Alternative Food/Feed Perspectives of an Underutilized Legume <Emphasis Type="Bold">Mucuna pruriens</Emphasis> var. <Emphasis Type="Bold">Utilis</Emphasis>—A Review

Mucuna pruriens var. utilis, an underutilized tropical legume has a nutritional quality comparable to soya beans and other conventional legumes as it contains similar proportions of protein, lipid, minerals, and other nutrients. The beans have been traditionally used as a food in a number of countries, viz., India, Philippines, Nigeria, Ghana, Brazil, and Malawi. Recently, the velvet beans are exploited as a protein source in the diets of fish, poultry, pig, and cattle after subjected to appropriate processing methods. Although the velvet beans contain high levels of protein and carbohydrate, their utilization is limited due to the presence of a number of antinutritional/antiphysiological compounds, phenolics, tannins, L-Dopa, lectins, protease inhibitors, etc., which may reduce the nutrient utilization. Unfortunately, even though many researchers all over the world working on Mucuna, only scanty and conflicting information are available regarding its utilization as a food/feed and no scientific gathering to date has focused on the food/feed applications of Mucuna. Hence, the present review has been emphasized on the nutritional potential of this underutilized, nonconventional legume and current state of its utilization as food/feed for both human beings and livestock throughout the world.     

Tepary beans (Phaseolus acutifolius var. latifolius): a potential food source for African and Middle Eastern cultures

Tepary bean (Phaseolus acutifolius var. latifolius), a native North American legume adapted to arid/semiarid lands was partially evaluated as a potential food source for people of African and Middle Eastern regions. To indicate the acceptability of these pulses, traditional Nigerian and Saudi Arabian foodstuffs were formulated with teparies substituted for beans commonly used in these regions. Organoleptic evaluation of these food products by students native to the area of recipe origin indicated the dishes to be moderately to highly acceptable. Chemical analyses of this species revealed tepary beans to be very similar in proximate composition, amino acid profile and content of various minerals to other grain legumes (cowpeas, chickpeas and fava beans) of the African/Middle Eastern region. Protein contents of tepary samples averaged 23.0%, whereas protein quality was found limiting in sulfur amino acids. Laboratory examination of raw tepary samples for antinutritional factors uncovered levels of flatulent oligo saccharides, trypsin inhibitors and phytic acid commonly associated with grain legumes. However, lectin assays revealed greater agglutination associated with tepary composites than in fava, chickpea and cowpea samples. All bean samples were simmered resulting in fully cooked materials which exhibited low levels of nutritional antagonists. Cooked beans were considered safe and nutritionally acceptable.Arizona Agricultural Experiment Station Paper No. 3814.     

Tannins,Trypsin Inhibitors and Lectin Cytotoxicity in Tepary (<Emphasis Type="Italic">Phaseolus acutifolius</Emphasis>) and Common (<Emphasis Type="Italic">Phaseolus vulgaris</Emphasis>) Beans

This study compared the levels of antinutritional components and cytotoxic effect of extracts, from tepary (Phaseolus acutifolius) and common (Phaseolus vulgaris) beans. Antinutritional factors were evaluated by determining their effect on the viability of epithelial cells isolated from rat small intestine. The protein and carbohydrates content were similar in all the genotypes studied (20 and 60%, respectively). Common beans presented higher content of trypsin inhibitors, tannins and lectins than tepary beans. There was not a significant correlation between tannins and cooking time. However, water absorption and cooking time correlated significantly (p < 0.05). Considerable variation was observed in lectin activity (1302–18161 Ul/mg) of extracts from different beans. Tannins, lectins, trypsin inhibitors and fat content differed between bean varieties whereas protein content was similar. The percent cellularity on rat epithelial cells was significantly different among protein extracts from different bean cultivars and ranged between 53.5% and 87.4% (p < 0.05). These results suggest that the incorporation of tepary beans in the diet would not alter the current nutritional contribution of common beans or introduce adverse toxic effects. The agronomic characteristics of tepary beans make them attractive for cultivation. However, the harder to cook phenomenon may be a limiting factor that needs further consideration.     

