Protein Isolates from Bambara Groundnut (Voandzeia SubterraneanL.): Chemical Characterization and Functional Properties

Techno-functional attributes of oilseed proteins: influence of extraction and modification techniques

Plant-based protein isolates and concentrates are nowadays becoming popular due to their nutritional, functional as well as religious concerns. Among plant proteins, oilseeds, a vital source of valuable proteins, are continuously being explored for producing protein isolates/concentrates. This article delineates the overview of conventional as well as novel methods for the extraction of protein and their potential impact on its hydration, surface properties, and rheological characteristics. Moreover, proteins undergo several modifications using physical, chemical, and biological techniques to enhance their functionality by altering their microstructure and physical performance. The modified proteins hold a pronounced scope in novel food formulations. An overview of these protein modification approaches and their effects on the functional properties of proteins have also been presented in this review.

Nutritional and pharmacological potentials of orphan legumes: Subfamily faboideae

Legumes are a major food crop in many developing nations. However, orphan or underutilized legumes are domesticated legumes that have valuable properties but are less significant than main legumes due to use and supply restrictions. Compared to other major legumes, they are better suited to harsh soil and climate conditions, and their great tolerance to abiotic environmental circumstances like drought can help to lessen the strains brought on by climate change. Despite this, their economic significance in international markets is relatively minimal. This article is aimed at carrying out a comprehensive review of the nutritional and pharmacological benefits of orphan legumes from eight genera in the sub-family Faboidea, namely Psophocarpus Neck. ex DC., Tylosema (Schweinf.) Torre Hillc., Vigna Savi., Vicia L., Baphia Afzel. ex G. Lodd., Mucuna Adans, Indigofera L. and Macrotyloma (Wight & Arn.) Verdc, and the phytoconstituents that have been isolated and characterized from these plants. A literature search was conducted using PubMed, Google Scholar, and Science Direct for articles that have previously reported the relevance of underutilized legumes. The International Union for Conservation of Nature (IUCN) red list of threatened species was also conducted for the status of the species. References were scrutinized and citation searches were performed on the study. The review showed that many underutilized legumes have a lot of untapped potential in terms of their nutritional and pharmacological activities. The phytoconstituents from plants in the subfamily Faboideae could serve as lead compounds for drug discovery for the treatment of a variety of disorders, indicating the need to explore these plant species.

Prediction and Evaluation of Bioactive Properties of Cowpea Protein Hydrolysates

Cowpea protein hydrolysates were prepared using thermolysin, alcalase, and trypsin and analysed for bioactive properties, and then, the release of bioactive peptides was investigated in silico. It was found that the degree of hydrolysis reached 48% after 24 h hydrolysis with alcalase. The hydrolysate prepared using alcalase showed higher ACE inhibitory (62%) and DPPH scavenging activity (19%). SDS-PAGE analysis revealed that vignin was the major protein in cowpea protein isolate. In silico analysis indicated the presence of potential bioactive peptides with potent bioactivity in the primary structure of proteins. The 3D structure of proteins was built, upon which bioactive peptides were mapped using their location in the primary structure. The secondary structure and solvent accessible surface around each bioactive peptide were then calculated. On this basis, the higher degree of hydrolysis and bioactive properties of cowpea protein hydrolysate prepared by alcalase were explained, and structural factors influencing the release of bioactive peptides were investigated.

Nutritional, functional, and bioactive properties of african underutilized legumes

