Phenolic composition and inhibitory effect against oxidative DNA damage of cooked cowpeas as affected by simulated in vitro gastrointestinal digestion

Metabolomic and transcriptomic changes in mungbean (Vigna radiata (L.) R. Wilczek) sprouts under salinity stress

Mungbean (Vigna radiata) sprouts are consumed globally as a healthy food with high nutritional values, having antioxidant and anticancer capacity. Under mild salinity stress, plants accumulate more secondary metabolites to alleviate oxidative stress. In this study, metabolomic and transcriptomic changes in mungbean sprouts were identified using a reference cultivar, sunhwa, to understand the regulatory mechanisms of secondary metabolites in response to salinity stress. Under salinity conditions, the contents of phenylpropanoid-derived metabolites, including catechin, chlorogenic acid, isovitexin, p-coumaric acid, syringic acid, ferulic acid, and vitexin, significantly increased. Through RNA sequencing, 728 differentially expressed genes (DEGs) were identified and 20 DEGs were detected in phenylpropanoid and flavonoid biosynthetic pathways. Among them, 11 DEGs encoding key enzymes involved in the biosynthesis of the secondary metabolites that increased after NaCl treatment were significantly upregulated, including dihydroflavonol 4-reductase (log₂FC 1.46), caffeoyl-CoA O-methyltransferase (1.38), chalcone synthase (1.15), and chalcone isomerase (1.19). Transcription factor families, such as MYB, WRKY, and bHLH, were also identified as upregulated DEGs, which play a crucial role in stress responses in plants. Furthermore, this study showed that mild salinity stress can increase the contents of phenylpropanoids and flavonoids in mungbean sprouts through transcriptional regulation of the key enzymes involved in the biosynthetic pathways. Overall, these findings will provide valuable information for molecular breeders and scientists interested in improving the nutritional quality of sprout vegetables.

Metabolic and Developmental Changes in Germination Process of Mung Bean (Vigna radiata (L.) R. Wilczek) Sprouts under Different Water Spraying Interval and Duration

Mung bean is one of the world’s most important legume crops and is a major protein source, particularly in developing countries. Various polyphenolic compounds and nutrients accumulate in mung bean sprouts during germination. Mung bean sprouts are consumed globally as an excellent food source of bioactive phenolic compounds. The contents of phenols and flavonoids and antioxidant activity were monitored for four days after germination under four different spraying conditions using three mung bean cultivars. On the third day after germination, the sprout extract showed the highest antioxidant capacity. The length and thickness of hypocotyl of mung bean sprouts appeared to be the most suitable for consumption on the third day after germination. Using high-performance liquid chromatography analysis, eight phytochemicals were identified, and neochlorogenic acid was identified for the first time in mung bean sprouts. End products (neochlorogenic acid, chlorogenic acid, vitexin, and isovitexin) showed certain trends in their contents for four days, while intermediates (caffeic acid, catechin, syringic acid, and p-coumaric acid) were highly responsive to watering condition and cultivars. Watering interval significantly affected the length of root and lateral root development. Both cultivars and watering conditions and/or their interaction significantly affected the biochemical and physical traits of mung bean sprouts. The results suggest that watering conditions need to be considered as an important factor to improve food quality of mung bean sprouts. Our phenotypic and metabolic profiling would provide potential information for production of mung bean sprouts that fit consumers’ preferences.

Flavonoid and Phenolic Acid Profiles of Dehulled and Whole Vigna subterranea (L.) Verdc Seeds Commonly Consumed in South Africa

