fruit pulp mass. Diameter and length (mm) of the fruits were measured with a precision caliper (0.01 mm) and mass of the fruits (fm) and pulps mass (pm) were determined using balance with precison is 1/10.000. Measurements were performed on 50 fruits chosen at random per sample and by shape (ellipsoid, globular, ovoid and ellipsoid twisted) from each park. The generated values allow calculating the proportion of pulp (%)= pm/fm×100.

Evaluation of physicochemical composition of P. butyracea fruit pulp
The proximate analysis of fruit pulp samples were analyzed using standard methods 11 . The moisture content was determined by drying about five grams of the fresh sample in an oven at 105°C to constant weight. Crude ash was determined by incineration of 5g of sample in a muffle furnace at 550°C for 8 h. The nitrogen (N) content was estimated by micro-Kjeldahl method and crude protein content calculated as N% x6. 25

Preparation of extracts for the determination of total phenolics and antioxidant activity
Samples were extracted in methanol/HCl (99:1 (v/v) following the method described by 14 . Fifty milligrammes (50 mg) of each sample were extracted at room temperature with 1.5 mL of solvent under agitation using a magnetic stirrer for 30 min. The mixtures were centrifuged at under the same conditions, resulting in 3 mL crude extract. All extracts were used as they were after centrifugation for various analyses.

Total phenolics determination
Total phenolics were measured following the method of 15 modified by 14 as follows: to 300 μL of extract, 4.2 mL of distilled water, 0.75 mL of Folin-Ciocalteu's reagent (Merck, Germany) and 0.75 mL of sodium carbonate solution (200 g L-1) were added. After incubation for 30 min, the optical density was measured at 760 nm against a blank. Gallic acid was used as standard and the results were expressed as gallic acid equivalent (GAE) per g of sample DM.

Antioxidant Activity determination
The antioxidant activity was measured using DPPH (2,2-diphenyl-1-picrylhydrazyl). The DPPH method was conducted by adaptation as described by Scherer and Godoy 16 . Equal volumes (100 L) of DPPH (50 M) and plant extracts (12,5mg.ml -1 ) were mixed and incubated for 20-30 min in the dark at room temperature. Then, the absorbance was read at 517 nm and the blank was a mixture of methanol and DPPH (v : v). This activity was given as % DPPH scavenging and calculated using equation 1: where A control is absorption of DPPH solution, and A sample is absorbance of the test sample.
The half maximal effective concentration (EC 50 ) is the amount of sample necessary to decrease the absorbance of DPPH by 50%. It was determined graphically using a calibration curve in the linear range by plotting the extract concentration and the corresponding scavenging effect.
Ascorbic and gallic acids were used as positive controls. All the analyses were carried out in triplicate.

Statistical analysis
All data were expressed as mean ± standard deviation (n= 3 replicates). Data were analyzed using one-way ANOVA using SPSS 16.0. Duncan's multiple-range test was used to determine the difference between means. A significant difference was considered at the level of p ≤ 0.05.

Intercultural convergence uses of P. butyracea fruit pulp in Benin
The different uses of P. butyracea fruit pulp by rural households in the study zones are presented in Table 1. Among the different ethnic groups involved in the P. butyracea fruit pulp use, the Fulani reported to know about trees producing fruits with bitter pulp and their yellow color.
The fruit pulp sometimes is consumed by the farmers in the fields. P. butyracea fruit pulp is used mainly in the therapeutic applications and to a lesser extent in cosmetic and food sector.
All the socio-cultural groups interviewed use the pulp for therapeutic applications. More holds the most proportion of pulp (36.74%) which is definitely higher than those of the ellipsoid twisted (33.30%), ellipsoid (33.05%) and globular shape (30.44%).

Nutritional compositions of P. butyracea fruit pulp
The data on the chemical composition of the P. butyracea fruit pulp, as determined, are presented in Table 4. The moisture content of the P. butyracea fruit pulp ranged from 85.77 to 86.47%, with no significant different between the P. butyracea parks (p>0.05). These values were similar to those of the pineapple (87%) and apple (86%) 19 and shea fruit pulp from various zones in Benin (77.56 -80.89) reported by 18 . The P. butyracea fruit pulp would not be microbiologically stable at this moisture content as it would allow the proliferation of microorganisms. The ash content of the pulps was comparable to that of the bush mango fruitt pulp (02.10%) 20 but higher than the 0.33 -0.71% reported for shea fruit pulp jam 21 .This is indicative of the high mineral content of P. butyracea fruit pulp. The pH of the pulps ranged shea fruit pulp juice. The acids present in food not only improve its palatability but also influence its nutritive value 20 . The proteins value of fruit pulp from different parks ranged from 3.33 to 4.61% dw. There was a significant difference (P≤0.05) between the parks studied for this parameter. These proteins values were lower than that of the shea fruit pulp (3.96 -6.34%) reported by 18 , but is higher than 1.5-3.5% obtained by 9 in Uganda and 1.09% reported by 24 from the fresh shea pulp. In addition, Protein content of P. butyracea fruit pulp was similar to that found in mango pulp (4.8%) reported by 20  provided by the jams processed from shea fruit pulp reported by 21 .
The minerals profile of the P. butyracea fruit pulp result was presented in Table 4.

Microbial characteristics of P. butyracea fruit pulp
Hygiene quality of P. butyracea fruit pulps samples from various parks in Benin was presented in Table 5. Samples of P. butyracea fruit pulp had various microbial load with low count of aerobic mesophilic germs (1.70 to 2.75 log10 CFU/g), yeasts and moulds (1.85 to 2.97 log10 CFU/g), total coliforms (1.11 to 2.37 log10 CFU/g) and staphylococcus aureus (1.05 to 1.37 log10 CFU/g) ( Table 1)