Key phytochemicals contributing to the bitterness of quinoa

Despite its nutritional components and potential health benefits, the bitterness of quinoa seed limits its utilization in the food industry. Saponins are believed to be the main cause of the bitterness, but it is still uncertain which specific compound is responsible. This study aimed to isolate the main components contributing to the bitterness in quinoa seed by solvent extraction and various column chromatography techniques guided by sensory evaluation. Five compounds were identified by mass spectrometry and nuclear magnetic resonance analyses, with the dose-over-threshold factors from 29.03 to 198.89. The results confirmed that triterpenoids are responsible for the bitter taste in quinoa seed, with phytolaccagenic acid derivatives being the primary contributor. Additionally, kaempferol 3-O-(2″, 6″-di-O-α-rhamnopyranosyl)-β-galactopyranoside (namely mauritianin), was demonstrated for the first time to be associated with the bitterness of quinoa. This study could provide new insight into the bitter compound identification in quinoa.

Analysis of widely targeted metabolites of quinoa sprouts (Chenopodium quinoa Willd.) under saline-alkali stress provides new insights into nutritional value

Quinoa sprouts are a green vegetable rich in bioactive chemicals, which have multiple health benefits. However, there is limited information on the overall metabolic profiles of quinoa sprouts and the metabolite changes caused by saline-alkali stress. Here, a UHPLC-MS/MS-based widely targeted metabolomics technique was performed to comprehensively evaluate the metabolic profiles of quinoa sprouts and characterize its metabolic response to saline-alkali stress. A total of 930 metabolites were identified of which 232 showed significant response to saline-alkali stress. The contents of lipids and amino acids were significantly increased, while the contents of flavonoids and phenolic acids were significantly reduced under saline-alkali stress. Moreover, the antioxidant activities of quinoa sprouts were significantly affected by saline-alkali stress. The enrichment analysis of the differentially accumulated metabolites revealed that flavonoid, amino acid and carbohydrate biosynthesis/metabolism pathways responded to saline-alkali stress. This study provided an important theoretical basis for evaluating the nutritional value of quinoa sprouts and the changes in metabolites in response to saline-alkali stress.

Protein extracts from amaranth and quinoa as novel fining agents for red wines

Due to allergenic concerns, only pea, potato, and wheat proteins have been approved as alternatives for replacing animal-based fining agents in wines. In pursuit of other substitutes, this work aimed to determine the fining ability of amaranth (Amaranthus caudatus L.) proteins (AP) in red wine, compared to quinoa (Chenopodium quinoa Willd.) (QP) and a commercial pea protein. Phenolic and volatile composition, as well as color characteristics, were analyzed. AP was as effective as QP at decreasing condensed tannins, with AP at 50 g/hL being the most effective treatment (25.6% reduction). QP and AP produced a minor or no statistical change in the total anthocyanins and wine color intensity. They reduced the total ester concentration, but the total alcohols remained unchanged. The outcomes of AP and QP were similar, and sometimes better than the pea proteins, thus suggesting that they could be promising options for the development of novel fining agents.

Encapsulation of chrysin and rutin using self-assembled nanoparticles of debranched quinoa, maize, and waxy maize starches

Chrysin and rutin are natural polyphenols with multifaceted biological activities but their applications face challenges in bioavailability. Encapsulation using starch nanoparticles (SNPs) presents a promising approach to overcome the limitations. In this study, chrysin and rutin were encapsulated into self-assembled SNPs derived from quinoa (Q), maize (M), and waxy maize (WM) starches using enzyme-hydrolysis. Encapsulation efficiencies ranged from 74.3 % to 79.1 %, with QSNPs showing superior performance. Simulated in vitro digestion revealed sustained release and higher antioxidant activity in QSNPs compared to MSNPs and WMSNPs. Variations in encapsulation properties among SNPs from different sources were attributed to the differences in the structural properties of the starches. The encapsulated SNPs exhibited excellent stability, retaining over 90 % of chrysin and 85 % of rutin after 15 days of storage. These findings underscore the potential of SNP encapsulation to enhance the functionalities of chrysin and rutin, facilitating the development of fortified functional foods with enhanced bioavailability and health benefits.

Refining quinoa storage stability through microwave-induced structural alterations and activity suppression of key enzymes

This study investigated the effects of microwave on preserving the quality of quinoa during storage. Quinoa treated with 9W/60s exhibited a significant decrease in fatty acid values compared to hot air treatment. Microwave effectively delayed lipid oxidation during quinoa storage by suppressing the increase in peroxide values. MDA gradually accumulated from peroxides during storage, reaching its peak at 0.423 μmol/L in the second week. Microwave disrupted the original hydrogen bonds in lipase, causing the unwinding of the α-helix and resulting in the loss of its regular structure. Microwave reduced the stability of the β-sheet structure in lipoxygenase, breaking the natural secondary structure composition. The observed fluorescence and UV spectra features were similar, indicating that microwave alter the peptide chain of the enzyme's skeletal structure, increasing the exposure of hydrophobic chromophores. These results indicated the potential of microwave to enhance the stability of quinoa during storage.

Potential structure-function relationships of pectic polysaccharides from quinoa microgreens: Impact of various esterification degrees

Pectic polysaccharides are one of the most vital functional ingredients in quinoa microgreens, which exhibit numerous health-promoting benefits. Nevertheless, the detailed information about the structure-function relationships of pectic polysaccharides from quinoa microgreens (QMP) remains unknown, thereby largely restricting their applications as functional foods or fortified ingredients. Therefore, to unveil the possible structure-function relationships of QMP, the mild alkali de-esterification was utilized to modify QMP, and then the correlations of esterification degrees of native and modified QMPs to their biological functions were systematically investigated. The results showed that the modified QMPs with different esterification degrees were successfully prepared by the mild alkali treatment, and the primary chemical structure (e.g., compositional monosaccharides and glycosidic linkages) of the native QMP was overall stable after the de-esterified modification. Furthermore, the results revealed that the antioxidant capacity, antiglycation effect, prebiotic potential, and immunostimulatory activity of the native QMP were negatively correlated to its esterification degree. In addition, both native and modified QMPs exerted immunostimulatory effects through activating the TLR4/NF-κB signaling pathway. These results are conducive to unveiling the precise structure-function relationships of QMP, and can also promote its applications as functional foods or fortified ingredients.

Change of physiochemical characteristics, nutritional quality, and volatile compounds of Chenopodium quinoa Willd. during germination

The impacts of varying germination periods (0-72 h) on morphological properties, proximate composition, amino acid profile, GABA levels, antioxidant attributes, polyphenol content (both free and bound), and volatile compounds of quinoa were evaluated. Germination significantly increased the content of fiber, amino acids, GABA, polyphenols, and in-vitro antioxidant activities in quinoa. The optimal nutritional quality and antioxidant capacity of quinoa were observed during the 36-72 h germination period. We examined the dynamics of 47 phenolic compounds in quinoa during germination and noted a substantial rise in free phenolic acids and bound flavonoids post-germination. A total of 53 and 84 volatile compounds were respectively identified in ungerminated quinoa and germinated quinoa. It was found that the germination period of 24-48 h contributed to reducing the presence of undesirable flavors. TEM analysis revealed significant structural damage to the ultrastructure and relaxation of the cell wall in germinated quinoa grains.

Elucidation of the beneficial role of co-fermented whole grain quinoa and black barley with Lactobacillus on rats fed a western-style diet via a multi-omics approach

Long-term consumption of Western-style diet (WSD) can lead to metabolic disorders and dysbiosis of gut microbiota, presenting a critical risk factor for various chronic conditions such as fatty liver disease. In the present study, we investigated the beneficial role of co-fermented whole grain quinoa and black barley with Lactobacillus kisonensis on rats fed a WSD. Male Sprague-Dawley (SD) rats, aged six weeks and weighing 180 ± 10 g, were randomly assigned to one of three groups: the normal control group (NC, n = 7), the WSD group (HF, n = 7), and the WSD supplemented with a co-fermented whole grain quinoa with black barley (FQB) intervention group (HFF, n = 7). The findings indicated that FQB was effective in suppressing body weight gain, mitigating hepatic steatosis, reducing perirenal fat accumulation, and ameliorating pathological damage in the livers and testicular tissues of rats. Additionally, FQB intervention led to decreased levels of serum uric acid (UA), aspartate aminotransferase (AST), and alanine aminotransferase (ALT). These advantageous effects can be ascribed to the regulation of FQB on gut microbiota dysbiosis, which includes the restoration of intestinal flora diversity, reduction of the F/B ratio, and promotion of probiotics abundance, such as Akkermansia and [Ruminococcus] at the genus level. The study employed the UPLC-Q-TOF-MSE technique to analyze metabolites in fecal and hepatic samples. The findings revealed that FQB intervention led to a regression in the levels of specific metabolites in feces, including oxoadipic acid and 20a, 22b-dihydroxycholesterol, as well as in the liver, such as pyridoxamine, xanthine and xanthosine. The transcriptome sequencing of liver tissues revealed that FQB intervention modulated the mRNA expression of specific genes, including Cxcl12, Cidea, and Gck, known for their roles in anti-inflammatory and anti-insulin resistance mechanisms in the context of WSD. Our findings indicate that co-fermented whole-grain quinoa with black barley has the potential to alleviate metabolic disorders and chronic inflammation resulting from the consumption of WSD.

