An underutilized bean: hyacinth bean [Lablab purpureus (L.) sweet]: bioactive compounds, functional activity, and future food prospect and applications

Hyacinth bean [Lablab purpureus (L.) Sweet], a plant belonging to the leguminous family and traditionally used for medicinal purposes in China, is a valuable resource with a wide range of health benefits. This review examines the bioactive compounds, health-promoting properties and functional food potential of hyacinth bean, highlighting its role in protecting against metabolic diseases and the underlying molecular mechanisms. According to existing research, hyacinth bean contains a diverse array of bioactive compounds, Consumption of hyacinth beans and hyacinth bean-related processed food products, as well as their use in medicines, is associated with a variety of health benefits that are increasingly favoured by the scientific community. In light of these findings, we posit that hyacinth bean holds great promise for further research and food application. © 2024 Society of Chemical Industry.

Antinutrients and metabolomic compounds of Bambara groundnut (Vigna subterranean) as affected by traditional processing by smallholder farmers

Bambara groundnut (BG) (Vigna subterranean) is an underutilized, indigenous crop in South Africa that has nutritional and associated health benefits. Decreasing the antinutrients in food sources can potentially increase the digestibility of proteins and mineral absorption. To determine the effect of traditional processing (cooking) on the antinutrient content and metabolome of this crop, BG was sampled from 12 rural farms in three districts of the Mpumalanga province, South Africa. The four main colors that were identified (cream, orange, brown, and purple) were pooled together according to the district they were obtained from. One-half of each color sample obtained from each of the three districts was dehulled, color sorted, milled, and subjected to subsequent antinutrient and metabolome analyses, while the other half was cooked, air-dried, and milled prior to analyses. Samples were analyzed for phytate and tannins (antinutrients) by hydrochloric acid extraction methods as well as metabolome constituents by ultraperformance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS). Phytate, tannins, as well as other metabolomic constituents, namely, catechin, epicatechin, procyanidin, as well as citric acid, were identified in all raw and cooked BG samples. The cooking process resulted in a significant decrease (p < 0.05) in the phytate and tannin content as well as an increase in the health-associated phenolic compounds.

Bambara Nut Root-Nodules Bacteria from a Semi-Arid Region of South Africa and Their Plant Growth-Promoting Traits

Rhizobial nitrogen-fixing bacteria are the main inhabitants of the root nodules of legume plants. Studying the bacterial community of legume nodules is important in understanding plant growth and nutrient requirements. Culture-based technique was used to examine the bacterial community of these underground organs from Vigna subterranea L. Verdc (Bambara nut), an underutilized legume in Africa, for plant growth-promoting traits. In this study, Bambara nuts were planted to trap root-nodule bacteria, and the bacteria were morphologically, biochemically, and molecularly characterized. Five selected isolates were screened in vitro for their plant growth-promoting traits and exhibited differences in their phenotypic traits. The polymerase chain reaction (PCR) products were subjected to partial 16S rRNA gene sequencing for phylogenetic analysis. Based on 16S rRNA gene sequence, the isolates were identified as BA1 (Stenotrophomonas maltophilia), BA2 (Chryseobacterium sp.), BA3 (Pseudomonas alcaligenes), BA4 (Pseudomonas plecoglossicida), and BA5 (Pseudomonas hibiscicola). Results showed that four of the five isolates could produce IAA. The capability to solubilize phosphate in Pikovskaya's agar plates was positively shown by four isolates (BA2, BA3, BA4, and BA5). Three isolates could produce hydrogen cyanide while isolates BA1, BA3, BA4, and BA5 were found to have ammonia-production traits. The results suggest that these plant growth-promoting isolates can be used as inoculants for plant growth and productivity.

Variations of Nutrient and Antinutrient Components of Bambara Groundnut (Vigna subterranea (L.) Verdc.) Seeds

Bambara groundnut (BGN) fits the bill when it comes to an acceptable level of nutrient and mineral composition. BGN is a balanced food that can help eradicate food and nutritional insecurity if it is incorporated into the major food system. However, there is a large degree of variation in nutrient composition and antinutritional factors among BGN accessions. Here, we show the degree of variability of nutrient and antinutrient components such as percentage ash, moisture, protein, fat, tryptophan, tannin, and phytate contents in seeds of 95 accessions of BGN. Data were subjected to analysis of variance (ANOVA), followed by correlation and principal component analysis. Clustering was done to show the relatedness between the accessions in response to the various traits. A high level of heterogeneity was observed among the accessions for the various traits studied. PC1 and PC2 show 41.2% of the total observed variations. Cluster analysis grouped accessions into four main clusters. This study was able to confirm the high level of diversity in the components of nutrients and antinutrients previously reported in BGN. The results of this study are expected to aid in identifying parent lines for improved breeding programs.

