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.

A short-term cooling of root-zone temperature increases bioactive compounds in baby leaf Amaranthus tricolor L

Leafy vegetables that are offered as seedling leaves with petioles are referred to as baby leaf vegetables. One of the most nutritious baby leaves, amaranth (Amaranthus tricolor L.), contains several bioactive compounds and nutrients. Here, we investigated the growth and quality of baby leaf amaranth using a variety of short-term cooling root-zone temperatures (RZT; 5, 10, 15, and 20°C), periods (1, 3, 5, and 7 days), and combinations thereof. We observed that exposing amaranth seedlings to RZT treatments at 5 and 10°C for 1-3 days increased the antioxidant capacity and the concentrations of bioactive compounds, such as betalain, anthocyanin, phenolic, flavonoid, and ascorbic acid; however, extending the treatment period to 7 days decreased them and adversely affected growth. For RZT treatments at 20°C, leaf photosynthetic pigments, bioactive compounds, nutrients, and antioxidant capacity increased gradually as the treatment period was extended to 7 days. The integration of RZTs at 5 and 10°C for one day preceded or followed by an RZT treatment at 20°C for 2 days had varied effects on the growth and quality of amaranth leaves. After one day of RZT treatment at 5°C followed by 2 days of RZT treatment at 20°C, the highest concentrations of bioactive compounds, nutrients, and antioxidant capacity were 1.4-3.0, 1.7, and 1.7 times higher, respectively, than those of the control, and growth was not impaired. The short-term cooling RZT treatments under controlled environments were demonstrated to be adequate conditions for the improvement of target bioactive compounds in amaranth baby leaf without causing leaf abnormality or growth impairment.

Enhancement of bioactive compounds in baby leaf Amaranthus tricolor L. using short-term application of UV-B irradiation

Baby-leaf vegetables are a trade name for leafy vegetables sold as leaves with petioles at the seedling stage. Amaranth (Amaranthus tricolor L.) is a nutritious baby-leaf vegetable containing many bioactive compounds. The effects of short-term ultraviolet B (UV-B) treatments on the growth and quality of baby leaf amaranth were studied, including the conditions of a 24-h recovery period after irradiation, and different irradiation intensities (3.0-9.0 W m^-2), irradiation periods (4-16 h), and cumulative energies (130-170 kJ m^-2). A recovery period experiment was conducted to observe the changes in the growth and quality of leaves at 0 and 24 h after UV-B irradiation. The results showed that the concentrations of phenolic compounds, flavonoids, anthocyanin, and ascorbic acid in the leaves, as well as the leaf antioxidant capacity increased 24 h after UV-B irradiation. Increases in target compound concentrations and antioxidant capacity without negative growth and appearance effects were observed in leaves irradiated with UV-B at 3, 6, and 9 W m^-2 for irradiation periods of 12 and 16, 8 and 12, and 4 h, respectively. The highest bioactive compound concentration was found in leaves irradiated with UV-B at 6 W m^-2 for 7 h (cumulative energy: 150 kJ m^-2). It was concluded that UV-B irradiation at 6 W m^-2 with a cumulative energy of 150 kJ m^-2 and a 24 h post-irradiation recovery period could be an appropriate treatment to increase bioactive compounds in baby leaf amaranth without causing appearance abnormalities.

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.

Antioxidant and alpha-glucosidase enzyme inhibitory properties of hydrolyzed protein and bioactive peptides of quinoa

The quinoa protein is gaining global attraction due to high content of gluten-free protein. It is a rich source of high-quality protein with all essential amino acids. The objective of this study was to evaluate the antioxidant activity and alpha-glucosidase inhibition effect of bioactive peptides obtained from quinoa protein that was hydrolyzed by alcalase and trypsin. Peptides were fractionated using ultrafiltration with MW cut-off = 3, 10 kDa. The peptide concentration was evaluated using OPA solution and peptide bonds were studied by SDS-PAGE. The highest antioxidant activity obtained from quinoa bioactive peptides by alcalase and trypsin was observed after 0.5 h (10 kDa≤) and 4 h (3 kDa≥), respectively. The highest α-glucosidase inhibition activity was observed in peptides with MW 3 kDa ≥ when hydrolyzed by trypsin. The amino acid composition of the most effective samples has been determined. Comparing the results showed that MW and the composition of peptides influenced the studied traits. From the result of this study, it concluded that bioactive peptides obtained from quinoa protein could be used in functional food and supplements formulation.