Formation mechanism of quinoa protein hydrolysate-EGCG complexes at different pH conditions and its effect on the protein hydrolysate-lipid co-oxidation in emulsions

This study aimed to investigate the interaction, structure, antioxidant, and emulsification properties of quinoa protein hydrolysate (QPH) complexes formed with (-)-epigallocatechin gallate (EGCG) at pH 3.0 and 7.0. Additionally, the effect of pH conditions and EGCG complexation on protein hydrolysate-lipid co-oxidation in QPH emulsions was explored. The results indicated that QPH primarily interacted with EGCG through hydrophobic interactions and hydrogen bonds. This interaction led to alterations in the secondary structure of QPH, as well as a decrease in surface hydrophobicity and free SH content. Notably, the binding affinity between QPH and EGCG was observed to be higher at pH 7.0 compared to pH 3.0. Consequently, QPH-EGCG complexes exhibited more significant enhancement in antioxidant and emulsification properties at pH 7.0 than pH 3.0. The pH level also influenced the droplet size, ζ-potential, and interfacial composition of emulsions formed by QPH and QPH-EGCG complexes. Compared to QPH stabilized emulsions, QPH-EGCG stabilized emulsions were more capable of mitigating destabilization during storage and displayed fewer lipid oxidation products, carbonyl generation, and sulfhydryl groups and fluorescence loss, which implied better oxidative stability of the emulsions. Furthermore, the QPH-EGCG complexes formed at pH 7.0 exhibited better inhibition of protein hydrolysate-lipid co-oxidation. Overall, these findings provide valuable insights into the potential application of QPH and its complexes with EGCG in food processing systems.

Enrichment and Quantitation of Dipeptidyl Peptidase IV Inhibitory Peptides in Quinoa upon Systematic Malting

Food-derived peptides with an inhibitory effect on dipeptidyl peptidase IV (DPP-IV) can be used as an additive treatment for type 2 diabetes. The inhibitory potential of food depends on technological protein hydrolysis and gastrointestinal digestion, as the peptides only act after intestinal resorption. The effect of malting as a hydrolytic step on the availability of these peptides in grains has yet to be investigated. In this study, quinoa was malted under systematic temperature, moisture, and time variations. In the resulting malts, the DPP-IV inhibition reached a maximum of 45.02 (±10.28) %, whereas the highest overall concentration of literature-known inhibitory peptides was 4.07 μmol/L, depending on the malting parameters. After in vitro gastrointestinal digest, the inhibition of most malts, as well as the overall concentration of inhibitory peptides, could be increased significantly. Additionally, the digested malts showed higher values in both the inhibition and the peptide concentration than the unmalted quinoa. Concerning the malting parameters, germination time had the highest impact on the inhibition and the peptide concentration after digest. An analysis of the protein sizes before and after malting gave first hints toward the origin of these peptides, or their precursors, in quinoa.

The beneficial effects of quinoa seed extract supplementation on ram sperm quality following cryopreservation

Although cryopreservation is a reliable method used in assisted reproduction to preserve genetic materials, it can stimulate the occurrence of oxidative stress, which affects sperm structure and function. This research was conducted to explore the effects of quinoa seed extracts (QSE) on ram sperm quality, oxidative biomarkers, and the gene expression of frozen-thawed ram sperm. Semen samples were diluted in extenders supplemented with 0 (QSE0), 250 (QSE1), 500 (QSE2), 750 (QSE3), and 1000 (QSE4) µg of QSE /mL, and then frozen according to the typical procedure. The findings indicate that the QSE3 and QSE4 groups provided the optimal results in terms of sperm viability and progressive motility. Sperm kinematics were considerably enhanced in the QSE3 group compared to the other groups (P<0.01). QSE (500-1000 µg/mL) significantly decreased the apoptosis-like changes (higher viable and lower apoptotic sperm) in ram sperm (P<0.001). The percentage of live sperm with intact acrosomes was significantly increased, while the percentage of detached and intact acrosomes in live and dead sperm were significantly decreased respectively by the QSE addition (P<0.001). All QSE groups had higher TAC and lower MDA and H2O2 levels than the control group (P<0.001). The expressions of SOD1, CAT, GABPB1, and GPX1 genes in sperm samples were significantly increased, while the CASP3 gene was significantly decreased in all QSE-supplemented samples. Our data suggest that QSE has beneficial effects on sperm quality of cryopreserved ram semen, which are achieved by promoting sperm antioxidant-related genes and reducing apoptosis-related gene.

Physicochemical and functional properties of short-chain fatty acid starch modified with different acyl groups and levels of modification

Rice and quinoa starches are modified with short-chain fatty acids (SCFA) with different SCFA acyl chain lengths and levels of modification. This work is aimed to investigate the impact of modifying rice and quinoa starches with short-chain fatty acids (SCFAs) on various physicochemical properties, including particle size, protein and amylose content, thermal behavior, pasting characteristics, and in vitro digestibility. Both native and SCFA-starches showed comparable particle sizes, with rice starches ranging from 1.58 to 2.22 μm and quinoa starches from 5.18 to 5.72 μm. SCFA modification led to lower protein content in both rice (0.218-0.255 %) and quinoa starches (0.537-0.619 %) compared to their native counterparts. Esterification led to the reduction of gelatinization and pasting temperatures as well as the hardness of the paste of SCFA-starches were reduced while paste clarity increased. The highest level of modification in SCFA-starch was associated with the highest amount of resistant starch fraction. Principal component analysis revealed that modification levels exerted a greater influence on starch properties than the types of SCFA used (acetyl, propionyl, and butyryl). These findings is importance in considering the degree of substitution or level of modification when tailoring starch properties through SCFA modification, with implications for various applications in food applications.

Physicochemical properties of esterified/crosslinked quinoa starches and their influence on bread quality

BACKGROUND

Starch is the main component of quinoa seeds. However, quinoa starch has poor solubility in cold water and poor mechanical resistance and is easily aged, which limit its application. Therefore, modification of its structure to improve its functional properties is necessary.

RESULTS

This research used acetic anhydride and sodium trimetaphosphate to modify the structure of starch molecules and investigated their influence on bread quality. The results showed that both esterification and crosslinking prevented the aggregation behavior of starch molecules. Moreover, they both decreased the gelatinization enthalpy change and relative crystallinity of the starch. Compared with native starch, modification significantly decreased the gelatinization temperature from 57.01 to 52.01 °C and the esterified starch exhibited the lowest enthalpy change with a 44.2% decrease. Modified starch increased the specific volume and decreased the hardness and chewiness of bread. Modification did not influence the moisture content in bread but impacted the water retention capacity, depending on the degree of modification. Low and medium degrees of modification improved the water retention capacity during storage. By contrast, a high degree of modification (10 g kg-1 crosslinking agent) decreased the water retention capacity. The dually modified quinoa starch (esterified and crosslinked) showed no influence on the textural properties of bread.

CONCLUSION

This study demonstrated that both esterification and crosslinking significantly improved the functional properties of quinoa starch. Crosslinked or esterified quinoa starches have the potential to improve the textural properties of bakery products. © 2024 Society of Chemical Industry.

