Evaluation of phenolic profile and antioxidant properties of Pardina lentil as affected by industrial dehydration

A comprehensive review of processing, functionality, and potential applications of lentil proteins in the food industry

There is a pressing need for sustainable sources of proteins to address the escalating food demands of the expanding global population, without damaging the environment. Lentil proteins offer a more sustainable alternative to animal-derived proteins (such as those from meat, fish, eggs, or milk). They are abundant, affordable, protein rich, nutritious, and functional, which makes them highly appealing as ingredients in the food, personal care, cosmetics, pharmaceutical and other industries. In this article, the chemical composition, nutritional value, and techno-functional properties of lentil proteins are reviewed. Then, recent advances on the extraction, purification, and modification of lentil proteins are summarized. Hurdles to the widespread utilization of lentil proteins in the food industry are highlighted, along with potential strategies to surmount these challenges. Finally, the potential applications of lentil protein in foods and beverages are discussed. The intention of this article is to offer an up-to-date overview of research on lentil proteins, addressing gaps in the knowledge related to their potential nutritional benefits and functional advantages for application within the food industry. This includes exploring the utilization of lentil proteins as nanocarriers for bioactive compounds, emulsifiers, edible inks for 3D food printing, meat analogs, and components of biodegradable packaging.

Attenuation of heterocyclic amine formation and lipid and protein oxidation in air-fried fish fillets by marination with selected legume seed extracts

The present study aimed to investigate the potential of marination with extracts prepared from five legume seeds on heterocyclic amine (HA) formation in chemical models and air-fried fish fillets. In terms of total HAs, clove seed marinade (CSM) was found with the maximum inhibitory effect (43.98 %), followed by tamarind seed marinade (TSM) (40.26 %), fenugreek seed marinade (FSM) (39.07 %), acacia seed marinade (ASM) (37.99 %), and black bean seed marinade (BSM) (29.95 %). In particular, at higher levels (3 mg/mL, 4 mg/mL), CSM and FSM achieved the greatest mitigating effect against 4,8-DiMeIQx, 7,8-DiMeIQx, and MeIQx. Furthermore, all marinades were effective in lowering thiobarbituric acid-reactive substances (TBARS) and carbonyl and retaining thiol content relative to the control. PCA analysis revealed that higher levels of ASM, BSM, and FSM had better mitigating effect against IQ and MeIQx formation, whereas Pearson correlation shows that TBARS and carbonyl were positively correlated to HAs.

Nutritional and chemical composition of Alpinia zerumbet leaves, a traditional functional food

Alpinia zerumbet, a species of the Zingiberaceae family, is a common plant in tropical and subtropical areas used in traditional medicine to treat various diseases and also included as food in the traditional Okinawan diet (Japan). The leaves and rhizomes of this plant are used as spice and flavoring in foods such as rice, meats, and pasta. Studies of the chemical and nutritional characteristics of fresh leaves and of leaves submitted to thermal treatments such as boiling and steaming are lacking. In the current study, the leaves of A. zerumbet were subjected to boiling or steaming for 10, 20, and 30 min as part of the thermal treatments. The study also provides noteworthy results regarding the proximate composition, physical-chemical data, minerals, phenolic compounds, antioxidant activity, volatile compounds, and LC-MS chromatographic profiles of the extracts produced with fresh leaves and with thermal treatments. The carbohydrate content of A. zerumbet leaves improved during the thermal treatments, showing an increase after steaming (18.86 to 19.79%) and boiling for 30 min (25.85%). After boiling treatment for 20 min, a significant amount of protein was found (6.79%) and all heat treatments resulted in low content of lipid (<1.0%). The boiling treatment for 10 min (BT10) resulted in the highest concentrations of total phenolic components (TPC), 339.5 mg/g, and flavonoids (TF), 54.6 mg/g, among the three thermal treatments (BT10, BT20 and BT30). The results of the steaming treatments (ST 10, 20, and 30 min) differed, with ST20 leading to higher TPC (150.4 mg/g) and TF (65.0 mg/g). The quantity of total phenolics and flavonoids, as well as the antioxidant activity, were significantly affected by the cooking method and the length of time of sample exposure to heat. The samples boiled for 30 and 10 min had higher concentrations of antioxidant activity as measured by the phosphomolybdenum and DPPH methods (151.5 mg/g of extract and 101.5 μg/mL, respectively). Thirty-eight volatile organic compounds (VOCs) were identified by chromatographic analysis of fresh and thermally treated leaves of A. zerumbet. Terpenoids were the predominant class of volatile compounds in the fresh leaves and in all thermal treatments. p-Cymene, 1,8-cineole, 4-terpineol, linalool, α-copaene and β-bisabolene have the greatest impact on overall aroma perception, with odor activity values (OAV) greater than five. Among the phenolic compounds identified by LC-HRMS in the extracts of fresh and thermally treated leaves were proanthocyanidins, (+) catechin, (-) epicatechin, quercetin-3-O-glucoronide, isorhamnetin-3-O-glucoronide, kaempferol-3-O-rutinoside, pinocembrin, alpinetin, pinostrobin, and other compounds. The present results support the traditional use of this plant as a potential food with properties that certainly contribute to health improvement.

