Effects of chemical- and bio-fertilizers on cowpea resistance to cowpea weevil,Callosobruchus maculatus (F.) (Coleoptera: Chrysomelidae)

The cowpea weevil, Callosobruchus maculatus (F.) (Coleoptera: Chrysomelidae) is a destructive pest of cowpea grains in the field and storage. Effects of two chemical fertilizers (triple superphosphate (TSP) and urea) and three bio-fertilizers (Bradyrhizobium japonicum, Pseudomonas putida and mycorrhizal fungi) compared to control were studied on resistance of cowpea pod and grain to C. maculatus. Pod resistance was evaluated as oviposition preference, egg-to-adult survival and developmental time, and grain resistance was measured as life history and life table parameters of the pest. Cowpea plants treated with tested fertilizers were grown under field condition. Then, the full-size green pods and their immature grains were harvested and used in the experiments. The highest oviposition preference and percentage of adults emergence were on control (untreated) pods as compared to treated ones. The longest developmental times were recorded on the pods obtained from TSP and B. japonicum treatments. In most cases, significant differences were observed for the life history and life table parameters of C. maculatus on the grains treated with examined fertilizers. Delayed developmental time was recorded when C. maculatus was fed with P. putida- and B. japonicum-treated grains. The highest and lowest number of eggs laid by each female (fecundity) was on the grains obtained from TSP and control treatments, respectively. The net reproductive rate (R₀), intrinsic rate of increase (r_m) and finite rate of increase (λ) were the lowest on cowpea grains fertilized with B. japonicum and highest on the grains treated with urea. Our results showed that B. japonicum can be suggested to utilize, as an alternative for chemical fertilizers, to minimize cowpea infestation by C. maculatus. These findings could be helpful in developing integrated management of the pest on cowpea.     

Semiochemical modulation of host preference of Callosobruchus maculatus on legume seeds

Host preference of Callosobruchus maculatus (F.) on seeds of three legume cultivars, Ife-brown and black-eyed cowpeas [Vigna unguiculata L. (Walp)], and soybean (Glycine max L.), was investigated. Mated female C. maculatus showed high (90–95%) attraction to the three legume cultivars in Y-tube bioassays. However, the weevils discriminated among the cultivars in four-choice tests and showed greater attraction to Ife-brown cowpea (50%) than to soybean (30%) and black-eyed cowpea (15%). Coupled gas chromatography-electroantennography (GC-EAD) and GC–MS analyses of the headspace volatile organic compounds (VOCs) emitted by the legume seeds identified 2-ethyl hexanol as the principal EAD active component. Emission of 2-ethyl hexanol was two-fold greater in Ife-brown cowpea (∼0.54 μg g⁻¹ seeds) compared with black-eyed cowpea (∼0.23 μg g⁻¹ seeds) and soybean (∼0.21 μg g⁻¹ seeds). Synthetic 2-ethyl hexanol attracted 68% of female C. maculatus at 0.01 μg dose in Y-tube bioassays. These results demonstrated that host preference in C. maculatus is odor-mediated, and identified 2-ethyl hexanol as a potential attractant for C. maculatus.     

Preparation and characteristics of lactic acid fermented cowpea milk

 Four Lactobacilli were isolated from both commercial cowmilk yoghurt ("Fan" yoghurt) and "wara", a West African soft cheese. They were identified as Lactobacillus acidophilus ("Fan" yoghurt), L. plantarum, L. brevis and unidentified Lactobacillus spp. ("wara"). L. acidophilus and L. plantarum were chosen as starter organisms for the production of a yoghurt-like product from cowpea milk. There was a decrease in the final pH and an increase in the titratable acidity of the cowpea milk samples at the end of the fermentation period. The crude protein, total ash, calcium, potassium and phosphorus values increased in the fermented cowpea milk, while a decrease was obtained for the lipid, moisture and crude fibre contents. A decreasing trend was noted in the phytic acid and trypsin inhibitor of the cowpea flour when processed into milk, followed by a further reduction at the end of fermentation. Consumer acceptability of the cowpea yoghurt varied, with preference being given to the banana and strawberry flavoured samples. Received: 10 June 1996 / Revised version: 17 September 1997     