Fermentation enrichment, structural characterization and immunostimulatory effects of β-glucan from Quinoa

We developed an efficient mixed-strain co-fermentation method to increase the yield of quinoa β-glucan (Q+). Using a 1:1 mass ratio of highly active dry yeast and Streptococcus thermophilus, solid-to-liquid ratio of 1:12 (g/mL), inoculum size of 3.8 % (mass fraction), fermentation at 32 °C for 27 h, we achieved the highest β-glucan yield of (11.13 ± 0.80)%, representing remarkable 100.18 % increase in yield compared to quinoa β-glucan(Q-) extracted using hot water. The structure of Q+ and Q- were confirmed through Fourier Transform Infrared (FTIR) and Nuclear Magnetic Resonance (NMR) spectroscopies. Q+ contained 41.66 % β-glucan, 3.93 % protein, 2.12 % uronic acid; Q- contained 37.21 % β-glucan, 11.49 % protein, and 1.73 % uronic acid. The average molecular weight of Q+(75.37 kDa) was lower than that of Q- (94.47 kDa). Both Q+ and Q- promote RAW264.7 cell proliferation without displaying toxicity. They stimulate RAW264.7 cells through the NF-κB and MAPK signaling pathways, primarily inducing NO and pro-inflammatory cytokines by upregulating CD40 expression. Notably, Q+ exhibited stronger immunostimulatory activity compared to Q-. In summary, the fermentation enrichment method yields higher content of quinoa β-glucan with increased purity and stronger immunostimulatory properties. Further study of its bioimmunological activity and structure-activity relationship may contribute to the development of new immunostimulants.

Does saponin in quinoa really embody the source of its bitterness?

While it is widely reported that saponins are the main source of the bitter taste in quinoa, this work found that some saponin compounds in quinoa husks elicit an umami response. The saponins were analyzed qualitatively and quantified by mass spectrometry (UPLC-MS). Two quinoa saponin compounds RT 46 (3-O-β-d-glucopyranosyl-(1 → 3)-α-l-arabino-pyranosyl-phytolaccagenic acid 28-O-β-d-gluco-pyranosyl), and RT 53 (3-O-β-d-glucopyranosyl-(1 → 4)-β-d-glucopyranosyl-28-O-hederagenin) were isolated from quinoa husks through separation and purification. According to eletronic tongue, the main taste response for those compounds was umami. It was found that the two quinoa saponins could bind to sweet and umami receptors. Besides saponins, various flavonoids and polyphenols also appeared in the UPLC-MS spectrum of crude saponins. The electronic tongue and sensory evaluation revealed that flavonoids and polyphenols showed obvious bitterness and astringency at very low concentrations. The study inferred that flavonoids and polyphenols are the main compounds that generate quinoa's bitter taste.

Transcriptome Analysis Reveals the Mechanisms of Accumulation and Conversion of Folate Derivatives during Germination of Quinoa (Chenopodium quinoa Willd.) Seeds

Folate was enriched during quinoa germination, while molecular mechanisms were not well understood. In this study, three quinoa varieties were selected for germination, and changes in substrate content and enzyme activity of the folate biosynthesis pathway were monitored. 5-Methyltetrahydrofolate (5-CH3-THF) and 5-formyltetrahydrofolate (5-CHO-THF) were significantly enriched in quinoa sprouts. Among the selected varieties, QL-2 exhibited the lowest content of the oxidation product MeFox and the highest total folate content. Based on transcriptome analysis, the p-ABA branch was found to be crucial for folate accumulation, while the pterin branch served as a key control point for the one carbon pool by folate pathway, which limited further folate biosynthesis. In the one carbon pool by folate pathway, genes CqMTHFR and CqAMT significantly contributed to the enrichment of 5-CH3-THF and 5-CHO-THF. Findings gained here would facilitate the potential application of quinoa sprouts as an alternative strategy for folate supplementation.

Flours from fermented lentil and quinoa grains as ingredients with new techno-functional properties

The need to provide novel, nutritious plant-based products requires seeking high-value, sustainable protein sources, like quinoa and lentils, having an increased digestibility and lacking antinutrients. Fungal fermentation has evidenced enhanced nutritional value of flours obtained from these grains. However, research into techno-functional properties, essential to the new product development, is lacking. This study investigated the techno-functional properties of flours made from lentil and quinoa after fermenting them with Pleurotus ostreatus and subjecting them to two drying techniques (lyophilisation and hot air drying). In both cases, the fermentation led to noteworthy improvements in swelling and water holding capacity, especially in those lyophilised than those dried. In contrast, the emulsifying, foaming, thickening, and gelling capacities decreased significantly. The loss of abilities was more severe for dried grains than for lyophilized ones. The thermomechanical analysis of the fermented flours showed lower thickening and gelling potential compared to untreated flours. Microscopy images revealed that the state and structure of starch granules were affected by both fermentation and drying processes. Starch granules in lentils were partly pre-gelatinised and trapped in the cotyledon cell, resulting in limited thickening and gelling abilities. In contrast, in quinoa, starch underwent pre-gelatinisation and retrogradation during the fermentation process, promoting the production of resistant starch and increasing fibre content. This study presents the potential of treated flours as ingredients possessing unique attributes compared to protein and fibre-rich conventional products.

Structural, physicochemical properties and noodle-making potential of quinoa starch and type 3, type 4, and type 5 quinoa resistant starch

This study prepared type 3, type 4, and type 5 quinoa resistant starch (QRS3, QRS4, and QRS5) from quinoa starch (QS), compared their structural and physicochemical properties and evaluated their noodle-making potential. The results showed that the molecular weight of QRS3 decreased, the number of short-chain molecules increased, and its crystal type changed to B-type after gelatinization, enzymatic hydrolysis, and retrogradation. QRS4 is a phosphorylated cross-linked starch, with a surface morphology, particle size range, and crystal type similar to QS, but displaying modified thermodynamic properties. QRS5 is a complex of amylose and palmitic acid. It displays typical V-type crystals, mainly composed of long chain molecules and primarily exhibits a block morphology. The noodles prepared by replacing 20 % wheat flour with QS, QRS3 and QRS5 have higher hardness and are suitable for people who like elasticity and chewiness. QRS4 noodles are softer and suitable for people like elderly and infants who prefer soft foods. In conclusion, significant differences were evident between the fine structures, crystal types, physicochemical properties and potential applications of QS and the three QRSs. The results may expand the application of QS and QRS in the food and pharmaceutical industries.

Nutritional composition of quinoa leafy greens: An underutilized plant-based food with the potential of contributing to current dietary trends

Quinoa (Chenopodium quinoa Willd.) leafy greens (QLGs) are plant-based foods of high nutritional value that have been scarcely studied. In this work, the nutritional and functional composition of three QLGs varieties was evaluated. A protein content higher than 35 g 100 g-1 dw with a well-balanced essential amino acid composition was found making them a good source of vegetable protein. In addition, elevated contents of dietary fibre and minerals, higher than those detected in quinoa seeds and other leafy vegetables, were found. The lipid profile showed higher contents of linoleic (C18:2, ω6) (20.2 %) and linolenic acids (C18:3, ω3) (52.8 %) with low ω6/ ω3 ratios (∼0.4/1). A total sugar content <1 g 100 g-1 dw was found for all varieties tested, lower than that obtained in seeds. The saponin content varied between 0.76 and 0.87 %. Also, high values of total phenolic compounds (969.8-1195.4 mg gallic acid 100 g-1), mainly hydroxycinnamic acids and flavonoids, and great antioxidant activities (7.64-8.90 g Trolox kg-1) were found. Multivariate analysis here used allowed us to classify the samples according to the quinoa variety evaluated, and the sequential stepwise multiple regression applied revealed that the PUFA and sucrose contents negatively influenced the protein content while the palmitic acid content affected positively this parameter. Overall, this study shows that QLGs are promising nutritious and functional plant-based foods supporting the necessity of promoting their cultivation, commercialization, and consumption.

Controlled oxidation and digestion of Pickering emulsions stabilized by quinoa protein and (-)-epigallocatechin-3-gallate (EGCG) hybrid particles

In this study, we prepared Pickering emulsions stabilized by quinoa protein isolate (QPI) and (-)-epigallocatechin-3-gallate (EGCG) non-covalent hybrid particles using ultrasonic emulsification technique and demonstrated lipid oxidation and in vitro digestion process of Pickering emulsions. The interaction forces between QPI and EGCG were characterized using fluorescence spectroscopy, isothermal titration calorimetry, and Fourier transform infrared spectroscopy. Results indicated that the non-covalent QPI/EGCG hybrid particles were formed mainly via hydrophobic interactions, hydrogen bonds, and electrostatic interactions at pH 5. Then, the QPI/EGCG non-covalent hybrid particles were applied to modify the Pickering emulsion with ultrasonic homogenization. The rheological experimental results showed that the energy storage modulus (G') was higher than the loss modulus (G″), indicating that the emulsion had solid-like properties. As a physical barrier, interfacial layer fabricated by antioxidant QPI/EGCG hybrid particles limited lipid oxidation at 60 °C for 15 days. At 37 °C, the QPI/EGCG hybrid particles stabilized Pickering emulsions with robust antioxidant interfacial structure limited the lipid digestion under simulated gastrointestinal tract (gastric, small intestine phases). Thus, EGCG and quinoa proteins were more resistant to free radical oxidation and gastrointestinal digestion with the assistance of ultrasound. It provides a basis for better development of food and drug delivery systems by fully utilizing the antioxidant properties of plant polyphenols.

