Carl Moses Mbofung

Development of taro (Colocasia esculenta (L.) Schott) flour as an ingredient for food processing: effect of gelatinisation and drying temperature on the dehydration kinetics and colour of flour

A study was carried out to determine the dehydration kinetics of pregelled taro slices. Towards this objective 0.5 cm thick taro slices were cooked for varying periods of 0, 20, 45 and 60 min and dried in an air convection oven at varying temperatures of 50, 60, 70 or 80 °C before milling into flour. Analysis of data obtained during the monitoring of the drying process showed the dehydration process to follow a two falling rate mass transfer model. Within each falling rate period, mass transfer coefficients did not vary with moisture content. While the rate of drying was observed to increase with drying temperature, it was inversely related to the degree of gelatinisation. Drying at high temperatures affected the colour and the susceptibility to gelatinisation of the flour especially that obtained from gelatinised slices.

Functional properties of cowpea–soy–dry red beans composite flour paste and sensorial characteristics of akara (deep fat fried food): effect of whipping conditions, pH, temperature and salt concentration

Abstract The common bean ( Phaseolus vulgaris ) and the black eye bean ( Vigna unguiculata ) flours are presently effective alternatives for the preparation of local dishes such as “koki” (steamed cooked paste) and “akara” (deep fat paste) in Cameroon. This study was undertaken to study the influence of paste preparation conditions (whipping time and speed) on the swelling capacity (SC). Also the effect of temperature, pH and the salt concentration of the mixing water on the water absorption capacity (WAC), water solubility index (WSI) and the swelling capacity (SC) of the paste were studied following a completely randomised factorial design. The result revealed that an increase in whipping speed was generally accompanied by an increase in the initial swelling capacity of the paste. Further whipping after the attainment of the maximum swelling capacity resulted in a decrease in swelling capacity. WAC and WSI of the paste increased with increase in NaCl concentration and in pH. The temperature range used in this experiment had no significant influence on WAC and WSI ( P >0.05). The swelling capacity of paste diminished with the increase in NaCl concentration and a decrease in temperature. Contour plots depicting the effect of changing levels of the different factors showed that optimum conditions for a good batter were pH of 4–10, NaCl concentration of 0.5 M and a temperature of about 30 °C. Application of these conditions gave akara with highly acceptable sensory characteristics.

Evaluation of some selected blood parameters and histopathology of liver and kidney of rats fed protein-substituted mucuna flour and derived protein rich product.

This comparative study reports the nutritional and toxicological characteristics of Mucuna pruriens flour and a protein-rich product developed from it. The protein-rich mucuna product (PRMP) was obtained by the three steps procedure: protein solubilization, heat-coagulation and sieving. Three weeks rats (n=6 per group) were fed for 28 days on standard protein-substituted rat feed with mucuna flour or PRMP. The experimental design was a factorial design with three mucuna accessions (Velvet, Black and White) and two treatments (flour and PRMP). The protein content ranged 27.2-31.5 g/100 g for flour and 58.8-61.1% for PRMP. Processing flour into PRMP led to a significant (p<0.05) reduction of tannins (50%), total polyphenols (50%) and trypsin inhibitors (94%). The rats fed PMRP diets witnessed weight gain similar to casein, while those fed mucuna flour lost weight. The levels of total cholesterol, HDL-cholesterol and LDL-cholesterol observed in animals groups fed mucuna flour and PRMP were significantly lower (p<0.05) than the control group. In addition lymphocytes, granulocytes, red blood cells, hemoglobin and hematocrit of rats fed mucuna flour were significantly (p<0.05) lower than values in other rats groups. Kidneys glomerular sclerosis and high creatinine levels were observed in group fed mucuna flour. PRMP then represents a good alternative of using mucuna proteins for human nutrition.