Globally, legumes are vital constituents of diet and perform critical roles in maintaining well-being owing to the dense nutritional contents and functional properties of their seeds. While much emphasis has been placed on the major grain legumes over the years, the neglected and underutilized legumes (NULs) are gaining significant recognition as probable crops to alleviate malnutrition and give a boost to food security in Africa. Consumption of these underutilized legumes has been associated with several health-promoting benefits and can be utilized as functional foods due to their rich dietary fibers, vitamins, polyunsaturated fatty acids (PUFAs), proteins/essential amino acids, micro-nutrients, and bioactive compounds. Despite the plethora of nutritional benefits, the underutilized legumes have not received much research attention compared to common mainstream grain legumes, thus hindering their adoption and utilization. Consequently, research efforts geared toward improvement, utilization, and incorporation into mainstream agriculture in Africa are more convincing than ever. This work reviews some selected NULs of Africa (Adzuki beans (Vigna angularis), African yam bean (Sphenostylis stenocarpa), Bambara groundnut (Vigna subterranea), Jack bean (Canavalia ensiformis), Kidney bean (Phaseolus vulgaris), Lima bean (Phaseolus lunatus), Marama bean (Tylosema esculentum), Mung bean, (Vigna radiata), Rice bean (Vigna Umbellata), and Winged bean (Psophocarpus tetragonolobus)), and their nutritional, and functional properties. Furthermore, we highlight the prospects and current challenges associated with the utilization of the NULs and discusses the strategies to facilitate their exploitation as not only sources of vital nutrients, but also their integration for the development of cheap and accessible functional foods.

Karakterisasi Fisiko-Kimia Biji dan Kulit Ari Kacang Bogor Asal Jampang-Sukabumi Jawa Barat

The traditional cultivation and limited use of bambara groundnut (Vigna subterranea) seed and coat have encouraged the development of this commodity. The aim of this research was to characterize the seed and coat of bambara groundnut from Jampang, Kab. Sukabumi, West Java. Analysis on bambara groundnut seed including proximate analysis, in vitro protein digestibility, starch content, and dietary fiber, as well as analysis on its coat including anthocyanin, total phenolic, antioxidant activity, phytic acid and tannin, were examined in this study. The results showed that bambara groundnut seed from Jampang-Sukabumi contained 16.53% proteins, 3.04% ash, 7.83% fats and 55.22% carbohydrates in dry basis (db). The carbohydrates consisted of starch 52.71% and dietary fiber 7.47% (db). The protein had an in vitro protein digestibility of 41.65% db. The purple seed coat contained of 1.51% anthocyanin, 25.85 mg/g total phenolic content (as gallic acid equivalent), antioxidant activity at 82.75% inhibition of free radical DPPH, 6.37 mg/g phytic acid, and 96.79 mg/g tannin (as tannic acid equivalent) in dry basis. The relatively high content of tannin and antioxidant activity but very low phytic acid content, make the bambara seed coat a potential source for tannin, meanwhile the bambara groundnut is potential as a nutrition source.

Plant growth-promoting rhizobacteria for orphan legume production: Focus on yield and disease resistance in Bambara groundnut

Orphan legumes are now experiencing growing demand due to the constraints on available major food crops. However, due to focus on major food crops, little research has been conducted on orphan legumes compared to major food crops, especially in microbiome application to improve growth and yield. Recent developments have demonstrated the enormous potential of beneficial microbes in growth promotion and resistance to stress and diseases. Hence, the focus of this perspective is to examine the potential of plant growth promoting rhizobacteria (PGPR) to improve Bambara groundnut yield and quality. Further insights into the potential use of PGPR as a biological control agent in the crop are discussed. Finally, three PGPR genera commonly associated with plant growth and disease resistance (Bacillus, Pseudomonas, and Streptomyces) were highlighted as case studies for the growth promotion and disease control in BGN production.

Orphan legumes: harnessing their potential for food, nutritional and health security through genetic approaches

Legumes, being angiosperm's third-largest family as well as the second major crop family, contributes beyond 33% of human dietary proteins. The advent of the global food crisis owing to major climatic concerns leads to nutritional deprivation, hunger and hidden hunger especially in developing and underdeveloped nations. Hence, in the wake of promoting sustainable agriculture and nutritional security, apart from the popular legumes, the inclusion of lesser-known and understudied local crop legumes called orphan legumes in the farming systems of various tropical and sub-tropical parts of the world is indeed a need of the hour. Despite possessing tremendous potentialities, wide adaptability under diverse environmental conditions, and rich in nutritional and nutraceutical values, these species are still in a neglected and devalued state. Therefore, a major re-focusing of legume genetics, genomics, and biology is much crucial in pursuance of understanding the yield constraints, and endorsing underutilized legume breeding programs. Varying degrees of importance to these crops do exist among researchers of developing countries in establishing the role of orphan legumes as future crops. Under such circumstances, this article assembles a comprehensive note on the necessity of promoting these crops for further investigations and sustainable legume production, the exploitation of various orphan legume species and their potencies. In addition, an attempt has been made to highlight various novel genetic, molecular, and omics approaches for the improvement of such legumes for enhancing yield, minimizing the level of several anti-nutritional factors, and imparting biotic and abiotic stress tolerance. A significant genetic enhancement through extensive research in 'omics' areas is the absolute necessity to transform them into befitting candidates for large-scale popularization around the globe.