Application of thermosonication for guava juice processing: Impacts on bioactive, microbial, enzymatic and quality attributes

The present work explores different conditions of thermosonication (TS) processing that would ensure microbiological and enzymatic safety for guava juice while simultaneously maximizing the preservation of its quality attributes. The guava juice was subjected to TS treatment (frequency: 40 kHz; power: 200 W; Temperature: 40, 60, and 80 °C; Time: 2, 6 and 10 min) and was compared with fresh and pasteurized (90 °C/60 s) juice samples. The objectives of the research work were to determine the effect of thermosonication on the quality attributes such as total soluble solids (TSS), pH, titratable acidity, cloud value, color attributes, total phenolic contents, total flavonoid contents, antioxidant activity, ascorbic acid levels, enzymatic, microbiological, and sensory properties. The thermosonicated and pasteurized samples showed no significant (p > 0.05) changes in pH, total soluble solids, and titratable acidity. TS improved the cloud value and color attributes. Furthermore, TS enhanced total phenols (10 to17%), flavonoids (5 to 25%), antioxidant activity (10.45% to 14.55%) and retention of ascorbic acid (61.98-83.32%) relative to control. Thermosonicated sample at 80 °C/10 min gives the maximum inactivation of Pectin methyl esterase (PME), Peroxidase (POD) and Polyphenol oxidase (PPO) enzymes. While both thermosonication and pasteurization drastically decreased the microbial count to undetectable levels, only TS exhibited modest improvement in sensory qualities. The results demonstrated that TS can enhance the overall safety, quality, and commercial viability of guava juice as a practical substitute to pasteurization.

Heme Oxygenase 1-Mediated Anti-Inflammatory Effect of Extract from the Aerial Part of Heracleum moellendorffii Hance

In this study, the anti-inflammatory effects of a methanolic extract from the aerial part of Heracleum moellendorffii Hance (HmAPE) and its underlying mechanisms were investigated. HmAPE demonstrated a significant reduction in nitric oxide production in lipopolysaccharide (LPS)-treated murine macrophage RAW264.7 cells, and HmAPE decreased the protein and mRNA expression of inducible nitric oxide synthase. Further mechanistic studies on inflammatory signaling pathways revealed that HmAPE-mediated downregulation of inflammatory gene expressions was not associated with mitogen-activated protein kinases or nuclear factor-κB signaling pathways. However, HmAPE treatment activated nuclear factor E2-related factor 2 (Nrf2) and upregulated heme oxygenase-1 (HO-1) expression, which is known to suppress pro-inflammatory cytokine production. Additionally, treatment with a selective HO-1 inhibitor, tin protoporphyrin IX, partially reversed the effects of HmAPE in LPS-treated RAW264.7 cells, indicating that HmAPE inhibited LPS-induced NO production, at least in part, through induction of Nrf2-mediated HO-1 expression. These findings suggest that HmAPE could serve as a potential edible source with anti-inflammatory properties, and further studies are required to ascertain its anti-inflammatory efficacy in vivo.

Study of the Total Antioxidant Capacity (TAC) in Native Cereal-Pulse Flours and the Influence of the Baking Process on TAC Using a Combined Bayesian and Support Vector Machine Modeling Approach

During the last few years, the increasing evidence of dietary antioxidant compounds and reducing chronic diseases and the relationship between diet and health has promoted an important innovation within the baked product sector, aiming at healthier formulations. This study aims to develop a tool based on mathematical models to predict baked goods' total antioxidant capacity (TAC). The high variability of antioxidant properties of flours based on the aspects related to the type of grain, varieties, proximal composition, and processing, among others, makes it very difficult to innovate on food product development without specific analysis. Total phenol content (TP), oxygen radical absorbance capacity (ORAC), and ferric-reducing antioxidant power assay (FRAP) were used as markers to determine antioxidant capacity. Three Bayesian-type models are proposed based on a double exponential parameterized curve that reflects the initial decrease and subsequent increase as a consequence of the observed processes of degradation and generation, respectively, of the antioxidant compounds. Once the values of the main parameters of each curve were determined, support vector machines (SVM) with an exponential kernel allowed us to predict the values of TAC, based on baking conditions (temperature and time), proteins, and fibers of each native grain.

Water-soluble phenolic compounds and their putative antioxidant activities in the seed coats from different lentil (Lens culinaris) genotypes

The seed coat is a major byproduct of lentil processing with potential as a sustainable source of antioxidant polyphenols. Profiles of water-soluble phenolic compounds and antioxidant activities of seven genotypes of lentil which includes both normal-tannin and low-tannin seed coats were investigated. Antioxidant activities were assessed using four antioxidant assays, and phenolic compounds were quantified using liquid chromatography mass spectrometry (LC-MS). Total phenolic content (TPC) varied significantly among genotypes and ranged between 1519 ± 140 and 6502 ± 154 μg/g. Thirty phenolic compounds were identified with kaempferol tetraglycoside, catechin-3-glucoside and procyanidins being the dominant compounds in normal-tannin seed coats. Kaempferol tetraglycoside predominated (80-90%) in low-tannin seed coats. Antioxidant activities strongly correlated with TPC (r > 0.93) with a 6-9 times higher activity in normal-tannin than that of low-tannin lentils. Without flavan-3-ols and procyanidins, low-tannin seed coat may not exert strong antioxidant potential, whereas normal-tannin seed coat contains water-extractable natural phenolic compounds with promising antioxidant potential.

Metabolomic Analysis Reveals Domestication-Driven Reshaping of Polyphenolic Antioxidants in Soybean Seeds

Crop domestication has resulted in nutrient losses, so evaluating the reshaping of phytonutrients is crucial for improving nutrition. Soybean is an ideal model due to its abundant phytonutrients and wild relatives. In order to unravel the domestication consequence of phytonutrients, comparative and association analyses of metabolomes and antioxidant activities were performed on seeds of six wild (Glycine soja (Sieb. and Zucc.)) and six cultivated soybeans (Glycine max (L.) Merr.). Through ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS), we observed a greater metabolic diversity in wild soybeans, which also displayed higher antioxidant activities. (-)-Epicatechin, a potent antioxidant, displayed a 1750-fold greater abundance in wild soybeans than in cultivated soybeans. Multiple polyphenols in the catechin biosynthesis pathway were significantly higher in wild soybeans, including phlorizin, taxifolin, quercetin 3-O-galactoside, cyanidin 3-O-glucoside, (+)-catechin, (-)-epiafzelechin, catechin-glucoside, and three proanthocyanidins. They showed significant positive correlations with each other and antioxidant activities, indicating their cooperative contribution to the high antioxidant activities of wild soybeans. Additionally, natural acylation related to functional properties was characterized in a diverse range of polyphenols. Our study reveals the comprehensive reprogramming of polyphenolic antioxidants during domestication, providing valuable insights for metabolism-assisted fortification of crop nutrition.