Bambara groundnut (BGN) is an underexploited crop with a rich nutrient content and is used in traditional medicine, but limited information is available on the quantitative characterization of its flavonoids and phenolic acids. We investigated the phenolic profile of whole seeds and cotyledons of five BGN varieties consumed in South Africa using UPLC-qTOF-MS and GC-MS. Twenty-six phenolic compounds were detected/quantified in whole seeds and twenty-four in cotyledon, with six unidentified compounds. Flavonoids include flavan-3-ol (catechin, catechin hexoside-A, catechin hexoside-B), flavonol (quercetin, quercetin-3-O-glucoside, rutin, myricetin, kaempherol), hydroxybenzoic acid (4-Hydroxybenzoic, 2,6 Dimethoxybenzoic, protocatechuic, vanillic, syringic, syringaldehyde, gallic acids), hydroxycinnamic acid (trans-cinnamic, p-coumaric, caffeic, ferulic acids) and lignan (medioresinol). The predominant flavonoids were catechin/derivatives, with the highest content (78.56 mg/g) found in brown BGN. Trans-cinnamic and ferulic acids were dominant phenolic acid. Cotyledons of brown and brown-eyed BGN (317.71 and 378.59 µg/g) had the highest trans-cinnamic acid content, while red seeds had the highest ferulic acid (314.76 µg/g) content. Colored BGN had a significantly (p < 0.05) higher content of these components. Whole BGN contained significantly (p < 0.05) higher amount of flavonoids and phenolic acids, except for the trans-cinnamic acid. The rich flavonoid and phenolic acid content of BGN seeds highlights the fact that it is a good source of dietary phenolics with potential health-promoting properties.

Attenuation of carbohydrate metabolism and lipid profile by methanolic extract of Euphorbia helioscopia and improvement of beta cell function in a type 2 diabetic rat model

Background

Traditional plant-based remedies prescribed to treat diabetes have shown promise in research-based setting. Current research was conducted to examine the antidiabetic and antioxidant effects of methanolic extract of a folk herbal plant Euphorbia helioscopia in a rat model of type 2 diabetes.

Methods

Diabetes was induced in male Wistar rats by administering 5% sucrose in drinking water and cafeteria diet for 8 weeks with subsequent nicotinamide and streptozotocin administration. Diabetic rats were then distributed into four individual groups (n = 8); Positive control (PC; no treatment), standard control (SC; Metformin @ 10 mg/kg bw), treatment 1 (EH1, E. helioscopia methanolic extract @200 mg/kg bw) and treatment 2 (EH2, E. helioscopia methanolic extract @400 mg/kg bw). After 21 days of treatments, the rats were decapitated for blood collection. Serum was evaluated for antidiabetic potential, antioxidant and lipid profile, thyroid hormone, amylin, leptin, and carbohydrate metabolic enzymes. Data were analyzed statistically by one-way analysis of variance (ANOVA).

Results

Serum levels of glucagon, glucose and C-peptide were significantly (P ≤ 0.05) decreased in EH1 (1915.33 ± 98.26^a pg/ml, 122.59 ± 2.99^a mg/dl, 277.59 ± 28.41^a pg/ml respectively) and EH2 (1575.28 ± 56.46^a pg/ml, 106.04 ± 5.21^a mg/dl, 395.06 ± 42.55^a pg/ml respectively) as compared to the PC (3135.78 ± 189.46^bpg/ml, 191.24 ± 17.75^bmg/dl, 671.70 ± 109.75^b pg/ml respectively) group. A similar trend was observed in serum insulin levels in EH1 and EH2 groups. The plant’s methanolic extract effectively reduced the total oxidant status (TOS) and MDA levels in the diabetic rats and increased the total antioxidant capacity (TAC) along with an increased level of SOD, Catalase, Paraoxonase, and arylesterase. The plant extract also induced antihyperlipidemic activity and recovered the thyroid hormones, amylin, and leptin levels to normal. The activity of different carbohydrate metabolic enzymes like Pyruvate Kinase, Glucose 6 phosphate dehydrogenase, phosphofructokinase, and glucokinase has also been restored by the extract treatment.

Conclusion

Current study indicates the antioxidant and antidiabetic potential of E. helioscopia methanolic extract in normalizing the lipid profile, thyroid hormones, amylin, leptin, and carbohydrate metabolism in type 2 diabetic rat model.