Physiochemical and Nutritional Characteristics of Ready-to-Use Therapeutic Food Prepared Using Bambara Groundnut-Moringa oleifera Leaf Protein Complex

The utilisation of local raw material in the production of ready-to-use therapeutic food (RUTF) is worthy of exploration for the replacement of full-fat milk, peanut butter, mineral and vitamin mix used in the standard formulation. The objective of this study was to produce snack bars that will meet the protein requirement set by World Health Organisation (WHO) for RUTF (13-16% by weight) using the Bambara groundnut-Moringa oleifera leaf protein complex (BAMOLP). The BAMOnut snack bars were simulated using the mixture preparation procedure in Superpro Designer to determine different proportions of BAMOLP, Moringa oleifera leaf powder, egusi, oats, and millet. Three bars formulated were; BAMOnut-OB3 (BAMOnut Bar enriched with oats and 3% BAMOLP), BAMOnut-MB2 (BAMOnut Bar enriched with millet and 2% BAMOLP), and BAMOnut-OMB5 (BAMOnut Bar enriched with oats, millets, and 5% BAMOLP). The snack bars were assessed for physical, nutritional, proximate and bench-top sensory properties. BAMOnut-OB3 was firmer and less crumbly, with a larger particle size. BAMOnut-OB3 had the lowest water activity, lightest colour and the best amino acid profile. The moisture (4.9%), protein (14.1%), fat (19.3%), carbohydrate (59.7%), and energy (468.6 Kcal/100 g) of BAMOnut-OB3, compare favourably with the requirements for RUTF (2.5% moisture, 13-16% protein, 26-36% fat, 41-58% carbohydrate, and 520-550 Kcal/100 g energy). Local raw materials can be successfully used in the production of RUTF.

Effect of heat treatment on the structure, functional properties and composition of Moringa oleifera seed proteins

Knowledge on how food processing conditions and protein composition can modulate individual or food matrix protein functionality is crucial for designing new protein ingredients. In this regard, we investigated how heat treatment and protein composition influence physicochemical and functional properties of Moringa oleifera seed protein isolate. Results showed that changes in processing temperature induced modifications in the conformation affecting the hydrophobic core of proteins. Protein isolate was more soluble at room temperature whereas prolamin fraction presented high solubility at 70 °C. Glutelin showed higher emulsifying properties at all temperatures. Protein composition also significantly affected physicochemical and functional properties of protein isolate. Increasing soluble glutelin enhanced solubility while increasing albumin, globulin and glutelin decreased hydrophobicity of the isolate. Likewise, increasing soluble globulin improved emulsifying capacity, and emulsion stability of the isolate was negatively affected by increase in albumin and glutelin. These findings could enhance application of Moringa oleifera protein in food formulations.

Functional Properties and Amino Acid Profile of Bambara Groundnut and Moringa oleifera Leaf Protein Complex

Combinations of indigenous ingredients lacking in certain essential amino acids could be used to obtain a protein isolate with a better amino acid profile that can be used as a functional food ingredient and suitable raw material for the food industry. Functional properties and amino acid profile of Bambara groundnut and Moringa oleifera leaf protein complex and its precursors (Bambara groundnut protein isolates (BGNPI) and Moringa oleifera leaf protein isolate (MOLPI)) were evaluated. The protein, fat, ash, carbohydrate, and moisture content of the protein isolates and complex ranged from 39.42 to 63.51%, 2.19 to 11.52%, 1.60 to 7.09%, 24.07 to 51.29%, and 2.61 to 9.57%, respectively, and differed significantly (p < 0.05) from one another. The total amino acids of the protein isolates and complex were 75.11, 50.00, and 71.83 g/100 g, respectively. The protein complex is higher in threonine, phenylalanine, lysine, and leucine when compared to the FAO/WHO reference pattern. The oil absorption capacity was between 0.89 and 2.26 g/g and the water absorption capacity was between 1.22 and 1.5 g/g. Herein, the water absorption capacity and swelling capacity increased with temperature with foaming capacity dependent on pH. The minimum solubility was at around pH 2–4 and 4–5. The protein isolates and complex can be used as a functional food ingredient in value-added products.

