Nicolas Y. Njintang

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.

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.

Cowpea Quality Seed Indicators as Influenced by Field Application of Selected Biofertilizers and Mycoinsecticide in Three Agroecological Zones of Cameroon

Inoculation of cowpea with biofertilizers (rhizobia + mycorrhiza), and spraying them with the mycoinsecticide Metarhizium anisoplae has been shown to improve growth and grain yield. However, the treatment may impair the technological properties of the grains, which have not yet been investigated. This study is a followup to our recent study on the effect of selected biofertilizers and mycoinsecticide in three agroecological zones of Cameroon, aimed at evaluating the physical properties and the protein content of cowpea seeds as affected by these bio-inoculants. Spraying cowpea plants at flowering with the mycoinsecticide M. anisopliae and/or inoculating cowpea seeds at sowing with biofertilizers (rhizobia, mycorrhizae) had no significant effect on the protein content, water absorption capacity, and the percentage of seed coat. They instead significantly affected the physical properties of seeds, such as the seed weight, length, geometric diameter, and sphericity, but this varied from one agroecological zone to another. Whereas the seed weight was increased in agroecological zone V, a significant decrease was observed in zones I and II. The changes in weight reflected those of diameter and volume as confirmed by the correlation analysis. Application of biofertilizers had no significant effect on the water absorption capacity, protein, and coating percentage of cowpea seeds, suggesting that the main qualities of cowpea seeds for industrial utilization remained the same. The increased yield generally associated with these treatments may result from changes in the geometric size, which depends on the agroecological zone.

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.

Characterization of Morphology and Structural and Thermal Properties of Legume Flours: Cowpea (Vigna unguiculata L. Walp) and Bambara Groundnut (Vigna subterranea L. Verdc.) Varieties

Abstract Bambara groundnut and cowpea legume seeds with a very high nutritive value are widely produced and consumed in most sub-Saharan African countries. The aim of this work which is part of a large study was to compare the potential of bambara groundnut and cowpea varieties of flour as basic raw material for the preparation of a widely legume-based food product known as koki. Toward this objective standard methods were used to analyze some morphological, microstructural and thermal properties of these legume flours along with their respective isolated starches and proteins. In general, thermal transition of proteins has slow enthalpy energy of less than 1 J g−1. The gelatinization temperature and the enthalpy of gelatinization of starches in the flours were lower as compared to those of isolated starches, suggesting here an interaction of starch with other components during the gelatinization process. All starches are of A-type and the degree of crystallinity of bambara starch was higher than that of cowpea starch. Scanning electronic microscopy revealed that starch granules of North cowpea (NC), West cowpea (WC) and White bambara groundnut (WB) were polygonal while that of Black bambara (BB) starch were spherical in shape. The flowability characteristic of the flour and starch shows that bambara flour with small particle size (~90%<100 µm) had a high compressibility (47.38–43.16%) as compared to cowpea flour (32.18–30.24%). NC and VB starch granules have a size between 10 and 35 µm while WC and BB are too small (6–15 µm). NC and WB starch granule sizes are between 10 and 35 µm while WC and BB’s sizes are too small (6–15 µm). Bambara groundnut and cowpea flour along with their respective isolated starches and proteins therefore appears to be a valuable raw material which may be useful for the preparation of many food products.

Effect of spices formulations on the physicochemical and sensory properties of Nnam gon, a Cameroonian dish prepared with cucurbitaceae seeds

Abstract Nnam gon, a cake made by steam cooking a mixture of Cucurbitaceae seeds paste and others ingredients specially spices, is a highly prized dish in Central African region. A preliminary investigation conducted as part of this study highlighted that formulations used in the processing of Nnam gon vary according to the spices used. This study was carried out to determine the best formulation for the preparation of this dish. For this purpose, Nnam gon samples were produced from four formulations which differ according to the number of spices used: F0 (no spices); F1 (0.91 g of Allium cepa paste); F2 (0.88 g of A. cepa paste, 0.35 g of Allium sativum paste, 0.41 g of fresh Officinale zingiber paste, 0.41 g of fresh Petroselinum crispum paste, 0.33 g of Monodora myristica, 0.48 g of fresh Celery graveolens paste, 1.19 g of fresh Allium porrum paste, 0.13 g of Allium lepidophyllus powder, and 0.13 g of Piper nigrum), and F3 (0.90 g of A. cepa paste, 0.35 g of A. sativum paste, and 0.42 g of fresh O. zingiber paste). The samples were evaluated for their physicochemical characteristics and sensory profile (Quantitative Descriptive Analysis). The results revealed that proteins (16.56–17.38%), carbohydrates (4.71–5.10%), lipids (23.14–24.25%), ash (4.03–5.92%), and fibers (2.17–2.68%) increased significantly (p < .05) with spices adding. The increase in polyphenols (310.55–592.80 mg/100 g FM) and phytates (2.23–12.49 mg/100 g FM) contents was positively correlated with antioxidant properties of Nnam gon which also increased with spices adding. Significant differences were observed between the samples for all attributes generated (appearance, odor, taste, flavor, texture, and oral texture). Spices adding induced a decrease in hardness, cohesivity, elasticity, and granulous of cake but enhanced oily. Nnam gon produced with spicy formulation (F2 and F3) had higher mean score for general acceptance which was highly correlated (p < .05) with spice odor (r = .99), spice taste (r = .92), and color (r = .84). From this study, it is suggested that spicy Cucurbitaceae paste could improve nutritional value, antioxidant properties, and general acceptance of Nnam gon.