Nutritional Components of Amaranth Seeds and Vegetables: A Review on Composition, Properties, and Uses

Genome-wide identification and expression profiling of WRKY gene family in grain Amaranth (Amaranthus hypochondriacus L.) under salinity and drought stresses

BACKGROUND

The WRKY gene family plays a significant role in plant growth, development, and responses to biotic and abiotic stresses. However, the role of the WRKY gene family has not been reported in Amaranthus hypochondriacus. This study presents a comprehensive genome-wide analysis of the WRKY gene family in grain amaranth (A. hypochondriacus L.), a resilient crop known for its high nutritional value and adaptability to challenging environments.

RESULTS

In this study, 55 WRKY genes (AhyWRKY1-55) were identified in A. hypochondriacus and distributed unevenly across 16 scaffolds. Of these, 50 contained conserved WRKY domains and were classified into three main groups. Group II was further divided into five subgroups (IIa-IIe) based on phylogenetic analysis, with each clade being well supported by conserved motifs. Additionally, the gene structure analysis revealed variations in exon-intron organization. In contrast, motif analysis showed the presence of conserved domains that were similar within the group but differed between groups, suggesting their functional diversity. Cis-acting elements related to plant growth and development and light, hormones, and stress responses were identified. Synteny analysis revealed that 34 (61.8%) of the genes originated from tandem duplication, indicating the role of tandem duplication in the expansion of the A. hypochondriacus WRKY gene family. Protein-protein interaction analysis suggested that AhyWRKY3, AhyWRKY27, AhyWRKY28, AhyWRKY36, and AhyWRKY52 were hub genes involved in the complex protein interaction network. Using in silico and real-time quantitative PCR, expression analysis revealed tissue- and condition-specific expression patterns of AhyWRKY genes. Notably, under drought stress, AhyWRKY39, AhyWRKY40, AhyWRKY54, and AhyWRKY01 showed increased expression, while under salt stress, AhyWRKY40, AhyWRKY54, AhyWRKY39, AhyWRKY49, and AhyWRKY8 were upregulated at 30 days, suggesting that these genes may play key role in response to salinity stress.

CONCLUSIONS

The present study provides valuable insights into the organization and evolutionary patterns of the WRKY gene family in amaranth. It also identifies putative candidate WRKY genes that may play a role in conferring drought and salt tolerance. Overall, this study lays a foundation for further functional validation of these WRKY candidate genes, facilitating their exploitation in the amaranth genetic improvement programs to develop stress-resilient varieties.

Exploring the Future of Extrusion with Andean Grains: Macromolecular Changes, Innovations, Future Trends and Food Security

This review aimed to explore the impact of extrusion on Andean grains, such as quinoa, kañiwa, and kiwicha, highlighting their macromolecular transformations, technological innovations, and contributions to food security. These grains, which are rich in starch, high-quality proteins, and antioxidant compounds, are versatile raw materials for extrusion, a continuous and efficient process that combines high temperatures and pressures to transform structural and chemical components. Extrusion improves the digestibility of proteins and starches, encourages the formation of amylose-lipid complexes, and increases the solubility of dietary fiber. However, it can degrade heat-sensitive nutrients, such as certain amino acids. The role of extrusion in food innovation is highlighted, especially in the creation of healthy and functional products such as snacks, gluten-free pastas, and meat analogs. Some innovations in the extrusion process and future trends, such as the use of artificial intelligence to optimize formulations and customize products, have been presented. The importance of Andean grains in the fight against food insecurity has been emphasized. These grains can be transformed into accessible, long-lasting, and nutritious foods, diversifying the diet and taking advantage of local resources. This review aims to serve as a valuable guide for researchers, food developers, and policymakers in their pursuit of creating more accessible, nutritious, and sustainable food options to meet escalating global demands for food security and enhanced nutrition.

Effect of Culture Media on the Yield and Protein Content of Pleurotus ostreatus (Jacq.) Kumm Mycelia

The development of alternative proteins derived from fungi-based sources is gaining recognition due to their health benefits and lower environmental impact, compared to traditional animal-based sources. In this study, we investigated the culture conditions for Pleurotus ostreatus mycelia, focusing on the nutritional requirements and yield optimization using solid surface culture and liquid-state culture methods. Our findings indicate that optimal culture conditions involve glucose as the primary carbon source, with an initial pH of 6.0. By the eighth day of the culture period, media formulated with amaranth seed flour and Bambara groundnut flour yielded the highest mycelial protein content, characterized by a compact filamentous network with fewer open pores. Additionally, urea supplementation at 0.01% concentration on amaranth seed-based nutrient medium significantly increased the protein content from 31.4% to 38.7% (dry weight basis). The research findings contribute to the development of fungal-based proteins, which are essential in the production of sustainable food products.

The potential of the amaranth collection maintained at VIR in the context of global plant breeding and utilization trends

Amaranth is an ancient crop of the family Amaranthaceae, but it is fairly new to Russia. Its seeds and leaf biomass contain a high-quality gluten-free protein, fatty acids, squalene (a polyunsaturated hydrocarbon), flavonoids, vitamins, and minerals. A comprehensive study of amaranth, enhancement of its breeding, and development of new cultivars will contribute to food quality improvement through the use of plant raw materials enriched for wholesome and highly nutritious components. At present, selection and hybridization still remain the main amaranth breeding techniques. Meanwhile, mutation breeding and polyploidy have been successfully employed to increase its seed yield and protein content. The genes encoding amaranth proteins have been used to produce transgenic plants of potato, bread wheat, and maize. Despite the great potential of amaranth, little research has been dedicated to the study of its genomics, concentrating mainly on the identification of its species diversity. Targets of breeding practice for amaranth include such characteristics as large size and nonshattering of seeds, short stem, earliness, high yield, cold hardiness, synchronized maturation, resistance to pests and diseases, and high nutritional value, including the content and quality of protein, lipids, squalene, and bioactive compounds. A unique collection of amaranth maintained at the N.I. Vavilov All-Russian Institute of Plant Genetic Resources (VIR) currently incorporates 570 accessions from various countries. For 70 years it has been replenished with local varieties, commercial cultivars, and wild species supplied by collecting missions, research centers, botanical gardens, genebanks, and experimental breeding stations from all over the world. Long-standing studies have resulted in the formation of trait-specific groups of accessions, with high yields of seeds and leaf biomass, earliness, cold hardiness, high protein content in seeds and biomass, short stems, and resistance to seed shattering, earmarked for vegetable or ornamental purposes. The gene pool of amaranth preserved at VIR can provide unlimited opportunities for breeding and meet the needs of the country's population, enriching the human diet with ingredients produced from such a health-friendly and useful crop.

Impact of consumer familiarity on acceptability and purchase intent of a novel amaranth‐based coffee creamer

The objective of the study was to identify the impact of consumer familiarity on liking, acceptability, purchase intention and textual description of a novel cream substitute formulated with popped amaranth flour. Four formulations were evaluated in different proportions of amaranth vs. a control. A total of 400 consumers from two regions participated (Veracruz: familiar with coffee and Tlaxcala: familiar with amaranth). Consumers from both regions had significant differences in liking the attributes of the different formulations. Liking across regions was mainly a function of product aroma. Regarding the acceptance of the product, it was found that the attributes flavour, colour and overall liking were significant (P < 0.05) for consumers from Veracruz, whereas appearance and mouthfeel were significant (P < 0.05) for consumers from Tlaxcala. In purchase intent, overall liking was significant for both regions (P < 0.05). In relation to the impact of amaranth on purchase intention, Tlaxcala showed higher purchase willingness. The words used for sensory characterisation and that are important for both regions were the amaranth aroma, and the creamy flavour in the formulation with the highest amaranth content. The findings of this study allowed for understanding the potential of amaranth to formulate new creamers in a cross‐cultural context, considering consumers from two different levels of familiarity with specific crops.