Effect of soaking,cooking and germination on the oligosaccharide content of selected Nigerian legume seeds

The identity and quantity of and effect ofprocessing on raffinose oligosaccharides in raw,mature seeds of lima beans (Phaseolus lunatus),pigeon peas (Cajanus cajan), African yam beans(Sphenostylis sternocarpa) and jackbeans (Canavalia ensiformis) were investigated. Sucrose,raffinose, stachyose and verbascose were identified byHPLC in all the legume seeds. The total-galactoside contents of the seeds in decreasing order were African yam beans3.84 mg/100 mg; white lima beans 3.62 mg/100 mg; creampigeon peas 3.51 mg/100 mg; red lima beans3.37 mg/100 mg; jackbeans 2.83 mg/100 mg and brownpigeon peas 2.34 mg/100 mg. The predominantoligosaccharide was verbascose in pigeon peas andstachyose in the other three legumes. Cooking unsoakedseeds brought about a greater reduction in the total-galactoside content than soaking for ninehours. The removal of oligosaccharides was higher inlegumes cooked in alkaline solution than in water.Germination quantitatively reduced raffinose,stachyose and verbascose while sucrose was increasedin all seeds except red lima beans and jackbeans.     

Protein,energy and mineral utilization in rats fed rice-legume diets

Protein, energy and mineral utilization were examined in growing rats fed cooked, dry legume seeds in combination with polished rice. The legumes tested included 3 varieties of common beans, black, white and brown (Phaseolus vulgaris), lentils (Lens esculenta) and peas (Pisum sativum). The rice:legume mixtures (1:1 N ratio) were the only dietary sources of protein, Zn, Fe and Cu. The rice:black bean mixture was also tested at a 4:1 N ratio. Nutrient utilization was studied by balance trials and mineral utilization was further assessed by tissue analyses. True protein digestibility (TD) and energy digestibility of the rice:legume (1:1) mixtures were high. Biological value (BV) varied only little but was lowest in the rice:lentil mixture. The rice:brown bean mixture had the lowest amount of utilizable protein (UP). The (1:1) rice:legume mixtures did not adversely affect Fe status, as measured by liver Fe content and blood hemoglobin and hematocrit, or Cu status, as measured by liver Cu content and plasma ceruloplasmin. However, femur zinc content indicated a sub-optimal Zn status. Increasing the dietary N from rice in combination with black beans resulted in a substantial improvement of BV, NPU and Zn status of the animals but had a negative effect on UP and Fe status of the rats.     

Optimizing the growth of forage and grain legumes on low pH soils through the application of superior Rhizobium leguminosarum biovar viciae strains

Climate variability and current farming practices have led to declining soil fertility and pH, with a heavy reliance on fertilizers and herbicides. The addition of forage and grain legumes to farming systems not only improves soil health but also increases farm profitability through nitrogen (N) fertilizer cost offsets. However, the formation of effective symbioses between legumes and rhizobia can be unreliable and is considered at risk when combined with dry sowing practices such as those that have been designed to obviate effects of climate change. This research was initiated to improve the robustness of the legume/rhizobia symbiosis in low pH, infertile and dry soils. Production from two cultivars of field pea (Pisum sativum) and two species of vetch (Vicia spp.), and symbiotic outcomes when inoculated with a range of experimental rhizobial strains (Rhizobium leguminosarum biovar viciae), was assessed in broad acre field trials which simulated farmer practice. New rhizobia strains increased nodulation, N fixation, produced more biomass and higher seed yield than comparator commercial strains. Strain WSM4643 also demonstrated superior survival when desiccated compared to current commercial strains in the laboratory and on seed when delivered as inoculant in peat carriers. WSM4643 is a suitable prospect for a commercial inoculant in Australia and other agricultural areas of the world where growing peas and vetch on soils generally considered problematic for this legume/rhizobia symbiosis. A particular advantage of WSM4643 may be that it potentiates sowing inoculated legumes into dry soil, which is a contemporary response by farmers to climate variation.     

