Compositional and nutritional properties of selected newly developed lines of cowpea (Vigna unguiculata L.Walp)

Legume seed system performance in sub-Saharan Africa: barriers, opportunities, and scaling options. A review

As a fundamental pillar of food security in sub-Saharan Africa (SSA), ensuring seed security is critical to empowering farmers in cultivating food and livestock feed, thereby fostering income generation from agricultural outputs. Among the crops cultivated by smallholders, legumes have the potential to deliver multifaceted benefits. Legumes are nutrient-dense and enhance soil health through their nitrogen-fixing qualities. However, in many instances, the development, release, and supply of improved legume varieties are insufficient to meet the needs of smallholder farmers in SSA. Here, we systematically reviewed the literature to (i) identify and categorize existing legume seed systems, (ii) map legume varieties available to smallholders, (iii) identify barriers hindering the adoption of various legume varieties, and (iv) identify potential strategies and opportunities for strengthening legume seed systems in SSA. Our results demonstrate the coexistence of formal and informal seed systems within legume seed supply chains in SSA, each employing unique seed distribution channels. Smallholders, however, are shown to predominantly depend on the informal seed system to source most legume seeds except for commercially available varieties. We also identified a diverse range of legume varieties available to smallholders in the region, with farmers having varying trait preferences based on crop type and gender. Notably, high yield and abiotic stress tolerance were the most preferred traits. The adoption of these varieties, however, is influenced by various factors, including lack of timely access to seeds in adequate quantities from the formal seed system, high seed costs, and limited information on new varieties. The reviewed literature highlighted that utilizing improved legume varieties had a positive effect on smallholders, leading to improved welfare, food security, dietary diversity, and income. We conclude that the effective scaling of legume systems in SSA is contingent upon the presence of supportive policy frameworks and well-established technical support structures.

Graphical Abstract

Packets of legume seeds within a legume germplasm and breeding program at the University of Zambia (Photo by Caitlin Breen, 2022).

Supplementary Information

The online version contains supplementary material available at 10.1007/s13593-024-00956-6.

Meat quality in broiler chickens fed on cowpea (Vigna unguiculata [L.] Walp) seeds

The study aimed to evaluate the effects of a diet containing untreated cowpea (CWP; Aura 26 variety) seeds as a protein source on quality parameters of chickens' breast (PM; Pectoralis major) and thigh muscles (BF; Biceps femoris). A total of 240 Ross 308 broiler chickens were randomly allotted to two groups: a control group fed with soybean meal (SBM) and an experimental group fed with CWP included at 200 g/kg as a replacement of SBM. Each group consisted of six pens as replicates, with 20 chicks per pen. At 6 weeks of age, twelve birds/group were slaughtered. Compared to SBM group, the group fed CWP had higher (P < 0.0001) lightness (L*) and redness (a*) values of PM and BF muscles, the latter had also higher yellowness (b*, P < 0.0001). The collagen and protein contents were significantly higher in CWP group in both PM and BF muscles, while fat was lower (P < 0.001) only in BF muscle. The use of CWP into broilers' diets did not negatively impact the textural properties, i.e., hardness, adhesiveness, cohesiveness, springiness, gumminess, chewiness, and resilience of PM and BF, showing similar values in both groups. Also, PM and BF muscles of birds fed CWP had significantly higher (P < 0.05) levels of C:18:3n-3 and C:20:5n-3 compared with birds fed SBM. The n-6/n-3 PUFA ratio was significantly lower in CWP group (11.72 and 7.00) compared to SBM (13.47 and 12.63) for both PM and BF muscles. These results indicate that CWP can be considered a promising protein source for broiler chickens' feed.