Purification, Structural Characterization, and Bioactivity of Amaranthus hypochondriacus Lectin

Lectin extracted from Amaranthus hypochondriacus was purified using an affinity column with an agarose-fetuin matrix specific to the lectin of interest. Purification was confirmed by SDS-PAGE, revealing a single protein band with a molecular mass of 34.4 kDa. A hemagglutination assay showed that the lectin had a higher affinity for human type A erythrocytes, and its hemagglutinating activity was inhibited only by fetuin, not by mono-, di-, or trisaccharides. This demonstrated the lectin's selectivity for the N-acetylgalactosamine present on the surface of type A erythrocytes and fetuin. Amaranth lectin exhibited antioxidant activity, which was attributed to the phenolic compounds, amino acids, and specific peptides within the protein structure that are known for their antioxidant properties. Infrared (IR) spectroscopy provided a structural analysis and confirmed lectin glycosylation, a crucial factor in its stability and its ability to bind specific glycans on cell surfaces. Cu2+, Mn2+, and Zn2+ ions were found in the lectin, and these ions were strongly bound to the protein, as dialysis against ethylenediaminetetraacetic acid (EDTA) did not remove them. pH and temperature influenced lectin stability, with higher hemagglutinating activity observed at pH 7, and it remained thermostable at 25 °C.

Amaranthus crop for food security and sustainable food systems

MAIN CONCLUSION

This review ascertains amaranth grains as a potent crop for food security and sustainable food systems by highlighting its agricultural advantages, health benefits and applications in the food, packaging, and brewing industry. The global population surge and rapidly transitioning climatic conditions necessitate the maximization of nutritional crop yield to mitigate malnutrition resulting from food and nutrition insecurity. The modern agricultural practices adopted to maximize the yield of the conventional staple crops are heavily contingent on the depleting natural resources and are contributing extensively to the contamination of these natural resources. Furthermore, these agricultural practices are also causing detrimental effects on the environment like rising emission of greenhouse gasses and increased water footprints. To address these challenges while ensuring sustainable nutrient-rich crop production, it is imperative to utilize underutilized crops like Amaranthus. Amaranth grains are gluten-free pseudo-cereals that are gaining much prominence owing to their abundance in vital nutrients and bio-active components, potential health benefits, resilience to adverse climatic and soil conditions, minimum agricultural input requirements, potential of generating income for small holder farmers as well as various applications across the sustainable value chain. However, due to the limited awareness of these potential benefits of the amaranth grains among the consumers, researchers, and policymakers, they have remained untapped. This review paper enunciates the nutritional composition and potential health benefits of the grains while briefly discussing their various applications in food and beverage industries and accentuating the need to explore further possibilities of valorizing amaranth grains to maximize their utilization along the value chain.

From 'Farm to Fork': Exploring the Potential of Nutrient-Rich and Stress-Resilient Emergent Crops for Sustainable and Healthy Food in the Mediterranean Region in the Face of Climate Change Challenges

In the dynamic landscape of agriculture and food science, incorporating emergent crops appears as a pioneering solution for diversifying agriculture, unlocking possibilities for sustainable cultivation and nutritional bolstering food security, and creating economic prospects amid evolving environmental and market conditions with positive impacts on human health. This review explores the potential of utilizing emergent crops in Mediterranean environments under current climate scenarios, emphasizing the manifold benefits of agricultural and food system diversification and assessing the impact of environmental factors on their quality and consumer health. Through a deep exploration of the resilience, nutritional value, and health impacts of neglected and underutilized species (NUS) such as quinoa, amaranth, chia, moringa, buckwheat, millet, teff, hemp, or desert truffles, their capacity to thrive in the changing Mediterranean climate is highlighted, offering novel opportunities for agriculture and functional food development. By analysing how promoting agricultural diversification can enhance food system adaptability to evolving environmental conditions, fostering sustainability and resilience, we discuss recent findings that underscore the main benefits and limitations of these crops from agricultural, food science, and health perspectives, all crucial for responsible and sustainable adoption. Thus, by using a sustainable and holistic approach, this revision analyses how the integration of NUS crops into Mediterranean agrifood systems can enhance agriculture resilience and food quality addressing environmental, nutritional, biomedical, economic, and cultural dimensions, thereby mitigating the risks associated with monoculture practices and bolstering local economies and livelihoods under new climate scenarios.

Grains in a Modern Time: A Comprehensive Review of Compositions and Understanding Their Role in Type 2 Diabetes and Cancer

Globally, type 2 diabetes (T2D) and Cancer are the major causes of morbidity and mortality worldwide and are considered to be two of the most significant public health concerns of the 21st century. Over the next two decades, the global burden is expected to increase by approximately 60%. Several observational studies as well as clinical trials have demonstrated the health benefits of consuming whole grains to lower the risk of several chronic non-communicable diseases including T2D and cancer. Cereals grains are the primary source of energy in the human diet. The most widely consumed pseudo cereals include (quinoa, amaranth, and buckwheat) and cereals (wheat, rice, and corn). From a nutritional perspective, both pseudo cereals and cereals are recognized for their complete protein, essential amino acids, dietary fibers, and phenolic acids. The bran layer of the seed contains the majority of these components. Greater intake of whole grains rather than refined grains has been consistently linked to a lower risk of T2D and cancer. Due to their superior nutritional compositions, whole grains make them a preferred choice over refined grains. The modulatory effects of whole grains on T2D and cancer are also likely to be influenced by several mechanisms; some of these effects may be direct while others involve altering the composition of gut microbiota, increasing the abundance of beneficial bacteria, and lowering harmful bacteria, increasing insulin sensitivity, lowering solubility of free bile acids, breaking protein down into peptides and amino acids, producing short-chain fatty acids (SCFAs), and other beneficial metabolites that promote the proliferation in the colon which modulate the antidiabetic and anticancer pathway. Thus, the present review had two aims. First, it summarized the recent knowledge about the nutritional composition and bioactive acids in pseudo cereals (quinoa, amaranth, and buckwheat) and cereals (wheat, rice, and corn); the second section summarized and discussed the progress in recent human studies, such as observational (cross-sectional studies, case-control studies, and cohort studies) and intervention studies to understand their role in T2D and cancer including the potential mechanism. Overall, according to the scientific data, whole grain consumption may reduce the incidence of T2D and cancer. Future studies should carry out randomized controlled trials to validate observational results and establish causality. In addition, the current manuscript encourages researchers to investigate the specific mechanisms by which whole grains exert their beneficial effects on health by examining the effects of different types of specific protein, dietary fibers, and phenolic acids that might help to prevent or treat T2D and cancer.

Nutritional and bioactive properties and antioxidant potential of Amaranthus tricolor, A. lividus, A viridis, and A. spinosus leafy vegetables

Climate change results in continuous warming of the planet, threatening sustainable crop production around the world. Amaranth is an abiotic stress-tolerant, climate-resilient, C4 leafy orphan vegetable that has grown rapidly with great divergence and potential usage. The C4 photosynthesis allows amaranth to be grown as a sustainable future food crop across the world. Most amaranth species grow as weeds in many parts of the world, however, a few amaranth species can be also found in cultivated form. Weed species can be used as a folk medicine to relieve pain or reduce fever thanks to their antipyretic and analgesic properties. In this study, nutritional value, bioactive pigments, bioactive compounds content, and radical scavenging potential (RSP) of four weedy and cultivated (WC) amaranth species were evaluated. The highest dry matter, carbohydrate content, ash, content of iron, copper, sodium, boron, molybdenum, zinc, β-carotene and carotenoids, vitamin C, total polyphenols (TP), RSP (DPPH), and RSP (ABTS+) was determined in Amaranthus viridis (AV). On the other hand, A. spinosus (AS) was found to have the highest content of protein, fat, dietary fiber, manganese, molybdenum, and total flavonoids (TF). In A. tricolor (AT) species the highest total chlorophyll, chlorophyll a and b, betaxanthin, betacyanin, and betalain content was determined. A. lividus (AL) was evaluated as the highest source of energy. AV and AT accessions are underutilized but promising vegetables due to their bioactive phytochemicals and antioxidants.