Effect of simulated in vitro upper gut digestion of processed cowpea beans on phenolic composition, antioxidant properties and cellular protection

The effect of simulated in vitro upper gut digestion on the phenolic composition and antioxidant properties of processed cowpea beans was studied. The samples comprised four cowpea cultivars: a cream, brownish-cream and two reddish-brown cultivars. Dry cowpea seeds were soaked in water, blended into paste and deep-fried in vegetable oil. The fried samples were taken through in vitro upper gut digestion followed by freeze-drying of the supernatant. Phenolic composition of extracts from the supernatants were determined using HPLC-MS. Radical scavenging activities were documented using the TEAC, ORAC and nitric oxide (NO) assays. In vitro digestion of the processed cowpeas resulted in phenolic-peptide complexes that were identified for the first time, and decreased extractable phenolic compounds. However, the radical scavenging activities increased. The processed cowpeas and their digests inhibited cellular NO production, and oxidative DNA and cellular damage. In conclusion, deep-fried cowpeas when consumed, could potentially help alleviate oxidative stress-related conditions.

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.

Untargeted Phytochemical Profile, Antioxidant Capacity and Enzyme Inhibitory Activity of Cultivated and Wild Lupin Seeds from Tunisia

Lupin seeds can represent a valuable source of phenolics and other antioxidant compounds. In this work, a comprehensive analysis of the phytochemical profile was performed on seeds from three Lupinus species, including one cultivar (Lupinus albus) and two wild accessions (Lupinus cossentinii and Lupinus luteus), collected from the northern region of Tunisia. Untargeted metabolomic profiling allowed to identify 249 compounds, with a great abundance of phenolics and alkaloids. In this regard, the species L. cossentinii showed the highest phenolic content, being 6.54 mg/g DW, followed by L. luteus (1.60 mg/g DW) and L. albus (1.14 mg/g DW). The in vitro antioxidant capacity measured by the ABTS assay on seed extracts ranged from 4.67 to 17.58 mg trolox equivalents (TE)/g, recording the highest values for L. albus and the lowest for L. luteus. The DPPH radical scavenging activity ranged from 0.39 to 3.50 mg TE/g. FRAP values varied between 4.11 and 5.75 mg TE/g. CUPRAC values for lupin seeds ranged from 7.20 to 8.95 mg TE/g, recording the highest for L. cossentinii. The results of phosphomolybdenum assay and metal chelation showed similarity between the three species of Lupinus. The acetylcholinesterase (AChE) inhibition activity was detected in each methanolic extract analyzed with similar results. Regarding the butyrylcholinesterase (BChE) enzyme, it was weakly inhibited by the Lupinus extracts; in particular, the highest activity values were recorded for L. albus (1.74 mg GALAE/g). Overall, our results showed that L. cossentinii was the most abundant source of polyphenols, consisting mainly in tyrosol equivalents (5.82 mg/g DW). Finally, significant correlations were outlined between the phenolic compounds and the in vitro biological activity measured, particularly when considering flavones, phenolic acids and lower-molecular-weight phenolics.

Efficacy of Euphorbia helioscopia in context to a possible connection between antioxidant and antidiabetic activities: a comparative study of different extracts

Background

Euphorbia helioscopia, conventionally known as sun spurge, has been used as a traditional medicine to treat different diseases owing to its reported antitumor, antiviral and antioxidant activities.

Methods

The current research was formulated to assess the in-vitro antioxidant and antidiabetic ability of Euphorbia helioscopia subsequent to the phytochemical analysis of its various extracts. For this purpose, methanol, ethanol and aqueous extracts were prepared using the whole dried plant. Phytochemical analysis of the extracts was done to evaluate the total flavonoid components (TFC) and total phenolic components (TPC) in the extracts. A total of seven phenolic and three flavonoid contents were documented and quantified using HPLC. Antioxidant values were found by DPPH^● assay, FRAP and ABTS assays. The antidiabetic potential of the extracts was evaluated by measuring the inhibition ability of the activity of enzymes α amylase and α glucosidase.