Influence of pH and temperature on the physicochemical and functional properties of Bambara bean protein isolate

Bambara bean is a rich low-cost protein source and a functional ingredient in the food industry. We investigated the effects of temperature and different pH on the physicochemical and functional properties of Bambara bean protein isolate. Vicilin was the major protein of Bambara bean as revealed by SDS PAGE analysis. The emulsifying capacity of protein isolate was highest at 80 °C, pH 9 while emulsion stability was highest at pH 4. Generally, increase in temperature decreased protein solubility at pH 4 and 7, while increase was observed at pH 9 and 100 °C. The hydrophobicity of isolate was highest at pH 4 and lowest at pH 9, regardless of temperature. Protein isolate possessed highly compact β-sheet and α-helix secondary structures in proportions greater than 75% (at pH 9 and 50 °C). Increase in temperature generally promoted protein rearrangement and partial unfolding. Protein secondary structure and surface hydrophobicity can predict food functionality, directly affecting protein behavior during formulation and long-term storage. This study clearly demonstrated the potential of exploiting pulse protein isolates as nutritional and functional ingredients through temperature and pH control.

Breeding Potentials of Bambara Groundnut for Food and Nutrition Security in the Face of Climate Change

Constant production of quality food should be a norm in any community, but climate change, increasing population, and unavailability of land for farming affect food production. As a result, food scarcity is affecting some communities, especially in the developing world. Finding a stable solution to this problem is a major cause of concern for researchers. Synergistic application of molecular marker techniques with next generation sequencing (NGS) technologies can unlock the potentials hidden in most crop genomes for improving yield and food availability. Most crops such as Bambara groundnut (BGN), Winged bean, and African yam bean are underutilized. These underutilized crops can compete with the major crops such as cowpea, soybean, maize, and rice, in areas of nutrition, ability to withstand drought stress, economic importance, and food production. One of these underutilized crops, BGN [Vigna subterranea (L.), Verdc.], is an indigenous African legume and can survive in tropical climates and marginal soils. In this review, we focus on the roles of BGN and the opportunities it possesses in tackling food insecurity and its benefits to local farmers. We will discuss BGN's potential impact on global food production and how the advances in NGS technologies can enhance its production.

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.

Physicochemical properties and gelling behaviour of Bambara groundnut protein isolates and protein-enriched fractions

Plant proteins, and specifically those from legume crops, are increasingly recognised as sustainable and functional food ingredients. In this study, we expand on the knowledge of Bambara groundnut (Vigna subterranea (L.) Verdc.) [BGN] proteins, by characterising the composition, microstructure and rheological properties of BGN protein isolates obtained via wet extraction and protein-enriched fractions obtained via dry fractionation. The BGN protein isolates were compared in the context of the major storage protein, vicilin, as previously identified. Molecular weight analysis performed with gel electrophoresis and size-exclusion chromatography coupled to light-scattering, revealed some major bands (190 kDa) and elution patterns with molecular weights (205.6-274.1 kDa) corresponding to that of BGN vicilin, whilst the thermal denaturation temperature (T_p 91.1 °C, pH 7) of BGN protein isolates also coincided to that of the vicilin fraction. Furthermore, the concentration dependence of the elastic modulus G' of the BGN protein isolates, closely resembled that of BGN vicilin (both upon NaCl addition); suggesting that vicilin is the main component responsible for gelation. Confocal laser scanning and scanning electron micrographs revealed inhomogeneous aggregate structures, which implies that fractal scaling were better suited for description of the BGN protein isolate gel networks. Concerning the BGN protein-enriched fractions, both rotor and impact milling with air jet sieving and air classification, respectively, were successfully applied to separate these fractions from those high in starch; as evident from compositional analysis, particle size distributions and microscopic imaging. When considering sustainability aspects, dry fractionation could thus be a viable alternative for producing BGN protein-enriched fractions.