Growth,hormonal status and protein turnover in rats fed on a diet containing peas (Pisum sativum L.) as the source of protein

The inclusion of peas (Pisum sativum L.) as the source of protein in the diet of growing rats brings about a reduction in growth rate as well as the impairment in the liver, muscle and spleen weights as compared with casein fed controls. Also, a fall in plasma glucose, triglycerides and protein was observed in the legume fed animals, while no changes in cholesterol levels were found. Furthermore, the rats fed on the diet containing peas showed lower levels of plasma insulin, corticosterone, IGF-I and T₄ as compared with casein controls. Liver and muscle total protein (mg) and total DNA (mg) were markedly decreased in the legume fed animals, but DNA/g, protein/DNA and RNA/protein ratios were similar in both dietary groups. Likewise, liver and muscle fractional synthesis rates were similar in the casein and legume groups, while the whole body protein synthesis is assumed to be lower in the legume fed animals due to differences in body weights. It is concluded that animals fed on a diet containing peas (Pisum sativum L.) as the only source of protein showed less adverse effects than those found with other legumes such asVicia faba L. orPhaseolus vulgaris L., in which protein quality, antinutritional factors and nutrient availability could be involved.     

Optimizing forage yield of durum wheat/field bean intercropping through N fertilization and row ratio

Intercropping (IC) cereals and legumes could be an option for obtaining forage suitable for ensiling and enabling reduced N fertilization. Two experiments were performed in central Italy with durum wheat (Triticum durum Desf.) and field bean (Vicia faba L. var. minor) grown for forage production in IC and as sole crops (SC) with different N rates (20 and 50 kg ha^?1) and row ratios (1:1 and 2:1 cereal/legume). The aims were to assess (i) whether IC is a feasible option to reduce N fertilization; (ii) the best combination of practices to obtain forage suitable for ensiling; and (iii) competition/facilitation effects exerted by field bean on durum wheat. Results showed IC allowed fertilizer‐N reduction and led to improved forage yield with better quality, compared with SC. Land equivalent ratio indicated a high efficiency of the IC, by up to 26% with respect to SC. Field bean was the dominant species of IC, but N fertilization reduced its competitive ability and enhanced that of wheat. In the intercrop fertilized with 50 kg N ha^?1, the proportion of the wheat in the herbage (0·34–0·41 of the total dry matter) was sufficient for ensiling of the forage mass. Field bean exerted both competition and facilitation effects on the cereal. N uptake of durum wheat was greater under IC with beans than as wheat SC.     

Cytotoxic effect of two legumes in epithelial cells of the small intestine

The previously known high toxicity and hemagglutinin concentration found in Escumite bean (Phaseolous acutifolius), widely consumed in the south-east of Mexico, induced us to study the cytotoxic effect of these beans on the epithelial cells of the small intestine of rats. Another, less toxic leguminosae, chick-pea (Cicer arietinum), was used for comparison. In vitro tests showed that the viability of the cells was much more affected by the Escumite bean extract than by the chick-pea extract (P<0.001). The cellularity was much diminished when the epithelial cells were treated with Escumite extract (P<0.001), but not with chick-pea extract. In vivo experiments confirmed these findings. The present results suggest that the deleterious effect of some toxicants present in the raw legume is due to an interaction with intestinal epithelium, which, in turn, may cause a reduced absorption of nutrients.     

Protein and amino acid composition of some wild leguminous seeds

The seeds of five different species ofAcacia, twoAlbizzia, twoErythrina and two species ofMucuna were analysed for their protein and amino acid composition. Some of these seeds are comparable to a popular food legume,Cicer arietinum, in protein and amino acid composition.     

Intestinal absorption of D-galactose in the presence of extracts fromPhaseolus vulgaris hulls