Plant-Based Antioxidants in Gluten-Free Bread Production: Sources, Technological and Sensory Aspects, Enhancing Strategies and Constraints

The recognized contribution of antioxidant compounds to overall health maintenance and spotted deficiencies in celiac patients' diets has driven more intensive research regarding antioxidant compounds' inclusion in gluten-free bread (GFB) production during the last decade. The presented review gathered information that provided insights into plant-based antioxidant sources which are applicable in GFB production through the resulting changes in the technological, sensory, and nutritional quality of the resulting antioxidant-enriched GFB. The influence of the bread-making process on the antioxidant compounds' content alteration and applied methods for their quantification in GFB matrices were also discussed, together with strategies for enhancing the antioxidant compounds' content, their bioaccessibility, and their bioavailability, highlighting the existing contradictions and constraints. The addition of plant-based antioxidant compounds generally improved the antioxidant content and activity of GFB, without a profound detrimental effect on its technological quality and sensory acceptability, and with the extent of the improvement being dependent on the source richness and the amount added. The determination of a pertinent amount and source of plant-based antioxidant material that will result in the production of GFB with desirable nutritional, sensory, and technological quality, as well as biological activity, remains a challenge to be combated by elucidation of the potential mechanism of action and by the standardization of quantification methods for antioxidant compounds.

Exploration of grape pomace peels and amaranth flours as functional ingredients in the elaboration of breads: phenolic composition, bioaccessibility, and antioxidant activity

This study evaluated the incorporation of two ingredients as a source of bioactive compounds: amaranth flour (AF) and grape pomace peels flour (GP) to improve the nutritional qualities and functional properties of a wheat bread, emphasising the revalorisation of agricultural residues from grape winemaking as an ethical and economically viable source of bioactive compounds. Specifically, wheat flour (WF) substitutions were carried out for the individual ingredients, replacing 20% WF (A20 bread) or 5% GP (GP5 bread) and a mixture of both ingredients 20% WF and 5% GP (A20GP5 bread), and the antioxidant potential of the breads was analysed. The effect of simulated gastrointestinal digestion (SGID) on the phenolic profile and antioxidant activity of the fortified breads was also investigated. The substitution of WF by AF or GP introduced several phenolic compounds, digestion increased the bioaccessibility of phenolic compounds and reshaped their phenolic composition profiles. The combined presence of AF and GP in the breads modified the phenolic compounds composition and improved their antioxidant activity after SGID. Interactions between the phenolic compounds and other AF components (possibly proteins) were observed, which could protect the phenols from degradation during SGID, allowing them to be released after SGID.

Effect of roasting times on bioactive compounds, fatty acids, polyphenol and nutrients of amaranth (Amaranthus cruentus L.) seed roasted in pan, and principal component analysis

In this study, the effect of roasting times on bioactive compounds, antioxidant capacity, fatty acids, polyphenol and nutrients of amaranth seed and oils roasted in pan at 120 °C was investigated. Total phenolic and flavonoid results of the seeds of unroasted (control) and roasted-amaranth were recorded between 48.81 (6 min) and 231.35 mg GAE/100 g (15 min) to 64.29 (6 min) and 144.29 mg/100 g (15 min), respectively. Antioxidant activities of unroasted and roasted-amaranth extracts were recorded between 5.50 (control) and 12.78 mmol/kg (15 min). L* values of amaranth seeds ranged from 51.21 to 78.53. Roasting for 3 min and 6 min was increased the L* values of samples, while roasting for 9-12 min caused a decrease in L* values. Gallic acid results of amaranth seeds were identified between 21.94 (control) and 71.06 mg/100 g (15 min). The linoleic acid results of amaranth seed oils were reported between 44.24 (control) and 45.76% (12 min). The highest amounts of elements in roasted and unroasted amaranth seeds were P, K,Ca, Mg and S. In general, it was observed that both macro and micro-elements of amaranth seed samples increased with the application of heat treatment. However, microelement contents differed depending on the roasting time.

Graphical abstract

In this study, the effect of thermal process times on total phenol, flavonoid, antioxidant activity, fatty acids, phenolic and minerals of amaranth seed and oils roasted in pan at 120 °C was investigated.

RNA Isolation Method in Marginal Crops with High Agronomic Potential

Ribonucleic Acid (RNA) isolation is a basic technique in the field of molecular biology. The purpose of RNA isolation is to acquire pure and complete RNA that can be used to evaluate gene expression. Many methods can be used to perform RNA isolation, all of them based on the chemical properties of nucleic acids. However, some of them do not achieve high RNA yields and purity levels when used in a number of marginally studied crops of agronomic importance, such as grain and vegetable amaranth plants. In the method described here, the use of guanidinium thiocyanate and two additional precipitation steps with different reagents designed to obtain high yields and RNA purity levels from diverse plant species employed for plant functional genomics studies is described.

1H NMR-Based Metabolomics Profile of Green and Red Amaranthus Grown in Open Field versus Greenhouse Cultivation System

Traditionally, indigenous African leafy vegetables such as Amaranthus, blackjack, jute mallow, cleome monophyla, and spider plants have been conventionally and organically grown as weeds in open fields. However, the lack of land space due to the increase in population has resulted in unconventional, modern, and advanced agricultural farming. The introduction of a greenhouse has recently become the second most popular growing system alongside shade net and glasshouse to increase productivity and meet consumers' demand. Several studies on Amaranthus species have solely focused on physiological parameters and nutritional composition, leaving a huge gap on their metabolomic profile of the leaves which is crucial to comprehend when growing Amaranthus species in different cropping systems. Therefore, the study aimed to determine the influence of different cropping systems on the release of metabolites of two commonly consumed Amaranthus species in South Africa. H1 -Nuclear Magnetic Resonance (NMR) tool was used to profile the untargeted metabolites of green (Amaranthus graecizans L.) and red (Amaranthus cruentus L.) species. A total of 12 metabolites-trehalose, betaine, glutamine, choline, sucrose, caprate, adenosine, asparagine, carnitine, caffeine, aspartate, and alanine-were detected in green amaranth grown in open fields. Except for caffeine, aspartate, and caprate, which were found in the green amaranth grown in open fields, all the other metabolites were detected in the greenhouse grown once. Interestingly, allantoin, which serves as an allelochemical, was the sole distinct metabolite detected in greenhouse cultivated green amaranth. On the contrary, seven similar metabolites were quantified in red amaranth grown in both open fields and greenhouses, apart from caffeine, which was only detected in greenhouse-cultivated red amaranth.

Chemical and cell antioxidant activity of amaranth flour and beverage after simulated gastrointestinal digestion. Role of peptides

The potential of peptides generated by simulated gastrointestinal digestion (SGID) of two products derived from Amaranthus manteggazianus seeds, flour (F) and beverage (B), to exert peroxyl scavenging activity (ORAC) and antioxidant action on intestinal cells was studied. B was prepared by solubilisation of seed proteins, with the addition of gums and the application of a pasteurization treatment. The gastrointestinal digests FD and BD showed some differences in the peptide/polypeptide composition. The SGID produced increased ORAC activity for both samples, with some differences in the ORAC of the whole digests BD and FD and of some gel filtration fractions. Bioaccessible fractions (FDdbs and BDdbs) were obtained after treatment with cholestyramine resin to remove bile salts due to their cytotoxicity and oxidative effect. BDdbs presented a greater ORAC potency (IC50: 0.05 ± 0.01 and 0.008 ± 0.004 mg protein/ml for FDdbs and BDdbs, respectively). These fractions showed low cytotoxicity values (measured by LDH release) and produced high intracellular ROS inhibition (around 80 %), increased the SOD activity and the GSH content, with no effect on GPx activity in Caco2-TC7 cells exposed to H2O2. Several fractions with MM < 2.2 kDa presented also these cellular actions; fractions from FD induced higher increases in GSH concentration. Amaranth flour and a processed matrix like the beverage are shown as sources of bioactive peptides with potential cell antioxidant activity.