Results

After analyzing statistically, the results showed that methanolic extract possesses the highest TFC and TPC values while aqueous extract encompassed the lowest level of these contents. Invitro results showed that methanolic extract of the Euphorbia helioscopia has the maximum antioxidant capability since it showed the highest scavenging ability towards the DPPH^● (IC₅₀ value = 0.06 ± 0.02 mg/ml), FRAP (758.9 ± 25.1 μMFe^+ 2/g), and ABTS (689 ± 25.94 μMTEq/g) due to the presence of high TPC (24.77 ± 0.35 mgGAEq/g) and TFC (17.95 ± 0.32 mgQEq/g) values. Antidiabetic activity in terms of inhibition potential of α amylase and α glucosidase activity was also observed maximum in methanolic extract having lowest IC₅₀ value (0.4 ± 0.01 mg/ml and 0.45 ± 0.01 mg/ml respectively) and minimum in the aqueous extract (IC₅₀ value = 0.57 ± 0.02 mg/ml and 0.76 ± 0.1 mg/ml respectively).

Conclusion

The experiment outcomes have shown that Euphorbia helioscopia extracts used in the current study contain antioxidant and antidiabetic activities; however, it is highest in its methanolic extract. The presence of the same trend towards the highest antidiabetic activity of the methanolic extract in terms of maximum inhibiting activity of α amylase and α glucosidase enzymes suggests a close association of TFC and TPC in minimizing diabetes.

Composition of Primary and Secondary Metabolite Compounds in Seeds and Pods of Asparagus Bean (Vigna unguiculata (L.) Walp.) from China

Asparagus bean immature pods and seeds are popular as food products for healthy and functional nutrition. Gas chromatography with mass spectrometry was used to compare metabolomic profiles of seeds and pods yielded by old Chinese landraces and the modern cultivars ‘Yunanskaya’ and ‘Sibirskiy razmer’. About 120 compounds were identified. The content of a majority among groups of compounds was higher in pods than in seeds. The amount of free amino acids in pods was 47 times higher, polyols and phytosterols 5 times higher, phenolics 4 times higher, and organic acids and saponins 3 times higher than in seeds. Differences were found in the relative content of compounds. Among phenolic compounds, the dominant one for seeds was protocatechuic acid, and for pods 4-hydroxycinnamic acid. Only polyols were identified in seeds, but pods additionally contained ethanolamine, phytol, and phytosphingosine. The ratio for nonsaturated/saturated fatty acids was 2.2 in seeds and 1.4 in pods. Seeds contained more stigmasterol, and pods more β-sitosterol. Aglycones of saponins were identified: cycloartenol in seeds, α- and β-amyrins in pods. Oligosaccharides dominated in both seeds and pods. Landraces manifested higher protein content in pods, while modern cultivars had pods with higher contents of organic acids, polyols, monosaccharides, and fatty acids. The results obtained confirm the high nutritional value of asparagus bean seeds and pods, and the prospects of their use in various diets.

Identification and Quantification of Phenolic Compounds in Grains of Biofortified Cowpea Cultivars, Before and After Cooking

Objective:

This study aimed to identify and quantify phenolic compounds in the grains of biofortified cowpea (Vigna unguiculata) cultivars before and after cooking.

Methods:

We analyzed two cultivars of genetically improved cowpeas, namely BRS Aracê and BRS Tumucumaque. Raw and cooked samples of the cultivars were analyzed (in triplicate). The concentrations of phenolics, flavonoids, anthocyanins, and flavanols, as well as the antioxidant activity, were determined. Phenolic compounds were identified and quantified using high-performance liquid chromatography.

Results:

Grains of cultivar BRS Tumucumaque had higher concentrations of total phenolic compounds before (297.23 ± 4.24 (mean ± standard deviation) mg/100 g) and after (147.15 ± 6.94 mg/100 g) cooking, and higher concentrations of total flavonoids before (49.36 ± 2.02 mg/100 g) and after (23.97± 0.67 mg/100 g) cooking. Anthocyanins were not measured in the grains of either cultivars. There was a statistically significant reduction in the concentration of total flavanols after cooking, with the greater retention in BRS Aracê. Similarly, the antioxidant activity was significantly reduced after cooking, with greater reductions in BRS Tumucumaque than in BRS Aracê. Five phenolic acids were identified and quantified, including gallic, caffeic, and ferulic acids.