The nutraceutical properties and health benefits of pseudocereals: a comprehensive treatise

This review article depicts the possible replacement of staple cereal sources with some pseudocereals like Chia, Quinoa, Buckwheat, and Amaranth, which not only provide recommended daily allowance of all nutrients but also help to reduce the chances of many non-communicable infections owing to the presence of several bioactive compounds. These pseudocereals are neglected plant seeds and should be added in our routine diet. Besides, they can serve as nutraceuticals in combating various diseases by improving the health status of the consumers. The bioactive compounds like rutin, quercetin, peptide chains, angiotensin I, and many other antioxidants present in these plant seeds help to reduce the oxidative stress in the body which leads toward better health of the consumers. All these pseudocereals have high quantity of soluble fiber which helps to regulate bowel movement, control hypercholesterolemia (presence of high plasma cholesterol levels), hypertension (high blood pressure), and cardiovascular diseases. The ultimate result of consumption of pseudocereals either as a whole or in combination with true cereals as staple food may help to retain the integrity of the human body which increases the life expectancy by slowing down the aging process.

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.

Diabetes and seeds: New horizon to promote human nutrition and anti-diabetics compounds in grains by germination

Type 2 diabetes (T2D) is a complex and heterogeneous chronic metabolic disorder disease that is associated with high blood sugar. Because of the side effects of synthetic drugs on T2D patients and their economic burden, interest in plant-derived functional foods like grains with biological activities has developed. Based on scientific reports, whole grains are rich sources of energy, nutrients, and bioactive compounds and are assumed to have beneficial health effects on glucose enzymes regulation or hyperglycemia. Nowadays, different methods have been applied to enhance whole seed healthful properties and anti-diabetic compounds, and germination is one of them. Germination (sprouting) is a cost-effective method for boosting the activity of endogenous seed enzymes and modifying the structure of macromolecules. Some of these macromolecules like bioactive peptides, polyphenols, dietary fiber, and vitamins are related to diabetes management. Determining the best germination condition can help to promote these anti-diabetics properties of compounds. This study presents relevant information about diabetes, the effect of seed germination on releasing bioactive compounds, and optimizing environmental germination conditions to improve the anti-diabetic compounds in seeds for reaching functional food.

Amaranthus hypochondriacus L. as a Sustainable Source of Nutrients and Bioactive Compounds for Animal Feeding

With the aim to explore the use of A. hypochondriacus seeds for animal feeding, the agronomic traits, nutrients, and bioactive compounds of four accessions with different origin (India, Nebraska, Iowa, and Pennsylvania) grown in a Mediterranean environment were studied. Proximate composition was determined using the official methods of analyses, fatty acid profile by gas chromatography, total phenolic content (TPC) and the scavenging activity (DPPH• and ABTS•+) by colorimetric method. A one-way ANOVA model was performed to determine the differences between accessions. The four A. hypochondriacus accessions showed interesting seed yield results. No significant differences were observed for crude protein and crude fiber; the oil content showed the significant highest values in the seeds from Nebraska and Pennsylvania, but their nutritional characteristics were significantly different. The accession from Nebraska showed the highest oleic and linoleic acid levels, the highest values of polyunsaturated fatty acids, the best atherogenic and thrombogenic indices and hypocholesterolemic/hypercholesterolaemic ratio, and the highest TPC content. The accession from Pennsylvania showed the highest antioxidant activity and lowest peroxidation index. On the whole, A. hypochondriacus seeds can be used as pseudo-cereal to balance the animal diet and the accession should be chosen according to the different metabolic pathways of unsaturated fatty acids in ruminant and monogastric animals.