Physico-Chemical and Nutritional Properties of Chia Seeds from Latin American Countries

In the last few decades, chia (Salvia hispanica L.) cultivation has expanded around the world, and the seeds have become well known due to their rich composition of nutrients and bioactive compounds. The aim of this work was to evaluate the physical, chemical, and nutritional profile of eight types of chia seeds grown in different Latin-American countries (Argentina, Bolivia, Chile, Ecuador, Mexico, Paraguay, and Peru). The results showed that several nutritional parameters of the seeds, such as the protein content and amino acid profile, dietary fiber content, lipid content, mineral composition, and presence of phytate, depend on the location in which they were grown. Other parameters, such as ash content, fatty acid profile, or various physical parameters, were uniform across locations (except for color parameters). The results support the notion that the nutritional characteristics of seeds are determined by the seeds' origin, and further analysis is needed to determine the exact mechanisms that control the changes in the seed nutritional properties of chia seeds.

Comparative Transcriptomic Analysis of the Metabolism of Betalains and Flavonoids in Red Amaranth Hypocotyl under Blue Light and Dark Conditions

Amaranth plants contain abundant betalains and flavonoids. Anthocyanins are important flavonoids; however, they cannot coexist in the same plant with betalains. Blue light influences metabolite synthesis and hypocotyl elongation; accordingly, analyses of its effects on betalain and flavonoid biosynthesis in Amaranthus tricolor may provide insight into the distribution of these plant pigments. We analyzed the betalain and flavonoid content and transcriptome profiles in amaranth hypocotyls under blue light and dark conditions. Furthermore, we analyzed the expression patterns of key genes related to betalains and flavonoids. Amaranth hypocotyls were shorter and redder and showed higher betalain and flavonoid content under blue light than in dark conditions. Key genes involved in the synthesis of betalains and flavonoids were upregulated under blue light. The gene encoding DELLA was also upregulated. These results suggest that blue light favors the synthesis of both betalains and flavonoids via the suppression of bioactive gibberellin and the promotion of DELLA protein accumulation, which also suppresses hypocotyl elongation. The metabolite profiles differed between plants under blue light and dark conditions. These findings improve our understanding of the environmental cues and molecular mechanisms underlying pigment variation in Amaranthus.

High phytoremediation and translocation potential of an invasive weed species (Amaranthus retroflexus) in Europe in metal-contaminated areas

We demonstrated the metal accumulation potential of Amaranthus retorflexus, a European weed species, both in moderately and strongly metal-contaminated sites. Metal accumulation in roots, stems, and leaves were studied. We also calculated the bioaccumulation factor (BAF), and translocation factor (TF) values to quantify the metal accumulation, and translocation between plant organs. Our findings indicated that metal accumulation correlated with metal concentration; that is plant organs accumulated higher concentration of metals in the contaminated area than in the control one. We found that the concentrations of Ba, Mn, Sr and Zn were the highest in leaves, and Al, Cr, Cu, Fe and Pb in roots. High BAF value was found for Sr in all studied areas, indicating this metal's high accumulation potential of Amaranthus retorflexus. High TF values were found for Al, Ba, Cu, Fe, Mn, Sr and Zn; these metals were successfully transported to aboveground plant organs. We demonstrated that A. retroflexus, a fast-growing, rapidly spreading weed in Europe, was especially useful for heavy metal phytoremediation and phytoextraction.

Physical and Chemical Characterization and Bioavailability Evaluation In Vivo of Amaranth Protein Concentrate

Special attention is being paid to the study of amaranth proteins. They are characterized by a high biological value that significantly exceeds those of grain crops. The production of protein concentrate from amaranth flour includes preliminary enzymatic hydrolysis, extraction of the resulting mixture, protein precipitation, microfiltration, and freeze-drying. In our study, the obtained amaranth protein concentrate was limited by valine, with an amino acid score of 74%. The true digestibility of the amaranth protein concentrate determined in vivo was 97.6 ± 0.3%, which was significantly lower than that of casein (99.3 ± 0.2%). The protein digestibility-corrected amino acid score value of the concentrate was 72.2%. The obtained concentrate was a rich source of selenium, copper, magnesium, manganese, and iron. Ferulic acid was the only polyphenolic compound found in the amaranth protein concentrate, but its content was significantly greater compared to the original flour. Saponins were not removed completely during the process of obtaining the amaranth protein concentrate. We identified 15 saponins in the concentrate, mainly of the bidesmoside type, the sapogenins of which are related derivatives of oleanolic acid. Thus, the developed amaranth protein concentrate can be used as an ingredient in functional food products, with a high biological value.

Effect of Dietary Amaranth (Amaranthus hybridus chlorostachys) Supplemented with Enzyme Blend on Egg Quality, Serum Biochemistry and Antioxidant Status in Laying Hens

A feeding trial was performed to assess the effects of dietary raw amaranth (Amaranthus hybridus chlorostachys) grain (RAG), with or without an enzyme blend, on the productive performance, blood biochemistry, and antioxidant status in laying hens. The trial was conducted following a completely randomized design by factorial method, including five levels of RAG (0, 10, 20, 30, and 40%, respectively) and two levels of enzyme blend (0 ^-E and 0.025 ^+E %). A total of 960 White Leghorn (Hy-line W-36) laying hens (56 weeks of age) were divided into 10 groups with eight repetitions, including 12 birds. The trial period was ten weeks. Results showed that RAG levels in feed (>10%) led to a significant decrease in blood total cholesterol (TC), but they also significantly decreased feed conversion ratio (FCR) (p ˂ 0.05) as measured by feed intake (FI), hen daily production (HDP), egg weight (EW), and mass (EM), leading to overall worse productivity compared to the control group. On the contrary, the addition of the enzyme blend led to an improvement in the investigated production traits (p ˂ 0.05), with the exception of HDP. The enzyme blend was also capable of recovering productive performance when combined with low concentrations of RAG (10%) (p ˂ 0.05), and RAG × enzyme blend groups showed the lowest values of TC (p ˂ 0.05). Moreover, the interaction effects for atherogenic index (LDL/HDL) indicated a significant and promising reduction in response to the addition of RAG both in the presence and absence of the enzyme blend (p ˂ 0.05), and this additive also significantly reduced levels of egg yolk cholesterol (p ˂ 0.05). In summary, the evidence gathered in this trial showed that dietary RAG had positive effects on egg quality characteristics, leading to the production of low-cholesterol eggs, and, at the same time, it may improve the health status of laying hens. Furthermore, the addition of an enzyme blend allowed feeding up to 10% RAG in the diet, leading to an optimal balance between animal productivity and the beneficial effects of RAG.

Identification of genetic and biochemical mechanisms associated with heat shock and heat stress adaptation in grain amaranths

Heat stress is poised to become a major factor negatively affecting plant performance worldwide. In terms of world food security, increased ambient temperatures are poised to reduce yields in cereals and other economically important crops. Grain amaranths are known to be productive under poor and/or unfavorable growing conditions that significantly affect cereals and other crops. Several physiological and biochemical attributes have been recognized to contribute to this favorable property, including a high water-use efficiency and the activation of a carbon starvation response. This study reports the behavior of the three grain amaranth species to two different stress conditions: short-term exposure to heat shock (HS) conditions using young plants kept in a conditioned growth chamber or long-term cultivation under severe heat stress in greenhouse conditions. The latter involved exposing grain amaranth plants to daylight temperatures that hovered around 50°C, or above, for at least 4 h during the day and to higher than normal nocturnal temperatures for a complete growth cycle in the summer of 2022 in central Mexico. All grain amaranth species showed a high tolerance to HS, demonstrated by a high percentage of recovery after their return to optimal growing conditions. The tolerance observed coincided with increased expression levels of unknown function genes previously shown to be induced by other (a)biotic stress conditions. Included among them were genes coding for RNA-binding and RNA-editing proteins, respectively. HS tolerance was also in accordance with favorable changes in several biochemical parameters usually induced in plants in response to abiotic stresses. Conversely, exposure to a prolonged severe heat stress seriously affected the vegetative and reproductive development of all three grain amaranth species, which yielded little or no seed. The latter data suggested that the usually stress-tolerant grain amaranths are unable to overcome severe heat stress-related damage leading to reproductive failure.