Phenolic Composition and Antioxidant Properties of Cooked Rice Dyed with Sorghum-Leaf Bio-Colorants

White rice is an important staple food globally. It is a rich source of energy but is low in dietary phenolic antioxidants. This current research aimed at providing scientific evidence for an alternative rice dish that has increased phenolic-antioxidant health-promoting potential by combining white rice with red cowpea beans and cooking with dye sorghum leaves hydrothermal extract, as a source of natural colorant. Boiled white rice and the rice–cowpea–sorghum extract dish were freeze-dried, and the free and bound phenolic compounds of raw and cooked samples were extracted. Phenolic composition, total phenolic content (TPC), and antioxidant activities (measured by 2,2-diphenyl-1-picrylhydrazyl radical scavenging capacity, Trolox equivalent antioxidant capacity, and oxygen radical absorbance capacity methods) of the raw and cooked samples were determined. Combining white rice with cowpea seeds and sorghum leaves extract significantly (p < 0.0001) increased the TPC and antioxidant activities of the rice due to the higher TPC and antioxidant activities of cowpea and sorghum leaves. Although boiling caused substantial losses of flavonoids and anthocyanins in the rice–cowpea–sorghum extract composite meal, the resulting dish had higher TPC and antioxidant activities than boiled white rice. Compositing white rice with phenolic-rich pulses can be an innovative approach to providing alternative healthy rice dishes to consumers.

Dissipation behavior, residue distribution and dietary risk assessment of cyromazine, acetamiprid and their mixture in cowpea and cowpea field soil

BACKGROUND

Cyromazine and acetamiprid are widely applied as pesticides in agriculture, causing increasing concerns about their residues in crops. In this study, cyromazine, acetamiprid and their mixture were applied to cowpea to investigate their degradation dynamics and perform a dietary risk assessment.

RESULTS

The dissipation behavior of cyromazine and acetamiprid in the single- and mixed-pesticide groups followed first-order kinetics, with a linear correlation coefficient of 0.910 to 0.987. The half-lives of cyromazine and acetamiprid were 1.56-11.18 days in the four different matrices. The half-life of cyromazine in the mixed-pesticide group was similar to or even shorter than that in the single-pesticide group. The highest levels of cyromazine and acetamiprid in cowpea occurred with a preharvest interval of 7 days and after two or three applications. These levels are below the maximum residue limits recommended by the Chinese Ministry of Agriculture for cyromazine and acetamiprid in cowpea. The risk quotient of cyromazine and acetamiprid ranged from 0.0018 to 0.0418, and the national estimated short-term intake values of the cyromazine and acetamiprid were far below the acute reference dose as recommended by the European Food Safety Authority.

CONCLUSION

These results suggest that the use of cyromazine and acetamiprid and a cyromazine-acetamiprid mixture in cowpea is safe under the Good Agricultural Practices for Chinese fields, and the use of a cyromazine-acetamiprid mixture affords even better results than the application of cyromazine alone. Moreover, the residue dynamics information will support the label claims for the application of cyromazine, acetamiprid and a cyromazine-acetamiprid mixture to cowpea fruit. © 2020 Society of Chemical Industry.

Natural Fermentation of Cowpea (Vigna unguiculata) Flour Improves the Nutritive Utilization of Indispensable Amino Acids and Phosphorus by Growing Rats

Cowpea (Vigna unguiculata) is among the most cultivated legumes, with interesting agronomic and environmental properties, and great potential as a nutritious food. The nutritional value of cowpea can be improved by technological processing. In this study, we showed that natural fermentation improved bioavailability of protein, amino acids, and dietary essential minerals from cowpea in growing rats, thus strengthening its potential value as functional food or food supplement. Forty Wistar albino rats (48 ± 1.8 g), were fed one of four experimental diets (n = 10 rats per diet): casein, raw cowpea, fermented cowpea or fermented and autoclaved cowpea. Despite lower growth indices of raw and fermented cowpea protein (PER, FTI) than casein, fermentation enhanced apparent digestibility of arginine, leucine, lysine, methionine, phenylalanine, tyrosine, and valine, and true digestibility of essential amino acids, except for tyrosine and valine, compared to raw cowpea. On the other hand, autoclaving of fermented cowpea flour decreased apparent, as did true digestibility of sulfur amino acids. Regarding the nutritive utilization of dietary essential minerals, Vigna unguiculata was a good source of available P, Mg, and K, while fermentation significantly improved the availability of P. Overall, cowpea was a good source of digestible essential amino acids and minerals and fermentation significantly improved its nutritional value that was not further enhanced by autoclaving.