The role of soaking, steaming, and dehulling on the nutritional quality of Bambara groundnuts (Vigna subterranea (L) Verdc.)

Bambara groundnut (Vigna subterranea (L) Verdc.) is a leguminous plant that is widely cultivated in West Africa for its nutritious seeds. However, the hard-to-cook phenomenon of this legume affects its patronage by consumers. The quality and bioavailability of nutrients are affected by processing techniques during cooking. This study evaluated the effects of processing techniques on the nutritional quality of two Bambara groundnut varieties (namely, Simbi-bile and Sinkpili-zee). For this, each variety was subjected to four processing techniques, namely, (i) dehulled and soaked in water, (ii) dehulled and soaked in 1% NaHCO3 + 1% NaCl, (iii) dehulled and steamed, and (iv) Control. After sample processing, the Association of Official Agricultural Chemists (AOAC) standard protocols were used for chemical analysis. The results on proximate composition, anti-nutritional factors, and seed minerals composition showed significant variations among treatments. The main effects of variety and processing technique markedly influenced the parameters measured. Soaked Bambara groundnut with NaHCO3 reduced anti-nutritional factors. Steamed treatments yielded highest amount of protein (25.87%) while dehulled treated Bambara groundnut produced the highest amount of carbohydrate (42.77%). Calcium, potassium, and iron showed significant reduction (p ≤ 0.05) when dehulled. Additional sodium in processing Bambara increased mineral content of the crop. Anti-nutritional factor levels were also reduced significantly in simbi-bile when soaked. Proximate components (crude protein, crude fat, crude fiber, carbohydrate, and water) had significant changes in their compositions across all the processing techniques. From the correlation analysis, oxalate and phytate have some levels of effect in all varieties on every nutritional or mineral component. Total ash correlated negatively with crude fat and positively with phytate and oxalate. Dehulled and control did not reduce the anti-nutritional factors compared to NaHCO3 + NaCl. From the results, soaking of Bambara groundnuts in 1% NaHCO3 + 1% NaCl prior to cooking was effective in improving nutritional quality while overcoming the hard-to-cook phenomenon. The findings highlight the need to adopt correct processing techniques that conserve the nutritional benefits of these edible seeds. Soaking Bambara groundnut in NaHCO3 + NaCl as a processing technique increases mineral content while reducing anti-nutritional factors, and hence should be adapted.

Health risk assessment of pesticide residue in freshly harvested Vigna subterranea (Bambara nut) in Nsukka South Eastern Nigeria

Two species of freshly harvested Bambara nut were analyzed for organophosphate and organochlorine pesticide residue using GC-FID and GC-ECD. The risk associated with the consumption of the Bambara nut was evaluated using the health risk index (HRI) and the probable cancer risk (PCR). A maximum of thirteen (13) organochlorines and eight (8) organophosphate pesticides were determined from both species respectively. The results revealed that almost all the quantified pesticides exceeded their respective FAO maximum residue levels (MRLs). The health risk index (HRI) values of the organochlorines and organophosphates were below 1 in adults indicating little or no risk to adults. While the HRI of the organophosphates and a few values in the organochlorines were above 1 in children indicating that organophosphate pesticides in the freshly harvested white and mixed Bambara nut could pose a great health risk to children within these areas. The Hierarchical Cluster Dendrogram indicated similar sources of the assessed organochlorine and organophosphate pesticides.

Bambara Groundnut (Vigna subterranea L. Verdc): A Crop for the New Millennium, Its Genetic Diversity, and Improvements to Mitigate Future Food and Nutritional Challenges