Microstructure, rheological and water mobility behaviour of plant-based protein isolates (pea and quinoa) and locust bean gum mixtures

This work reports the impact of locust bean gum (LBG) in the continuous phase of plant-based proteins, i.e. quinoa protein (QPI) and pea protein isolates (PPI). Experimental measurements such as confocal microscopy, rheological analysis and water mobility via nuclear magnetic resonance (nmr) spin-spin relaxation time (T2) were carried out. The influence of LBG on the rheological properties of QPI and PPI is consistent with an exchange-based nmr interpretation of T2 for biopolymer and water. Addition of LBG increased the viscoelastic properties (storage and loss modulus) and shear viscosities of the mixtures. LBG interacted with both plant proteins, resulting in the formation of more dense protein networks and protein coacervates. A stronger interaction between the PPI and LBG was observed, resulting in higher shear viscosities with lower water mobility as compared to QPI:LBG formulations. Results indicated that the interaction between the protein and polysaccharide played a significant role in the microstructure, its rheological properties and consequently water mobility.

Functional divergence of Heat Shock Factors (Hsfs) during heat stress and recovery at the tissue and developmental scales in C4 grain amaranth (Amaranthus hypochondriacus)

Two major future challenges are an increase in global earth temperature and a growing world population, which threaten agricultural productivity and nutritional food security. Underutilized crops have the potential to become future climate crops due to their high climate-resilience and nutritional quality. In this context, C4 pseudocereals such as grain amaranths are very important as C4 crops are more heat tolerant than C3 crops. However, the thermal sensitivity of grain amaranths remains unexplored. Here, Amaranthus hypochondriacus was exposed to heat stress at the vegetative and reproductive stages to capture heat stress and recovery responses. Heat Shock Factors (Hsfs) form the central module to impart heat tolerance, thus we sought to identify and characterize Hsf genes. Chlorophyll content and chlorophyll fluorescence (Fv/Fm) reduced significantly during heat stress, while malondialdehyde (MDA) content increased, suggesting that heat exposure caused stress in the plants. The genome-wide analysis led to the identification of thirteen AhHsfs, which were classified into A, B and C classes. Gene expression profiling at the tissue and developmental scales resolution under heat stress revealed the transient upregulation of most of the Hsfs in the leaf and inflorescence tissues, which reverted back to control levels at the recovery time point. However, a few Hsfs somewhat sustained their upregulation during recovery phase. The study reported the identification, physical location, gene/motif structure, promoter analysis and phylogenetic relationships of Hsfs in Amaranthus hypochondriacus. Also, the genes identified may be crucial for future gene functional studies and develop thermotolerant cultivars.

Addition of Amaranth Flour of Different Particle Sizes at Established Doses in Wheat Flour to Achieve a Nutritional Improved Wheat Bread

Amaranth is an underutilized pseudocereal that can be used to supplement wheat flour (WF) in order to improve the nutritional quality of bread. Bread digestibility is impacted by particle size which produces different nutritional properties. This research aims to evaluate the baking characteristics of optimal wheat−amaranth composite flour for each studied amaranth flour (AF) particle size at doses previously established based on an optimization process and to characterize from a physical, textural, nutritional, and sensorial point of view the obtained bread. The results revealed that the optimal wheat−amaranth composite flour with medium and small particle size, respectively showed a slightly lower α-amylase activity, while dough development time was significantly higher compared to the WF. A significant (p < 0.05) decrease was observed in the elasticity, deformation energy, and dynamic rheological parameters of the optimal composite dough for all the particle sizes, whereas fermentation parameters showed higher values compared to the control, indicating the ability of the gluten structure in large, medium, and small particle sizes of AF to hold the gas and to expand without collapsing. The physical, textural, and especially nutritional characteristics of the optimal WF-AF bread were enhanced. The sensory evaluation results revealed high scores (8.70) for the acceptability of optimal bread with a medium particle size as compared to wheat bread (8.25). The protein and ash content of the optimal breads with large, medium, and small AF particle sizes, respectively, increased significantly, from 8.92 to 10.58%, and 0.82 to 0.99%, respectively, relative to the wheat flour bread (8.35% and 0.72%, respectively). The mineral content was up to two times higher in the optimal breads compared to wheat flour bread. The findings generated from this study are helpful in bakery industry for designing products with enhanced nutritional properties and for introducing new products to the market.

Salt Eustress Induction in Red Amaranth (Amaranthus gangeticus) Augments Nutritional, Phenolic Acids and Antiradical Potential of Leaves

Earlier researchers have highlighted the utilization of salt eustress for boosting the nutritional and phenolic acid (PA) profiles and antiradical potential (ARP) of vegetables, which eventually boost food values for nourishing human diets. Amaranth is a rapidly grown, diversely acclimated C4 leafy vegetable with climate resilience and salinity resistance. The application of salinity eustress in amaranth has a great scope to augment the nutritional and PA profiles and ARP. Therefore, the A. gangeticus genotype was evaluated in response to salt eustress for nutrients, PA profile, and ARP. Antioxidant potential and high-yielding genotype (LS1) were grown under four salt eustresses (control, 25 mM, 50 mM, 100 mM NaCl) in a randomized completely block design (RCBD) in four replicates. Salt stress remarkably augmented microelements, proximate, macro-elements, phytochemicals, PA profiles, and ARP of A. gangeticus leaves in this order: control < low sodium chloride stress (LSCS) < moderate sodium chloride stress (MSCS) < severe sodium chloride stress (SSCS). A large quantity of 16 PAs, including seven cinnamic acids (CAs) and nine benzoic acids (BAs) were detected in A. gangeticus genotypes. All the microelements, proximate, macro-elements, phytochemicals, PA profiles, and ARP of A. gangeticus under MSCS, and SSCS levels were much higher in comparison with the control. It can be utilized as preferential food for our daily diets as these antiradical compounds have strong antioxidants. Salt-treated A. gangeticus contributed to excellent quality in the end product in terms of microelements, proximate, macro-elements, phytochemicals, PA profiles, and ARP. A. gangeticus can be cultivated as an encouraging substitute crop in salt-affected areas of the world.

Chromosome-scale Amaranthus tricolor genome provides insights into the evolution of the genus Amaranthus and the mechanism of betalain biosynthesis

Amaranthus tricolor is a vegetable and ornamental amaranth, with high lysine, dietary fibre and squalene content. The red cultivar of A. tricolor possesses a high concentration of betalains, which has been used as natural food colorants. Here, we constructed the genome of A. tricolor, the first reference genome for the subgenus Albersia, combining PacBio HiFi, Nanopore ultra-long and Hi-C data. The contig N50 size was 906 kb, and 99.58% of contig sequence was anchored to the 17 chromosomes, totalling 520 Mb. We annotated 27,813 protein-coding genes with an average 1.3 kb coding sequence and 5.3 exons. We inferred that A. tricolor underwent a whole-genome duplication (WGD) and that the WGD shared by amaranths occurred in the last common ancestor of subfamily Amaranthoideae. Moreover, we comprehensively identified candidate genes in betalain biosynthesis pathway. Among them, DODAα1 and CYP76ADα1, located in one topologically associated domain (TAD) of an active (A) compartment on chromosome 16, were more highly expressed in red leaves than in green leaves, and DODAα1 might be the rate-limiting enzyme gene in betalains biosynthesis. This study presents new genome resources and enriches our understanding of amaranth evolution, betalains production, facilitating molecular breeding improvements and the understanding of C4 plants evolution.

Valorization of Amaranth (Amaranthus cruentus) Grain Extracts for the Development of Alginate-Based Active Films

This research work investigates the development of alginate-based films incorporating phenolic compounds extracted from Amaranthus cruentus grain using different solvents. Alginate, glycerol, and amaranth grain phenolic compounds at various concentrations were used to produce the films. An experimental Central Composite Rotatable Design (CCRD) was used to evaluate the effect of these variables on different film’s properties, i.e., water vapor permeability, hydrophobicity, moisture content, solubility, thermal, mechanical, and optical properties. This study demonstrated that high phenolic compound content and antioxidant capacity were obtained from amaranth grain using ethanol as the extraction solvent. Alginate films incorporating amaranth phenolic compounds were successfully manufactured, and this study can be used to tailor the formulation of alginate films containing amaranth phenolic compounds, depending on their final food application. For example, less flexible but more resistant and water-soluble films can be produced by increasing the alginate concentration, which was confirmed by a Principal Component Analysis (PCA) and Partial Least Squares (PLS) analysis. This study showed that active alginate films with amaranth phenolic compounds can be tailored to be used as food packaging material with potential antioxidant activity.

