Extraction, chemical composition and nutrional characterization of vegetable oils: Case of Amaranthus hybridus (var 1 and 2) of Congo Brazzaville

Amaranthus hybridus is a vegetable which is eaten in Congo Brazzaville and in other countries. Two varieties of A. hybridus seeds (var 1 and 2) were selected for this study. Average oil content varies between 11 and 14%. A. hybridus seeds are also rich in proteins (17%) and minerals. Red oils obtained have a high saponification value (130-190) and the iodine value is between 100 and 113. The quantity of unsaponifiable matter (5 - 7%) in these oils is important. The fatty acids composition gives the following average profile: 18: 2n-6 > 18: 1 n-9 > 16: 0 > 22: 6n-3 > 18: 0. A. hybridus seeds oils also have long chain poly unsaturated fatty acids such as DHA (5.63-21.46%) and the results indicated that the n-6/n-3ratios were 1.48 to 5.63. The triacylglycerols analysis shows that oils extracted by Bligh and Dyer method contains 6 major TAGs in A. hybridus var1: LLnLn › OLL › POL. › OLL › PLL › LLL and Amaranthus hybridus var2: LLnLn › OLL › PLL › POL. › OLL › LLL. The A. hybridus seeds can be used ascattle food and baby complement food. These oils have nutritive and dietetic potentialitie

Extraction and nutritional properties of Solanum nigrum L seed oil

With the aim of diversifying the lipids sources eaten by the African populations and those of Congo Brazzaville in particular, a physicochemical study of Solanum nigrum L seeds was carried out and three chemical methods (Soxhlet, Bligh and Dyer, and Folch) were used to extract the oil. The dry matter content of the seeds is 94.22%. Average lipids content varies between 34.5 and 37.5% dry matter, proteins content is 17% dry matter and crude ash content averages 7.18% dry matter and the principal mineral element is Mg (180 mg/100g). The acid value of the oil is about 2.5, saponification value varies between 157.3 and 190.1, peroxide value is low at 5.13 and iodine is 102.33.The fatty acid compositions of S. nigrum seeds oil shows that it has 67.9% of linoleic acid, indicating its high unsaturation. Apart from linoleic acid, other prominent fatty acids were palmitic, stearic and oleic acids. The following average profile is: 18: 2n-6 > 18: 1 n-9 > 16: 0 > 18: 0. The oil is liquid at room temperature and green in colour. Oil viscosity varies between 20 and 35 mPa.s at 25°C. Three activation energies which vary between 0.8 to 26.58 kJ.mol-1 were determined using Arrhenius’s equation. The melting points estimated by Differential Scanning Calorimetry were found to be between -22.0 and -12.0°C for the Soxhlet and Folch-extracted oils. Bligh and Dyer oil have three melting points at -36.2, -15.2 and 33.7°

Volatile compounds produced in two traditional fermented foods of the Congo: Nsamba (palm wine) and bikedi (retted cassava dough)

The "nsamba" (palm wine) and "bikedi" (retted cassava dough) are respectively produced by fermentation from the sap of the oil palm (Elaeis guineensis Jack) and lactic acid fermentation from cassava root (Manihot cassava Crantz). The study is focused on the determination of volatile compounds present in these two traditional fermented foods of Congo at the end of fermentation. The characterization of these volatile compounds at the end of fermentation for “nsamba" and "bikedi" revealed as the main compounds esters, terpenes, fatty acids and long chain alcohols. Indeed, it was noted: for "nsamba" 86% esters (ethyl caprylate, ethyl decenoate, N-ethyl decanoic, ethyl laurate) and decanoic acid; for "bikedi" 43% terpenes and 37% alcohols: estragol, limonene, linalol, myrcene and menthol.Keywords: Palm wine, dough, cassava, aroma, fermentation.African Journal of Biotechnology, Vol 13(42) 4119-412