Quinoa protein Pickering emulsion improves the freeze-thaw stability of myofibrillar protein gel: Maintaining protein composition, structure, conformation and digestibility and slowing down protein oxidation

In this work, the effects of quinoa protein Pickering emulsion (QPPE) on protein oxidation, structure and gastrointestinal digestion property of myofibrillar protein gels (MPGs) after freeze-thaw (F-T) cycles are revealed. SDS-PAGE results indicated that 5.0 %-10.0 % QPPE addition slowed down the protein degradation. Meanwhile, 5.0 %-7.5 % QPPE maintained the stability of the protein secondary and tertiary structure of MPGs after F-T cycles. The sulfhydryl group, disulfide bond and dityrosine content increased with QPPE supplementation. The conformations of disulfide bond changed from g-g-t and t-g-t to g-g-g after F-T cycles, and 5.0 %-7.5 % QPPE stabilized the changes of t-g-t conformation. Furthermore, the increase of dityrosine content after F-T cycles was significantly reduced with 7.5 % QPPE addition, indicating its effect to slow down protein oxidation of MPGs. In addition, MPGs with 5.0 % and 7.5 % QPPE showed noticeably higher zeta potential values than other groups, indicating the enhanced electrostatic repulsion and weakened aggregation caused by F-T damage. This work showed that 7.5 % QPPE improved the F-T stability of MPGs and reduced the protein denaturation and oxidation caused by F-T treatments, exerting no side effect on the digestion property of MPGs. QPPE can be used as a green and effective antifreeze in meat industry.

Effect of Starch on the Solubility of Quinoa Protein Isolates during Heat Treatment

There is increasing interest in developing quinoa products due to their unique nutritional value. Starch and protein are the primary components in quinoa, and the interaction between them affects the quality of quinoa products. This study extracted the starch and protein from quinoa and simulated the thermal processing of quinoa to investigate the effects of starch on the solubility and structure of quinoa protein isolates during heat treatment. The structure of quinoa protein isolates was characterized by fluorescence spectroscopy, Fourier transform infrared spectroscopy, laser particle size analysis, and scanning electron microscopy. The results showed that starch decreased protein solubility, and the maximum solubility was obtained after heating for 5 min. After starch addition during heat treatment, the surface charge distribution of protein changed, the degree of protein aggregation increased, the particle size of proteins increased, the thermal stability increased, and the β-sheet ratio of the proteins increased, suggesting that the protein structure is more ordered, which is the structural foundation of protein solubility decreasing. The research about the interaction between starch and protein and the effects on the solubility of protein could provide a reference for quinoa products processing.

The potential of young vegetative quinoa (Chenopodium quinoa) as a new sustainable protein-rich winter leafy crop under Mediterranean climate

The demand for protein products has significantly risen in the last few years. In western countries, animals are the primary source of protein; however, plants could take a share of this market due to lower production costs, among other advantages such as a lower environmental footprint. Quinoa (Chenopodium quinoa Willd.) is a well-known but under-utilized protein-rich crop, commonly cultivated for grain production. These plants were recently evaluated for their use as a non-traditional, green leafy crop. Here we assessed the potential of young vegetative quinoa as a new sustainable winter leafy crop in Israel-serving as a model for Mediterranean semi-arid regions, by evaluating yield, protein content and quality. Five quinoa accessions were sown on three winter sowing dates over two consecutive years. Plants were harvested when they reached 10% dry matter (DM). DM yield ranged between 574 and 1,982 kg ha-1 and was generally higher in the second year. Protein content ranged from 14.4-34% and was generally higher in the first year. Protein yield ranged from 111-471 kg ha-1 and was greatest on the December sowing date. DM and protein yields were positively correlated with plant density. Protein content was negatively correlated with plant density and DM yield. Our findings show that 200 g DM of young vegetative quinoa can meet the protein and most essential amino acid requirements for a 70 kg human adult. Prospects for cultivating young vegetative quinoa in Mediterranean countries as a new sustainable, protein-rich winter leafy crop are therefore high, as supported by its high protein yields and quality, and its requirement for only scant irrigation. Further studies should examine economic and other agrotechnical parameters toward the geographical distribution and expansion of young vegetative quinoa cultivation.

Quinoa germ-enriched pasta: Technological, nutritional, textural, and morphological properties

Germ is the most significant component of quinoa having good nutritional value. Quinoa germ (QG), with balanced amino acid profile and unsaturated fatty acid, is a unique ingredient for human nutrition. In present study, pasta supplemented with QG was characterized for physical, nutritional, morphological, and textural properties. Dough rheology showed increased farinograph water absorption and decreased dough stability with the addition of QG. Addition of QG up to 30% significantly improved the pasta protein content from 13.55% to 20.55%. The substitution of QG to pasta showed decrease in whiteness index and increase in optimum cooking time, swelling index, cooked weight, and cooking loss. It is reported that 20% QG supplement pasta was found to be acceptable; beyond, this level the pasta quality was inferior. Firmness value of pasta significantly increased up to 20% supplementation of QG from 157 to 178 g. The micrographs of pasta with the addition of QG observed increased protein matrix around the starch granules. The results inferred that the QG can serve as a potential functional ingredient for the development of nutritionally enhanced pasta for food industry. PRACTICAL APPLICATION: Quinoa germ (QG) is concentrated source of nutrient with unique nutrition and alternative source of protein. Pasta is the one the popular and fast-growing food in world and explored for enhancement of its nutritional composition to target a larger population with specific nutrient demand. Hence, pasta becomes important vehicle for the supplementation. Developed QG-enriched high-protein pasta will help industry to produce nutritious products at large scale.

Influence of in vitro gastrointestinal digestion and colonic fermentation on carbonyl scavenging capacity of fiber-bound polyphenols from quinoa

Whole grain insoluble dietary fiber (IDF) is a good source of bound-form polyphenols. In the present study, insoluble dietary fiber rich in bound polyphenols (BP-IDF) from quinoa, rye and wheat was prepared. The carbonyl scavenging capacities of these three BP-IDFs and the effects of in vitro gastrointestinal (GI) digestion and colonic fermentation on their scavenging activities were studied. The results indicated that the fiber-bound polyphenols from quinoa showed the highest carbonyl scavenging capacity compared to those from rye and wheat. After colonic fermentation, more than 73% of the bound polyphenols were still retained in the fermented residues of the quinoa BP-IDF. The fiber-bound polyphenols in the GI-digested residues of quinoa retained considerable carbonyl scavenging activities. During the fermentation process, the residual fiber-bound polyphenols in the fermented residues still scavenged 35.8% to 45.2% of methylglyoxal, 19.3% to 25.4% of glyoxal, 50.7% to 60.5% of acrolein and 5.2% to 9.7% of malondialdehyde, showing a critical role in the scavenging of carbonyl compounds compared to the released and metabolized polyphenols. These findings confirm the capacity of fiber-bound polyphenols from three whole grains to scavenge carbonyls during in vitro digestion and fermentation processes, suggesting that they could be used as functional ingredients to maintain continuous defenses against carbonyls along the digestive tract.

Synergistic improvement of quinoa protein heat-induced gel properties treated by high-intensity ultrasound combined with transglutaminase

BACKGROUND

Quinoa protein is enriched with a wide range of amino acids, including all nine essential amino acids necessary for the human body, and in appropriate proportions. However, as the main ingredient of gluten-free food, it is difficult for quinoa to form a certain network structure for lack of gluten protein. The aim of this work was to enhance the gel properties of quinoa protein. Therefore, the texture characteristics of quinoa protein treated with different ultrasound intensities coupled with transglutaminase (TGase) were investigated.

RESULTS

The gel strength of quinoa protein gel increased markedly by 94.12% with 600 W ultrasonic treatment, and the water holding capacity increased from 56.6% to 68.33%. The gel solubility was reduced and free amino content increased the apparent viscosity and the consistency index. Changes in the free sulfhydryl group and hydrophobicity indicated that ultrasound stretched protein molecules and exposed active sites. The enhanced intrinsic fluorescence intensity at 600 W demonstrated that ultrasonic treatment affected the conformation of quinoa protein. New bands emerged in sodium dodecylsulfate-polyacrylamide gel electrophoresis indicating that high-molecular-weight polymers were generated through TGase-mediated isopeptide bonds. Furthermore, scanning electron microscopy showed that the gel network structure of TGase-catalyzed quinoa protein was more uniform and denser, thereby improving the gel quality of quinoa protein.