Effects of Germination and Popping on the Anti-Nutritional Compounds and the Digestibility of Amaranthus hypochondriacus Seeds

Amaranth seeds, although a valuable food in Mexico, contain anti-nutritional compounds that can affect food quality. As a part of this work, the proximate composition, fatty acid profile, protein digestibility, and the effect of germination and popping of Amaranthus hypochondriacus seeds was analyzed with the aim of eliminating anti-nutritional compounds. Untreated seeds comprised of 11.35-18.8% protein and 0.27-13.39% lipids, including omega 3, 6, and 9 fatty acids such as oleic, linoleic, linolenic, and arachidonic acid. The main minerals detected were Ca+2, K+1, and Mg+2. Nevertheless in vitro studies indicate that germination significantly improved digestibility, whereby treatments aimed at reducing anti-nutritional compounds decreased lectin concentration, while significantly increasing tannins and completely eliminating trypsins and saponins.

Effects of salinity on germination dynamics and seedling development in two amaranth genotypes

Amaranth (Amaranthus caudatus L.), commonly known as "kiwicha", is a pseudo-cereal considered as the crop of future regarding its excellent nutritional value. It has also been suggested as a robust alternative to traditional cereal crops in arid and semi-arid regions where abiotic stresses such as drought and salinity have increased due to climate change. In order to study the seedling behavior and germination dynamics of this species against salinity stress, two amaranth genotypes (Red and Green) were randomly chosen among others and our investigation focused on both morphological and physiological traits. Salt stress was applied for 10 days. Our results show that Red genotype was more tolerant to salinity compared to Green since that the first gave a higher final germination rate and produced higher biomass. Moreover, the germination parameters are less affected in Red compared to those in Green genotype. The radicules of the first genotype accumulated more Na⁺ compared to those of the second one. Moreover, at low level of salinity (50 mM NaCl), Red genotype showed significant increase in the volatile polyphenol compound content, as well as in the total antioxidant activity, compared to the control (0 mM NaCl). Even if the inhibitory action of the methanoic extracts of both Red and Green genotypes was affected by the salinity, they showed an important activity against P. aeruginosa pathogen.

Prospects and potentials of underutilized leafy Amaranths as vegetable use for health-promotion

Climate change causes environmental variation worldwide, which is one of the most serious threats to global food security. In addition, more than 2 billion people in the world are reported to suffer from serious malnutrition, referred to as 'hidden hunger.' Dependence on only a few crops could lead to the loss of genetic diversity and high fragility of crop breeding in systems adapting to global scale climate change. The exploitation of underutilized species and genetic resources, referred to as orphan crops, could be a useful approach for resolving the issue of adaptability to environmental alteration, biodiversity preservation, and improvement of nutrient quality and quantity to ensure food security. Moreover, the use of these alternative crops will help to increase the human health benefits and the income of farmers in developing countries. In this review, we highlight the potential of orphan crops, especially amaranths, for use as vegetables and health-promoting nutritional components. This review highlights promising diversified sources of amaranth germplasms, their tolerance to abiotic stresses, and their nutritional, phytochemical, and antioxidant values for vegetable purposes. Betalains (betacyanins and betaxanthins), unique antioxidant components in amaranth vegetables, are also highlighted regarding their chemodiversity across amaranth germplasms and their stability and degradation. In addition, we discuss the physiological functions, antioxidant, antilipidemic, anticancer, and antimicrobial activities, as well as the biosynthesis pathway, molecular, biochemical, genetics, and genomic mechanisms of betalains in detail.

Colorant Pigments, Nutrients, Bioactive Components, and Antiradical Potential of Danta Leaves (Amaranthus lividus)

In the Indian subcontinent, danta (stems) of underutilized amaranth are used as vegetables in different culinary dishes. At the edible stage of the danta, leaves are discarded as waste in the dustbin because they are overaged. For the first time, we assessed the colorant pigments, bioactive components, nutrients, and antiradical potential (AP) of the leaves of danta to valorize the by-product (leaf) for antioxidant, nutritional, and pharmacological uses. Leaves of danta were analyzed for proximate and element compositions, colorant pigments, bioactive constituents, AP (DPPH), and AP (ABTS+). Danta leaves had satisfactory moisture, protein, carbohydrates, and dietary fiber. The chosen danta leaves contained satisfactory magnesium, iron, calcium, potassium, manganese, copper, and zinc; adequate bioactive pigments, such as betacyanins, carotenoids, betalains, β-carotene, chlorophylls, and betaxanthins; and copious bioactive ascorbic acid, polyphenols, flavonoids, and AP. The correlation coefficient indicated that bioactive phytochemicals and colorant pigments of the selected danta leaves had good AP as assessed via ABTS+ and DPPH assays. The selected danta leaves had good ROS-scavenging potential that could indicate massive possibilities for promoting the health of the nutraceutical- and antioxidant-deficit public. The findings showed that danta leaves are a beautiful by-product for contributing as an alternate origin of antioxidants, nutrients, and bioactive compounds with pharmacological use.

Effect of different LED light quality combination on the content of vitamin C, soluble sugar, organic acids, amino acids, antioxidant capacity and mineral elements in green onion (Allium fistulosum L.)

The effects of blue-white, green-white, yellow-white, and red-white light combinations on the nutrient composition and antioxidant capacity of pseudo-stems and leaves of 'Yuanzang' green onion were investigated using light-emitting diodes (LEDs) with precise modulation of light quality, using white light as the control. The results showed that the leaf pigment, vitamin C, soluble sugar, organic acids, free amino acids, mineral elements, and antioxidant levels were significantly higher in green onion under blue-white combined light treatment, followed by white and red-white combined light, while green-white and yellow-white combined light significantly reduced fruit quality and antioxidant capacity. In conclusion, supplementation with blue LED light was the most effective light condition to improve palatability, nutritional value, and storage resistance of green onion by enhancing various nutrients in the plants, increasing antioxidant levels, and delaying plant aging.

Characterization of Phytochemicals, Nutrients, and Antiradical Potential in Slim Amaranth

Slim amaranth (A. hybridus) having a C₄ photosynthetic pathway with diverse variability is a climate-resilient crop that tolerates abiotic stresses. Owing to the high productivity of the C₄ pathway, we have been searching for suitable accessions as preferable high-yielding antioxidant-enriched cultivars with ample bioactive compounds, or for future breeding programs to improve bioactive compounds as a source of natural antioxidants. Twelve slim amaranth accessions were tested for nutraceuticals, phytopigments, radical scavenging capacity (two different assays), vitamins, total flavonoids, and total polyphenols content. Slim amaranth leaves contained ample dietary fiber, protein, moisture, and carbohydrates. The current investigation demonstrated that there was remarkable K, Ca, Mg (8.86, 26.12, and 29.31), Fe, Mn, Cu, Zn, (1192.22, 275.42, 26.13, and 1069.93), TP, TF (201.36 and 135.70), pigments, such as chlorophyll a, ab, and b, (26.28, 38.02, and 11.72), betalains, betaxanthins, betacyanins (78.90, 39.36, 39.53,), vitamin C (1293.65), β-carotene, total carotenoids, (1242.25, 1641.07), and TA (DPPH, ABTS⁺) (27.58, 50.55) in slim amaranth leaves. The widespread variations were observed across the studied accessions. The slim amaranth accessions, AH11, AH10, and AH12, exhibited high profiles of antioxidants including high potentiality to quench radicals and can be selected as preferable high-yielding antioxidant-enriched cultivars with ample bioactive compounds. Phytopigments, flavonoids, vitamins, and phenolics of slim amaranth leaves showed intense activity of antioxidants. Slim amaranth could be a potential source of proximate phenolics, minerals, phytopigments, vitamins, and flavonoids for gaining adequate nutraceuticals, bioactive components, and potent antioxidants. Moderate yielding accessions having moderate phytochemicals can be used to develop new high-yielding antioxidant-enriched cultivars for future breeding programs to improve bioactive compounds as a source of natural antioxidants.

