Unraveling the impact of starch granule-associated proteins on the emulsifying ability of quinoa starch granules at multiple scales.

Total starch granule-associated proteins (tGAP), including granule-channel (GCP) and granule-surface proteins (GSP), alter the physicochemical properties of starches. Quinoa starch (QS) acts as an effective emulsifier in Pickering emulsion. However, the correlation between the tGAP and the emulsifying capacity of QS at different scales remains unclear. Herein, GCP and tGAP were selectively removed from QS, namely QS-C and QS-A. Results indicated that the loss of tGAP increased the water permeability and hydrophilicity of the starch particles. Mesoscopically, removing tGAP decreased the diffusion rate and interfacial viscous modulus. Particularly, GSP had a more profound impact on the interfacial modulus than GCP. Microscopically and macroscopically, the loss of tGAP endowed QS with weakened emulsifying ability in terms of emulsions with larger droplet size and diminished rheological properties. Collectively, this work demonstrated that tGAP played an important role in the structural and interfacial properties of QS molecules and the stability of QS-stabilized emulsions.

Impact of genotypic variation and cultivation conditions on the techno-functional characteristics and chemical composition of 25 new Canadian quinoa cultivars.

The utilization of quinoa in food production requires comprehensive information on its processing characteristics. Twenty-five new quinoa cultivars developed by the Northern Quinoa Breeding Program, grown in three Canadian locations over two seasons, were characterized for their proximate composition, pasting properties, thermal properties, water absorption index, water solubility index, foaming capacity, foaming stability, oil holding capacity, and emulsion activity crucial for potential food applications. Results showed significant variations in the proximate composition among the cultivars, which was also influenced by the growing location and harvest year. Significant differences (p < 0.05) were also observed in the pasting properties, thermal stability, hydration properties, foaming properties, oil holding capacity, and emulsion activity. The hierarchical cluster and principal component analyses were associated with five distinct clusters of quinoa cultivars, each with unique techno-functional attributes, suggesting their potential for different food applications. These findings emphasize the need for further research to explore the performance of quinoa flours in specific food products and their impact on end-product quality.

Application of synthesized metal-trimesic acid frameworks for the remediation of a multi-metal polluted soil and investigation of quinoa responses.

Metal-organic frameworks (MOFs) are structures with high surface area that can be used to remove heavy metals (HMs) efficiently from the environment. The effect of MOFs on HMs removal from contaminated soils has not been already investigated. Monometallic MOFs are easier to synthesize with high efficiency, and it is also important to compare their structures. In the present study, Zn-BTC, Cu-BTC, and Fe-BTC as three metal-trimesic acid MOFs were synthesized from the combination of zinc (Zn), copper (Cu), and iron (Fe) nitrates with benzene-1,3,5-tricarboxylic acid (H3BTC) by solvothermal method. BET analysis showed that the specific surface areas of the Zn-BTC, Cu-BTC, and Fe-BTC were 502.63, 768.39 and 92.4 m2g-1, respectively. The synthesized MOFs were added at the rates of 0.5 and 1% by weight to the soils contaminated with 100 mgkg-1 of Zn, nickel (Ni), lead (Pb), and cadmium (Cd). Then quinoa seeds were sown in the treated soils. According to the results, the uptakes of all four HMs by quinoa were the lowest in the Cu-BTC 1% treated pots and the lowest uptakes were observed for Pb in shoot and root (4.87 and 0.39, µgpot-1, respectively). The lowest concentration of metal extracted with EDTA in the post-harvest soils was for Pb (11.86 mgkg-1) in the Cu-BTC 1% treatment. The lowest metal pollution indices were observed after the application of Cu-BTC 1%, which were 20.29 and 11.53 for shoot and root, respectively. With equal molar ratios, highly porous and honeycomb-shaped structure, the most crystallized and the smallest constituent particle size (34.64 nm) were obtained only from the combination of Cu ions with H3BTC. The lowest porosity, crystallinity, and a semi-gel like feature was found for the Fe-BTC. The synthesized Cu-BTC showed the highest capacity of stabilizing HMs, especially Pb in the soil compared to the Zn-BTC and the Fe-BTC. The highly porous characteristic of the Cu-BTC can make the application of this MOF as a suitable environmental solution for the remediation of high Pb-contaminated soils.