Evaluation of nutritional and phytochemical variability of cowpea Recombinant Inbred Lines under contrasting soil moisture conditions in the Guinea and Sudan Savanna Agro-ecologies

Plant breeders’ efforts in developing drought tolerant and high-yielding cowpea varieties may be in vain unless the developed varieties are evaluated to ascertain the influence of water stress on their nutritive value, antioxidants, and phenolic contents under contrasting moisture regimes. The study was set up to evaluate the nutritional value, phytochemical content and antioxidant activity of cowpea Recombinant Inbred Lines (RILs) under contrasting soil moisture in the Guinea and Sudan Savanna agro-ecologies of Ghana. Forty-eight cowpea RILs seed samples from well-watered and water stress experiment were pulverized. Distillation and titration was carried out and the organic samples extracted and various biochemical analyses were carried out using standard protocols and methodologies. The dried grain mineral contents were determined using an Atomic Absorption Spectrophotometer, while the protein content was determined by the combustion method. Correlation and regression analysis and principal component analysis were performed using STATA version 13. Biochemical analysis for seed related traits revealed that inbred lines responded differently to drought. Significant differences of watering regimes on various phytochemical traits were only observed in phosphorus and lead. Inbred line with family number 57 had the highest crude protein content of 46.90% under well-watered conditions. Inbred line 84 under water stress conditions had high levels of Mg and K. Inbred line 20 under well-watered conditions had the highest antioxidant content. For phenolic acid content, inbred line 255 scored the highest. Quercetin and rutin were most abundant in inbred line 186 for both water-stress and well-watered conditions. The indication is that moisture stress could affect seed yield but no effects on the phytochemical and nutritional variables. Genotypic differences could arise from parental combination used for developing the inbred lines for the study.

Complementary Feeding of Sorghum-Based and Corn-Based Fortified Blended Foods Results in Similar Iron, Vitamin A, and Anthropometric Outcomes in the MFFAPP Tanzania Efficacy Study

BACKGROUND

Fortified blended foods (FBFs) are micronutrient-fortified food aid products containing cereals and pulses. It has been suggested to reformulate FBFs to include whey protein concentrate, use alternative commodities (e.g., sorghum and cowpea), and utilize processing methods such as extrusion to produce them. The Micronutrient Fortified Food Aid Pilot Project (MFFAPP) efficacy study was designed to test the efficacy of complementary feeding of newly formulated FBFs.

OBJECTIVES

The aim of this study was to test the effectiveness of 5 newly formulated FBFs in combating iron deficiency anemia and vitamin A deficiency compared with traditionally prepared corn-soy blend plus (CSB+) and no intervention. A secondary aim was to determine the impact on underweight, stunting, wasting, and middle-upper arm circumference.

METHODS

A 20-wk, partially randomized cluster study was completed. Two age groups (aged 6-23 and 24-53 mo) with hemoglobin status <10.3 g/dL, and weight-for-height z scores >-3 were enrolled and assigned to diet groups. Biochemical and anthropometric measurements were collected at 0, 10, and 20 wk.

RESULTS

Both hemoglobin concentrations and anemia ORs were significantly improved in all intervention groups except for CSB+ and the no-intervention groups at week 20. Only extruded corn-soy blend 14 and the no-intervention age groups failed to significantly decrease vitamin A deficiency risk (P < 0.04). There were no consistent significant differences among groups in anthropometric outcomes.

CONCLUSIONS

FBFs reformulated with sorghum, cowpea, corn, and soy significantly improved anemia and vitamin A deficiency ORs compared with week 0 and with no intervention. Although newly formulated FBFs did not significantly improve vitamin A deficiency or anemia compared with CSB+, CSB+ was the only FBF not to significantly improve these outcomes over the study duration. Our findings suggest that newly formulated sorghum- and cowpea-based FBFs are equally efficacious in improving these micronutrient outcomes. However, further FBF refinement is warranted. This trial was registered at clinicaltrials.gov as NCT02847962.