Phytonutrients, Colorant Pigments, Phytochemicals, and Antioxidant Potential of Orphan Leafy Amaranthus Species

The underutilized Amaranthus leafy vegetables are a unique basis of pigments such as β-cyanins, β-xanthins, and betalains with radical scavenging capacity (RSC). They have abundant phytonutrients and antioxidant components, such as pigments, vitamins, phenolics, and flavonoids. Eight selected genotypes (four genotypes from each species) of underutilized Amaranthus leafy vegetables were evaluated for phytonutrients, pigments, vitamins, phenolics, flavonoids, and antioxidants in a randomized complete block design under ambient field conditions with three replicates. The studied traits showed a wide range of variations across eight genotypes of two species of Amaranthus leafy vegetables. The highest fat, β-xanthins, K, dietary fiber, Mg, β-cyanins, Mn, chlorophyll ab, Zn, TP, TF, betalains, chlorophyll a content, and (RSC) (DPPH) and RSC (ABTS+) were obtained from A. tricolor accessions. Conversely, the highest protein, Cu, carbohydrates, Ca, and chlorophyll b content were obtained from A. lividus accessions. The highest dry matter, carotenoids, Fe, energy, and ash were obtained from A. tricolor and A. lividus. The accession AT2 confirmed the highest vit. C and RSC (DPPH) and RSC (ABTS+); AT5 had the highest TP content; and AT12 had the highest TF content. A. tricolor accessions had high phytochemicals across the two species, such as phytopigments, vitamins, phenolics, antioxidants, and flavonoids, with considerable nutrients and protein. Hence, A. tricolor accessions can be used as high-yielding cultivars comprising ample antioxidants. The correlation study revealed that vitamin C, pigments, flavonoids, β-carotene, and phenolics demonstrated a strong RSC, and showed a substantial contribution to the antioxidant potential (AP) of A. tricolor. The investigation exposed that the accessions displayed a plentiful origin of nutritional values, phytochemicals, and AP with good quenching ability of reactive oxygen species (ROS) that provide enormous prospects for nourishing the mineral-, antioxidant-, and vitamin-threatened community.

Bioactive Phytochemicals and Quenching Activity of Radicals in Selected Drought-Resistant Amaranthus tricolor Vegetable Amaranth

Leafy vegetables are susceptible to drought stress. Amaranthus tricolor vegetables are resistant to abiotic stress, including drought, and are a source of ample natural phytochemicals of interest to the food industry due to their benefits to consumers’ health. Hence, the selected drought-resistant amaranth genotypes were evaluated for phytochemicals and antioxidant activity in an RCBD study with three replicates. The selected drought-resistant amaranth accessions contained ample carbohydrates, protein, moisture, and dietary fiber. We noticed many macroelements and microelements including iron, copper, manganese, zinc, sodium, molybdenum, boron, potassium, calcium, magnesium, phosphorus, and sulfur; adequate phytopigments, including betacyanins, betalains, betaxanthins, carotenoids, and chlorophylls; plentiful bioactive phytochemicals, including ascorbic acid, flavonoids, polyphenols, and beta-carotene; and antioxidant potential in the selected drought-resistant amaranth accessions. The drought-resistant amaranth accessions VA14 and VA16 were proven to have high ascorbic acid, beta-carotene, and polyphenol levels. The drought-resistant accessions VA12 and VA14 had high flavonoid levels. The drought-resistant accessions VA3, VA14, and VA16 had high AC both in regard to both DPPH and ABTS⁺. These drought-resistant accessions, VA3, VA14, and VA16, can be utilized as high-yielding varieties with antioxidant profiles for purposes of drinks. The correlation study revealed that bioactive phytopigments and phytochemicals of amaranth accessions had good free radical quenching capacity against 2,2′-azino-bis (3-ethylbenzothiazo-6-sulfonic acid) and diphenyl-1-picrylhydrazyl, equivalent to Trolox. It was revealed in the present study that these drought-resistant accessions contain plentiful proximate, nutraceuticals, phytopigments, bioactive phytochemicals, and antioxidant potentiality. Their drought resistance and quenching of ROS offer huge prospects for the promotion of health benefits and the feeding of communities in drought-prone semiarid and arid areas of the globe, especially those deficient in nutraceuticals, phytopigments, and antioxidants.

A Systematic Review on Amaranthus-Related Research

Leafy vegetables promote reparation of energy loss due to oxidative stress, and they have the potential to alleviate hunger and malnutrition as well as other forms of metabolic imbalance ravaging the world. However, these vegetables are underutilized, despite the fact that they harbor essential minerals needed for critical cellular activities. As amaranth is one of the earliest vegetables reputed for its high nutraceutical and therapeutic value, in this study, we explored research on the Amaranthus species, and identified areas with knowledge gaps, to harness the various biological and economic potentials of the species. Relevant published documents on the plant were retrieved from the Science Citation Index Expanded accessed through the Web of Science from 2011 to 2020; while RStudio and VOSviewer were used for data analysis and visualization, respectively. Publications over the past decade (dominated by researchers from the USA, India, and China, with a collaboration index of 3.22) showed that Amaranthus research experienced steady growth. Findings from the study revealed the importance of the research and knowledge gaps in the underutilization of the vegetable. This could be helpful in identifying prominent researchers who can be supported by government funds, to address the malnutrition problem in developing countries throughout the world.

Amaranth Seed Polyphenol, Fatty Acid and Amino Acid Profile

In this paper, the extraction of polyphenols from amaranth seed using a Box–Benhken design using four factors—ultra-turrax speed, solid-to-liquid ratio (RSL), methanol concentration and extraction time—were studied. There were two responses studied for the model: total phenolic content (TPC) and total flavonoid content (TFC). The factors which influenced the most the extraction of the TPC and TFC were the RSL, methanol concentration and ultra-turrax speed. Twelve phenolic acids (rosmarinic acid, p-coumaric acid, chlorogenic acid, vanillic acid, caffeic acid, p-hydroxybenzoic acid, protocatechuic acid and gallic acid) and flavonoids (kaempferol, quercetin, luteolin and myricetin) were studied, and the most abundant one was kaempferol followed by myricetin. The amaranth seed is a valuable source of fatty acids, and 16.54% of the total fatty acids determined were saturated fatty acids, while 83.45% of the fatty acids were unsaturated ones. Amaranth seed is a valuable source of amino acids, with 9 essential amino acids being reported: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine.

Features of Bread Made from Different Amaranth Flour Fractions Partially Substituting Wheat Flour

Amaranth flour (AF) is recognized as high-quality raw material regarding nutrients and bioactive compounds, essential in supplying human health benefits, compared with white flour (WF). In this study, the effects of factors, different particles sizes (large, medium, and small), and levels of AF (5, 10, 15, and 20%) substituting WF on the responses, empirical and dynamic dough rheological properties, and some quality parameters of bread were successfully modeled using predictive models. Finally, the optimization of a formulation to maximize the AF level whilst maintaining bread quality for each type of particle size (PS) was performed based on the response surface methodology models generated. The rheological properties of the composite flour formulated were evaluated using Mixolab, alveograph, rheofermentometer, and dynamic rheometer. In addition, bread quality parameters, loaf volume, instrumental texture features, and firmness were evaluated. The anticipation of the optimal value for each response in terms of dough rheological properties during mixing, protein weakening, starch gelatinization and retrogradation, biaxial extension, fermentation, viscoelastic moduli, and creep and recovery compliance depending on PS. The optimal addition level was determined by a multi-objective optimization approach. The optimal addition level was 9.41% for large, 9.39% for medium, and 7.89% for small PS. The results can help manufacturers to develop bread products with the desired particle size with optimal technological and physical features.