Milk-clotting potential of fruit extracts from Solanum esculentum , Solanum macrocarpon L. and Solanum melongena

Fruit extracts from Solanum esculentum, Solanum macrocarpon L. and Solanum melongena were tested for their milk-clotting potential. The release of substances associated with milk-clotting was highly dependent upon quantity of berries, extraction duration and sodium chloride concentration. The highest milk-clotting activity was obtained after 8 h (for S. esculentum and S. melongena), and 12 h (for S. macrocarpon) of soaking 20 g of fruit in 6% NaCl 4°C. In these conditions, there was a non linear relationship between the milk-clotting time and the amount of fruit extracts from each species. The loss of milk-clotting activity was dramatic after wet-heating of extracts from S. esculentum and S. macrocarpon at 80°C for 10 min and after dry-heating of fruits at 100°C for 24 h. Heat treatment did not significantly affect the clotting activity of extract from S. melongena. Fruit extracts from S. esculentum had the greatest milk-clotting activity followed by extracts from S. macrocarpon and S. melongena. Extracts from S. esculentum and S. macrocarpon exhibited a proteolytic activity on the casein.

Glycosyl part identified within Balanites aegyptiaca fruit protease

The many milk-clotting proteases from plant are glycosylated; attachment of monosaccharides to enzyme is an advantage for its activity and stability. In this study, gas chromatography coupled to mass spectrometry-electrospray ionization was used to identify glycans bond to proteases purified from Balanites aegyptiaca fruits pulp through cation exchange chromatography. Carbohydrates were identified according to the retention time and the ion at m/z after derivation by heptafluorobutyric acid. The chromatograms obtained from monosaccharides analysis revealed the presence of galactose, mannose, arabinose, xylose, rhamnose and glucuronic acid. The mass spectrometry-electrospray ionization spectra corroborated these findings.

Production of Bambara Groundnut (Voandzeia subterranean) Flour for Use in the Preparation of Koki (a Steamed Cooked Paste): Effect of pH and Salt Concentration on the Physicochemical Properties of Flour

The present study is part of a project aimed at producing bambara groundnut (Voandzeia subterranean) flours for the preparation of koki (a steamed cooked paste). The flours were produced from the black (BBG) and white (WBG) varieties by the combined processes of soaking, drying, dehulling and milling. Some physicochemical characteristics of the flours were evaluated and the effects of flour particle size, salt concentration and pH on their functional properties were investigated. Significant varietal influence was indicated on the proteins and carbohydrates with the WBG variety showing high level of proteins (19.7%) and the BBP variety the highest carbohydrate content (61.7%). It was equally observed that an increase in NaCl tends to induce a reduction in the water absorption capacity (WAC), foam capacity and emulsion properties. The emulsion and foam capacities were observed to be at their minimum values within the pH range 2 and 4.

Optimization of Variables for Aqueous Extraction of Gum from Grewia mollis Powder

Grewia gum is a polysaccharide derived from the inner stem bark of the edible plant Grewia mollis. Juss (family Tiliaceae). It is a savanna shrub that grows wildly but is usually cultivated in Nigeria and Northern part of Cameroon. The main goal of the present study was to investigate the effect of aqueous extraction conditions on the extraction yield and physicochemical properties of the Grewia mollis. The studied aqueous extraction variables were water/powder (W/P) ratio (10 : 1–80 : 1 w/p), temperature (25.0–85.0∘C), time (1–3 h), and pH (4.0–10.0). The results indicated that the aqueous extraction variables exhibited the least significant () effect on the yield and the viscosity of the gum. The result shows that the ratio of extraction is the main factor affecting the extraction of gum. The optimized extraction condition for higher viscosity was at the powder/water ratio of 1 : 55.4, pH of 7, time of 1 h, and temperature of 50∘C. However, the optimized extraction condition for higher yield was at the powder/water ratio of 1 : 80, pH of 4, time of 3 h, and temperature of .