Molecular investigation of soybean protein for improving the stability of quinoa (Chenopodium quinoa willd.) milk substitute.

Soybean could greatly improve stability of quinoa milk substitute. However, the key compound and underlying mechanisms remained unclear. Here we showed that soybean protein was the key component for improving quinoa milk substitute stability but not oil or okara. Supplementary level of soybean protein at 0%, 2%, 4%, and 8% of quinoa (w/w) was optimized. Median level at 4% could effectively enhance physical stability, reduce particle size, narrow down particle size distribution, and decrease apparent viscosity of quinoa milk substitute. Microscopic observation further confirmed that soybean protein could prevent phase separation. Besides, soybean protein showed increased surface hydrophobicity. Molecular docking simulated that soybean protein but not quinoa protein, could provide over 10 anchoring points for the most abundant quinoa vanillic acid, through hydrogen bond and Van-der-Waals. These results contribute to improve stability of quinoa based milk substitute, and provide theoretical basis for the interaction of quinoa phenolics and soybean protein.

Multivariate characterization of salicylic acid and potassium induced physio-biochemical and phytoremediation responses in quinoa exposed to lead and cadmium contamination.

The levels of soils pollutants such as lead (Pb) and cadmium (Cd) have significantly increased recently resulting in ecological disturbances and threatening crop production. Various amendments have been employed to enhance the tolerance of crops to withstand Cd and Pb stresses. However, the role of combined application of potassium (K) and of salicylic acid (SA) for Cd and Pb stress mitigation and phytoremediation by quinoa (Chenopodium quinoa Willd) has not been comprehended well. In the present study, the effect of 10 mM K and 0.1 mM SA was tested on the quinoa plants subjected to 250 µM Pb and/or 100 µM Cd. The Pb and Cd treatments were applied separately or together. Phytotoxicity induced by Pb and Cd resulted in drastic decrease (>60%) in chlorophyll contents, stomatal conductance, and plant biomass. The collective treatment of Pb and Cd induced an increase in the concentration of hydrogen peroxide (13-fold) and lipid peroxidation (16-fold) that resulted in a 61% reduction in membrane stability. The application of 10 mM K and/or 0.1 mM SA was remarkable in mitigating the adverse effect of Pb and Cd. The reduction in plant biomass was 17% when 10 mM K and 0.1 mM SA were applied together under the combined treatment of both the metals. The simultaneous application of K and SA effectively mitigated oxidative stress by enhancing the activities of superoxide dismutase, peroxidase, ascorbate peroxidase, and catalase by 12, 10, 7 and 10-folds respectively. The positive effect of K and SA on these attributes resulted in a remarkable reduction in metal accumulation and translocation and lipid peroxidation. The stressed plants supplemented with K and SA exhibited a significant improvement in the membrane stability index, chlorophyll content, and stomatal conductance. This study concluded that the combined application of K and SA could be a good approach for reducing Pb and Cd phytotoxicity in quinoa and enhancing their phytostabilization potential in the contaminated soils.

Flour Fortification Using Lablab Purpureus Evaluation with a Biosensor.