CONCLUSION

The results suggested that high-intensity ultrasound combined with TGase would be an effective way to develop higher-quality quinoa protein gel. © 2023 Society of Chemical Industry.

Characterization of the aroma profile of quinoa (Chenopodium quinoa Willd.) and assessment of the impact of malting on the odor-active volatile composition

BACKGROUND

Quinoa (Chenopodium quinoa Willd.) is a gluten-free pseudocereal, rich in starch and high-quality proteins. It can be used as a cereal. Recently, a variety of nontraditional food products were developed; however, the sharp bitterness and the earthy aroma of unprocessed quinoa interfered with the acceptance of these products. Malting of cereals is known to improve their processing properties and enhance their sensory quality. To evaluate the acceptance and potential of quinoa malt as a raw material for beverage production, malt quality indicators (e.g., soluble protein) and the aroma profiles of different quinoa malts were compared.

RESULTS

Initial sensory assessment of quinoa in its native and malted state identified differences in their aroma profiles and revealed that pleasant nutty and caramel aromas were formed by malting. Subsequently, three complementary isolation techniques and gas chromatography-olfactometry/mass spectrometry (GC-O/MS) were used for volatile analysis. Instrumental analysis detected 34 and 62 odor-active regions in native quinoa and quinoa malt, respectively. In the second part, storage and the impact of three malting parameters on volatile formation were examined. By varying the malting parameters, seven additional odor-active malting byproducts were revealed.

CONCLUSION

Three naturally occurring methoxypyrazines were identified as important contributors to the characteristic quinoa aroma. In all fresh quinoa malts a similar number of volatile compounds was perceived but their intensity and composition varied. Higher germination temperature promoted the formation of lipid oxidation products. Fatty smelling compounds and carboxylic acids, formed during storage, were classified as aging indicators of quinoa malt. © 2022 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Ultrasonic treatment influences the compactness of quinoa protein microstructure and improves the structural integrity of quinoa protein at the interfaces of high internal phase emulsion

For native quinoa protein with a loose disordered structure and low structural integrity, once the protein is absorbed to the oil-water interface, the stress of interfacial tension and hydrophobic interaction can easily trigger the conformation change and denaturation of quinoa protein, leading to the instability of high internal phase emulsion (HIPE). Ultrasonic treatment can induce the refolding and self-assembling of quinoa protein microstructure, which is expected to frustrate the disruption of protein microstructure. The particle size, tertiary structure, and secondary structure of quinoa protein isolate particle (QPI) were investigated by multi-spectroscopic technology. The study demonstrates that QPIs prepared with ultrasonic treatment of 5 kJ/mL exhibit more robust structural integrity compared with native QPIs. The relatively loose structure (random coil, 28.15 ± 1.06 %∼25.10 ± 0.28 %) transformed to a more ordered and compact form (α-helix, 5.65 ± 0.07 %∼6.80 ± 0.28 %). Through the addition of QPI-based HIPE as an alternative for commercial shortening, the specific volume of white bread was increased (2.74 ± 0.35 ∼ 3.58 ± 0.04 cm³/g).

The effects of quinoa and okra incorporation on the quality of diet cake

Producing quality products in baking industry has been facing several challenges including meeting the needs of the growing population, lack of sufficient water resources for producing enough wheat, lack of quality products made from wheat flour and high amount of waste. Recently, the quality of baking products has been improved by mixing different types of flour, which increases the nutritional value and improves the quality of the final product. This study evaluates the possibility of making a cake by incorporating wheat flour with quinoa and okra flour. Moreover, basil gum is used to improve the gluten network. The cake samples were prepared with quinoa flour at two levels (15 and 30%), okra flour at two levels (0.8 and 0.16%) and basil gum at a level of 0.4%; finally, their physicochemical, rheological, SEM, and sensory properties were evaluated. Based on the results, adding quinoa and okra flour and basil gum increases the density and consistency of the batter. Hardness, springiness, chewiness, cohesiveness, and adhesiveness of the blend Q2B1R was improved. The granule structure of the quinoa flour cakes were affected, and the gluten network was not well formed as shown in the electron microscopy images. However, the gluten network was improved in the samples with 0.4% basil gum and 0.8% okra flour. By adding okra and quinoa, better specific volume, porosity, and moisture content was obtained. Sensory evaluation of the cakes indicated that the blend Q2B1R was scored close to the control sample.

Purification of an antiviral protein from the seeds of quinoa (Chenopodium quinoa Willd.) and characterization of its antiviral properties

Plant viral pathogens cause damaging diseases in many agriculture systems, and emerging viral infections are a serious threat for providing adequate food to a continuously growing population. Recent studies of biogenic substances have provided new opportunities for producing novel antiviral agents. The present work has been conducted to evaluate the antiviral activity of quinoa (Chenopodium quinoa Willd.) seeds crude extract. The antiviral activity was retained in different buffer solutions of various pH ranges (5.2-8.5) and remained after the diafiltration process. The putative virus inhibitor was sensitive to treatment with sodium dodecyl sulfate and trichloroacetic acid. An antiviral protein with ~ 25 kDa molecular weight was isolated from the seed quinoa extract using ammonium sulfate precipitation, anion and cation exchange chromatography. The purified protein (Quinoin-I) significantly inhibited TMV on tobacco leaves with an IC₅₀ value at a 6.81 μg/ml concentration. Enzyme activity assay revealed the RNase activity of Quinoin-I, and this feature was retained in the presence of β-mercaptoethanol and ethylene diamine tetraacetic acid. This antiviral protein has been shown as a promising leading molecule for further development as a novel antiviral agent.

Metabolome and transcriptome profiles in quinoa seedlings in response to potassium supply

BACKGROUND

Quinoa (Chenopodium quinoa Willd.) is a herb within the Quinoa subfamily of Amaranthaceae, with remarkable environmental adaptability. Its edible young leaves and grains are rich in protein, amino acids, microorganisms, and minerals. Although assessing the effects of fertilization on quinoa yield and quality has become an intensive area of research focus, the associated underlying mechanisms remain unclear. As one of the three macro nutrients in plants, potassium has an important impact on plant growth and development. In this study, extensive metabolome and transcriptome analyses were conducted in quinoa seedlings 30 days after fertilizer application to characterize the growth response mechanism to potassium.  RESULTS: The differential metabolites and genes present in the seedlings of white and red quinoa cultivars were significantly enriched in the photosynthetic pathway. Moreover, the PsbQ enzyme on photosystem II and delta enzyme on ATP synthase were significantly down regulated in quinoa seedlings under potassium deficiency. Additionally, the differential metabolites and genes of red quinoa seedlings were significantly enriched in the arginine biosynthetic pathway.

CONCLUSIONS

These findings provide a more thorough understanding of the molecular changes in quinoa seedlings that occur under deficient, relative to normal, potassium levels. Furthermore, this study provides a theoretical basis regarding the importance of potassium fertilizers, as well as their efficient utilization by growing quinoa seedlings.

Biological functions of active ingredients in quinoa bran: Advance and prospective

Quinoa is known to be a rich source of nutrients and bioactive components. Quinoa bran, used mainly as animal feed in processing by-products, is also a potential source of bioactive ingredients being conducive to human health. The importance of nutrition and function of quinoa seed has been discussed in many studies, but the bioactive properties of quinoa bran often are overlooked. This review systemically summarized the progress in bioactive components, extraction, and functional investigations of quinoa bran. It suggests that chemically assisted electronic fractionation could be used to extract albumin from quinoa bran. Ultrasound-assisted extraction method is a very useful method for extracting phenolic acids, triterpene saponins, and flavonoids from quinoa bran. Based on in vitro and in vivo studies for biological activities, quinoa bran extract exhibits a wide range of beneficial properties, including anti-oxidant, anti-diabetes, anti-inflammation, anti-bacterial and anti-cancer functions. However, human experiments and action mechanisms need to investigate. Further exploring quinoa bran will promote its applications in functional foods, pharmaceuticals, and poultry feed in the future.

Microwaving released more polyphenols from black quinoa grains with hypoglycemic effects compared with traditional cooking methods

BACKGROUND

Polyphenols were reported to exhibit inhibitory effects on digestive enzymes to regulate carbohydrates and lipid digestion. However, different cooking methods might cause differences in the composition of polyphenols in cereal grains and thus further affect their activities.