Impact of Air-Drying Temperature on Antioxidant Properties and ACE-Inhibiting Activity of Fungal Fermented Lentil Flour

Solid-state fermentation (SSF) with Pleurotus ostreatus enhances the nutritional value of legumes. However, drying can cause significant changes in physical and nutritional properties of the final products. Thus, this work studies the impact of air-drying temperature (50, 60, and 70 °C) on relevant properties (antioxidant properties, ACE-inhibitory capacity, phytic acid, colour, and particle size) of two fermented lentils flour (Pardina and Castellana) using freeze-drying as a reference method. Castellana variety is a better substrate for Pleurotus, generating four times more biomass. In addition, an almost total reduction of phytic acid from 7.3 to 0.9 mg/g db is achieved in this variety. Air-drying significantly decreased the particle size and the final colour with ΔE > 20; nonetheless, the temperature does not play a crucial role. SSF decreased the total phenolic content and the antioxidant capacity regardless of the variety, however, drying at 70 °C increased total phenolic content (186%) in fermented Castellana flour. Comparing drying methods, freeze-drying implied a higher decrease in those parameters, reducing the TPC from 2.4 to 1.6 and from 7.7 to 3.4 mg gallic acid/g db in Pardina and Castellana dried flours. Finally, the flours inhibit the angiotensin I-converting-enzyme, and fermentation and drying increased their potential cardiovascular benefits.

Selection of Enzymatic Treatments for Upcycling Lentil Hulls into Ingredients Rich in Oligosaccharides and Free Phenolics

In this study, the comprehensive chemical characterization of red lentil hulls obtained from the industrial production of football and split lentils was described. The lentil hulls were rich in dietary fiber (78.43 g/100 g dry weight with an insoluble to soluble fiber ratio of 4:1) and polyphenols (49.3 mg GAE/g dry weight, of which 55% was bound phenolics), which revealed the suitability of this lentil by-product as a source of bioactive compounds with recognized antioxidant and prebiotic properties. The release of oligosaccharides and phenolic compounds was accomplished by enzymatic hydrolysis, microwave treatment and a combination of both technologies. The key role played by the selection of a suitable enzymatic preparation was highlighted to maximize the yield of bioactive compounds and the functional properties of the lentil hull hydrolysates. Out of seven commercial preparations, the one with the most potential for use in a commercial context was Pectinex^® Ultra Tropical, which produced the highest yields of oligosaccharides (14 g/100 g lentil hull weight) and free phenolics (45.5 mg GAE/100 g lentil hull weight) and delivered a four-fold increase in terms of the original antioxidant activity. Finally, this enzyme was selected to analyze the effect of a microwave-assisted extraction pretreatment on the yield of enzymatic hydrolysis and the content of free phenolic compounds and oligosaccharides. The integrated microwave and enzymatic hydrolysis method, although it increased the solubilization yield of the lentil hulls (from 25% to 34%), it slightly decreased the content of oligosaccharides and proanthocyanidins and reduced the antioxidant activity. Therefore, the enzymatic hydrolysis treatment alone was more suitable for producing a lentil hull hydrolysate enriched in potential prebiotics and antioxidant compounds.

Polyphenols, Saponins and Phytosterols in Lentils and Their Health Benefits: An Overview

The lentil (Lens culinaris L.) is one of the most important legumes (family, Fabaceae). It is a natural functional food rich in many bioactive compounds, such as polyphenols, saponins and phytosterols. Several studies have demonstrated that the consumption of lentils is potentially important in reducing the incidence of a number of chronic diseases, due to their bioactive compounds. The most common polyphenols in lentils include phenolic acids, flavan-3-ol, flavonols, anthocyanidins, proanthocyanidins or condensed tannins, and anthocyanins, which play an important role in the prevention of several degenerative diseases in humans, due to their antioxidant activity. Furthermore, lentil polyphenols are reported to have antidiabetic, cardioprotective and anticancer activities. Lentil saponins are triterpene glycosides, mainly soyasaponins I and βg. These saponins have a plasma cholesterol-lowering effect in humans and are important in reducing the risk of many chronic diseases. Moreover, high levels of phytosterols have been reported in lentils, especially in the seed coat, and β-sitosterol, campesterol, and stigmasterol are the most abundant. Beyond their hypocholesterolemic effect, phytosterols in lentils are known for their anti-inflammatory activity. In this review, the current information on the nutritional composition, bioactive compounds including polyphenols, saponins and phytosterols, and their associated health-promoting effects are discussed.

Effect of Microwave Treatment on Adzuki Beans (Vigna angularis L.) under Dry State-Analyzing Microstructure, Water Absorption, and Antioxidant Properties

In this study, a microwave was used on adzuki beans (Arari and Geomguseul) without water, in order to investigate their changes in microstructure, water absorption, and antioxidative properties. As the microwave treatment time increased (2450 MHz, 0 to 60 s), the lightness, redness, and yellowness were reduced, and moisture content significantly decreased in both varieties. The microstructure space between the seed coat, cotyledon, and pores within the cotyledon were observed, due to the loss of moisture. Regardless of microwave treatment, the water absorption behavior of the adzuki beans was sigmoidal. However, the water absorption kinetics of Arari increased after microwave treatment, whereas with microwave-treated Geomguseul, the water absorption rate decreased, compared to the control, except for the sample treated for 30 s. During soaking, the water absorption and softening rates in the microwave-treated adzuki bean were twice as fast as the untreated beans. Antioxidant activity, total phenolic compounds, and total flavonoid compounds were greatly improved by microwave treatment. These results indicate that microwave treatment affects the color, hydration, and bioactive compounds, and it can be used as a pretreatment method before processing adzuki beans.