BACKGROUND/AIMS: Due to rapid metabolic and growth rates during the first two years of life, the nutritional needs of young children are high. Given the small portion sizes consumed by children between the ages of 6 and 24 months, it is necessary to improve diets to meet the nutritional needs of this age group. Therefore, the analysis of lysine content is an important parameter in the evaluation of enriched foods. METHODS: The utilization of an enzymatic sensor employing lysine-α-oxidase (LOx) as a biorecognition element represents an alternative to the existing methods. This sensor was optimized for quantifying the lysine content in flour mixtures: Quinoa-Lablab purpureus rye - Lablab purpureus, and pole beans - Lablab purpureus, with a maximum ratio of 85g/100g. RESULTS: The addition of lablab purpureus significantly increased the lysine concentration in the enriched samples. When 30 percent was substituted in quinoa, it reached a 143 percent increase. And when 15 percent was substituted in the rye flour, the final concentration of this amino acid increased by 64 percent. In order to quantify the lysine concentration, it was necessary to optimize various parameters during the use of the sensor, e.g. a potentiometric signal was detected upon the depletion of oxygen present during the oxidation of lysine in the samples, and the sensor response was recorded at 2 s. This was possible due to the modification of the pH and the thickness of the membrane. The oxidation of lysine is catalyzed by LOx using molecular oxygen as the electron acceptor. The corresponding acidic compounds and hydrogen peroxide were formed in the reaction medium. CONCLUSION: It was possible to increase and verify the concentration of lysine in all the flours tested through the use of the biosensor, which turned out to be a valid method for controlling the nutritional quality of flours.

Enhancing quinoa (Chenopodium quinoa) growth in saline environments through salt-tolerant rhizobacteria from halophyte biotope.

The use of plant growth-promoting rhizobacteria (PGPR) in agriculture is one of the most promising approaches to improve plants' growth under salt stress and to support sustainable agriculture under climate change. In this context, our goal was to grow and enhance quinoa growth using native rhizobacteria that can withstand salt stress. To achieve this objective, we isolated rhizobacteria from three saline localities in a semi-arid region in Tunisia, which are characterized by different halophyte species and tested their plant growth-promoting (PGP) activities. Then, we inoculated quinoa seedlings cultivated on 300 mM NaCl with the three most efficient rhizobacteria. A positive effect of the three-salt tolerant rhizobacteria on the growth of quinoa under salinity was observed. In fact, the results of principal component analysis indicated that the inoculation of quinoa by salt-tolerant PGPR under high salinity had a prominent beneficial effect on various growth and physiological parameters of stressed plant, such as the biomass production, the roots length, the secondary roots number, proline content and photosynthesis activities. Three rhizobacteria were utilized in this investigation, and the molecular identification revealed that strain 1 is related to the Bacillus inaquosorum species, strain 2 to Bacillus thuringiensis species and strain 3 to Bacillus proteolyticus species. We can conclude that the saline soil, especially the halophytic rhizosphere, is a potential source of salt-tolerant plant growth-promoting rhizobacteria (ST-PGPR), which stimulate the growth of quinoa and improve its tolerance to salinity.

Molecular mechanisms regulating glucose metabolism in quinoa (Chenopodium quinoa Willd.) seeds under drought stress.

BACKGROUND: Abiotic stress seriously affects the growth and yield of crops. It is necessary to search and utilize novel abiotic stress resistant genes for 2.0 breeding programme in quinoa. In this study, the impact of drought stress on glucose metabolism were investigated through transcriptomic and metabolomic analyses in quinoa seeds. Candidate drought tolerance genes on glucose metabolism pathway were verified by qRT-PCR combined with yeast expression system. RESULTS: From 70 quinoa germplasms, drought tolerant material M059 and drought sensitive material M024 were selected by comprehensive evaluation of drought resistance. 7042 differentially expressed genes (DEGs) were indentified through transcriptomic analyses. Gene Ontology (GO) analysis revealed that these DEGs were closely related to carbohydrate metabolic process, phosphorus-containing groups, and intracellular membrane-bounded organelles. The Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis detected that DEGs were related to pathways involving carbohydrate metabolisms, glycolysis and gluconeogenesis. Twelve key differentially accumulated metabolites (DAMs), (D-galactose, UDP-glucose, succinate, inositol, D-galactose, D-fructose-6-phosphate, D-glucose-6-phosphate, D-glucose-1-phosphate, dihydroxyacetone phosphate, ribulose-5-phosphate, citric acid and L-malate), and ten key candidate DEGs (CqAGAL2, CqINV, CqFrK7, CqCELB, Cqbg1x, CqFBP, CqALDO, CqPGM, CqIDH3, and CqSDH) involved in drought response were identified. CqSDH, CqAGAL2, and Cqß-GAL13 were candidate genes that have been validated in both transcriptomics and yeast expression screen system. CONCLUSION: These findings provide a foundation for elucidating the molecular regulatory mechanisms governing glucose metabolism in quinoa seeds under drought stress, providing insights for future research exploring responses to drought stress in quinoa.