Evaluating the freezing impact on the proximate composition of immature cowpea (Vigna unguiculata L.) pods: classical versus spectroscopic approaches

BACKGROUND

Freezing represents a common conservation practice regarding vegetal foodstuffs. Since compositional features need to be monitored during storage, the development of rapid monitoring tools suitable for assessing nutritional characteristics arises as a pertinent issue. In this study, cowpea (Vigna unguiculata L.) pods, both fresh and after 6 and 9 months of freezing at -18 °C, were evaluated by high-performance liquid chromatography for their content of protein as well as of essential and nonessential amino acids, while their Fourier transform infrared spectra in the mid infrared (MIR) and near infrared (NIR) ranges were concomitantly registered to assess the feasibility of this approach for the traceability of these frozen matrices.

RESULTS

For the NIR interval, the application of the 1st derivative to the spectral data retrieved the best results, while for lower concentrations the application of the Savitzky-Golay algorithm was indispensable to achieve quantification models for the amino acids. MIR is also suitable for this purpose, though being unable to quantify amino acids with concentrations below 0.07 mmol g^-1 dry weight, irrespective of the data treatment used.

CONCLUSIONS

The spectroscopic approach constitutes a methodology suitable for monitoring the impact of freezing on the nutritional properties of cowpea pods, allowing accurate quantification of the protein and amino acid contents, while NIR displayed better performance. © 2017 Society of Chemical Industry.

Spectrophotometric versus NIR-MIR assessments of cowpea pods for discriminating the impact of freezing

BACKGROUND

Freezing represents an important storage method for vegetal foodstuffs, such as cowpea pods, and thus the impact of this process on the chemical composition of these matrices arises as a prominent issue. In this sense, the phytochemical contents in frozen cowpea pods (i.e. at 6 and 9 months) have been compared with fresh cowpea pods material, with the samples being concomitantly assessed by Fourier-transform infrared spectroscopy (FTIR), both mid-infrared (MIR) and near infrared (NIR), aiming to evaluate the potential of these techniques as a rapid tool for the traceability of these matrices.

RESULTS

A decrease in phytochemical contents during freezing was observed, allowing the classification of samples according to the freezing period based on such variations. Also, MIR and NIR allowed discrimination of samples: the use of the first derivative demonstrated a better performance for this purpose, whereas the use of the normalized spectra gave the best correlations between the spectra and specific contents. In both cases, NIR displayed the best performance.

CONCLUSION

Freezing of cowpea pods leads to a decrease of phytochemical contents, which can be monitored by FTIR spectroscopy, both within the MIR and NIR ranges, whereas the use of this technique, in tandem with chemometrics, constitutes a suitable methodology for the traceability of these matrices. © 2017 Society of Chemical Industry.

Cowpea (Vigna unguiculata L. Walp), a renewed multipurpose crop for a more sustainable agri-food system: nutritional advantages and constraints

The growing awareness of the relevance of food composition for human health has increased the interest of the inclusion of high proportions of fruits and vegetables in diets. To reach the objective of more balanced diets, an increased consumption of legumes, which constitutes a sustainable source of essential nutrients, particularly low-cost protein, is of special relevance. However, the consumption of legumes also entails some constraints that need to be addressed to avoid a deleterious impact on consumers' wellbeing and health. The value of legumes as a source of nutrients depends on a plethora of factors, including genetic characteristics, agro-climatic conditions, and postharvest management that modulate the dietary effect of edible seeds and vegetative material. Thus, more comprehensive information regarding composition, especially their nutritional and anti-nutritional compounds, digestibility, and alternative processing procedures is essential. These were the challenges to write this review, which focusses on the nutritional and anti-nutritional composition of Vigna unguiculata L. Walp, an emerging crop all over the world intended to provide a rational support for the development of valuable foods and feeds of increased commercial value. © 2016 Society of Chemical Industry.