Conclusion:

We conclude that cooking affected the concentrations of phenolic compounds in the cultivars, as well as the antioxidant activity exhibited by these cultivars. The cultivars contained beneficial compounds that can contribute to disease prevention and health maintenance.

Effect of Natural Food Antioxidants against LDL and DNA Oxidative Changes

Radical oxygen species formed in human tissue cells by many endogenous and exogenous pathways cause extensive oxidative damage which has been linked to various human diseases. This review paper provides an overview of lipid peroxidation and focuses on the free radicals-initiated processes of low-density lipoprotein (LDL) oxidative modification and DNA oxidative damage, which are widely associated with the initiation and development of atherosclerosis and carcinogenesis, respectively. The article subsequently provides an overview of the recent human trials or even in vitro investigations on the potential of natural antioxidant compounds (such as carotenoids; vitamins C and E) to monitor LDL and DNA oxidative changes.

Cowpea: an overview on its nutritional facts and health benefits

Cowpea (Vigna unguiculata) is a legume consumed as a high-quality plant protein source in many parts of the world. High protein and carbohydrate contents with a relatively low fat content and a complementary amino acid pattern to that of cereal grains make cowpea an important nutritional food in the human diet. Cowpea has gained more attention recently from consumers and researchers worldwide as a result of its exerted health beneficial properties, including anti-diabetic, anti-cancer, anti-hyperlipidemic, anti-inflammatory and anti-hypertensive properties. Among the mechanisms that have been proposed in the prevention of chronic diseases, the most proven are attributed to the presence of compounds such as soluble and insoluble dietary fiber, phytochemicals, and proteins and peptides in cowpea. However, studies on the anti-cancer and anti-inflammatory properties of cowpea have produced conflicting results. Some studies support a protective effect of cowpea on the progression of cancer and inflammation, whereas others did not reveal any. Because there are only a few studies addressing health-related effects of cowpea consumption, further studies in this area are suggested. In addition, despite the reported favorable effects of cowpea on diabetes, hyperlipidemia and hypertension, a long-term epidemiological study investigating the association between cowpea consumption and diabetes, cardiovascular disease and cancer is also recommended. © 2018 Society of Chemical Industry.

Phenolic Compounds and Bioactivity of Cytisus villosus Pourr

The present study focuses on the chemical composition, antioxidant, antimicrobial, and antiproliferative activities of the ethyl acetate and aqueous extracts obtained from the aerial parts of Cytisus villosus Pourr. HPLC-DAD-ESI/MSn was used to identify the phenolic compounds, being (epi)gallocatechin dimer the major compound (111 ± 5 µg/g·dw) in the aqueous extract, while myricetin-O-rhamnoside (226 ± 9 µg/g·dw) was the main molecule in the ethyl acetate extract. Both extracts exhibited good scavenging activities against DPPH radical (EC₅₀ µg/mL of 59 ± 2 and 31 ± 2 for aqueous and ethyl acetate extracts, respectively). However, the ethyl acetate extract demonstrated more potent quenching activities than the aqueous extract. The antimicrobial activities were assessed on selected Gram-positive (Staphylococcus epidermidis) and Gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacteria, as well as on pathogenic fungus Candida glabrata. The extracts possessed selective and potent antimicrobial activities against the Gram-positive bacterium (IC₅₀ of 186 ± 9 μg/mL and 92 ± 3 μg/mL for aqueous and ethyl acetate extracts, respectively). Finally, C. villosus extracts were evaluated for their antiproliferative potential on three human cancer cell lines representing breast and colon cancers. Although both extracts demonstrated sufficient growth inhibition of the three different cell lines, the ethyl acetate extract exhibited higher activity (LD₅₀ values of 1.57 ± 0.06 mg/mL, 2.2 ± 0.1 mg/mL, and 3.2 ± 0.2 mg/mL for T47D, MCF-7, and HCT-116 cell lines). Both the extracts obtained from the aerial parts of C. villosus revealed very promising results and could be applied as functional agents in the food, pharmaceutical, and cosmeceutical industries.