The relatively low nutritional value of protein from legume seeds has been attributed to the occurrence of some antinutritional factors and the poor content in sulphur aminoacids, which leads to undesirable physiological and biochemical alterations. However, the intimate nature of these processes remains unclear. In order to evaluate the influence of naturally occurring substances of legume constituents on nutrient utilization, the intestinal absorption of D-galactose in the presence of aqueous or alcoholic extracts, obtained fromPhaseolus vulgaris hulls, has been measured by use of thein vivo successive absorption technique.Aqueous extracts inhibited significantly (p<0.01) the uptake of D-galactose at different times of exposure, while no changes in sugar transport were observed with the alcoholic solutions. Polyamide treatment (a polyphenolic complexing agent) of the aqueous extracts decreased its ability to inhibit sugar uptake. Kinetic studies showed that the aqueous fractions modifyV _max values for D-galactose absorption and alsoK _T data. This inhibition appeared to be reversible after short periods of exposure, affecting mainly the active component of transport. Therefore, it can be suggested that some substances, contained in aqueous extracts ofPhaseolus vulgaris reduce sugar absorption. Furthermore, our studies seem to indicate that polyphenols are, at least partly, involved in this phenomenon.     

Field response of Lathyrus cicera germplasm to crenate broomrape (Orobanche crenata)

Crenate broomrape (Orobanche crenata Forks.) is a major constraint for grain and forage legume cultivation in Mediterranean agriculture, to which little resistance is available. We studied the response to O. crenata of a germplasm collection of chickling pea (Lathyrus cicera L.) in field trials over two seasons showing that resistance although scarce and masked by confounding factors, is available and can be used in breeding. The level of infection was highly influenced by environmental factors and plant growth cycle. Earlier accessions were less infected due to competition of the earlier settled pods with O. crenata tubercles. O. crenata infection strongly reduced host biomass and grain yield. Deviations from the polynomic regression gave an improved approximation of the true genetic resistance levels present in the germplasm.     

Multifunctional benefits of sainfoin mixtures: Effects of partner species,sowing density and cutting regime

Grass–legume mixtures have proven successful at improving the sustainability of grasslands. Their ability to suppress unsown species is particularly important for sainfoin (Onobrychis viciifolia), a forage crop with valuable bioactive compounds, yet low competitiveness. In this 3‐year study, the suitability of six partner species cultivated in mixtures with sainfoin at different annual numbers of cuts and partner sowing densities were evaluated. Mixture yields outperformed average monoculture yields by 31%, reduced the ratio of unsown species by 65% and increased the symbiotic N₂ fixation up to 158 kg ha^?1. A key finding of the study was the highly differential patterns of development of the partner grass species over the 3 years. These patterns of development had a large effect on the persistency of the proportion of sainfoin in the mixtures, which varied in the third year between 17% (when grown with Dactylis glomerata) and 38% (with Lolium perenne). These findings contribute to the further development of sustainable grass–legume systems, as evidence for the successful cultivation of sainfoin as an alternative legume species can help diversification, and knowledge of mixture development supports more persistent legume proportions.     

Relationship Among Antimutagenic, Antioxidant and Enzymatic Activities of Methanolic Extract from Common Beans (Phaseolus vulgaris L)

Common beans are rich in phenolic compounds, which can provide health benefits to the consumer. The objective of this work was to study the relationship among antimutagenicity, antioxidant and enzymatic activities of methanolic extract and trolox by principal components multivariate analysis. Antimutagenicity of phenolic compounds present in methanolic extract from the seed coat of common beans (P. vulgaris, Flor de Mayo Bajío cultivar) and trolox against AFB₁ mutagenicity were evaluated in the Salmonella typhimurium microsuspension assay. Antioxidant capacity of methanolic extract and trolox were evaluated using β-carotene and 1,1-diphenyl-2-picryhydrazyl (DPPH) in vitro model assays. Cythrome P450 activity was measured by fluorometric assay. For phenolic extract, trolox and phenolic extract + trolox, the inhibition on AFB₁ mutagenicity in tester strain TA100 was 47, 59 and 69%, respectively. While in TA98 was 39, 48 and 68%. The inhibition of phenolic compounds, trolox and phenolic compounds + trolox on cytochrome P450 (CYP450) activity was 48, 59 and 88%, respectively. Correlation analysis showed that phenolic extract and trolox have high antimutagenic and antioxidant activity and also inhibited enzymatic activity. The results suggest that the primary mechanism of action of phenolic compounds in beans against AFB₁ mutagenicity may be extra-cellular in the microsuspension assay.     