Nutritional and antioxidant changes in lentils and quinoa through fungal solid-state fermentation with Pleurotus ostreatus

Solid-state fermentation (SSF) may be a suitable bioprocess to produce protein-vegetal ingredients with increased nutritional and functional value. This study assessed changes in phenol content, antinutrient content, biomass production and protein production resulting from the metabolic activity of Pleurotus ostreatus, an edible fungus, in lentils and quinoa over 14 days of SSF. The impact of particle size on these parameters was also assessed because the process was conducted in both seeds and flours. Fungus biomass increased during fermentation, reaching 30.0 ± 1.4 mg/g dry basis and 32 ± 3 mg/g dry basis in lentil grain and flour and 52.01 ± 1.08 mg/g dry basis and 45 ± 2 mg/g dry basis in quinoa seeds and flour after 14 days of SSF. Total protein content also increased by 20% to 25% during fermentation, in all cases except lentil flour. However, the soluble protein fraction remained constant. Regarding phytic acid, SSF had a positive impact, with a progressive decrease being higher in flours than in seeds. Regarding antioxidant properties, autoclaving of the substrates promoted the release of polyphenols, together with antioxidant activity (ABTS, DPPH and FRAP), in all substrates. However, these parameters drastically decreased as fermentation progressed. These results provide scientific knowledge for producing lentil- or quinoa-based ingredients with low antinutrient content enriched with protein fungal biomass.

Antioxidant Activity of Polyphenols, from Mauritia flexuosa (Aguaje), Based on Controlled Dehydration

Plant polyphenols offer several benefits for the prevention of diverse illnesses. Fruit’s edible and inedible parts (pulp, seeds, peels, stems, flowers) are important sources of polyphenols. Different industrial processes for fruit treatment and commercialization affect the total polyphenol content (TPC), and probably the biological activity. The purpose of the present work was to determine the TPC and antioxidant activity (by DPPH) of polyphenols extracted from the pulp and seeds of Mauritia flexuosa (aguaje), in fresh and dehydrated forms, in order to determine the possible connection with the quantity of polyphenols and their specific antioxidant activity. The highest phenolic content for M. flexuosa seeds in fresh form (non-dehydrated) was 270.75 mg GAE/100 g with a 96-h extraction. With respect to the dehydrated samples, the best yield was quantified in the 96-h dehydrated seed sample. For all pulp and seeds, dehydrated for 24, 48, and 96 h, TPC showed a slightly decreasing pattern. The DPPH results were the highest in the 96-h dehydrated samples and the differences among all dehydrated pulp and seed samples were minimal. More studies testing the presence of other antioxidant components could help in understanding the detailed antioxidant activity, and related more to the specific action, rather than only total polyphenol content.

Overview of fermentation process: structure-function relationship on protein quality and non-nutritive compounds of plant-based proteins and carbohydrates

Demands for high nutritional value-added food products and plant-based proteins have increased over the last decade, in line with the growth of the human population and consumer health awareness. The quality of the plant-based proteins depends on their digestibility, amino acid content, and residues of non-nutritive compounds, such as phenolic compounds, anti-nutritional compounds, antioxidants, and saponins. The presence of these non-nutritive compounds could have detrimental effects on the quality of the proteins. One of the solutions to address these shortcomings of plant-based proteins is fermentation, whereby enzymes that present naturally in microorganisms used during fermentation are responsible for the cleavage of the bonds between proteins and non-nutritive compounds. This mechanism has pronounced effects on the non-nutritive compounds, resulting in the enhancement of protein digestibility and functional properties of plant-based proteins. We assert that the types of plant-based proteins and microorganisms used during fermentation must be carefully addressed to truly enhance the quality, functional properties, and health functionalities of plant-based proteins.Supplemental data for this article is available online at here. show.

Development of Antioxidant and Nutritious Lentil (Lens culinaris) Flour Using Controlled Optimized Germination as a Bioprocess

Germination is an efficient and natural strategy that allows the modification of the nutritional value and the nutraceutical properties of seeds, enabling one to tailor the process according to its final use. This study aimed at optimization of germination conditions to produce novel lentil flours with improved nutritional and functional features. Response Surface Methodology (RSM) was applied to model the effect of temperature (15–27 °C) and time (1–5 days) on different nutritional and quality parameters of lentil flours including proximate composition, content and profile of fatty acids, content of phytic acid, ascorbic acid and γ-aminobutyric acid (GABA), content and profile of phenolic compounds, antioxidant activity, expected glycemic index (GI) and color during germination. As shown by RSM polynomial models, sprouting promoted the reduction of phytic acid content and enhanced the levels of ascorbic acid, GABA, insoluble phenolic compounds, antioxidant activity and expected GI, and modified the color of the resultant lentil flours. RSM optimization of germination temperature and time using desirability function revealed that the optimal process conditions to maximize the nutritional, bioactive and quality properties of sprouted lentil flours were 21 °C for 3.5 days.

Phytochemical and Antioxidant Profile of Pardina Lentil Cultivars from Different Regions of Spain

Lentils (Lens culinaris spp.) are an important food consumed worldwide given their high protein, fiber, mineral, and phytochemical contents, and can be used as a potential source of good nutrition for many people. With the purpose of valuing the Pardina variety, the quality brand from a protected geographical indication “Lenteja de Tierra de Campos”, a full assessment of the nutritional, chemical, and antioxidant properties of 34 samples from this variety was carried out. Besides its actual rich nutritional profile, three phenolic compounds by high performance liquid chromatography equipped with photodiode array detection-mass (HPLC-DAD-ESI/MS) were identified (kaempferol derivatives) with slight differences between them in all extracts. Sucrose by high-performance liquid chromatography with a refraction index detector (HPLC-RI) and citric acid by ultra-fast liquid chromatography coupled with a photodiode array detector (UFLC-PDA) were the major identified sugar and organic acid components, respectively, as well as α-tocopherol and γ-tocopherol isoforms (HPLC-fluorescence). Additionally, all the extracts presented excellent antioxidant activity by the oxidative hemolysis inhibition assay (OxHLIA/TBARS). Briefly, Pardina lentils from this quality brand are a good source of nutritional and chemical components and should therefore be included in a balanced diet.