A Combination of Cowpea Mosaic Virus and Immune Checkpoint Therapy Synergistically Improves Therapeutic Efficacy in Three Tumor Models

Immune checkpoint therapy (ICT) has the potential to treat cancer by removing the immunosuppressive brakes on T cell activity. However, ICT benefits only a subset of patients because most tumors are “cold”, with limited pre‐infiltration of effector T cells, poor immunogenicity, and low‐level expression of checkpoint regulators. It has been previously reported that Cowpea mosaic virus (CPMV) promotes the activation of multiple innate immune cells and the secretion of pro‐inflammatory cytokines to induce T cell cytotoxicity, suggesting that immunostimulatory CPMV could potentiate ICT. Here it is shown that in situ vaccination with CPMV increases the expression of checkpoint regulators on Foxp3^?CD4⁺ effector T cells in the tumor microenvironment. It is shown that combined treatment with CPMV and selected checkpoint‐targeting antibodies, specifically anti‐PD‐1 antibodies, or agonistic OX40‐specific antibodies, reduced tumor burden, prolonged survival, and induced tumor antigen‐specific immunologic memory to prevent relapse in three immunocompetent syngeneic mouse tumor models. This study therefore reveals new design principles for plant virus nanoparticles as novel immunotherapeutic adjuvants to elicit robust immune responses against cancer.     

Effect of milling method on selected physical and functional properties of cowpea (Vigna unguiculata) paste

Particle size distribution (PSD) of cowpea meal is an important determinant of paste functionality and end product quality. Samples from various mills and screen sizes were used to determine PSD, water‐holding capacity (WHC) and swelling capacity (SWC). Hammer mill (1.73 mm screen) meal had a geometric mean diameter (d_gw) of 221 microns, whereas PM‐360 [plate mill with one complete turn (360°) of clearance] meal had a d_gw of 1559 microns. All other milling processes resulted in meal with an intermediate particle size. To reduce the particle size of cowpea pastes, cowpea meals were hydrated to pre‐determined moisture contents, held for 15 min, and then blended in a blender before whipping. Blending increased the WHC and SWC of all samples.     

Impact of cowpea addition on the Protein Digestibility Corrected Amino Acid Score and other protein quality parameters of traditional African foods made from non-tannin and tannin sorghum

Protein malnutrition is a problem in Africa where sorghum is a staple foodstuff. Improvement in the protein quality of traditional African sorghum (Sorghum bicolor L. Moench) foods through the addition of cowpea (Vigna unguiculata L. Walp), an indigenous African legume, was investigated. Two sorghum cultivars, a red, tannin-type (NS 5511) and a white tan-plant, non-tannin type (Orbit) were complemented with cowpea (70:30 ratio). Ugali (thick porridge), uji (fermented thin porridge) and injera (fermented flatbread) were prepared. The protein lysine scores of cowpea-complemented foods were about double the levels of sorghum-only foods. The in vitro protein digestibility of the foods increased by 13–62%. The increase in lysine and protein digestibility improvement resulted in three- and two-fold improvement in the Protein Digestibility Corrected Amino Acid Score (PDCAAS) of NS 5511, and Orbit foods, respectively. Addition of cowpea to tannin, as well as non-tannin sorghum is a viable option for improving the protein quality of a wide range of traditional African foods.     

Nutritional,physicochemical, and textural properties of gluten-free extruded snacks containing cowpea and whey protein concentrate

Ready-to-eat extruded snacks with high protein and fibre were developed from a composite flour comprising rice flour, cowpea flour and whey protein concentrate (WPC). Nutritional, physicochemical, and textural properties of extrudates were evaluated, at five ratios of cowpea: WPC (10:0, 15:05, 20:10, 25:15, 30:20); rice flour was used as a control. The protein and fibre content in the extrudates significantly increased (P ≤ 0.05) with cowpea (10%–30%) and WPC (5%–20%) incorporation compared to the control. The extrudates with higher levels of cowpea and WPC showed a significant increase in bulk density and hardness. A slight decrease of 12% was observed in the expansion of 15% cowpea and 5% WPC fortified extrudates compared to the control. The number of peaks during compression increased with incorporations of cowpea and WPC. All cowpea and WPC containing snacks were darker than the control. Significant correlations were found between the protein, fibre, colour values and textural properties. The essential and non-essential amino acid profiles increased in the extrudates, proportionally to the cowpea and WPC fortification.     