Transglutaminase-mediated crosslinking of Bambara groundnut protein hydrogels: Implications on rheological, textural and microstructural properties

Interest in plant protein-based hydrogels with desirable strength has been increasing in recent years. In this study, Bambara groundnut protein isolate (BPI) was crosslinked with transglutaminase (TGase) (0 - 25 U/g protein) during gelation and rheological, textural and microstructural properties of the resulting hydrogels were investigated. Treatment with TGase up to 15 U/g protein resulted in the formation of hydrogels with small pores and an organised homogeneous network. G' of TGase-treated BPI hydrogels was more than ten-fold higher than G" throughout the frequency range of 0-100 rad/s, suggesting dominance of the elastic like behaviour. BPI hydrogel with the highest G' (6967 Pa) and hardness (5.60 N) was formed at 15 U/g protein of TGase activity. The hydrogel had a high distribution β-sheets (53.52%) and α-helixes (26.17%) as compared to the β-turns and random coils. However, a further increase in TGase activity did not improve the hydrogel properties. Transglutaminase mediated crosslinking of BPI hydrogel was demonstrated by the reduction in amine and thiol groups and the formation of a new protein band (56 kDa) in crosslinked hydrogels. Overall, TGase promoted the formation of a strong gel with an organised network.

Nutritive bambara groundnut powdered drink mix: characterization and in-vivo assessment of the cholesterol-lowering effect

Drought has become more frequent due to climate change and its effects on the agricultural sector can be devastating. This increases the need for drought tolerant crops such as the Bambara groundnut (BGN) to be farmed in Malaysia. The development of BGN to a product suitable for consumers in this region has not been studied. Therefore, this research aimed to determine consumer acceptability of a nutritive BGN powdered drink mix using the Just-About-Right (JAR) method. BGN flour was produced by mixing soy powder with 0% BGN powder (0B100S), 10% BGN powder (10B90S), 20% BGN powder (20B80S) and 30% BGN powder (30B70S), respectively. The physicochemical properties of the powdered drink mix and its microbiological changes upon storage for six months were then determined. In addition, in-vivo assessment of the cholesterol-lowering effect of this product was conducted. Sample 10B90S was the most preferred sample among the sensory panellists (overall acceptability = 72%). Sample 10B90S remained stable after six months of ambient storage. Rats fed with sample 30B70S showed the most improvement in blood cholesterol levels. In conclusion, nutritive BGN powdered drink mix exhibited good physicochemical properties and could be useful for food applications.

Fonio and Bambara Groundnut Value Chains in Mali: Issues, Needs, and Opportunities for Their Sustainable Promotion

As the effects of climate change are severely straining West African agricultural systems, the adoption of more incisive interventions in support of sustainable development agendas for the region is highly critical and cannot be further delayed by governments. Neglected and underutilized species (NUS) are one important ally in pursuing resilience in both production and food systems because of their promising traits in terms of nutrition, adaptation to local agroecosystems, and economic potential for local populations. Focusing on fonio, a gluten-free traditional cereal, and Bambara groundnut, a protein-rich leguminous crop, we investigate issues in their production, commercialization, and consumption in southern Mali. The aim was to assess needs and opportunities for improving their value chains and increasing their use and societal benefits. Using a Rapid Market Appraisal method, we surveyed traders, producers, processors, and consumers of target crops in 2017 and 2018. Our findings indicate that while both crops are consumed and praised by local populations, critical bottlenecks inhibit their wider socioeconomic potential. Lack of access to inputs and equipment and presence of sand in the commercialized product are important issues for fonio, whereas the Bambara groundnut value chain suffers from poor processing facilities and lack of market promotion. Policy recommendations to tackle the identified bottlenecks are proposed.