In Vitro Assay of Quinoa (Chenopodium quinoa Willd.) and Lupin (Lupinus spp.) Extracts on Human Platelet Aggregation

Cardiovascular disease (CVD) is the leading cause of death throughout the world. A major risk factor for CVD is platelet aggregation. Various plant extracts exhibit anti-aggregatory action in vitro. The dietary intake of traditional plant crops such as quinoa (Chenopodium quinoa Willd) and lupin (Lupinus spp., Fabaceae family), highly recognized for their high nutritional value, is increasing worldwide. The aim of the study was to assay possible antiplatelet effects of quinoa and lupin bean extracts in vitro. The proximate chemical composition of quinoa grains and the three most widely known lupin cultivars: blue (L. angustifolius), yellow (L. luteus or mutabilis) and white (L. albus) grown in Chile were analyzed. The anti-aggregation activity of the ethanol extracts of the crops was assayed using flow cytometry in ADP-stimulated human platelets, and their inhibition of the maximal platelet aggregation was measured. All the lupin extracts exhibited a significant anti-aggregatory effect (p < 0.0001), while quinoa extracts did not exert this effect compared to control platelets. In conclusion, lupin beans extracts exhibited an anti-aggregatory effect on activated human platelets.

Pseudocereals: a novel source of biologically active peptides

The interest in the research about underexploited foods has increased in the last two decades. Pseudocereals have been consumed by the ancient populations for hundreds of years. These plants that do not belong to the family of cereals, but that have properties and uses similar to them, stand out among underexploited foods. Some of the most representative species are quinoa, amaranth, chia and buckwheat. They do not contain gluten but high valued proteins and peptides can be obtained from them, as well as other nutritional and bioactive compounds such as flavonoids, phenolic acids, fatty acids, vitamins and minerals. Anticancer, antioxidant, anti-inflammatory, hypocholesterolemic and antihypertensive properties have been found and postulated for pseudocereals protein derived peptides. These interesting characteristics of pseudocereals are producing an increase of the relevance of these crops. The purpose of this work was to carry out an exhaustive revision of the scientific literature describing the biological activities of peptides and protein hydrolysates obtained from the most widely studied pseudocereals: quinoa, amaranth, chia and buckwheat.

Comparative Examination of Antioxidant Capacity and Fingerprinting of Unfractionated Extracts from Different Plant Parts of Quinoa (Chenopodium quinoa) Grown under Greenhouse Conditions

Integrated surveys of metabolic profiles and antioxidant capacity from Chenopodium quinoa have been limited and have particularly focused on an examination of seeds and leaves. According to this, the main aim of the present study was to address an evaluation of the antioxidant activity of crude ethanolic extracts from different plant parts (leaves, stems, roots, flowers, and seeds) harvested at different times during growth and processed by two distinct drying methods: Air-drying and freeze-drying. In order to characterize the resulting extracts, the total content of phenolics (TPC) and flavonoids (TFC) was then measured through the Folin–Ciocalteu method, while antioxidant capacity was determined using 2,2-diphenyl-1-picrylhydrazyl (DPPH^•) free radical scavenging and ferric-reducing antioxidant power (FRAP) methods. Parallel to this evaluation, extracts were profiled by LC-DAD-ESI-MS. Data analysis was supported by statistics. Most of the extracts obtained from freeze-dried samples showed higher TPC values ranging from 6.02 to 43.47 milligram of gallic acid equivalents per gram of plant material and a TFC between 1.30 and 12.26 milligram of quercetin equivalents per gram of plant material. After statistical analysis, a low correlation between TPC and TFC values was observed regarding antioxidant capacity from DPPH and FRAP measurements of both drying methods. A multivariate analysis showed that antioxidant components and antioxidant capacity in C. quinoa changed during growth and between plant parts and drying methods. These changes need to be taken into consideration when comparing the production/accumulation of beneficial bioactive compounds in this pseudocereal.