Complementary effects of cereal and pulse polyphenols and dietary fiber on chronic inflammation and gut health

Cereal grains and grain pulses are primary staples often consumed together, and contribute a major portion of daily human calorie and protein intake globally. Protective effects of consuming whole grain cereals and grain pulses against various inflammation-related chronic diseases are well documented. However, potential benefits of combined intake of whole cereals and pulses beyond their complementary amino acid nutrition is rarely considered in literature. There is ample evidence that key bioactive components of whole grain cereals and pulses are structurally different and thus may be optimized to provide synergistic/complementary health benefits. Among the most important whole grain bioactive components are polyphenols and dietary fiber, not only because of their demonstrated biological function, but also their major impact on consumer choice of whole grain/pulse products. This review highlights the distinct structural differences between key cereal grain and pulse polyphenols and non-starch polysaccharides (dietary fiber), and the evidence on specific synergistic/complementary benefits of combining the bioactive components from the two commodities. Interactive effects of the polyphenols and fiber on gut microbiota and associated benefits to colon health, and against systemic inflammation, are discussed. Processing technologies that can be used to further enhance the interactive benefits of combined cereal-pulse bioactive compounds are highlighted.

Optimal germination condition impacts on the antioxidant activity and phenolic acids profile in pigmented desi chickpea (Cicer arietinum L.) seeds

Legume sprouts are considered natural, healthy products that provide a source of bioactive compounds to fight against chronic diseases. This study aims to identify the optimal germination temperature (GT) and germination time (Gt) to maximize total phenolic and flavonoid contents (TPC, FC), and antioxidant activity (AoxA) of desi chickpea. Response surface methodology was used as an optimization tool. An experimental design with two factors (GT and Gt) and five levels was used (13 treatments). The sprouts from each treatment were lyophilized, tempered, and milled to obtain germinated chickpea flours (GCF). To predict the phytochemicals composition and AoxA in GCF, regression models were developed. Maximum TPC, FC, and AoxA were attained during germination 33.7 °C for 171 h. Optimized germinated chickpea flour produced applying the optimal germination conditions resulted in an increase of protein and total dietary fibre content, TPC, FC, phenolic acids profile, and AoxA. Germination at optimal conditions also increased the level of coumaric, ferulic, synapic, ellagic, and syringic acids. This study demonstrated that germination carried out under optimal conditions enhanced the nutraceutical value of desi chickpea seeds.

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.

Qualitative and quantitative changes in polyphenol composition and bioactivity of Ribes magellanicum and R. punctatum after in vitro gastrointestinal digestion

The wild Chilean currants Ribes magellanicum and R. punctatum are a good source of polyphenolic compounds. The effect of simulated gastrointestinal digestion (GID) on phenolic content, composition and antioxidant capacity was determined. The inhibitory activity of the non-digested and digested samples towards metabolic syndrome-associated enzymes (α-amylase, α-glucosidase and lipase) was evaluated. The total phenolic (TP) and flavonoid contents (TF) decreased by about 50% at the end of the in vitro GID. Main anthocyanins and hydroxycinnamic acids were strongly affected by this process, with a loss of about 80%. A decrease in the antioxidant activity was observed throughout the digestion steps, which was correlated with the reduction in the TP and TF content. After the in vitro GID of the samples, only the inhibition of α-glucosidase was preserved. Our results show that the simulated GID modified the health-promoting properties of the studied currants.

Production and characterization of cowpea protein hydrolysate with optimum nitrogen solubility by enzymatic hydrolysis using pepsin

BACKGROUND

Cowpea is a source of low-cost and good nutritional quality protein for utilization in food formulations in replacement of animal proteins. Therefore it is necessary that cowpea protein exhibits good functionality, particularly protein solubility which affects the other functional properties. The objective of this study was to produce cowpea protein hydrolysate exhibiting optimum solubility by the adequate combination of hydrolysis parameters, namely time, solid/liquid ratio (SLR) and enzyme/substrate ratio (ESR), and to determine its functional properties and molecular characteristics.

