Evaluation of the fungal microflora infesting pigeon pea (Cajanus cajan L. Millspaugh) in southern Benin and associated mycological hazards

Pigeon pea is a perennial legume with a good nutritional value. Unfortunately, it is also a substrate for fungi contamination. Then, a qualitative semi-structured survey was carried out in the main production areas of pigeon pea in southern Benin. This survey was coupled with samples collection. A total of 60 samples of pigeon pea were collected and analyzed for associated fungal microflora by using a taxonomic schemes primarily based on morphological characters of mycelium and conidia. Obtained results indicated a low technological valorization of pigeon pea seeds in southern Benin and their used only in direct consumption after cooking. Microbiological analyses revealed the high contamination of pigeon pea seeds by fungi, with the most occurrence of Aspergillus (71.42%), followed by Fusarium (26.19%). Fungal species such as Aspergillus ochraceus, A. parasiticus, A. flavus and Fusarium oxysporum were also detected in analyzed samples. Taking into account the toxicity of the secondary metabolites produced by these fungi, mycological hazards are discussed and important methods for the control of mycotoxin-contamination are further provided. More attention should be paid to the mycological quality of this legume, in order to protect the consumers’ health

Aspect botanique, profil nutritionnel et implications du pois d'Angole (Cajanus cajan (L.) Millspaugh) dans le développement communautaire en Afrique subsaharienne

Le pois d’Angole est une importante légumineuse à graines appartenant à la famille des Fabaceae. Il représente une culture intéressante pour l’agriculture africaine grâce sa richesse en éléments nutritifs, son adaptabilité aux conditions climatiques, sa capacité exceptionnelle de régénération des sols et ses usages très diversifiés pour l’homme et le bétail. C’est donc une culture à promouvoir dans la lutte contre la malnutrition et l’insécurité alimentaire en Afrique subsaharienn

Antimicrobial and physico-chemical effects of essential oils on fermented milk during preservation

Objectives: Milk and milk products are known to be the good media for development of many microorganisms. Some essential oils are known to have antimicrobial activities against bacteria, mould and fungi. With the aim of contributing to the preservation of the fermented dairy products, the present study explored the use of essential oils for biopreservation in food pathogen control. The objectives were to study the effect of two essential oils extracted from local plants Xylopia aethiopica (Dunal) A.Rich. and Pimenta racemosa (Mill.) J.W. Moore on the physico-chemical, microbiological and organoleptic characteristics of the fermented milk.Methodology and Results: At the first level, essential oils were extracted from the leaves of plants and the minimum inhibitory concentration (MIC) of each one was detected using the serial dilution method and Muller Hinton Broth medium. The references strains used were Staphylococcus aureus ATCC 25923 and Escherichia coli ATCC 25922. Based on the MICs determined, essential oils were added to fermented milk and determination of its physicochemical characteristic, evolution of the microbial flora (meophilic flora, lactic flora, coliforms, Staphylococcus aureus ) were done during two weeks of preservation. The results showed that Xylopia aethiopica had a lowest minimum inhibitory concentration. After fifteen days of preservation, a decrease of mesophilic flora and lactic bacteria was observed and a disappearance was noticed for coliforms, thermotolerant coliforms and Staphylococcus aureus during the same time. These results prove the efficiency of those essential oils in fermented milk preservation. Moreover, microorganisms’ inhibition was more pronounced with Xylopia aethiopica essential oil than the Pimenta racemosa one.Conclusion and applications of findings: The study results showed a possible way of using essential oils as an alternative to chemical additives used for preservation of food products. As there are natural products, there could take an important part in the food safety policies.Keywords: Essential oils, biopreservation, fermented mil

EFFECT OF ESSENTIAL OIL OF MENTHA SPICATA L. FROM BENIN ON THE QUALITY OF MANGO PUREE IN STORAGE MODEL FOOD SYSTEMS AT 4° AND 25°C

The present study aims to evaluate the effect of essential oil from fresh leaves of Mentha spicata L. on the quality of mango puree in storage model food systems at 4°C and 25°C. The results of physico-chemical characterization of mango puree underlined its high nutritional potential, with carbohydrates, carotenoids and vitamin C contents of 9.5±0.4%, 20.05±0.03 mg/100g and 21.03±0.05 mg/100g respectively. The microbiological analyses using taxonomic schemes primarily based on morphological characters of mycelium and conidia revealed that Aspergillus parasiticus, Fusarium versicolor and Mucor spp. were the most common fungi identified in mango puree in the southern Benin. Antifungal assay, performed by the agar diffusion assay, indicated that essential oil exhibited high antifungal activity against the growth of fungi. The minimal inhibitory concentration (MIC) of the essential oil was found to be 2.0 μL.mL-1for Aspergillus parasiticus and Fusarium versicolor; and 1.0 μL.mL-1 for Mucor spp. The chemical analysis of the oil made by GC/MS led to the identification of 35 components, characterized by carvone (67.5%), and limonene (12.0%) as major components. The results obtained during the evaluation of the microbiological, physico-chemical and sensorial characteristics of the mango puree stored by adding essential oil, revealed the high potential of the essential oil of Mentha spicata L. in food quality preservation. This essential oil offers a novel approach to the management of fruit derivate products during storage