Mise en evidence de la biodisponibilité du calcium et du magnésium au cours de la fermentation du lait par des bactéries lactiques isolées du lait caillé de zébu

Resume Fermentation of skim milk by wild Streptococcus thermophilus and Lactobacillus bulgaricus , isolated from Cameroonian traditional fermented zebu milk showed high solubilisation of calcium and magnesium, indicating an excellent bioavailability of these minerals. Combination of the bacteria strains, while performing a high level of mineral solubilisation, appears less efficient than individual strains. These results suggest that scientific and technological characterisation of the bacteria from traditional source is important, in order to determine their contribution to the quality of traditional fermented milk. Des souches sauvages de Streptococcus thermophilus et de Lactobacillus bulgaricus , isolees du lait caille de zebu Camerounais, ont ete utilisees pour fermenter du lait UHT ecreme. Le dosage du calcium et du magnesium solubles dans les laits fermentes obtenus montre, quelle que soit la souche bacterienne, une augmentation de la solubilite de ces mineraux, donc de leur biodisponibilite. L’association des deux souches, tout en maintenant un niveau eleve de solubilisation des mineraux, apparait moins performante que les souches en culture individuelle. L’efficacite de ces souches sauvages vis-a-vis de la biodisponibilite des mineraux justifient l’interet de leur caracterisation biochimique afin de mieux preciser leur contribution a la qualite des laits fermentes locaux.

Effect of Soaking and Roasting on the Physicochemical and Pasting Properties of Soybean Flour

The effects of soaking and roasting on the physicochemical and pasting properties of soybean flour were evaluated. Soybean seeds were soaked overnight in tap water for 0–72 h, hand dehulled, dried, and part of the sample was roasted. Roasted and unroasted soy beans were milled into flour and analyzed. The results showed that the total carbohydrates (22.8–27.9 g/100 g), the ash content (3.5–3.6 g/100 g), and the total polyphenols (0.29–0.51 g/100 g) did not significantly change during both the soaking and roasting processes. However, the total proteins (35.8–46.0 g/100 g) and lipid contents (21.4–29.5 g/100 g) were significantly (p < 0.05) affected only by soaking, with a decrease in total protein and an increase in lipid contents. Phytate content (0.22–0.26 g/100 g) decreased significantly (p < 0.05) only with roasting. The tannins (0.01–0.30 g/100 g) and soluble proteins (4.0–29.0 g/100 g) significantly (p < 0.05) diminished with both treatments. There was a significant increase in the least gelation concentration (20–30 g/100 mL), a decrease in the swelling power (1.3–2.0 mL/mL), and consequently, reduction in the viscosity (range peak viscosity 18–210 cP) of the flour slurry after soaking and roasting. All these qualities—needed for producing nutritious flour for infants—highlighted the efficiency of these endogenous technologies.

Lipid-lowering properties of protein-rich mucuna product

BackgroundThe objective of this study is to evaluate the effect of protein-rich mucuna product (PRMP) on lipid parameters of hyperlipidemic rats.MethodsHyperlipidemia was induced in male rats for 3 weeks through high-fat diet. After induction, 30 hyperlipidemic rats were divided into five groups of six rats: control group (CG) received casein and four groups received PRMP as protein source at different proportions: 8.2, 16.4, 24.6, and 32.8 % corresponding, respectively, to 25, 50, 75, and 100 % substitution of casein in the diet for 3 weeks. Lipid and oxidative stress parameters of rats were assessed.ResultsThere were no significant differences in food intake and body weight loss among the experimental groups. The concentrations of the serum low-density lipoprotein cholesterol, total cholesterol, and triglycerides were lower in groups fed on PRMP 50, 75, and 100 % than in the CG group (p < 0.05). Histological analysis of the liver revealed that animals fed on PRMP diets presented a lower level of steatosis than the CG group. The most significant reduction of lipid parameters was obtained when PRMP was used as unique source of protein (PRMP 100 %). PRMP also influenced oxidative stress parameters as evidenced by a decrease in malondialdehyde and an increase in catalase and superoxide dismutase.ConclusionsThese findings demonstrated that PRMP exerts hypolipidemic effect; it has a metabolic effect on endogenous cholesterol metabolism and a protector effect on the development of hepatic steatosis. Our results also suggest that PRMP could manage metabolic diseases associated with oxidative stress.