White Lupin as a Promising Source of Antioxidant Phenolics for Functional Food Production

Although white lupin is the oldest known legume in the history, it has been forgotten for many years. Now, the interest of food producers concerning white lupin is increased again. The aim of this study was to evaluate the total phenolic content (TPC), antioxidant activity (AA), and the content of selected phenolics in 11 white lupin cultivars. The determined TPC was in the interval 4260–5663 mg GAE/kg DM and the values of AA determined using DPPH•, ABTS•+, and FRAP methods were in the ranges 0.993–1.878, 5.496–7.924, and 1.328–1.741 μmol TE/g DM, respectively. Individual phenolics content (4-hydroxybenzoic acid, caffeic acid, trans-p-coumaric acid, trans-ferulic acid, myricetin, quercetin, apigenin, and genistein) were determined, too. Caffeic acid (442.9–766.2 mg/kg DM) and myricetin (11.2–21.2 mg/kg DM) are the dominant phenolics in the investigated lupin cultivars. Statistically significant differences in all investigated variables were observed between the tested cultivars except for quercetin. The obtained results show that the Astra and Nelly cultivars are a rich source of phenolic acids.

Metabolite Fingerprinting of Kersting's Groundnut [Macrotyloma geocarpum (Harms) Maréchal & Baudet] Seeds Using UPLC-qTOF-MS Reveals the Nutraceutical and Antioxidant Potentials of the Orphan Legume

The identification and subsequent quantification of phenolic compounds in plants is the first step toward harnessing their associated nutritional and health benefits. Due to their diverse phenolic compound compositions, grain legumes are known for their high nutritional and health values. The aim of this study was to assess the inter-variations in chemical composition, phytochemical content, and antioxidant capacity of seed extracts from eight Kersting's groundnut [Macrotyloma geocarpum (Harms) Marechal & Baudet] landraces. The chemical profiles were evaluated using UPLC-qTOF-MS. Total phenolics and flavonoids content were determined by the Folin-Ciocalteu and aluminum chloride methods, respectively. The antioxidant capacities in the forms of DPPH and ABTS were evaluated using spectrophotometric methods. Principal component analysis was used to define similarities/differences between the landraces. Based on untargeted metabolomics analysis, 57 metabolites were identified, with phenolics, triterpenes, fatty acids, and sphingolipids being the most predominant. The results showed that the black seeded KG1 (Puffeun) had the highest total phenolic (9.44 mg GAE/g) and flavonoid (3.01 mg QE/g) contents, as well as antioxidant capacity (9.17 μg/mL and 18.44 μg/mL based on DDPH and ABTS assays, respectively). The concentrations of ferulic acid hexoside, procyanidin B2, eryodictyiol-7-rutinoside and quercetin pentoside ranged from 51.78–441.31, 1.86–18.25, 3.26–13.95 to 5.44–63.85 μg/mg, respectively. This study presents a useful report on the phytochemical characterization of Kersting's groundnuts and shows that the grains can be used as a source of nutraceuticals for human consumption.

The Composition and Antioxidant Activity of Bound Phenolics in Three Legumes, and Their Metabolism and Bioaccessibility of Gastrointestinal Tract

The composition and antioxidant activity of bound phenolics in three legumes (soybean, vicia faba, and kidney bean), and their metabolism and bioaccessibility in the gastrointestinal tract were investigated in this study. The total phenolic content, total flavonoid content, and antioxidant activities (ABTS and FRAP) were evaluated. The phytochemical compositions of the three legumes after acid/alkaline hydrolysis, simulated gastrointestinal digestion, and colonic fermentation were identified and quantified by UPLC-ESI-QTOF-MS/MS and HPLC-ESI-QqQ-MS/MS. The results showed that the three legumes were rich in bound phenolic compounds, and possessed a strong antioxidant activity; among which kidney bean showed a higher bound flavonoid content and antioxidant activity than the other two legumes. Alkaline hydrolysis allowed a more thorough extraction of the bound phenolics of the three legumes than acid hydrolysis. The released contents of bound phenolics were extremely low in in vitro digestion, whereas colonic fermentation favored the release of more phenolic compounds. Kidney bean, which presented the highest bound flavonoid content and antioxidant activity, had the lowest bioaccessibility. Our study provides a wider insight into the constituents and bioavailability of bound phenolic compounds in the three legumes.

Polyphenol profile comparisons of seed coats of five pulse crops using a semi-quantitative liquid chromatography-mass spectrometric method

INTRODUCTION

Pulse crops are nutritious and therefore widely grown. Pulse seed coats are typically discarded, despite their high content of polyphenols that are known for their antioxidant properties and health benefits. A better understanding of polyphenol diversity and biochemical pathways will ultimately provide insight into how polyphenols are linked to health benefits, which will help to better utilise these seed coats.

OBJECTIVES

To explore polyphenol profiles among seed coats of diverse genotypes of five pulse crops using a targeted liquid chromatography mass spectrometry (LC-MS) method.

METHODS

Four genotypes of each of common bean, chickpea, pea, lentil and faba bean seed coats were selected for analysis. Following extraction, polyphenols were quantified using LC-MS.