RESULTS

The present study used boiling, roasting and microwaving to cook black quinoa and extracted polyphenols from them. Their total phenolic content (TPC) and total flavonoids content were determined, and phenolic composition was analyzed via high-performance liquid chromatography-mass spectrometry (HPLC-MS). Compared with other cooking methods, phenolic extract from microwaved black quinoa (PEM) showed the highest TPC value (about 2.64 mg GAE g^-1 ). Microwaving released more phenolic acids (ferulic acid and gallic acid) from black quinoa grains. PEM also exhibited the strongest antioxidant and α-glucosidase inhibitory activities. Lineweaver-Burk plots showed that PEM inhibited α-glucosidase in an uncompetitive mode, which was supported by circular dichroism analysis. PEM further reduced about 20.04% of digested starch in an in vitro digestion model and suppressed postprandial blood glucose increases (about 16.91% reduction) in vivo.

CONCLUSION

Collectively, our data suggested that microwaving could be an ideal method to cook quinoa in regards of its polyphenols in management of postprandial blood glucose. © 2022 Society of Chemical Industry.

Innovatively processed quinoa (Chenopodium quinoa Willd.) food: chemistry, structure and end-use characteristics

BACKGROUND

Quinoa (Chenopodium quinoa Willd.) flour and processed traditional Peruvian quinoa breakfast foods were studied to evaluate the effect of extrusion and post-processing on protein properties, morphology and nutritional characteristics (amino acids and dietary fibers).

RESULTS

The extrusion increased quinoa protein crosslinking and aggregation observed by size exclusion high-performance liquid chromatography and the amount of soluble fibers, as well as decreasing the amounts of insoluble fibers in the processed foods. The post-processing drying resulted in additional crosslinking of large protein fractions in the quinoa products. The microstructure of the extruded quinoa breakfast flakes and heat-post-processed samples studied by scanning electron microscopy and X-ray tomography differed greatly; post-drying induced formation of aerated protein microstructures in the heat-treated samples. Nanostructures revealed by small-angle and wide-angle X-ray scattering indicated that extrusion imparted morphological changes in the quinoa protein and starch (dominance of V-type). Overall, extrusion processing only reduced the content of most of the essential amino acids to a minor extent; the content of valine and methionine was reduced to a slightly greater extent, but the final products met the requirements of the Food and Drug Organization.

CONCLUSION

This study presents innovative examples on how extrusion processing and post-processing heat treatment can be used to produce attractive future food alternatives, such as breakfast cereal flakes and porridge powder, from quinoa grains. Extrusion of quinoa flour into Peruvian foods was shown to be mostly impacted by the processing temperature and processing conditions used. Protein crosslinking increased due to extrusion and post-processing heating. Starch crystallinity decreased most when the product was dried after processing. © 2021 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Supramolecular structure of quinoa starch affected by nonenyl succinic anhydride (NSA) substitution

Quinoa starch granular structure as affected by nonenyl succinic anhydride (NSA) substitution was investigated by multiple approaches, including scattering, spectroscopic, and microscopic techniques. The modification had little impact on the morphology of starch granules. The NSA substitution was found mainly in the amorphous lamellae and amorphous growth rings. The NSA modification increased the thickness of the amorphous lamellae. The homogeneity of the ordered structure in the granules was improved, probably because the NSA modification reduced the amount of defects in the semi-crystalline growth ring. Compared to other chemical modifications such as acylation, succinylation was more effective in modifying the starch lamellar structure. A possible reaction pattern of NSA modification on quinoa starch is proposed, in which the NSA modification may follow the sequence of amorphous growth rings, the amorphous matrices among blocklets, amorphous and crystalline lamellae in semi-crystalline growth rings. This study provides new insights on the structural changes of starch granules induced by succinylation on the supramolecular level.

Formation of carboxylated and decarboxylated betalains in ripening grains of Chenopodium quinoa by a dual dioxygenase

Chenopodium quinoa (quinoa) is a pseudo-cereal that forms part of the cultural heritage of Andean countries, and its grains have high nutritional value and potential health benefits. Betalains are nitrogenous water-soluble pigments and bioactive molecules that contribute to these health-promoting properties. Betalains are restricted to plants of the order Caryophyllales, to which quinoa belongs. A new family of betalains has been discovered in the form of unconventional decarboxylated pigments. Here, we show that these pigments accumulate in ripening quinoa grains of fluorescent nature, and are putatively based on a dopamine-cleaving activity. This study describes for the first time the purification and molecular and functional characterization of a 4,5-dopamine extradiol dioxygenase enzyme from plants. It is a monomeric protein with a molecular mass of 34.5 kDa characterized by chromatography, electrophoresis, and time-of-flight mass spectrometry. We demonstrate that this key enzyme has a dual function in a square-shaped biosynthetic pathway towards the formation of both carboxylated and decarboxylated pigments. Enzyme kinetic properties are characterized for the production of 6-decarboxy-betalamic acid and 3,4-dihydroxy-l-phenylalanine-derived betalamic acid, the two structural units of plant pigment in nature. The profile of multiple betalains present in quinoa grains has been reproduced in one-pot bioreactors containing the novel enzyme and two competing substrates.

Are quinoa proteins a promising alternative to be applied in plant-based emulsion gel formulation?

Emulsion gels are structured emulsion systems that behave as soft solid-like materials. Emulsion gels are commonly used in food-product design both as fat replacers and as delivery carriers of bioactive compounds. Different plant-derived proteins like soy, chia, and oat have been used in emulsion gel formulation to substitute fat in meat products and to deliver some vegetable dyes or extracts. Quinoa protein isolates have been scarcely applied in emulsion gel formulation although they seem to be a promising alternative as emulsion stabilizers. Quinoa protein isolates have a high protein content with a well-balanced amino acid profile and show good emulsifying and gelling capabilities. Unlike quinoa starch, quinoa protein isolates do not require any chemical modification before being used. The present article reviews the state of the art in food emulsion gels stabilized with vegetable proteins and highlights the potential uses of quinoa proteins in emulsion gel formulation.

Impact of the Hydrolysis and Methanolysis of Bidesmosidic Chenopodium quinoa Saponins on Their Hemolytic Activity

Saponins are specific metabolites abundantly present in plants and several marine animals. Their high cytotoxicity is associated with their membranolytic properties, i.e., their propensity to disrupt cell membranes upon incorporation. As such, saponins are highly attractive for numerous applications, provided the relation between their molecular structures and their biological activities is understood at the molecular level. In the present investigation, we focused on the bidesmosidic saponins extracted from the quinoa husk, whose saccharidic chains are appended on the aglycone via two different linkages, a glycosidic bond, and an ester function. The later position is sensitive to chemical modifications, such as hydrolysis and methanolysis. We prepared and characterized three sets of saponins using mass spectrometry: (i) bidesmosidic saponins directly extracted from the ground husk, (ii) monodesmosidic saponins with a carboxylic acid group, and (iii) monodesmosidic saponins with a methyl ester function. The impact of the structural modifications on the membranolytic activity of the saponins was assayed based on the determination of their hemolytic activity. The natural bidesmosidic saponins do not present any hemolytic activity even at the highest tested concentration (500 µg·mL⁻¹). Hydrolyzed saponins already degrade erythrocytes at 20 µg·mL⁻¹, whereas 100 µg·mL⁻¹ of transesterified saponins is needed to induce detectable activity. The observation that monodesmosidic saponins, hydrolyzed or transesterified, are much more active against erythrocytes than the bidesmosidic ones confirms that bidesmosidic saponins are likely to be the dormant form of saponins in plants. Additionally, the observation that negatively charged saponins, i.e., the hydrolyzed ones, are more hemolytic than the neutral ones could be related to the red blood cell membrane structure.