Combined effects of high hydrostatic pressure and pulsed electric fields on quinoa starch: Analysis of microstructure, morphology, thermal, and pasting properties.

The aim of this study was to evaluate the impact of non-thermal methods, using high hydrostatic pressure (HHP) and pulsed electric field (PEF), on the dual modification of quinoa starch and to analyze the microstructural, morphological, thermal, pasting, and texture properties. Starch was treated with HHP at 400 MPa for 10 min, while PEF was applied using voltages of 10 and 30 kV cm-1 for a total time of 90s. The modification techniques were effective in breaking down amylose molecules and amylopectin branches, where for the dual treatment, higher values of DP6-12 were found. The average diameter and gelatinization temperatures were elevated after HHP, thus forming clusters that require more energy for paste formation. The use of 30 kV cm-1 and 400 MPa (HP30) in starch facilitates the creation of new food products with better texture, stability and nutritional value, making them suitable for use in food emulsions and the cosmetics industry.

Rheological and sensory properties of chickpea and quinoa pastes and gels for plant-based product development.

The aim of this study was to investigate the modification of mechanical, rheological, and sensory properties of chickpea pastes and gels by incorporating other ingredients (olive oil or quinoa flour), to develop plant-based alternatives that meet consumer demands for healthy, natural, and enjoyable food products. The pastes and gels were made with different amounts of chickpea flour (9% and 12%, respectively). For each product, a first set of products with different oil content and a second set with quinoa flour (either added or replaced) were produced. The viscoelastic properties of the pastes and the mechanical properties of the gels were measured. Sensory evaluation and preference assessment were carried out with 100 participants using ranking tests. The study found remarkable differences in rheological, mechanical, and sensory properties of chickpea products upon the inclusion of oil and quinoa flour. The addition of oil increased the viscosity and decreased the elastic contribution to the viscoelasticity of the pastes, while it improved the firmness and plasticity in gels. It also increased the creaminess and preference of both pastes and gels. Replacing chickpea with quinoa flour resulted in less viscous pastes and gels with less firmness and more plasticity. In terms of sensory properties, the use of quinoa as a replacement ingredient resulted in less lumpiness in the chickpea paste and less consistency and more creaminess in both the pastes and gels, which had a positive effect on preference. The addition of quinoa increased the viscosity of pastes and the firmness and stiffness of gels. It increased the consistency and creaminess of both pastes and gels. Quinoa flour and/or olive oil are suitable ingredients in the formulation of chickpea-based products. They contribute to the structure of the system, providing different textural properties that improve acceptance.

Monascus-fermented quinoa alleviates hyperlipidemia in mice by regulating the amino acid metabolism pathway.

Monascus has the ability to produce secondary metabolites, such as monacolin K (MK), known for its physiological functions, including lipid-lowering effects. Widely utilized in industries such as health food and medicine, MK is a significant compound derived from Monascus. Quinoa, recognized by the Food and Agriculture Organization of the United Nations as "the only plant food that can meet human basic nutritional needs by itself", possesses dual advantages of high nutritional value and medicinal food homology. This study employed animal experiments to investigate the hypolipidemic activity of Monascus-fermented quinoa (MFQ) and explored the molecular mechanism underlying the lipid-lowering effect of MFQ on hyperlipidemic mice through transcriptomic and metabolomic analyses. The results demonstrated that high-dose MFQ intervention (1600 mg kg-1 d-1) effectively decreased weight gain in hyperlipidemic mice without significant changes in cardiac index, renal index, or spleen index. Moreover, hepatic steatosis in mice was significantly improved. Serum levels of total cholesterol, triglycerides, and low-density lipoprotein cholesterol were markedly reduced, demonstrating that the lipid-lowering effect of MFQ was comparable to the drug control lovastatin. Conversely, both low-dose MFQ (400 mg kg-1 d-1) and unfermented quinoa exhibited no significant lipid-lowering effect. Integrated analysis of the transcriptome and metabolome suggested that MFQ may regulate amino acid levels in hyperlipidemic mice by influencing metabolic pathways such as phenylalanine, tyrosine, and tryptophan metabolism. This regulation alleviates hyperlipidemia induced by a high-fat diet, resulting in a significant reduction in blood lipid levels in mice.