RESULTS

An LC-MS method was developed to quantify 98 polyphenols from 13 different classes in 30 min. The low-tannin seed coats had the lowest concentrations of all polyphenols. Chickpea and pea seed coats had the most similar polyphenolic profiles. The black common bean showed the most diverse seed coat polyphenol profile, including several anthocyanins not detected in any of the other seed coats.

CONCLUSION

The LC-MS method reported herein was used to show polyphenol diversity within several polyphenol classes among the pulse crop seed coats. Detected in all seed coats, flavonols and hydroxybenzoic acids appear well-conserved in the edible Fabaceae. The presence of anthocyanins, flavan-3-ols and proanthocyanins in the coloured seed coats suggests that unique divergent branches were introduced in the flavonoid biosynthetic pathway, possibly in response to environmental stressors.

Characterization of dried horseradish leaves pomace: phenolic compounds profile and antioxidant capacity, content of organic acids, pigments and volatile compounds

Horseradish (Armoracia rusticana) leaves pomace, which contains high-value bioactive compounds, is the product resulting from pressing horseradish leaves for juice production. The aim of the current research was to investigate the effect of convective, microwave-vacuum and freeze-drying on the content of bioactive compounds in horseradish leaves pomace. Convective hot air-drying was performed at 40, 60 and 80 °C. The total phenolic content (TPC), total flavonoid content (TFC), total flavan-3-ol content, total phenolic acid content, total flavonol content, chlorophylls and total carotenoids, and antioxidant activity were determined by spectrophotometric methods. Individual profiles of phenols and organic acids are estimated by high-performance liquid chromatography (HPLC), but volatile compounds are estimated by gas chromatography (GC). Totally, 14 individual phenolic compounds, 8 organic acids, and 49 volatile compounds were analysed in the studied samples. The main phenolic compound identified in horseradish leaves pomace was rutin (3231 mg/100 g DW), among organic acids—quinic and malic acids, and volatile compounds—allyl isothiocyanate, 3-butenenitrile and benzyl alcohol. In the drying process, the content of some (total flavan-3-ols, total carotenoids content) compounds increased, but others (TPC, total organic acids content) decreased, and it was drying method-dependent. Freeze-drying caused the reduction of TPC by 29%, whereas convective drying by 53–59%. Fresh pomace contains such isothiocyanates as allyl isothiocyanate and butyl isothiocyanate, which were completely lost in the drying process. Freeze-drying allowed the best retention of various phenolic and volatile compounds in horseradish leaves pomace.

A comprehensive profiling of free, conjugated and bound phenolics and lipophilic antioxidants in red and green lentil processing by-products

A systemic approach was taken in profiling the hydrophilic and lipophilic antioxidants in lentil hulls using a combination of HPLC, LC-ESI-MS2 and GC techniques. A total of 37 phenolics were tentatively identified in the hydrophilic fractions, while four carotenoids and three tocopherols were found in the lipophilic fraction. Results showed that in addition to the high free extractable phenolics, phenolic compounds in conjugated and bound forms also exist in similar amounts. Information on conjugated and bound phenolics are particularly important as these forms of phenolics often go unnoticed by chromatographic profiling of extractables. All phenolic, carotenoid and tocopherol fractions contributed to antioxidant activities. Information about bioactives from lentil hulls, specifically conjugated and bound phenolics are reported here for the first time. The comprehensive profiling of these bioactives lays a good foundation for further assessment of the value-added uses of lentil hulls which are by-products of pulse processing.

Polyphenolic Composition of Lentil Roots in Response to Infection by Aphanomyces euteiches

Polyphenols comprise the largest group of plant secondary metabolites and have critical roles in plant physiology and response to the biotic and abiotic environment. Changes in the content of polyphenols in the root extracts and root tissues of wild (Lens ervoides) and cultivated (Lens culinaris) lentil genotypes were examined in response to infection by Aphanomyces euteiches using liquid chromatography mass spectrometry (LC-MS). Genotype, infection and their interaction determined the composition of polyphenols in lentil roots. The levels of several polyphenols were lower in the root extract of the low-tannin genotype L. culinaris ZT-4 compared to L. ervoides L01-827A. Kaempferol derivatives including kaempferol dirutinoside and kaempferol 3-robinoside 7-rhamnoside were more concentrated in the healthy root tissues of L. ervoides L01-827A than in L. culinaris genotypes. Infection increased the concentration of kaempferol, apigenin, and naringenin in the root tissues of all genotypes, but had no effect on some polyphenols in the low-tannin genotype L. culinaris ZT-4. The concentrations of apigenin, naringenin, apigenin 4-glucoside, naringenin7-rutinoside, diosmetin, and hesperetin 7-rutinoside were higher in the infected root tissues of L. ervoides L01-827A compared with the L. culinaris genotypes. Organic acids including coumaric acid, vanillic acid, 4-aminosalicylic acid, 4-hydroxybenzoic acid, and 3,4-dihydroxybenzoic acid effectively suppressed the in-vitro hyphal growth of A. euteiches. Some of these bioactive polyphenols were more concentrated in roots of L. ervoides L01-827A but were low to undetectable in ZT-4. This study shows that genotypic differences exist in the composition of root polyphenols in lentil, and is related to the response to infection caused by A. euteiches. Polyphenols, particularly the organic acid content could be useful for selection and breeding of lentil genotypes that are resistant to Aphanomyces root rot (ARR) disease.

Bioactive compounds and antioxidant capacity of extruded snack-type products developed from novel formulations of lentil and nutritional yeast flours

Pulses are well known to be gluten-free functional foods that provide a rich source of nutritional and healthy compounds with antioxidant-promoting activity.