RESULTS

A Box-Behnken experimental design was used for the experiments, and a second-order polynomial to model the effects of hydrolysis time, SLR and ESR on the degree of hydrolysis and nitrogen solubility index. The optimum hydrolysis conditions of time 208.61 min, SLR 1/15 (w/w) and ESR 2.25% (w/w) yielded a nitrogen solubility of 75.71%. Protein breakdown and the peptide profile following enzymatic hydrolysis were evaluated by sodium dodecyl sulfate polyacrylamide gel electrophoresis and size exclusion chromatography. Cowpea protein hydrolysate showed higher oil absorption capacity, emulsifying activity and foaming ability compared with the concentrate.

CONCLUSION

The solubility of cowpea protein hydrolysate was adequately optimized by response surface methodology, and the hydrolysate showed adequate functionality for use in food. © 2016 Society of Chemical Industry.

Indigenous leafy vegetables of Eastern Africa - A source of extraordinary secondary plant metabolites

Indigenous African leafy vegetables vary enormously in their secondary plant metabolites whereat genus and the species have a great impact. In African nightshade (Solanum scabrum), spiderplant (Cleome gynandra), amaranth (Amaranthus cruentus), cowpea (Vigna unguiculata), Ethiopian kale (Brassica carinata) and common kale (Brassica oleracea) the specific secondary metabolite profile was elucidated and gained detailed data about carotenoids, chlorophylls, glucosinolates and phenolic compounds all having an appropriate contribution to health beneficial properties of indigenous African leafy vegetables. Exemplarily, various quercetin glycosides such as quercetin-3-rutinoside occur in high concentrations in African nightshade, spiderplant, and amaranth between ~1400-3300μg/g DW. Additionally the extraordinary hydroxycinnamic acid derivatives such as glucaric isomers and isocitric acid isomers are found especially in amaranth (up to ~1250μg/g DW) and spiderplant (up to 120μg/g DW). Carotenoids concentrations are high in amaranth (up to101.7μg/g DW) and spiderplants (up to 64.7μg/g DW) showing high concentrations of β-carotene, the pro-vitamin A. In contrast to the ubiquitous occurring phenolics and carotenoids, glucosinolates are only present in the Brassicales species Ethiopian kale, common kale and spiderplant characterized by diverse glucosinolate profiles. Generally, the consumption of a variety of these indigenous African leafy vegetables can be recommended to contribute to different benefits such as antioxidant activity, increase pro-vitamin A and anticancerogenic compounds in a healthy diet.

Evaluation of total polyphenol content and antioxidant capacity of different verity lupin seeds

Legumes, including lupins, beans, lentil and chickpea, are one of the most important crops in the world because of their nutritional quality. Lupin seeds have been used as human food and animal feed since ancient times. It was known that antioxidant photochemical in foods have many health benefits including prevention of various diseases associated with oxidative stress such as cancer, cardiovascular disease, neuro-degeneration and diabetes. Lupin grains are rich sources of complex carbohydrates, protein, vitamins and minerals. Antioxidants can be found naturally in foods. Total polyphenols content and antioxidant activity were measured in four varieties of lupin, namely in white lupin, blue lupin, yellow lupin and Mutabilis lupin species. A majority of antioxidants naturally present in foods occur in phenolic structures and especially in flavonoid structures. The content of the total polyphenols was determined by using the Folin-Ciocalteu reagent (FCR). Antioxidant activity was measured by using a compound DPPH˙ (2.2-diphenyl-1-picrylhydrazyl). In the present experiment according to the average contents of total polyphenols (TPC) in dry matter of lupin seeds there was the following line: L. Angustifolius (blue) lupin (696.212 mg GAE.100g-1) > L. Albus (white) lupin (614.13 mg GAE.100g-1) > L. Luteus (yellow) lupin (467.78 mg GAE.100g-1) > L. Mutabilis (pearl) lupin (367.36 mg GAE.100g-1). Based on the measured values of total antioxidant capacity (TAC) of lupin samples can be classified as follows: L. Albus (white) lupin (43.44%) >L. Angustifolius (blue) lupin (38.27%) >L. Luteus (yellow) lupin (22.29%) >L. Mutabilis (Pearl) lupin (20.80%). The relationship of antioxidant capacity with total polyphenolic was discussed. According to used statistical analyzes. Correlation between the phenolic contents and antioxidant capacity was significantly positive (r = 0.88). Our results confirmed that legumes can be a good source of bioactive compounds in the human nutrition. The main objective of the present work was to evaluated the content of total polyphenols and an antioxidant capacity of four Lupine species.

