Antioxidant activities of essential oil of Bidens pilosa (Linn. Var. Radita) used for the preservation of food qualities in North Cameroon.

This study aimed to determine the total antioxidant capacity of the essential oil (EO) of leaves of Bidens pilosa (Linn. Var. Radita) used as protectant of stored grains in Northern Cameroon. EO was characterized by GC-FID, antioxidant activity (AA) was determined by combining: evaluation of radical-scavenging activity, reducing power (RP) and co-oxidation of ß-carotene methods. Tests were carried out on crude and stored EO kept for two weeks at 31.48 ± 2.88°C and 58.56 ± 6.78% relative humidity. These conditions are the same as those of grain storage. GC analyses enabled the identification of 27 compounds, representing around 97.57% of the total oil contents. The major constituents of the EO were α-pinene (14.7%), ε-caryophyllene (13.5), and ß-ocimene (12.8%). The AA of the crude and stored EO are proportional to the concentrations and time of exposition. Exposed at the day light, this EO inhibit 77.4-18.69% for the DPPH system, 59.55-19.14% for RP method and 91.88-21.8% for ß-carotene-linoleate model system, respectively, from crude and 15 days storage EO at 20 mg L(-1). For the EC50 values, ß-carotene method is excellent and in the decreasing order of DPPH method, PR with 2.52 mg L(-1), 2.77 mg L(-1) and 4.13 mg L(-1), respectively, for the crude oil. The ET50 were 1.59 days for the RP method and 2.88 days DPPH system and ß-carotene-linoleate model system at 20 mg L(-1). These results showed that the EO of B. pilosa leaves exhibits AA that might be an added value for this EO preventing stored products from pest attacks.

Optimization of vegetable milk extraction from whole and dehulled Mucuna pruriens (Var Cochinchinensis) flours using central composite design.

Extraction conditions for maximum values of protein yield, protein content, sugar content and dry matter of vegetable milk extracts from dehulled Mucuna cochinchinensis bean flour and whole Mucuna cochinchinensis bean flour were investigated using response surface methodology. A Central Composite Design (CCFD) with three factors: temperature (25 to 95 °C); extraction time (6 to 74 min.) and water to flour ratio (6 to 24 mL/g) were used. Data analysis showed that all the factors significantly (p < 0.05) affected the responses variables. The optimal conditions determined for extraction were temperature 63-66 °C, water to flour ratio 12-13 mL/g and extraction time of 57-67 min. At these optimum points the protein and sugar contents, extraction yield of protein and dry matter were respectively 14.0 g/100 mL, 4.8 g/100 mL, 53.8 g/100 g, 12.1 g/100 g for vegetable milk produced from dehulled M. cochinchinensis bean flour and 6.4 g/100 mL, 3.5 g/100 mL, 50.0 g/100 g and 8.0 g/100 g for vegetable milk extracted from whole M. cochinchinensis bean flour milk. The optimal condition was verified at the optimum points for model validation and the response values were not significantly different from the predicted values.