Antioxidant Activity and Phenolic Composition of Amaranth (Amaranthus caudatus) during Plant Growth

The antioxidant activity and phenolic composition of the aerial part of Amaranthus caudatus at seven stages of development were investigated. Total phenolic content, ABTS•+, DPPH•, and O2•- scavenging activity, ferric-reducing antioxidant power (FRAP), and Fe2+ chelating ability were evaluated. The phenolic profile was characterized by 17 compounds. Rutin was predominant in all growth stages, although its content, similar to the quantity of other phenolics, changed during the growth cycle. Flavonols were most abundant in the plants of early flowering and grain fill stages. In contrast, the highest content of hydroxycinnamic acid derivatives was found in the early vegetative stage. The results of antioxidant assays also showed significant differences among plant stages. Generally, the lowest antioxidant activity was found in the shooting and budding stages. Significantly higher activity was observed in amaranths in earlier (vegetative) and later (early flowering and grain fill) stages, suggesting that plants in these stages are valuable sources of antioxidants.

The effects of hydrolysis condition on antioxidant activity of protein hydrolyzate from quinoa

In the present study, quinoa protein hydrolyzate was prepared using alcalase and pepsin enzymes. Then, the effect of different temperatures (40, 45, 50, and 55°C), periods of time (60, 120, 150, 180, and 210 min), and the ratio of enzyme to substrate (30, 60, and 90 Anson unit/kg protein) on degree of hydrolysis were examined. Also, the antioxidant activity was assessed using DPPH radical scavenging test, and investigated using a completely randomized design. According to results, the optimum condition to produce hydrolyzates with the highest degree of hydrolysis (24.65%) was 55°C, 210 min, with ratio of enzyme to substrate of 60 Anson unit/kg protein, The highest antioxidant activity (35.44) of protein hydrolyzed was achieved at 150 min, 50°C, and the ratio of enzyme to substrate 60 (Anson unit/kg protein). Moreover, there was no significant (p > 0.05) between the level of hydrolysis and the antioxidant activity was among different time and temperatures. In conclusion, the peptide derived from quinoa protein showed a sufficient antioxidant activity to be incorporated in food products.

A virus-induced gene-silencing system for functional genetics in a betalainic species, Amaranthus tricolor (Amaranthaceae)

PREMISE OF THE STUDY

Research in Amaranthaceae could be accelerated by developing methods for targeted gene silencing. Most amaranths, including Amaranthus tricolor, produce betalains. However, the physiological and ecological roles of these pigments are uncertain. We sought to establish a virus-induced gene-silencing (VIGS) method for amaranths, using silencing of betalain pigments as a proof-of-principle.

METHODS

We targeted AtriCYP76AD1, a putative cytochrome P450 component of the betalain biosynthetic pathway, using VIGS, and compared two different methods of introducing the VIGS construct into plants. We measured transcript abundance and concentrations of betalains and their l-DOPA precursor in VIGS-treated plants, and compared these to controls.

RESULTS

We observed that when AtriCYP76AD1 was targeted by VIGS in normally red plants, AtriCYP76AD1 and the related genes AtriCYP76AD6 and AtriCYP76AD5 had diminished transcript abundance. Furthermore, newly emergent petioles and leaves of VIGS-treated plants appeared green, betacyanin accumulation was strongly reduced, and l-DOPA accumulation was increased. No betaxanthin could be detected in this variety of A. tricolor, either before or after VIGS treatment.

DISCUSSION

These results help to establish the genetic basis of betalain synthesis in amaranths. Furthermore, this is the first report of VIGS in amaranths and demonstrates the potential of this technique for basic and applied research in these species.

Characterization of quinoa (Chenopodium quinoa) fermented by Rhizopus oligosporus and its bioactive properties