[Amaranth grain proteins: prospects for use in specialized food products]

Amaranth is a widespread genus of predominantly annual herbaceous plants belonging to the Amaranthaceae family, which is one of the most widely used pseudocereals along with quinoa and buckwheat in nutrition. The aim of the research was to review and analyze the results of the studies on the characteristics of amaranth grain proteins, the effect of various food processing methods on their quality, and the prospects for using amaranth protein hydrolysates in therapeutic nutrition. Material and methods. For the main search for the literature, the PubMed bibliographic database was used, which covers about 75% of the world's medical publications. In addition, Scopus and Web of Science databases and non-commercial search engine Google Scholar were used. The depth of the search was 15 years. Results. The paper presents a brief review of modern approaches for obtaining amaranth protein isolates and concentrates, including the use of a complex of physicochemical methods: grinding, sifting, extraction at high pH values, defatting, ultrafiltration, centrifugation, isoelectric precipitation, and drying of the protein product. A comparative characteristic of amino acid content of protein fractions of pseudocereals is presented. Basically, leucine, isoleucine, and valine are limiting amino acids for the grain protein of various varieties of amaranth. When substantiating and developing modern effective food technologies for processing amaranth grain, the studies dedicated to the evaluation of their impact on the biological value of amaranth protein deserve special attention. Methods of grain fermentation, sprouting, steaming, malting, boiling can be used to increase the bioavailability and digestibility of its ingredients. The results of in vitro and in vivo studies indicate the presence of hypotensive, hypolipidemic and antioxidant activity of the amaranth protein and its hydrolysates what determines the prospects for their use as part of foods for special dietary uses and therapeutic nutrition. An analysis of the scientific publications presented in the review indicates an increase in demand for high-quality gluten-free products and an increase in the range of mass-consumption foods, such as bakery, pasta, flour confectionery, with pseudo-cereals in their composition, including amaranth. Conclusion. The high biological value and technological properties of amaranth protein concentrates/isolates determine the prospects for their use to create a wide range of specialized foods for various purposes.

Proteins from pseudocereal seeds: solubility, extraction, and modifications of the physicochemical and techno-functional properties

Pseudocereals (amaranth, buckwheat and quinoa) are emerging as popular gluten-free crops. This may be attributed to their wide-ranging health benefits, including antioxidant, hypoglycemic and serum-cholesterol reducing properties. Proteins of these crops have a high nutritional quality as a result of the presence of essential amino acids. Additionally, amaranth, buckwheat and quinoa proteins (AP, BP and QP, respectively) have physicochemical properties that are useful for the manufacture of different types of food. However, native pseudocereal proteins demonstrate a low solubility in water, mainly because of their composition. The major components of these proteins are albumins (water-soluble) and globulins (salt-soluble), although some proportions of glutelin (alkali-soluble) and prolamins (alcohol-soluble) are also found. The most commonly used method for extracting pseudocereal proteins is the alkaline extraction method, which may contribute to the low solubility of pseudocereal protein. Fortunately, different methods for modifying physicochemical (or techno-functional) properties have been proposed to extend their industrial application. For example, high-intensity ultrasound (HIUS) proved useful for improving the solubility of API and QP. Heating can allow for the formation of soluble aggregates of QP. The combination of heating and HIUS can improve the digestibility, solubility and foam properties of AP. Conjugation through the Maillard reaction can improve BPI and QP interfacial properties. Thus, present study provides a review of the solubility, extraction and modification of the techno-functional properties of AP, BP and QP. © 2022 Society of Chemical Industry.

Physicochemical, Antioxidant and Anticancer Characteristics of Seed Oil from Three Chenopodium quinoa Genotypes

Chenopodium quinoa Willd. is recognized to be an excellent nutrient with high nutritional content. However, few genotypes of quinoa were analyzed, so we found a knowledge gap in the comparison of quinoa seeds of different genotypes. This study aims to compare the physicochemical, antioxidant, and anticancer properties of seed oil from three C. quinoa genotypes. Seeds of three genotypes (white, red, and black) were extracted with hexane and compared in this study. The oil yields of these quinoa seeds were 5.68–6.19% which contained predominantly polyunsaturated fatty acids (82.78–85.52%). The total tocopherol content ranged from 117.29 to 156.67 mg/kg and mainly consisted of γ-tocopherol. Total phytosterols in the three oils ranged from 9.4 to 12.2 g/kg. Black quinoa seed oil had the highest phytosterols followed by red and white quinoas. The chemical profile of quinoa seed oils paralleled by their antioxidant and anticancer activities in vitro was positively correlated with the seed coat color. Black quinoa seed oil had the best antioxidant and anti-proliferation effect on HCT 116 cells by the induction of apoptosis in a dose-dependent manner, which may play more significant roles in the chemoprevention of cancer and other diseases related to oxidative stress as a source of functional foods.

Characterization of epidermal bladder cells in Chenopodium quinoa

Chenopodium quinoa (quinoa) is considered a superfood with its favourable nutrient composition and being gluten free. Quinoa has high tolerance to abiotic stresses, such as salinity, water deficit (drought) and cold. The tolerance mechanisms are yet to be elucidated. Quinoa has epidermal bladder cells (EBCs) that densely cover the shoot surface, particularly the younger parts of the plant. Here, we report on the EBC's primary and secondary metabolomes, as well as the lipidome in control conditions and in response to abiotic stresses. EBCs were isolated from plants after cold, heat, high-light, water deficit and salt treatments. We used untargeted gas chromatography-mass spectrometry (GC-MS) to analyse metabolites and untargeted and targeted liquid chromatography-MS (LC-MS) for lipids and secondary metabolite analyses. We identified 64 primary metabolites, including sugars, organic acids and amino acids, 19 secondary metabolites, including phenolic compounds, betanin and saponins and 240 lipids categorized in five groups including glycerolipids and phospholipids. We found only few changes in the metabolic composition of EBCs in response to abiotic stresses; these were metabolites related with heat, cold and high-light treatments but not salt stress. Na⁺ concentrations were low in EBCs with all treatments and approximately two orders of magnitude lower than K⁺ concentrations.

Pickering emulsifiers based on enzymatically modified quinoa starches: Preparation, microstructures, hydrophilic property and emulsifying property

Quinoa starch was developed as a new kind of Pickering emulsifier by enzymatic modification. The morphological structure, crystalline structure, lamellar structure, fractal structure, particle size distribution, contact angle, emulsion index (EI), and emulsion micromorphology were studied to explore the relationship between structure characteristics, hydrophilic property, and emulsifying properties of enzymatically modified (EM) quinoa starches. With the increasing enzymatic hydrolysis time in the test range of 0-9 h, particle size of EM quinoa starch decreased, and the broken starch and contact angle of EM quinoa starch increased; the EI value of emulsions with EM quinoa starch increased, and the oil droplet size of emulsions with EM quinoa starch decreased. It suggested that both the smallest particle size and the closest extent of the contact angle to 90° derived the best emulsifying property of EM-9. The EM quinoa starch had higher emulsifying capacity at higher oil volume fraction (Φ) (50%) than at lower Φ (20%), proving that the EM starch has potential to be used as Pickering emulsifiers in higher oil products, such as salad dressing.

Therapeutic potential of quinoa seed extract as regenerative and hepatoprotective agent in induced liver injury wistar rat model

The liver is a fundamental metabolic organ that performs many essential functions including the detoxification of toxic substances present in the body. Exposure to various toxicants leads the liver towards hepatic injury. This study was planned to estimate the hepatoprotective and regenerative efficacy of Quinoa seeds (Chenopodium quinoa) extract against carbon tetrachloride (CCl4) induced liver damage. At a dose of 1ml/kg (153.8mg/kg) body weight carbon tetrachloride (CCl4) was used intraperitoneally to induce hepatic injury in Wistar rats. Silymarin (30mg/kg body weight, p.o.), an antioxidant was used as a reference standard drug. Subsequently, ethanolic extract of Quinoa seeds (QEE) was administered at 400 and 600mg/kg body weight through oral gavage. Various biochemical and regenerative biomarkers were assessed to evaluate the potential efficacy of QEE in liver tissue regeneration. Results revealed that QEE administration significantly reduced the CCl4-induced raised quantities of alanine transaminase (ALT), aspartate transaminase (AST), and total oxidative stress (TOS) while, significantly improved the level of triiodothyronine (T3), thyroxine (T4), albumin and total protein concentration in QEE treated groups. The expression level of IGF-1, FOXA-2, Stmn-2, SPP-1 was found significantly down-expressed. It is concluded that QEE treatment has the regenerative and hepatoprotective effect.

Effects on Microbiota Composition after Consumption of Quinoa Beverage Fermented by a Novel Xylose-Metabolizing L. plantarum Strain

Demands for novel lactic acid bacteria with potential to be used as probiotics along with healthy fermented plant-based products increase worldwide. In this study, a novel Lactiplantibacillus plantarum P31891 strain with enzymatic capacity to degrade tannins and ferment xylose was used as starter culture for fermentation of a quinoa-based beverage. The probiotic potential of the selected strain was evaluated in healthy volunteers. Twenty participants consumed the beverage for 14 days; microbiota changes in saliva and faecal samples were analyzed by Terminal Restriction Fragment Length Polymorphism (T-RFLP), Next Generation Sequencing (NGS) and qPCR; and gastrointestinal well-being and digestive symptoms were recorded. The results indicated that the consumption of the beverage with Lactiplantibacillus plantarum P31891 in a probiotic dose (10¹² CFU/mL) increased the number of Lactobacillus in the feces but not in saliva. Overall, the bacterial community did not seem to be influenced by the bacterium or by the beverage, as expressed by the diversity indexes, but specific genera were affected, as reflected in changes in amplicon sequence variants. Consequently, Lactiplantibacillus plantarum P31891 showed potential to be categorized as a probiotic strain in the fermented quinoa-based beverage.