Forage legumes in grass pastures in tropical Brazil and likely impacts on greenhouse gas emissions: A review

Beef cattle producers seldom use fertilizers for their pastures in tropical regions of Brazil. Slowly, this is changing but because of the need for repeated applications, N fertilizer is rarely applied. The introduction of a forage legume is an appropriate solution for this problem, but until recently adoption has been very low as the legumes generally have not persisted in the sward. We report research on how grazing management can affect the persistence of stoloniferous legumes in pastures of Brachiaria spp. and the problems of establishing and maintaining crown-forming legumes such as Stylosanthes spp. With suitable management, milk or bovine carcass yields can be equal or greater from mixed than from grass-alone pastures fertilized with 120 or 150 kg Nha^-1 year⁻¹. In addition to savings in CO₂ emissions from fossil fuels for the production and distribution of N fertilizers, nitrous oxide emissions from cattle excreta and legume residues are lower than those from N-fertilized brachiaria grass monocultures. Other studies indicate that enteric methane emissions from cattle may be mitigated when forage legumes are included in their diet. The use of forage legumes in mixed pastures for tropical regions is emerging as a feasible strategy to keep meat and milk production at acceptable levels with reduced greenhouse gas emission rates.     

A staggered maize–legume intercrop arrangement robustly increases crop yields and economic returns in the highlands of Central Kenya

Smallholder farmers in East-Africa commonly intercrop maize (Zea mays L.) with grain legumes to maximize utilisation of land and labour, and attain larger crop yields. Conventionally, one legume line is intercropped between each pair of maize lines. This study evaluated the potential of a modified two-by-two staggered arrangement (MBILI) to increase crop yields and economic benefits in two sites in Central Kenya with contrasting soil fertility levels during 7 consecutive seasons. Common beans (Phaseolus vulgaris L.), cowpea (Vigna unguiculata (L.) Walp.) and groundnut (Arachis hypogaea L.) were grown as legume intercrops. The MBILI system resulted in increased maize yields in both sites, and increased cowpea yields in the poor site. In the fertile site, using beans as an intercrop was most profitable, and the MBILI system increased net benefits by 40%, relative to the conventional system. In the poor site, groundnut and cowpea were better adapted, and the MBILI system increased net benefit by 12–37%. Positive effects of the MBILI system were most pronounced in the poor site, but occurred independent of soil fertility level. Rainfall amounts and distribution varied widely, but the MBILI system increased yields both under conditions of ample and inadequate rainfall. N balances were negative with beans and groundnut, but neutral with cowpea as the intercrop. A modest N fertilizer application is therefore essential to sustain yields in the long term, especially when beans or groundnuts are intercropped. In conclusion, the MBILI system, when combined with adjusted nutrient inputs, resulted in superior and robust improvements in crop yields and economic benefits, relative to the conventional intercropping system.     

“Summer sowing”: A successful innovation to increase the adoption of key species of annual forage legumes for agriculture in Mediterranean and temperate environments

This paper reports on the evaluation of “summer sowing,” an innovative approach to increase the adoption of recently domesticated species of hard seeded annual legumes in Mediterranean and temperate Agriculture. The research revealed that several species of annual legumes whose seed can be readily harvested on‐farm and which possess natural hard seed dormancy, may be sown into dry soil in late summer without additional processing. These studies proved that the hard seed dormancy was broken down sufficiently in the soil over 4–6 weeks to produce robust legume pastures with more than 150 seedlings per m² following the first winter rains, in replicated field sites established across wide agro‐ecological zones in Western Australia (WA) and New South Wales (NSW). Ornithopus sativus Brot., O. compressus L. and Trifolium spumosum L. were suitable for summer sowing based on both hard seed breakdown patterns and subsequent seedling survival in WA. While in NSW, in addition to these legumes, Biserrula pelecinus L., T. vesiculosum Savi. and T. glanduliferum Boiss. were also suitable for summer sowing. A 1.5‐ to 10‐fold increase in herbage production was achieved relative to conventionally sown T. subterraneum L. This development represents a step change in forage legume development for renovated pastures in these environments. Importantly, the experiments revealed differences in G x E effects on seedling establishment, total herbage production and seed yield in different climatic zones. The summer sowing approach is presented as a revolutionary method for pasture renovation that overcomes significant barriers to adoption.     