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.

Phenolic Profiles and Antioxidant Activity of Germinated Legumes

Bioactive compounds, which are naturally produced in plants, have been concerned with the food and pharmaceutical industries because of the pharmacological effects on humans. In this study, the individual phenolics of six legumes during germination and antioxidant capacity from sprout extracts were determined. It was found that the phenolic content significantly increased during germination in all legumes. Peanuts showed the strongest antioxidant capacity in both the DPPH• (1,1-diphenyl-2-picrylhydrazyl) method and the reducing power assay (32.51% and 84.48%, respectively). A total of 13 phenolic acids were detected and quantified. There were 11 phenolic constituents identified in adzuki beans; 10 in soybeans; 9 in black beans, mung beans, and white cowpeas; and 7 compounds in peanuts. Sinapic acid and cinnamic acid were detected in all six legume sprouts, and their quantities in germinated peanuts were the highest (247.9 µg·g⁻¹ and 62.9 µg·g⁻¹, respectively). The study reveals that, among the investigated legumes, germinated peanuts and soybeans obtained maximum phenolics and antioxidant capacity.

Sorghum-cowpea composite porridge as a functional food, Part II: Antioxidant properties as affected by simulated in vitro gastrointestinal digestion

The effect of compositing red non-tannin sorghum with brownish-cream cowpea and in vitro gastrointestinal digestion on total phenolic and flavonoid contents and antioxidant properties of a sorghum-cowpea composite porridge was studied. Maize-soybean composite porridge was used as a reference sample. Antioxidant properties were studied using radical scavenging activities against the 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid), peroxyl and NO radicals as well as inhibition of low density lipoprotein (LDL) oxidation and oxidative damage of vector DNA. Hydroperoxide content of the samples was also measured. All the samples demonstrated radical scavenging activity. Simulated duodenal digests of the porridges had hydroperoxides and therefore caused LDL oxidation. The undigested porridges and simulated gastric digests inhibited LDL oxidation. Compositing the cereals with legumes increased total phenolic and flavonoid contents and NO scavenging activity of their porridges. In vitro gastrointestinal digestion of the porridges increased their total phenolic and flavonoid contents, radical scavenging activities and LDL oxidation inhibitory activity.

Improvement of the antioxidant and hypolipidaemic effects of cowpea flours (Vigna unguiculata) by fermentation: results of in vitro and in vivo experiments

BACKGROUND

The antioxidant capacity and hypolipidaemic effects of Vigna unguiculata, as well as their potential improvement by different fermentation and thermal processes were studied using in vitro and in vivo methods.

RESULTS

Phenolic content and reducing capacity of legume acetone extract were significantly increased by different fermentation processes, and by the thermal treatment of fermented legume flours. TBARS inhibiting capacity was increased by fermentation but not by thermal treatment. A higher ability to decrease Cu(2+)/H2O2-induced electrophoretic mobility of LDL was found in fermented when compared to raw legume extracts, and a higher protective effect on short term metabolic status of HT-29 cells was found for raw and lactobacillus-fermented Vigna followed by naturally fermented Vigna extracts. Significant improvements in plasma antioxidant capacity and hepatic activity of antioxidant enzymes were observed in rats that consumed fermented legume flours when compared to the untreated legume or a casein-methionine control diet. In addition, liver weight and plasma levels of cholesterol and triglycerides were also positively affected by untreated or naturally fermented Vigna.

CONCLUSION

V. unguiculata has demonstrated its potential as a functional food with interesting antioxidant and lipid lowering properties, which can be further augmented by fermentation processes associated or not to thermal processing.