Nutritional Properties and Consumer's Acceptance of Provitamin A-Biofortified Amahewu Combined with Bambara (Vigna Subterranea) Flour

Amahewu is a fermented non-alcoholic cereal grain beverage, popular in Southern Africa. This study evaluates the possibility of producing an acceptable provitamin A (PVA)-biofortified maize amahewu, complemented with bambara flour, to contribute towards the alleviation of protein energy malnutrition (PEM) and vitamin A deficiency (VAD). Germinated, roasted, and raw bambara flours, were added at 30% (w/w) substitution level, separately, to either white maize or PVA-biofortified maize flour, and processed into amahewu. Wheat bran (5% w/w) was used as reference inoculum. Amahewu samples were analyzed for nutritional properties and acceptability. The protein and lysine contents of amahewu almost doubled with the inclusion of germinated bambara. Protein digestibility of amahewu samples increased by almost 45% with the inclusion of bambara. PVA-biofortified maize amahewu samples complemented with bambara were extremely liked for their color, aroma, and taste when compared with their white maize counterparts. The principal component analysis explained 96% of the variation and PVA-biofortified maize amahewu samples were differentiated from white maize amahewu samples. The taste of amahewu resulting from roasting and germination of bambara was preferred in PVA-biofortified maize amahewu, compared to white maize amahewu. We conclude that PVA-biofortified maize amahewu, complemented with germinated bambara, has the potential to contribute towards the alleviation of PEM and VAD.

Effect of pH on protein extraction from sour cherry kernels and functional properties of resulting protein concentrate

The aims of this research were to examine the effect of pH on extraction of proteins from sour cherry (Prunus cerasus L.) kernels, and to investigate the functional properties of the resulting protein concentrate. The optimum pH values for the protein extraction and isoelectric precipitation were determined as 10.0 and 4.5, respectively. The protein concentrate contained 4.03 ± 0.16% moisture, 3.31 ± 0.17% ash, 2.94 ± 0.36% carbohydrate, 1.93 ± 0.16% lipid, and 80.48 ± 2.38% protein. Water holding capacity, oil holding capacity and the least gelling concentration of the protein concentrate were 2.42 ± 0.09 g water/g, 1.73 ± 0.17 g oil/g and 8%, respectively. Results showed that emulsifying activity and stability indices, foaming capacity and stability of protein concentrate were 38.91 ± 2.50 m²/g, 37.49 ± 2.41 min, 35.00 ± 3.54% and 71.80 ± 7.25% (after 30 min), respectively. The functional and chemical properties of the protein concentrate indicate that it may find application as functional ingredient for various food products.

Influence of infrared heating processing technology on the cooking characteristics and functionality of African legumes: a review

African legumes are an important protein source in the human diet. However, a long and often extended cooking process has been identified as a major challenge in the consumption and utilisation of these legumes. The application of infrared heating as a method of shortening the cooking-time of African legume seeds and flour, by increasing their water absorption rates and pasting viscosity is emphasised in literature. Structural changes caused by infrared heating of moisture-conditioned African legumes include microstructural, molecular and interaction of the biomolecules in the seeds. However, to the best of the authors' our knowledge, no overview on elucidated mechanisms surrounding the microstructural and molecular changes of infrared heated African legumes has been done. The authors' therefore, present current knowledge of these mechanisms including certain highlighted factors such as seed sizes, moisture, surface temperature and time, affecting the efficacy of the application of infrared heating to African legumes. In conclusion, infrared heating is a promising technology that provides a potential solution to the consumption and utilisation challenges of African legumes and flour from these legumes, to enhance their consumption in the food industry.

Effects of thermal processing on the nutritional and functional properties of defatted conophor nut (Tetracarpidium conophorum) flour and protein isolates

Conophor nut (Tetracarpidium conophorum) was processed using different heat treatments to explore its full potential as food ingredients. The raw, boiled, and toasted nuts were defatted and the proteins isolated by alkaline solubilization and isoelectric precipitation. The variously processed nuts were analyzed for the proximate and amino acid compositions, and functional properties. The protein contents of the isolate ranges between 86.86 g/100g and 87.74 g/100 g, about 1.5-fold higher than those of the defatted flour samples. The essential amino acids of the isolates ranged between 40.57%-41.55%. Glutamic acid, aspartic acid, and arginine were the most predominant amino acids, while methionine and lysine were the first and second limiting amino acids, respectively. The protein efficiency ratio, biological values as well as the functional properties of the proteins were improved with processing. These properties may enhance the potential use of conophor nut protein isolates as high-quality protein ingredient in food systems.