Polyphenol-Rich Lentils and Their Health Promoting Effects

Polyphenols are a group of plant metabolites with potent antioxidant properties, which protect against various chronic diseases induced by oxidative stress. Evidence showed that dietary polyphenols have emerged as one of the prominent scientific interests due to their role in the prevention of degenerative diseases in humans. Possible health beneficial effects of polyphenols are measured based on the human consumption and their bioavailability. Lentil (Lens culinaris; Family: Fabaceae) is a great source of polyphenol compounds with various health-promoting properties. Polyphenol-rich lentils have a potential effect on human health, possessing properties such as antioxidant, antidiabetic, anti-obesity, anti-hyperlipidemic, anti-inflammatory and anticancer. Based on the explorative study, the current comprehensive review aims to give up-to-date information on nutritive compositions, bioactive compounds and the health-promoting effect of polyphenol-rich lentils, which explores their therapeutic values for future clinical studies. All data of in vitro, in vivo and clinical studies of lentils and their impact on human health were collected from a library database and electronic search (Science Direct, PubMed and Google Scholar). Health-promoting information was gathered and orchestrated in the suitable place in the review.

Profiling the Phenolic Compounds of the Four Major Seed Coat Types and Their Relation to Color Genes in Lentil

Phenolic compounds can provide antioxidant health benefits for humans, and foods such as lentils can be valuable dietary sources of different subclasses of these secondary metabolites. This study used LC-MS analyses to compare the phenolic profiles of lentil genotypes with four seed coat background colors (green, gray, tan, and brown) and two cotyledon colors (red and yellow) grown at two locations. The mean area ratio per mg sample (MARS) values of various phenolic compounds in lentil seeds varied with the different seed coat colors conferred by specific genotypes. Seed coats of lentil genotypes with the homozygous recessive tgc allele (green and gray seed coats) had higher MARS values of flavan-3-ols, proanthocyanidins, and some flavonols. This suggests lentils featuring green and gray seed coats might be more promising as health-promoting foods.

Genetics and Biochemistry of Zero-Tannin Lentils

The zero-tannin trait in lentil is controlled by a single recessive gene (tan) that results in a phenotype characterized by green stems, white flowers, and thin, transparent, or translucent seed coats. Genes that result in zero-tannin characteristics are useful for studies of seed coat pigmentation and biochemical characters because they have altered pigmentation. In this study, one of the major groups of plant pigments, phenolic compounds, was compared among zero-tannin and normal phenotypes and genotypes of lentil. Biochemical data were obtained by liquid chromatography-mass spectrometry (LC-MS). Genomic sequencing was used to identify a candidate gene for the tan locus. Phenolic compound profiling revealed that myricetin, dihydromyricetin, flavan-3-ols, and proanthocyanidins are only detected in normal lentil phenotypes and not in zero-tannin types. The molecular analysis showed that the tan gene encodes a bHLH transcription factor, homologous to the A gene in pea. The results of this study suggest that tan as a bHLH transcription factor interacts with the regulatory genes in the biochemical pathway of phenolic compounds starting from flavonoid-3',5'-hydroxylase (F3'5'H) and dihydroflavonol reductase (DFR).

Effect of dehulling, germination and cooking on nutrients, anti-nutrients, fatty acid composition and antioxidant properties in lentil (Lens culinaris)

The changes in chemical composition, antioxidant activity and fatty acid composition of lentil flour after dehulling, germination and cooking of seeds were investigated. Dehulling showed no significant effect on protein content, however, protein content decreased in most of the varieties after germination and cooking. Total soluble sugars (TSS) content increased significantly after dehulling (2.0-41.64 %) and cooking (2.08-31.07 %) whereas, germination had no significant effect on TSS content. Total lipids increased significantly after dehulling (21.56-42.86 %) whereas, it decreased significantly after germination (2.97-26.52 %) and cooking (23.05-58.63 %). Cooking was more effective than other methods in reducing trypsin inhibitors (80.51-85.41 %). Dehulling was most effective in reducing tannins (89.46-92.99 %) and phytic acid (52.63-60.00 %) content over raw seed. Myristic, palmitic, stearic, oleic and linoleic acid content decreased while linolenic acid content increased after dehulling. Dehulling, germination and cooking decreased the content of antioxidant metabolite (gallic acid, catechin and quercetin) and also antioxidant activities. Raw samples followed by germinated samples showed the highest concentrations of phytochemicals responsible for antioxidant activity and also the antioxidant capacities. Present study showed germination and cooking would be useful in formulation and development of lentil based functional foods for human health benefits.

Current Knowledge on Genetic Biofortification in Lentil

Micronutrient deficiency in the human body, popularly known as "hidden hunger", causes many health problems. It presently affects >2 billion people worldwide, especially in South Asia and sub-Saharan Africa. Biofortification of food crop varieties is one way to combat the problem of hidden hunger using conventional plant breeding and transgenic methods. Lentils are rich sources of protein, micronutrients, and vitamins including iron, zinc, selenium, folates, and carotenoids. Lentil genetic resources including germplasm and wild species showed genetic variability for these traits. Studies revealed that a single serving of lentils could provide a significant amount of the recommended daily allowance of micronutrients and vitamins for adults. Therefore, lentils have been identified as a food legume for biofortification, which could provide a whole food solution to the global micronutrient malnutrition. The present review discusses the current ongoing efforts toward genetic biofortification in lentils using classical breeding and molecular marker-assisted approaches.

Valle Agricola lentil, an unknown lentil (Lens culinaris Medik.) seed from Southern Italy as a novel antioxidant and prebiotic source

In order to promote 'Valle Agricola' lentil, an autochthonous lentil of the Campania Region, a thorough investigation of its biochemical and nutritional properties has been carried out. The macronutrient content (proteins, carbohydrates and lipids), free and total amino acids, and unsaturated fatty acids were determined. The antioxidant capability of raw 'Valle Agricola' lentils, as well as of boiled ones, was estimated in terms of their total phenol content (TPC), ORAC value, and free radical scavenging capacities using DPPH and ABTS assays. The data obtained evidenced that the boiling process slightly decreased Valle Agricola lentil's antioxidant power. Furthermore, when trypsin and chymotrypsin inhibitory activities were measured, a large decrease of the levels of anti-nutritional factors was estimated. In order to have a phytochemical overview of this autochthonous lentil seed, LC-ESI-MS/MS analysis was applied to raw and boiled lentil extracts. Flavonol glycosides and free flavanols, as well as typical seed prebiotic saccharides, were the most representative constituents.