Comparison of Grain Processing Techniques on Saponin Content and Nutritional Value of Quinoa (Chenopodium quinoa Cv. Yellow Pang-da) Grain

&lt;b&gt;Background and Objective:&lt;/b&gt; Quinoa grain contained saponin in pericarp, which causes bitter flavor. After harvesting, quinoa grain is required to remove saponin before being consumed. Thus, this study aimed to study post harvest management of grain processing on the saponin and nutrition value of quinoa grain. &lt;b&gt;Materials and Methods:&lt;/b&gt; The experiment was arranged in a Completely Randomized Design (CRD) with three replications and saponin removal technique with milling process (T&lt;sub&gt;1&lt;/sub&gt;-T&lt;sub&gt;2&lt;/sub&gt;) and reagent washing (T&lt;sub&gt;3&lt;/sub&gt;-T&lt;sub&gt;8&lt;/sub&gt;) were used as experimental treatments comparing with non-process grains as a control (T&lt;sub&gt;9&lt;/sub&gt;). Nutrition analysis was an indication of quality in post-process quinoa grain. &lt;b&gt;Results:&lt;/b&gt; The experiment found that T&lt;sub&gt;1&lt;/sub&gt;, T&lt;sub&gt;3&lt;/sub&gt;, T&lt;sub&gt;4&lt;/sub&gt;, T&lt;sub&gt;5&lt;/sub&gt;, T&lt;sub&gt;6&lt;/sub&gt; and T&lt;sub&gt;7&lt;/sub&gt; could reduce saponin content significantly different from T&lt;sub&gt;9&lt;/sub&gt;, while T&lt;sub&gt;2&lt;/sub&gt; and T&lt;sub&gt;8&lt;/sub&gt; still show high saponin content when compared with T&lt;sub&gt;9&lt;/sub&gt;. T&lt;sub&gt;2&lt;/sub&gt; and T&lt;sub&gt;4&lt;/sub&gt; techniques could maintain most of the nutritional value of quinoa grain when compared with control (T&lt;sub&gt;9&lt;/sub&gt;). &lt;b&gt;Conclusion:&lt;/b&gt; Finally, this experiment could be concluded that quinoa was washed by alkaline solution (pH 8) for 8 min by three times (T&lt;sub&gt;4&lt;/sub&gt;) could be an optimum of saponin removal technique. This technique not only removed saponin but could also maintain quinoa grain qualities. Meanwhile, it potentially reduced for 66.03 percent of saponins content when compared with control treatment, which did not change in protein content, flavonoid content, moisture content, starch content, phenolic content and color (L*) of quinoa grain.

Effect of ultrasonic on the structure and quality characteristics of quinoa protein oxidation aggregates

Protein oxidation leads to covalent modification of structure and deterioration of functional properties of quinoa protein. The objective of this study was to investigate the effects of ultrasonic treatment on the functional and physicochemical properties of quinoa protein oxidation aggregates. In this concern, 2,2'-azobis (2-amidinopropane) dihydrochloride (AAPH) was selected as oxidative modification of quinoa protein. The microstructure of quinoa protein displayed by scanning electron microscope (SEM) indicated that oxidation induced extensive aggregation, leading to carbonylation and degradation of sulfhydryl groups. Aggregation induced by oxidation had a negative effect on the solubility, turbidity, emulsifying stability. However, according to the analysis of physicochemical properties, ultrasonic significantly improved the water solubility of quinoa protein. The quinoa protein treated by ultrasonic for 30 min exhibited the best dispersion stability in water, which corresponded to the highest ζ-potential, smallest particle size and most uniform distribution. Based on the FT-IR, SDS-PAGE and surface hydrophobicity analysis, the increase of α-helix, β-turn and surface hydrophobicity caused by cavitation effect appeared to be the main mechanism of quinoa protein solubilization. In addition, the hydrophobic region of the protein was re-buried by excessive ultrasonic treatment, and the protein molecules were reaggregated by disulfide bonds. Microstructural observations further confirmed that ultrasonic treatment effectively inhibited protein aggregation and improved the functional properties of quinoa protein.

Impact of germination on phenolic composition, antioxidant properties, antinutritional factors, mineral content and Maillard reaction products of malted quinoa flour

The study aimed at improving and comparing the nutritional profile of black (BQ) and white quinoa (WQ) through malting at different germination periods (24, 48, 72 and 96 h), followed by drying at 50 °C, decluming, grinding and sieving to obtain malt flour. The changes in protein, reducing sugar, Maillard reaction products (MRPs), minerals, free and bound polyphenols and antioxidant activity were noted. Malting caused significant increase in polyphenolic content, antioxidant capacity and fluorescence of advanced MRP (FAST) index. The highest increment was noted in malts germinated for 48 and 72 h. BQ malts were marked by higher bound hydroxycinnamic acids, flavan-3-ols, magnesium, potassium and antioxidant activity, while, WQ malts had lower saponin, phytic acid but higher protein, iron, calcium, FAST index. WQ exhibited highest increment (27.23%) in antioxidant activity even though it had lower polyphenols than BQ after malting. Major loss in polyphenols and proteins occurred in malt germinated for 96 h.

Bioactivities of Pseudocereal Fractionated Seed Proteins and Derived Peptides Relevant for Maintaining Human Well-Being

Food proteins and peptides are able to exert a variety of well-known bioactivities, some of which are related to well-being and disease prevention in humans and animals. Currently, an active trend in research focuses on chronic inflammation and oxidative stress, delineating their major pathogenetic role in age-related diseases and in some forms of cancer. The present study aims to investigate the potential effects of pseudocereal proteins and their derived peptides on chronic inflammation and oxidative stress. After purification and attribution to protein classes according to classic Osborne's classification, the immune-modulating, antioxidant, and trypsin inhibitor activities of proteins from quinoa (Chenopodium quinoa Willd.), amaranth (Amaranthus retroflexus L.), and buckwheat (Fagopyrum esculentum Moench) seeds have been assessed in vitro. The peptides generated by simulated gastro-intestinal digestion of each fraction have been also investigated for the selected bioactivities. None of the proteins or peptides elicited inflammation in Caco-2 cells; furthermore, all protein fractions showed different degrees of protection of cells from IL-1β-induced inflammation. Immune-modulating and antioxidant activities were, in general, higher for the albumin fraction. Overall, seed proteins can express these bioactivities mainly after hydrolysis. On the contrary, higher trypsin inhibitor activity was expressed by globulins in their intact form. These findings lay the foundations for the exploitation of these pseudocereal seeds as source of anti-inflammatory molecules.

Synergistic consequences of salinity and potassium deficiency in quinoa: Linking with stomatal patterning, ionic relations and oxidative metabolism

Quinoa emerged as an ideal food security crop due to its exceptional nutritive profile and stress enduring potential and also deemed as model plant to study the salt-tolerance mechanisms. However to fill the research gaps of this imperative crop, the present work aimed to study the effect of potassium (K) deficiency either separately or in combination with salinity. First, we investigated the stomatal and physiological based variations in quinoa growth under salinity and K, then series of analytical tools were used with model approach to interpret the stomatal aperture (SA) and photosynthesis (Pn) changes. Results revealed that quinoa efficiently deployed antioxidants to scavenge the excessive reactive oxygen species (ROS), had high uptake and retention of K⁺, Ca²⁺, Mg²⁺ with Cl⁻ as charge balancing ion, increased stomata density (SD) and declined the SA to maintain the Pn which resulted the improved growth under salinity. Whereas, K-deficiency caused the stunted growth more severally under salinity due to disruption in ionic homeostasis, excessive ROS production elicited the oxidative damages, SD and SA reduced and ultimately declined in Pn. Our best fitted regression model explored that dependent variables like Pn and SA changed according to theirs signified explanatory variables with quantification per unit based as stomatal conductance (Gs, 51), SD (0.05), ROS (-0.79) and K⁺ (0.08), Cl⁻ (0.34) and Na^{+ (-} 0.52) respectively. Overall, moderate salinity promoted the quinoa growth, while K-deficiency particularly with salinity reduced the quinoa performance by affecting stomatal and non-stomatal factors.