Inhibitory properties of bambara groundnut protein hydrolysate and peptide fractions against angiotensin-converting enzymes, renin and free radicals

BACKGROUND

An increased rate of high blood pressure has led to critical human hypertensive conditions in most nations. In the present study, bambara protein hydrolysates (BPHs) obtained using three different proteases (alcalase, trypsin and pepsin) and their peptide fractions (molecular weight: 10, 5, 3 and 1 kDa) were investigated for antihypertensive and antioxidant activities.

RESULTS

Alcalase hydrolysate contained the highest amount of low molecular weight (LMW) peptides compared to pepsin and trypsin hydrolysates. LMW peptides fractions (<1 kDa) exhibited the highest inhibitory activity against angiotensin-converting enzyme (ACE) for all the enzymes hydrolysates. For renin inhibition, alcalase hydrolysate showed the highest inhibition at 59% compared to other hydrolysates and their corresponding membrane fractions. The antioxidant power of bambara protein hydrolysates and peptide fractions was evaluated through the inhibition of linoleic acid peroxidation and ABTS scavenging activity. Among the hydrolysates, alcalase exhibited the highest inhibition of linoleic acid oxidation. Furthermore, all BPHs were able to scavenge ABTS^•+ to a three-fold greater extent compared to the isolate.

CONCLUSION

BPH and LMW peptide fractions could potentially serve as useful ingredients in the formulation of functional foods and nutraceuticals against high blood pressure and oxidative stress. © 2016 Society of Chemical Industry.

Physico-chemical properties, antioxidant activities and antihypertensive effects of walnut protein and its hydrolysate

BACKGROUND

Some food proteins hydrolysates are found to possess multiple health effects. In this study, walnut protein (WP) was enzymatically hydrolysed by alcalase and trypsin under optimal conditions. The physico-chemical properties, antioxidant and angiotensin-converting enzyme (ACE) inhibitory activities of WP, alcalase-generated walnut protein hydrolysate (AWPH) and trypsin-generated walnut protein hydrolysate (TWPH) were comparatively studied. Stability properties of the walnut protein hydrolysate (WPH) and the antihypertensive activity in spontaneously hypertensive rats (SHRs) were also investigated.

RESULTS

The WPH showed higher physico-chemical properties, antioxidant activities, ACE inhibitory activity and stability against thermal treatment and gastrointestinal digestion than WP. The results of antihypertensive effects in SHRs showed that the most potent decrease of AWPH and TWPH in the systolic blood pressure occurred at 4 h (-26 mmHg) and 6 h (-30 mmHg) after administration. The study indicated that the WPH could significantly decrease the systolic blood pressure (P < 0.05).

CONCLUSION

The WPH exhibited high physico-chemical properties, potent inhibitory activities and high stability. TWPH was more effective than AWPH in the detected properties. The results would be helpful for the comprehensive utilisation of the walnut resources. © 2015 Society of Chemical Industry.

Effects of Extraction Conditions on the Functional Properties of Bambara Bean Protein Concentrates

Functional properties of Bambara bean protein concentrates (BPCs), as a function of extraction pH and NaCl concentration, were investigated. The results showed that protein content of the concentrates ranged between 69.27% and 74.40%. The addition of NaCl during protein extraction favourably affected water solubility index particularly at pH 10–11. Moreover, the maximum water absorption capacity (4.28 g/g) and oil-holding capacity (OHC) (2.50 g/g) were recorded at extraction pH 11 and in the absence of NaCl. It was also noticed that protein extraction at pH 8–10 was not recommended for applications where high OHC is required. BPCs presenting high emulsifying activity were prepared at NaCl concentration of 0.5 M and pH 7, and at pH 11 without NaCl. Finally, foaming ability (FA) increased with NaCl concentration, and the maximum FA was recorded at pH 7 (114%).

Antioxidant activities of bambara groundnut (Vigna subterranea) protein hydrolysates and their membrane ultrafiltration fractions

In this study, the bambara protein isolate (BPI) was digested with three proteases (alcalase, trypsin and pepsin), to produce bambara protein hydrolysates (BPHs).