Effects of essential oil from Cymbopogon citratus leaves and its susceptibility on the quality of fresh orange juice during storage

The present study aims to evaluate the effect of essential oil (EO) from Cymbopogon citratus leaves against the spoilage flora of fresh orange juice. Thus, the EO was extracted by hydrodistillation from fresh leaves of Cymbopogon citratus collected in southern Benin and its chemical composition was determined by gas chromatography, coupled to mass spectrometry (GC/MS). Orange samples were collected from large production areas of South and Central Benin and juices were extracted by mechanical pressing. After identification of spoilage flora of fresh orange juice, antimicrobial tests were carried out with the EO of Cymbopogon citratus to evaluate its antimicrobial activity on spoilage flora of fresh orange juice.  Results indicate that the spoilage flora of fresh orange juice is mainly composed of fungi belonging to the genera of Cladosporium, Penicillium and Fusarium. Bacteria such as Enterobacter cloacae and Enterobacter aerogenes were also identified in some samples. The major compounds identified in the EO by GC/MS are Neral (33.0%) and geranial (41.3%) with a predominance of oxygenated monoterpenes (85.5%). Antimicrobial tests have revealed a high antibacterial activity of the EO, with minimum bactericidal concentrations (MBC) between 0.1 and 0.15 μL.mL-1. Antifungal tests revealed that fungi are also susceptible to this EO with minimum fungicidal concentration (MFC) between 0.15 and 0.25 μL.mL-1. Results obtained during the evaluation of the physicochemical characteristics of the orange juice stored by adding EO, indicated a significant decrease in the pH and vitamin C content. However, with EO concentration of 0.250 μL.mL-1, the pH of stored juice was 6.4 ± 0.1 after 15 days of preservation, with a best vitamin C content of 28.06 ± 0.03 mg / 100mL. The EO of Cymbopogon citratus, with high antimicrobial activity, could be used as an alternative in the preservation of fruit juices, replacing antimicrobials from chemical synthesis

Efficacité des huiles essentielles de trois plantes aromatiques contre la mycoflore d’altération du niébé (Vigna unguiculata L., Walp) collecté dans les magasins de vente du Sud-Bénin

Objectif : La présente étude vise à évaluer l’activité antimicrobienne des huiles essentielles extraites des feuilles fraîches de Cymbopogon citratus (L.), de Cymbopogon nardus (L.), et de Eucalyptus saligna (S.), sur les moisissures isolées des stocks de niébé de quelques magasins de vente du sud-Bénin.Méthodologie et Résultats : Pour ce faire, un échantillonnage a été réalisé dans les grands magasins de stockage du niébé situés dans les marchés de Ouando (Porto-Novo) et de Dantokpa (Cotonou) suivi de la recherche et l’isolement de la mycoflore d’altération. Des tests antifongiques ont été réalisés avec les huiles essentielles de Cymbopogon citratus (L.), Cymbopogon nardus (L.), et de Eucalyptus saligna (S.), afin d’évaluer leur potentiel antifongique. Des résultats obtenus, il ressort que les souches fongiques isolées des échantillons de niébé sont essentiellement Aspergillus flavus (L.), Aspergillus tamarii (K.) et Penicillium roqueforti (T.). Les tests antifongiques ont permis de démontrer l’activité des huiles essentielles testées contre la flore fongique contaminant le niébé, avec des concentrations minimales d’inhibition (CMI) dépendantes du type fongique et de la dose d’huile essentielle testée. Les fortes activités antifongiques sont obtenues avec les huiles essentielles de Cymbopogon citratus (L.) et de Cymbopogon nardus (L.) avec des CMI comprises entre de 0,05 et 1Al/ml.Conclusion : Le potentiel antifongique de ces plantes offre donc une approche novatrice dans la gestion intégrée des stocks de niébé au Sud du Bénin.Mots clés : niébé, moisissures, huiles essentielles, activité antifongique

Essential oils as natural antioxidants for the control of food preservation

Despite advancements in food preservation ways, the nature of preservatives remains one of the real problems that must be taken into account for the preservation of consumer health. To cope with the problems of contamination and oxidation of foodstuffs, the chemistry development has favored the appearance and application of new chemical substances such as benzoates, sulphites, calcium chloride, acid citric etc. used as synthetic food preservatives. Subsequently, several of these synthetic preservatives have been banned in some countries because of their long-term adverse toxicological effects. The current trend of consumers seeking healthier diets is forcing them to use natural products with antimicrobial and antioxidant activities such as essential oils. These aromatic plant extracts, whose antioxidant power has been widely proven in the literature, also contain substances with very interesting biological activities, less polluting for the environment, with minor effects on the health of consumers. In this review, we have highlighted the antioxidant potential of essential oils for food quality improvement and preservation