The world’s food and agricultural schemes have gradually fallen into an alarming state due to challenges such as high population birth rates, diverse agro-climatic zones, a lack of measures to counter global warming, severe practices of sole-culture cultivation, and asset reduction. A very high dependency on limited staple food crops is associated with repetitious diets, deprivation of food, and shortages of trace minerals, which often causes dietary sicknesses. To ensure nutritious diets worldwide, a real-world and justifiable scheme is provided to garner extra attention towards variation in both agriculture/farming approaches and food habits. The EAT-Lancet statement emphasized an increase in agri-based diets as a way of attaining global generational health. Enlarging neglected crops with plenty of genomic stocks and potentially profitable attributes is a solution that could address food and nutritional security concerns. Bambara groundnut is one such imperative and neglected legume crop that contributes positively to improving global food and nutrient safety. As a “complete food”, this crop has recently been treated as a new millennium crop, and furthermore, it is more adjusted to poor soil and climatic conditions than other dominant crops. Bambara groundnut is a repository of vital nutrients that provides carbohydrates, crucial amino acids, proteins, and energy as well as minerals and vitamins to developed and low-income countries where animal proteins are not readily available. This review explores the potential of Bambara groundnut in ensuring food and nutrient security; its variables, production, processing, nutrient values, role in reducing the nutritional gap, and diverse uses; and attempts in improving its traits. To strengthen food production, an agricultural revolution is required for underutilized crop species to feed the ever-expanding population in the world. Henceforth, advanced plant-breeding procedures, such as next-generation breeding techniques, various molecular tools, TILLING, Eco-TILLING, proteomics, genomics, and transcriptomics (which has been used for major crops), also need to be practiced to intensify production. To boost productivity and to feed the most starved and malnourished populations of the world, it is assumed that the application of modern techniques will play a vital role in the advancement of the underutilized Bambara groundnut.

Dietary implications of toasted Jatropha curcas kernel on the growth, haematology, and organ histology of Clarias gariepinus fingerlings

The nutritional value of Jatropha curcas kernel (JCK) can be improved through different processing methods; however, when using a thermal treatment, optimization of the process is needed to prevent denaturation of nutrients. In this study, JCK was toasted for varying durations (0, 10, 20, and 30 min) and nutritionally evaluated. The implication of feeding Clarias gariepinus with dietary inclusions (35% CP; 315 kcal g^-1) of the toasted JCK was also reported. The results obtained suggest that prolonged duration of toasting improved the nutritional characteristics of the JCK until the 20th min. Beyond this time, the protein content and essential amino acids are reduced. However, the antinutrients continuously decreased with prolonged processing. The growth, carcass analysis, and haematology of the fish groups fed toasted JCK at varying duration also did better than those fed raw JCK. Importantly, the performance tends to reduce for those fed JCK toasted beyond 20 min. The estimated cost of producing 1 kg of the fish also substantially reduced with feeding the processed JCK than feeding raw JCK. Histological examination of the intestine and liver tissues further revealed fewer signs of histopathological degeneration for fish-fed processed JCK compared to the control. It was concluded that the processing of JCK by toasting should not exceed 20 min to improve the nutritional composition of the feed ingredients and their dietary utilization by fish.

Potassium reduction in food by preparation technique for the dietetic management of patients with chronic kidney disease: a review

BACKGROUND

Chronic kidney disease patients often use food preparation techniques to reduce potassium intake. However, the most effective techniques have not yet been determined for all food groups. The present study aimed to analyse all of the available information on potassium reduction in the food and identify the best preparation techniques by comparing the trend of change in potassium level.

METHODS

Nine databases were searched from 1976 to May 2020, according to the PRISMA Statement. We included all articles reporting the amount of potassium before and after the application of food preparation techniques. Data were analysed using the Wilcoxon test and statistical simulation.

RESULTS

A wide variety of food and culinary processes was observed in the 65 included articles. Cooking in water, pressure cooking and cooking in a microwave oven reduced potassium levels in all food groups, particularly in cereals and derivatives, fruits and derivatives, meats and derivatives, legumes, and leafy and cruciferous vegetables. Soaking food significantly reduced the potassium content in tubers and roots and leafy and cruciferous vegetables. Steam cooking and dry heating cooking also reduced potassium, although at a level lower than the other techniques.

CONCLUSIONS

The present review shows that, in general, all food preparation techniques can reduce the potassium content, although cooking in water and soaking promotes a greater reduction; however, more studies with standardised techniques and complete data are necessary.

Bambara Groundnut: An Underutilized Leguminous Crop for Global Food Security and Nutrition

Rapid population growth, climate change, intensive monoculture farming, and resource depletion are among the challenges that threaten the increasingly vulnerable global agri-food system. Heavy reliance on a few major crops is also linked to a monotonous diet, poor dietary habits, and micronutrient deficiencies, which are often associated with diet-related diseases. Diversification-of both agricultural production systems and diet-is a practical and sustainable approach to address these challenges and to improve global food and nutritional security. This strategy is aligned with the recommendations from the EAT-Lancet report, which highlighted the urgent need for increased consumption of plant-based foods to sustain population and planetary health. Bambara groundnut (Vigna subterranea (L.) Verdc.), an underutilized African legume, has the potential to contribute to improved food and nutrition security, while providing solutions for environmental sustainability and equity in food availability and affordability. This paper discusses the potential role of Bambara groundnut in diversifying agri-food systems and contributing to enhanced dietary and planetary sustainability, with emphasis on areas that span the value chain: from genetics, agroecology, nutrition, processing, and utilization, through to its socioeconomic potential. Bambara groundnut is a sustainable, low-cost source of complex carbohydrates, plant-based protein, unsaturated fatty acids, and essential minerals (magnesium, iron, zinc, and potassium), especially for those living in arid and semi-arid regions. As a legume, Bambara groundnut fixes atmospheric nitrogen to improve soil fertility. It is resilient to adverse environmental conditions and can yield on poor soil. Despite its impressive nutritional and agroecological profile, the potential of Bambara groundnut in improving the global food system is undermined by several factors, including resource limitation, knowledge gap, social stigma, and lack of policy incentives. Multiple research efforts to address these hurdles have led to a more promising outlook for Bambara groundnut; however, there is an urgent need to continue research to realize its full potential.