Technological functionality of composite flours from sorghum,tapioca and cowpea

Composite flours from accessible raw materials may interest developing countries, cutting wheat import costs, bolstering domestic agriculture and boosting nutrition. Technological functionality (WHC and OHC, pasting, swelling and thermal properties) of composite tapioca, sprouted sorghum, cowpea and wheat flours (at 50%, 33% and 25% (w/w) flour basis) was evaluated. PCA revealed that, in a 50% w/w blend, sprouted sorghum and tapioca were technologically similar to wheat, and thus of interest when gluten's viscoelastic properties are not required (e.g. flatbread). Since cowpea flour can enhance nutrients, a flour from sprouted sorghum, tapioca and cowpea is preferable nutritionally and technologically, and potentially sustainable, its raw materials being available locally. Furthermore, PCA showed that composites of sprouted sorghum, tapioca, cowpea and wheat flours at 25% w/w offer a good compromise between technological and nutritional qualities, while reducing wheat imports and cassava post-harvest losses. These results may herald technologically satisfactory, nutritional, sustainable bakery products.     

Antioxidant Properties of Peptide from Cowpea Seed

The amino acids, hydrophobicity, preparation technology, and antioxidant activity of peptide from cowpea seed isolated protein were investigated. The ratio of essential amino acid to total amino acid of cowpea seed and cowpea seed isolated protein were 35.60 and 36.27%, respectively, and the essential amino acid to non-essential amino acid were 55.27 and 56.96%, respectively. The mole ratio of hydrophobic amino acids and branched chain amino acids in cowpea seed isolated protein were 38.10 and 31.75%. The hydrophobicity value of cowpea seed isolated protein was 5.01 KJ/?mol. The optimum hydrolyzing parameters obtained from orthogonal experiment (L₉(3)⁴) were as follows: hydrolyzing temperature, 50°C; cowpea seed isolated protein concentration, 5%; pH, 9.0; and hydrolyzing time, 2 h. Under optimized conditions, the degree of hydrolysis was 26.85%. Available data obtained with in vitro models exhibited that peptides had significant inhibitory effects on 2,2-diphenyl-1-picrylhydrazyl and hydroxyl radical with half inhibitory concentration (IC₅₀) values of (6.38 ± 0.15) mg/mL and 2.03 mg/mL, respectively, suggesting that cowpea seed peptide possessed higher antioxidative activity and could be used as a potential functional food ingredient.     

Effect of soybean substitution for cowpea on physical,compositional, sensory and sorption properties of<Emphasis Type="Italic"> akara</Emphasis> Ogbomoso

Akara Ogbomoso was prepared from cowpea:soybean flour mixture ratios of 100:0, 80:20, 60:40 and 40:60. Physical, compositional, sensory and sorption characteristics of the akara were evaluated. Protein and fat content increased, while carbohydrate content decreased as the soy content of the flour mixture of akara Ogbomoso increased. There were no significant differences (P<0.01) in the colour, taste, aroma and overall acceptability for either the freshly prepared akara Ogbomoso or the akara Ogbomoso stored for 10 weeks. There were significant differences (P<0.01) in crunchiness, increasing as the soy substitution increased both in the freshly prepared and stored akara Ogbomoso. The adsorption isotherms of akara Ogbomoso varied with varying levels of soy substitution and at 20, 30 and 40 °C, had sigmoid shaped, type II isotherms according to Brunauer-Emmet-Teller (BET) classification, and were affected by temperature and composition. Increased levels of soy substitution and temperature depressed the isotherms. Calculated monolayer moisture contents using BET and Guggenhein Anderson deBoer models decreased with increasing soy substitution and temperature.