Forage production and nutritive value of Dactylis glomerata and Trifolium subterraneum mixtures under different shading treatments

Production and nutritive value of forage in silvopastural systems can be improved by introducing shade‐ tolerant grass and legume species in appropriate mixtures. The management of these systems can present a challenge regarding the selection of the proper grass and legume species as well as the maintenance of the optimum balance between the two species in the grass–legume stand. The objectives of the present study were to evaluate the performance of pure stands and mixtures (75:25, 50:50, 25:75) of Dactylis glomerata:Trifolium subterraneum under full sun, 60% shade and 90% shade. Dry matter production of D. glomerata was not affected by shading, while that of T. subterraneum was drastically reduced. Shading increased the crude protein (CP) and acid detergent lignin content, but did not affect the acid detergent fibre and neutral detergent fibre content. The dry matter production of the 75:25 and 25:75 mixtures was higher compared to the one of the 50:50 mixture, while the CP content of the 75:25 mixture was the highest under moderate shading. However, relative yield, aggressivity index and competitive balance index indicated higher competitive ability for D. glomerata compared with T. subterraneum especially under shade. Therefore, the 25:75 mixture is suggested as the most suitable under moderate shade (60%), to perpetuate the stand and avoid the frequent re‐sowing of T. subterraneum.     

The degradation of lectins,phaseolin and trypsin inhibitors during germination of white kidney beans,Phaseolus vulgaris L.

White kidney beans (Phaseolus vulgaris), cv Processor, contain a relatively high content of phaseolin (storage protein), lectins and a special group of glycoproteins as well as a considerable amount of protein-type trypsin inhibitors. Protein digestion of raw Processor beans in monogastrics, for example pigs, is disturbed by poorly digested, phaseolin lectins, which can bind to carbohydrates in brush border membranes of the small intestinal epithelium, and trypsin inhibitors. The effect of the germination of white kidney beans on lectins, phaseolin and trypsin inhibitors was studied in order to achieve a degradation of lectins, phaseolin and trypsin inhibitors and an increase ofin vitro enzymatic hydrolysis of the protein of bean flour. Therefore, whole bean extracts were examined throughout a germination period of up to seven days for their lectin and phaseolin pattern, lectin content, binding capacities of functional lectins towards brush border membranes and trypsin inhibitor content. In addition thein vitro enzymatic hydrolysis by pepsin and pancreatin of the protein from flours of (un)germinated white kidney beans was studied. SDS-PAGE demonstrated a degradation of E-lectins and a disappearance of L-lectins and phaseolin during germination. Results indicated a decrease of the lectin content by 85%, a loss of binding capacities of functional lectins towards brush border membranes by 91%, and a decrease of trypsin inhibitors by 76%, in bean flour after germination for seven days. A maximum inin vitro enzymatic hydrolysis of protein from bean flour was already established after germination for half a day.     

Dioclea grandiflora andDioclea sclerocarpa seeds. A nutritional study

A nutritional study ofDioclea grandiflora (Mucuna) andDioclea sclerocarpa, two legume seeds related toCanavalia which grow extensively in South America and are used as a human food source, has been carried out. Whilst both seeds, when fed to rats at a level equivalent to 100g seed protein kg^–1 diet gave poor nutritional performance, the anti-nutritional factors involved were apparently different. WithDioclea grandiflora, the presence in the seed of a soluble small molecular weight component, which caused food intake to be reduced to levels well below that required to meet minimum protein, energy, vitamin and mineral requirements, led to poor growth. This factor could be reduced substantially by exhaustive dialysis or by aqueous ethanol extraction of the meal. These procedures may have potential practical applications. In addition, the constitutent lectin, which was partially resistant in vitro and in vivo to degradation by gastrointestinal enzymes, also contributed to growth depression. WithDioclea sclerocarpa, a non-haemagglutinating pH 7 soluble factor was primarily responsible for the poor performance of rats. This factor could not be removed by exhaustive dialysis. The apparently poor protein digestibility observed may be due to increased secretion of endogenous nitrogen.