Quinoa is a pseudocereal that contains high quality protein, minerals, vitamins, polyphenols, and phytosterols. In this study, quinoa was fermented by Rhizopus oligosporus (R. oligosporus) up to 5 days and the functional compounds (l-carnitine, GABA, vanillic acid and gallic acid) were analyzed by LC/MS. The amounts of l-carnitine and GABA were 0.13 mg/kg and 540 mg/kg for nonfermented quinoa (NF), 3.15 mg/kg and 1040 mg/kg for fermented quinoa at 3 days (3F), and 1.54 mg/kg and 810 mg/kg for fermented quinoa at 5 days (5F). The vanillic acid and gallic acid were 1.3 and 0.1 mg/kg for NF, 1.55 and 2.37 mg/kg for 3F, and 1.83 and 0.84 mg/kg for 5F, respectively. Total phenolic contents and total flavonoids contents were 41 mg gallic acid (GAE)/kg and 13 mg quercetin equivalent (QE)/kg for NF, 74 mg GAE/kg and 16 mg QE/kg for 3F, and 80 mg GAE/kg and 19 mg QE/kg for 5F, respectively. Antioxidant activity (SC₅₀) was 3.6 mg/mL for NF, 3.4 mg/mL for 3F, and 2.3 mg/mL for 5F. Nitric oxide production on RAW264.7 macrophages of fermented quinoa revealed 29% and 56% inhibition of nitric oxide production for NF and 5F, respectively. Therefore, fermented quinoa can be used as a healthy and valuable food product.

Quinoa bitterness: causes and solutions for improving product acceptability

Awareness of the several agronomic, environmental, and health benefits of quinoa has led to a constant increase in its production and consumption not only in South America, where it is a native crop, but also in Europe and the USA. However, producing wheat or gluten-free based products enriched with quinoa alters some quality characteristics, including sensory acceptance. Several anti-nutritional factors such as saponins are concentrated in the grain pericarp. These bitter and astringent substances may interfere with the digestion and absorption of various nutrients. Developing processes to decrease or modify the bitterness of quinoa can enhance palatability, and thus consumption, of quinoa. In addition to the production of sweet varieties of quinoa, other processes have been proposed. Some of them (i.e. washing, pearling and the combination of the two) have a direct effect on saponins, either by solubilization and/or the mechanical removal of seed layers. Others, such as fermentation or germination, are able to mask the bitterness with aroma compounds and/or sugar formation. This review presents the major sources of the undesirable sensory attributes of quinoa, including bitterness, and various ways of counteracting the negative characteristics of quinoa. © 2018 Society of Chemical Industry.

Characterization of quinoa seed proteome combining different protein precipitation techniques: Improvement of knowledge of nonmodel plant proteomics

A shotgun proteomics approach was used to characterize the quinoa seed proteome. To obtain comprehensive proteomic data from quinoa seeds three different precipitation procedures were employed: MeOH/CHCl3 /double-distilled H2 O, acetone either alone or with trichloroacetic acid; the isolated proteins were then in-solution digested and the resulting peptides were analyzed by nano-liquid chromatography coupled to tandem mass spectrometry. However, since quinoa is a nonmodel plant species, only a few protein sequences are included in the most widely known protein sequence databases. To improve the data reliability a UniProt subdatabase, containing only proteins of Caryophillales order, was used. A total of 352 proteins were identified and evaluated both from a qualitative and quantitative point of view. This combined approach is certainly useful to increase the final number of identifications, but no particular class of proteins was extracted and identified in spite of the different chemistries and the different precipitation protocols. However, with respect to the other two procedures, from the relative quantitative analysis, based on the number of spectral counts, the trichloroacetic acid/acetone protocol was the best procedure for sample handling and quantitative protein extraction. This study could pave the way to further high-throughput studies on Chenopodium Quinoa.

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

 A few decades ago Amaranthus was rediscovered as a most promising plant genus that may provide high-quality protein, unsaturated oil, and various other valuable constituents. Since then research has focused on various Amaranthus spp. and has been rapidly expanding, and a large number of reports have been published. Several review articles focusing on different aspects, such as botanical, agrotechnological, compositional, biological, chemical, and technological properties, as well as applications and health effects, have also been published since then. This comprehensive review is focused on amaranth composition, antioxidant properties, applications, and processing. The composition includes macrocomponets (lipids, proteins, carbohydrates, and dietary fiber) and other important constituents, such as squalene, tocopherols, phenolic compounds, phytates, and vitamins. These aspects of amaranth studies have not been comprehensively reviewed for a long time.