Individualistic impact of unit operations of production, at household level, on some antinutritional factors in selected cowpea-based food products

The individualistic effect of unit operations of production, at household level, on some antinutritional factors in selected cowpea-based food products (moin-moin, akara, and gbegiri) was investigated. Four cowpea types (IT93K-452-1, IT95K-499s-35, IT97K-568-18, and market sample) were used for the study, whereas the three traditional food products were produced from each of the cowpea types, respectively. The results revealed that every unit operation involved in the production of moin-moin, akara or gbegiri contributed to the overall reduction of trypsin inhibitor activity (TIA), phytic acid (PA), and tannin; though at varying degrees. In the production of moin-moin, the major contributions to the overall reduction in TIA were from steaming (64.2-72.0%), second-stage soaking (9.7-11.9%), and dehulling (9.4-10.2%). The contributions to the overall reduction in PA were from dehulling (34.0-40.4%), preliminary soaking (15.4-21.0%), and steaming (7.8-14.0%), whereas that of tannin were from dehulling (39.7-47.6%), steaming (19.6-24.7%), and preliminary soaking (9.8-15.9%). For akara production, the major contributions to TIA reduction were from deep frying (64.2-72.0%), second-stage soaking (9.7-11.9%), and dehulling (9.4-10.2%). The PA reduction was from dehulling (34.0-40.4%), preliminary soaking (15.4-21.0%), and deep frying (9.6-15.9%), whereas that of tannin reduction was from dehulling (39.7-47.6%), deep frying (20.7-25.3%), and preliminary soaking (9.8-15.9%). In the production of gbegiri, the overall reduction in TIA was contributed from pressure cooking (79.0-84.8%), preliminary soaking (5.8-11.3%), and dehulling (9.4-10.2%). The reduction in PA was contributed by dehulling (34.0-40.4%), pressure cooking (24.7-35.0%), and preliminary soaking (15.4-21.0%), whereas the overall reduction in tannin content was similarly contributed by dehulling (39.7-47.6%), pressure cooking (29.8-34.4%), and preliminary soaking (9.8-15.9%).

Cowpeas in Northern Ghana and the factors that predict caregivers' intention to give them to schoolchildren

BACKGROUND

Cowpeas are important staple legumes among the rural poor in northern Ghana. Our objectives were to assess the iron and zinc content of cowpea landraces and identify factors that predict the intention of mothers/caregivers to give cowpeas to their schoolchildren.

METHODS AND FINDINGS

We performed biochemical analysis on 14 landraces of cowpeas and assessed the opinion of 120 caregiver-child pairs on constructs based on the combined model of the Theory of Planned Behaviour and Health Belief Model. We used correlations and multiple regressions to measure simple associations between constructs and identify predictive constructs. Cowpea landraces contained iron and zinc in the range of 4.9-8.2 mg/100 g d.w and 2.7-4.1 mg/100 g d.w respectively. The landraces also contained high amounts of phytate (477-1110 mg/100 g d.w) and polyphenol (327-1055 mg/100 g d.w). Intention of mothers was strongly associated (rs = 0.72, P<0.001) with and predicted (β = 0.63, P<0.001) behaviour. The constructs, barriers (β = -0.42, P = 0.001) and attitudes towards behaviour (β = 0.25, P<0.028), significantly predicted intention albeit the predictive ability of the model was weak.

CONCLUSIONS

We conclude that some cowpea landraces from northern Ghana have appreciable amounts of iron and zinc but probably with poor bioavailability. Attitudes towards giving cowpeas and perception of barriers are important predictors of caregivers' intention to give cowpeas to their schoolchildren. Finally our results suggest that increasing knowledge on nutritional benefits of cowpeas may increase health values caregivers hold for their children in support of giving cowpeas to schoolchildren.

Chemical composition, nutritive value, and toxicological evaluation of Bauhinia cheilantha seeds: a legume from semiarid regions widely used in folk medicine

Among the Bauhinia species, B. cheilantha stands out for its seed protein content. However, there is no record of its nutritional value, being used in a nonsustainable way in the folk medicine and for large-scale extraction of timber. The aim of this study was to investigate the food potential of B. cheilantha seeds with emphasis on its protein quality to provide support for flora conservation and use as raw material or as prototype for the development of bioproducts with high added socioeconomic value. B. cheilantha seeds show high protein content (35.9%), reasonable essential amino acids profile, low levels of antinutritional compounds, and nutritional parameters comparable to those of legumes widely used such as soybean and cowpea. The heat treatment of the seeds as well as the protein extraction process (to obtain the protein concentrate) increased the acceptance of diets by about 100% when compared to that of raw Bc diet. These wild legume seeds can be promising alternative source of food to overcome the malnutrition problem faced by low income people adding socioeconomic value to the species.