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European Journal of Applied Sciences – Vol. 12, No. 1

Publication Date: February 25, 2024

DOI:10.14738/aivp.121.16434

Mambou, L. B., Loumouamou, B. W., & Dzondo, G. M. (2024). Chemical Properties and Proximate Composition of Pellonula

leonensis Fish from the Congo River and Nanga Lake. European Journal of Applied Sciences, Vol - 12(1). 473-486.

Services for Science and Education – United Kingdom

Chemical Properties and Proximate Composition of Pellonula

leonensis Fish from the Congo River and Nanga Lake

Léa Béatrice Mambou

Multidisciplinary Food and Nutrition Research Team: Regional Center of

Excellence in Food and Nutrition, Faculty of Science and Technology, Marien

Ngouabi University, Brazzaville, Congo and Molecular and Sensory Food

Engineering Laboratory, National Polytechnic School (ENSP), Marien Ngouabi

University, Brazzaville, Congo

Bob Wilfrid Loumouamou

Multidisciplinary Food and Nutrition Research Team: Regional Center of

Excellence in Food and Nutrition, Faculty of Science and Technology, Marien

Ngouabi University, Brazzaville, Congo and UNESCO-ENSP Chair, Process

Engineering Laboratory,Marien NGOUABI.B P.69 University, Brazzaville, Republic

of Congo

Gadet Michel Dzondo

Molecular and Sensory Food Engineering Laboratory, National Polytechnic

School (ENSP), Marien Ngouabi University, Brazzaville, Congo

ABSTRACT

Pellonula leonensis is a small fish, with a maximum size of around 102,8 mm,

consumed in Congo Brazzaville, most of which comes from the Congo River and

Nanga Lake. For the nutritional importance of Pellonula leonensis fish in the diet of

Congolese populations, this study aims to determine the proximate composition of

this fish. The moisture content was obtained after drying the samples in an oven at

70°C for 24 hours. The total lipid content was determined after Soxhlet extraction.

The Kjeldahl method was used to determine total protein content. Total soluble

sugars were determined using the phenol and sulphuric acid method of Dubois et

al. The total ash content was measured after incineration in a muffle furnace at

550°C. Magnesium, phosphorus and calcium contents were measured by atomic

absorption spectrometry. Regarding the Pellonula leonensis fish studied, the

protein content varies from 38.71 to 39.93%, from 40.27 to 41.12% and from 39.75

to 39.96% respectively for the dried fish of Brazzaville, Boko and Pointenoire. Lipid

levels vary from one source to another, with levels of around 20% and 30%

respectively in samples from Nanga Lake and the Congo River. The carbohydrate

content ranged from 2.01 (± 0.09) to 4.88 (± 0.07) % for samples from the Congo

River and from 8.14 (± 1.22) to 9.26 (± 0.95) % for samples from Nanga Lake. The

samples studied gave ash contents ranging from 13.95 ± 1.01 to 15.81 ± 0.79 % for

both origins. The crude fibre content varied from 0.26 to 0.29%, from 0.30 to 0.33%

and from 0.37 to 0.39% respectively for samples from Brazzaville, Boko and Pointe- Noire.

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Mambou, L. B., Loumouamou, B. W., & Dzondo, G. M. (2024). Chemical Properties and Proximate Composition of Pellonula leonensis Fish from the

Congo River and Nanga Lake. European Journal of Applied Sciences, Vol - 12(1). 473-486.

URL: http://dx.doi.org/10.14738/aivp.121.16434

Figure 1: Pellonula leonensis fish

Nine samples of Pellonula leonensis fish were studied. Three samples from Brazzaviille (BV1,

BV2 and BV3), three samples of Boko fish (BK1, BK2 and BK3) and three other samples from

Lake Nanga (PN1, PN2 and PN3).

Fresh samples from Brazzaville were oven-dried at 70°C for 12 hours. All nine samples were

then ground using a manual mechanical grinder. The powder from each of the samples obtained

was wrapped in polyethylene film, sealed in zip-lock bags and placed in a freezer at around -

18°C until analysis.

METHODS

Moisture Content

Moisture content was determined by heating 5.0 g (mass M0) of each sample to a constant

weight (MS) in a crucible placed in an oven maintained at 105°C for 24 hours. Moisture content

was determined by the following relationship:

Moisture content= (M0-MS) x100/M0. (1)

Determination of Lipid Content

The Soxhlet (S) method was used to extract lipids from fish. A 30 g mass of fish was put into the

extraction cartridge and placed in the Soxhlet. Using 200 mL of hexane contained in a 250 mL

flask, the fat contained in the grind was depleted by refluxing the solvent (at around 80°C) for

6 hours. The extract was cooled and then dried with anhydrous sodium sulphate. The oil is

obtained after evaporation of the solvent in à rotary evaporator at 40°C under vacuum at 200

mbar. The oil content is then determined in relation to the mass of crushed material using

equation 2 below:

Lipid content= (M1-M0) x100/M. (2)

Where: M1 : mass of the flask containing the oil, M0 : mass of the empty flask, M : mass of the

crushed material.

Determination of Protein Content

Protein content was determined by determining total nitrogen using the Kjeldahl method [9]

after sulphuric mineralisation in the presence of a selenium catalyst. The nitrogen content value

obtained was multiplied by 6.25 to quantify the protein content.