Collagen biosynthesis stimulation and anti-melanogenesis of bambara groundnut (Vigna subterranea) extracts

CONTEXT

Bambara groundnut (BG), originally from Africa, is widely distributed in Asian countries, especially in southern Thailand, and is used for food and functional foods. There is no report on the use of BG for ethnomedicine or cosmetics.

OBJECTIVE

To investigate collagen biosynthesis stimulation and anti-melanogenesis of the BG extracts.

MATERIALS AND METHODS

The hulls (H) and seeds (S) of BG were collected from Trang province, Thailand and extracted by Soxhlet (S) and maceration (M) using ethanol, and boiled with distilled-water (B). Total phenolic (TPC) and total flavonoid (TFC) contents were quantified. The three antioxidant and tyrosinase inhibition activities were determined by DPPH, FIC and FTC; and the modified dopachrome methods, respectively. The collagen biosynthesis and the anti-melanogenesis activities were investigated by Sirius-Red and the melanin content assay.

RESULTS

The yields of BG extracts ranged from 1.72% to 9.06%. The BG-SS extract gave the highest TPC and TFC. The BG-HM extract showed the highest antioxidant activities (SC₅₀ of 0.87 ± 0.02 mg/mL, MC₅₀ of 1.83 ± 0.09 mg/mL and LC₅₀ of 0.70 ± 0.06 mg/mL), tyrosinase inhibition activity (IC₅₀ of 0.45 ± 0.23 mg/mL), and anti-melanogenesis activities (72.9 ± 0.08%), whereas the BG-SB extract exhibited the highest stimulation of collagen biosynthesis (18.04 ± 0.03%). All BG extracts at 0.1 mg/mL showed no cytotoxicity on human dermal fibroblasts.

DISCUSSION

The biological activities of BG extracts might be from their phytochemicals, especially phenolic and flavonoid contents.

CONCLUSION

The BG-HB and BG-HM extracts might be promising novel active sources for anti-aging and whitening cosmeceuticals.

Ageing, dehulling and cooking of Bambara groundnuts: consequences for mineral retention and in vitro bioaccessibility

Postharvest storage of legumes is a strategy to ensure food security. However, the hard-to-cook phenomenon, partly explained by pectin-cation-phytate theory, may develop during storage. Based on this theory, minerals could be redistributed within the matrix, affecting the concentration of free/bound minerals and hence their bioaccessibility. Therefore, this study investigated the influence of storage-induced ageing and subsequent dehulling, soaking and cooking treatments on the concentration and in vitro bioaccessibility of Ca, Mg, Fe and Zn in Bambara groundnuts. ICP-OES was performed to determine Ca, Mg, Fe and Zn concentrations after applying different treatments and after simulated digestion in the context of bioaccessibility determination. This study illustrates that while the seed coat is rich in Ca (51%), it contains only less than 15% of Mg, Fe or Zn. Hence, dehulling negatively influenced Ca, but not Mg, Fe or Zn concentration. During soaking, up to 10% or 56% of the initial Mg concentration leaches into whole or dehulled seeds, respectively. Prolonging the cooking time (300 min) of whole aged Bambara groundnuts (32 weeks), necessary for obtaining palatable textures, decreased the overall Mg, Fe and Zn concentrations by 72%, 57% and 48%, respectively. Storage-induced ageing significantly decreased Ca solubility and bioaccessibility. Bioaccessibility of trace minerals in Bambara groundnuts is low, especially for Fe, and cannot be improved by dehulling or cooking treatments. Ageing did not influence Fe and Zn bioaccessibility. Populations relying on both fresh and aged Bambara groundnuts may still be at risk for mineral deficiencies.