Functional Characterization of an Amaranth Natterin-4-Like-1 Gene in Arabidopsis thaliana

The functional characterization of an Amaranthus hypochondriacus Natterin-4-Like-1 gene (AhN4L-1) coding for an unknown function protein characterized by the presence of an aerolysin-like pore-forming domain in addition to two amaranthin-like agglutinin domains is herewith described. Natterin and nattering-like proteins have been amply described in the animal kingdom. However, the role of nattering-like proteins in plants is practically unknown. The results described in this study, obtained from gene expression data in grain amaranth and from AhN4L-1-overexpressing Arabidopsis thaliana plants indicated that this gene was strongly induced by several biotic and abiotic conditions in grain amaranth, whereas data obtained from the overexpressing Arabidopsis plants further supported the defensive function of this gene, mostly against bacterial and fungal plant pathogens. GUS and GFP AhN4L-1 localization in roots tips, leaf stomata, stamens and pistils also suggested a defensive function in these organs, although its participation in flowering processes, such as self-incompatibility and abscission, is also possible. However, contrary to expectations, the overexpression of this gene negatively affected the vegetative and reproductive growth of the transgenic plants, which also showed no increased tolerance to salinity and water-deficit stress. The latter despite the maintenance of significantly higher chlorophyll levels and photosynthetic parameters under intense salinity stress. These results are discussed in the context of the physiological roles known to be played by related lectins and AB proteins in plants.

Biochemistry of Amaranthus polyphenols and their potential benefits on gut ecosystem: A comprehensive review of the literature

ETHNOPHARMACOLOGICAL RELEVANCE

The genus Amaranthus is phytonutrients-rich plant distributed worldwide and has been recognized as having medicinal value in traditional use against several diseases and conditions. There are a large amount of research data on the polyphenol profiles of Amaranthus plants and their links with potential benefits against gastrointestinal disorders.

AIM OF THE REVIEW

This review article aims to provide a comprehensive review of Amaranthus phenolic compounds and their microbial metabolites, as well as the biological and/or pharmacological effects of those compounds/metabolites.

METHODOLOGY

The relevant information about the genus Amaranthus was collected from various sources and databases, including Google Scholar, Google Books, PubMed, Web of Science, Scopus, Science Direct, and other internet sources. The World Flora Online (2021) database was used to verify the scientific names of the plants.

RESULTS

Comprehensive review of identified compounds in Amaranthus plants revealed the presence of phenolic acids, flavonoids, and coumarins in each part of the plants. The biotransformation by gut microbiota enzymes prominently produces diverse bioactive metabolites that are potentially active than their precursors. Lines of the evidence support the beneficial roles of Amaranthus extracts in several gastrointestinal diseases, particularly with the polar extracts of several plant parts. Dietary fibers in Amaranthus plants also coordinate the alteration of gut microbiota-related metabolisms and may be beneficial to certain gastrointestinal disorders in particular, such as constipation.

CONCLUSIONS

Amaranthus plants are rich in polyphenols and dietary fibers. Several microbial metabolites are biologically active, so alteration of gut microbiota is largely linked to the metabolic feature of the plants. Based on the evidence available to date, several Amaranthus plants containing a combination of phytonutrients, particularly polyphenols and dietary fibers, may be a promising candidate that is of interest to be further developed for use in the treatment of certain gastrointestinal conditions/disorders.

Salinity differently affects antioxidant content and amino acid profile in two cultivars of Amaranthus cruentus differing in salinity tolerance

BACKGROUND

Amaranthus cruentus is a promising leafy vegetable with high nutritional value and is able to cope with salt stress but the impact of sodium chloride (NaCl) on its main properties have not been studied in detail. Plants from two contrasting cultivars (Rouge: salt-tolerant and Locale: salt-sensitive) were exposed to NaCl (0, 30, 60 and 90 mmol L^-1 ) in nutrient solution for 2 weeks. Plant growth, mineral content, oxidative status and antioxidant concentration, salicylic acid concentration, protein content and amino acid profile were analyzed in the harvested leaves.

RESULTS

Low dose (30 mmol L^-1 NaCl) increased plant growth while Na⁺ accumulated to higher extent in salt-sensitive Locale than in salt-tolerant Rouge. A total of 30 mmol L^-1 NaCl increased magnesium (Mg), phosphorus (P) and iron (Fe) content, as well as total antioxidant activity, ascorbate, phenolics, α-tocopherol and carotenoids content to higher extent in cultivar (cv.) Rouge than in cv. Locale. Low (30 mmol L^-1 ) and moderate salinities (60 mmol L^-1 ) increased γ-tocopherol and total protein in cv. Locale. They also increased lysine, valine, methionine and proline concentration as well as chemical score of protein in this cultivar. The highest NaCl (90 mmol L^-1 ) dose had a detrimental impact on both cultivars.

CONCLUSIONS

It is concluded that A. cruentus is a promising plant species for saline agriculture since moderate doses of salt improve both quantitative and qualitative parameters in cultivar dependent manner. © 2021 Society of Chemical Industry.

Optimisation of the ultrasound-assisted extraction of betalains and polyphenols from Amaranthus hypochondriacus var. Nutrisol

The present study optimised the ultrasound-assisted extraction (UAE) of bioactive compounds from Amaranthus hypochondriacus var. Nutrisol. Influence of temperature (25.86-54.14 °C) and ultrasonic power densities (UPD) (76.01-273.99 mW/mL) on total betalains (BT), betacyanins (BC), betaxanthins (BX), total polyphenols (TP), antioxidant activity (AA), colour parameters (L*, a*, and b*), amaranthine (A), and isoamaranthine (IA) were evaluated using response surface methodology. Moreover, betalain extraction kinetics and mass transfer coefficients (KLa) were determined for each experimental condition. BT, BC, BX, TP, AA, b*, KLa, and A were significantly affected (p < 0.05) by temperature extraction and UPD, whereas L*, a*, and IA were only affected (p < 0.05) by temperature. All response models were significantly validated with regression coefficients (R2) ranging from 87.46 to 99.29%. BT, A, IA, and KLa in UAE were 1.38, 1.65, 1.50, and 29.93 times higher than determined using conventional extraction, respectively. Optimal UAE conditions were obtained at 41.80 °C and 188.84 mW/mL using the desired function methodology. Under these conditions, the experimental values for BC, BX, BT, TP, AA, L*, a*, b*, KLa, A, and IA were closely related to the predicted values, indicating the suitability of the developed quadratic models. This study proposes a simple and efficient UAE method to obtain betalains and polyphenols with high antioxidant activity, which can be used in several applications within the food industry.

Integrating Omics and Gene Editing Tools for Rapid Improvement of Traditional Food Plants for Diversified and Sustainable Food Security

Indigenous communities across the globe, especially in rural areas, consume locally available plants known as Traditional Food Plants (TFPs) for their nutritional and health-related needs. Recent research shows that many TFPs are highly nutritious as they contain health beneficial metabolites, vitamins, mineral elements and other nutrients. Excessive reliance on the mainstream staple crops has its own disadvantages. Traditional food plants are nowadays considered important crops of the future and can act as supplementary foods for the burgeoning global population. They can also act as emergency foods in situations such as COVID-19 and in times of other pandemics. The current situation necessitates locally available alternative nutritious TFPs for sustainable food production. To increase the cultivation or improve the traits in TFPs, it is essential to understand the molecular basis of the genes that regulate some important traits such as nutritional components and resilience to biotic and abiotic stresses. The integrated use of modern omics and gene editing technologies provide great opportunities to better understand the genetic and molecular basis of superior nutrient content, climate-resilient traits and adaptation to local agroclimatic zones. Recently, realizing the importance and benefits of TFPs, scientists have shown interest in the prospection and sequencing of TFPs for their improvements, cultivation and mainstreaming. Integrated omics such as genomics, transcriptomics, proteomics, metabolomics and ionomics are successfully used in plants and have provided a comprehensive understanding of gene-protein-metabolite networks. Combined use of omics and editing tools has led to successful editing of beneficial traits in several TFPs. This suggests that there is ample scope for improvement of TFPs for sustainable food production. In this article, we highlight the importance, scope and progress towards improvement of TFPs for valuable traits by integrated use of omics and gene editing techniques.