Effect of domestic cooking on carotenoids, tocopherols, fatty acids, phenolics, and antioxidant activities of lentils (Lens culinaris)

The phytochemicals and antioxidant activity in lipophilic and hydrophilic (extractable and bound) fractions of lentils before and after domestic cooking were investigated. The hydrophilic fractions in lentils contributed much more to the antioxidant activity than the lipophilic fraction. The phenolic content of lentils was mainly composed of extractable compounds. Significant changes (P < 0.05) in carotenoid, tocopherol, total phenolic, and condensed tannin contents of both extractable and bound phenolics fractions, as well as in antioxidant activities, were found in lentils before and after cooking. More specifically, cooking was found to favor the release of carotenoids and tocopherols and flavonols (kaempferol glycosides), but led to losses of flavanols (monomeric and condensed tannin). Whereas reduced flavanols and other phenolic compounds may have negatively affected the antioxidant activity, other components, especially the lipophilic antioxidants, were increased. The present study suggests that incorporation of cooked lentils into the diet will not cause significant loss to the phytochemical antioxidants and thus will retain the potential health benefits.

Effect of illumination on the content of melatonin, phenolic compounds, and antioxidant activity during germination of lentils (Lens culinaris L.) and kidney beans (Phaseolus vulgaris L.)

This study reports the effects of two different illumination conditions during germination (12 h light/12 h dark vs 24 h dark) in lentils (Lens culinaris L.) and kidney beans (Phaseolus vulgaris L.) on the content of melatonin and phenolic compounds, as well as the antioxidant activity. Germination led to relative increase in melatonin content and significant antioxidant activity, while the content of phenolic compounds decreased. The highest melatonin content was obtained after 6 days of germination under 24 h dark for both legumes. These germinated legume seeds with improved levels of melatonin might play a protective role against free radicals. Thus, considering the potent antioxidant activity of melatonin, these sprouts can be consumed as direct foods and be offered as preventive food strategies in combating chronic diseases through the diet.

Phenolic profiles of 20 Canadian lentil cultivars and their contribution to antioxidant activity and inhibitory effects on α-glucosidase and pancreatic lipase

Phenolic extracts from 20 Canadian lentil cultivars (Lens culinaris) were evaluated for total phenolic contents and composition, antioxidant activities (DPPH, FRAP, ORAC), and inhibitory properties against α-glucosidase and pancreatic lipase. Twenty one phenolic compounds were identified in the present study, with the majority being flavonoids, including kaempeferol glycosides, catechin/epicatechin glucosides and procyanidins. These phenolic compounds not only contributed significantly to the antioxidant activities, but they were also good inhibitors of α-glucosidase and lipase, two enzymes, respectively, associated with glucose and lipid digestion in the human intestine, thus contributing significantly to the control of blood glucose levels and obesity. More interestingly, it was the flavonols, not the flavanols, which showed the inhibitory activities against α-glucosidase and pancreatic lipase. Our result provides supporting information for developing lentil cultivars and functional foods with improved health benefits and suggests a potential role of lentil consumption in managing weight and control of blood glucose.

Development of a fast extraction method and optimization of liquid chromatography-mass spectrometry for the analysis of phenolic compounds in lentil seed coats

A systematic set of optimization experiments was conducted to design an efficient extraction and analysis protocol for screening six different sub-classes of phenolic compounds in the seed coat of various lentil (Lens culinaris Medik.) genotypes. Different compounds from anthocyanidins, flavan-3-ols, proanthocyanidins, flavanones, flavones, and flavonols sub-classes were first optimized for use as standards for liquid chromatography mass spectrometry (LC-MS) with UV detection. The effect of maceration duration, reconstitution solvent, and extraction solvent were investigated using lentil genotype CDC Maxim. Chromatographic conditions were optimized by examining column separation efficiencies, organic composition, and solvent gradient. The results showed that a 1h maceration step was sufficient and that non-acidified solvents were more appropriate; a 70:30 acetone: water (v/v) solvent was ultimately selected. Using a Kinetex PFP column, the organic concentration, gradient, and flow rate were optimized to maximize the resolution of phenolic compounds in a short 30-min analysis time. The optimized method was applied to three lentil genotypes with different phenolic compound profiles to provide information of value to breeding programs.

Fatty acid, carotenoid and tocopherol compositions of 20 Canadian lentil cultivars and synergistic contribution to antioxidant activities

Understanding the profile of lipophilic phytochemicals in lentils is necessary to better understand the health benefits of lentils. The fatty acid, carotenoid and tocopherol compositions and antioxidant activities of the lipophilic extracts of 20 lentil cultivars (10 red and 10 green) were therefore examined. Lentils contained 1.52-2.95% lipids, of which 77.5-81.7% were unsaturated essential fatty acids. Total tocopherols ranged from 37 to 64μg/g DW, predominantly γ-tocopherol (96-98% of the tocopherol content), followed by δ- and α-tocopherol. trans-Lutein was the primary and major carotenoid (64-78%) followed by trans-zeaxanthin (5-13%). Carotenoids and tocopherols showed weak correlation with 2,2-diphenyl-1-picrylhydrazyl (DPPH) activity (r=0.4893 and 0.3259, respectively), but good correlation when combined (r=0.6688), suggesting they may act synergistically. Carotenoids were found to contribute the most to the strong antioxidant activity measured by photochemiluminescence (PCL) assay. Results from this study contribute to the development of lentil cultivars and related functional foods with increased health benefits.