Insight Into the Prospects for the Improvement of Seed Starch in Legume-A Review

In addition to proteins and/or oils, mature seeds of most legume crops contain important carbohydrate components, including starches and sugars. Starch is also an essential nutritional component of human and animal diets and has various food and non-food industrial applications. Starch is a primary insoluble polymeric carbohydrate produced by higher plants and consists of amylose and amylopectin as a major fraction. Legume seeds are an affordable source of not only protein but also the starch, which has an advantage of being resistant starch compared with cereal, root, and tuber starch. For these reasons, legume seeds form a good source of resistant starch-rich healthy food with a high protein content and can be utilized in various food applications. The genetics and molecular details of starch and other carbohydrate components are well studied in cereal crops but have received little attention in legumes. In order to improve legume starch content, quality, and quantity, it is necessary to understand the genetic and molecular factors regulating carbohydrate metabolism in legume crops. In this review, we assessed the current literature reporting the genetic and molecular basis of legume carbohydrate components, primarily focused on seed starch content. We provided an overview of starch biosynthesis in the heterotrophic organs, the chemical composition of major consumable legumes, the factors influencing starch digestibility, and advances in the genetic, transcriptomic, and metabolomic studies in important legume crops. Further, we discussed breeding and biotechnological approaches for the improvement of the starch composition in major legume crops. The information reviewed in this study will be helpful in facilitating the food and non-food applications of legume starch and provide economic benefits to farmers and industries.

Consumer Perceptions and Acceptability of Traditional Dishes Prepared with Provitamin A-Biofortified Maize and Sweet Potato

Vitamin A deficiency (VAD) is prevalent in South Africa, particularly among predominantly poor rural communities. Provitamin A (PVA)-biofortified crops could be used to address VAD; however, there are challenges of poor consumer acceptability. This study investigated the effect of replacing white maize and cream-fleshed sweet potato (CFSP) with PVA-biofortified maize and orange-fleshed sweet potato (OFSP), respectively, on consumer acceptability and perceptions of traditional dishes of rural communities in South Africa. Consumer acceptability of PVA-biofortified phutu (a crumbly maize porridge) served with either curried cabbage, chicken or bambara groundnut, separately, and boiled OFSP was evaluated by black South African adults (n = 120) using a five-point facial hedonic scale. Focus group discussions (FGDs) were conducted with 56 subjects recruited from the consumer panel to assess consumer perceptions of the food samples. The majority of the participants rated the composite dishes containing PVA-biofortified phutu as "4 = good" and the acceptability of the composite dishes varied significantly (p < 0.05). Compared to other age groups, the 50-59-year age group showed higher preference for white phutu and chicken curry, whereas the 30-39-year age group showed higher preference for PVA-biofortified phutu and chicken curry. The acceptability of OFSP and CFSP was similar. The study participants showed positive perceptions of the OFSP, as well as PVA-biofortified phutu if served with either curried chicken or cabbage. The findings suggest that PVA-biofortified maize and OFSP can replace white maize and CFSP, respectively, in selected traditional dishes of the rural communities studied to alleviate VAD.

The effects of extraction techniques and quantitative determination of oxalates in Nerium oleander and feeds

Shrubs represent the most affordable and accessible form of feed that livestock can rely on to acquire both essential and non-essential elements of life. In addition to their inherent toxins, they contain endogenous substances commonly referred to as 'antinutritive factors' (ANFs) that often interfere with the utilisation of nutrients. Their abundance may lead to severe clinical trauma. Hence, the objective of the study was to investigate the effects of different extraction techniques on Nerium oleander L. and animal feeds as well as to quantify oxalates. Organic (hexane, acetone and methanol) sequential and aqueous (infusion and decoction) extractions were explored. Qualitative and quantitative analyses were conducted to determine the presence of various phytochemicals and oxalate contents as putative ANFs, respectively. The results showed higher extraction yields of 22.6% and 43.1% in the decoction and infusion of N. oleander, respectively. The quantification methods were validated for linearity, accuracy and precision. Oxalate contents of 6.76 ± 0.245 (0.65%) mg/g and 5.74 ± 0.236 mg/g dry weight (0.55%) were obtained in N. oleander and feeds, respectively. This difference was statistically significant with p < 0.05. Percentage recoveries of 98.5 (percent relative standard deviation [% RSD] = 2.3), 85.7 (% RSD = 1.03) and 80.3 (% RSD = 1.22) at 76%, 95% and 112% fortifications were obtained, respectively. Relative standard deviation for precision was 0.99% and 1.13% at 0.33 mg and 0.39 mg fortifications, respectively, while reproducibility showed 2.21% RSD. Therefore, these methods can be used to provide a valuable basis for qualitative determination of ANFs, particularly in shrub foliage.