Raw and heat-treated quinoa protein protects against glucose metabolism disorders in high-fat diet (HFD)-induced mice by reshaping gut microbiota and fecal metabolic profiles.

Plant-based proteins have received considerable global attention due to their nutritional value and potential health effects. As a high-quality plant protein, the hypoglycemic effect of quinoa protein and its potential mechanism have not been fully elucidated. In the present study, we compared the hypoglycemic effects of raw quinoa protein (RP-quinoa) and heat-treated quinoa protein (HP-quinoa) and further explored their potential mechanisms using multi-omics analysis based on gut microbiota and fecal metabolic profiles in HFD-fed mice. Our results showed that both RP-quinoa and HP-quinoa effectively improved glucose metabolism and protected against alterations in gut microbiota induced by a chronic HFD. In addition, quinoa protein increased the relative abundance of beneficial bacteria such as the g__Lachnospiraceae_NK4A136_group, g__Eubacterium_xylanophilum_group, and g__Negativibacillus, followed by an increase in short-chain fatty acids and potentially beneficial metabolites such as L-phenylalanine and L-cysteine. Together, these findings provided the basis for linking gut microbiota and their metabolites to the hypoglycemic effect of quinoa protein.

Physiological traits, crop growth, and grain quality of quinoa in response to deficit irrigation and planting methods.

Climate change has become a concern, emphasizing the need for the development of crops tolerant to drought. Therefore, this study is designed to explore the physiological characteristics of quinoa that enable it to thrive under drought and other extreme stress conditions by investigating the combined effects of irrigation water levels (100%, 75%, and 50% of quinoa's water requirements, WR as I1, I2 and I3) and different planting methods (basin, on-ridge, and in-furrow as P1, P2 and P3) on quinoa's physiological traits and gas exchange. Results showed that quinoa's yield is lowest with on-ridge planting and highest in the in-furrow planting method. Notably, the seed protein concentrations in I2 and I3 did not significantly differ but they were 25% higher than those obtained in I1, which highlighted the possibility of using a more effective irrigation method without compromising the seed quality. On the other hand, protein yield (PY) was lowest in P2 (mean of I1 and I2 as 257 kg ha-1) and highest in P3 (mean of I1 and I2 as 394 kg ha-1, 53% higher). Interestingly, PY values were not significantly different in I1 and I2, but they were lower significantly in I3 by 28%, 27% and 20% in P1, P2, and P3, respectively. Essential plant characteristics including plant height, stem diameter, and panicle number were 6.1-16.7%, 6.4-24.5%, and 18.4-36.5% lower, respectively, in I2 and I3 than those in I1. The highest Leaf Area Index (LAI) value (5.34) was recorded in the in-furrow planting and I1, while the lowest value was observed in the on-ridge planting method and I3 (3.47). In I3, leaf temperature increased by an average of 2.5-3 oC, particularly during the anthesis stage. The results also showed that at a similar leaf water potential (LWP) higher yield and dry matter were obtained in the in-furrow planting compared to those obtained in the basin and on-ridge planting methods. The highest stomatal conductance (gs) value was observed within the in-furrow planting method and full irrigation (I1P3), while the lowest values were obtained in the on-ridge and 50%WR (I3P2). Finally, photosynthesis rate (An) reduction with diminishing LWP was mild, providing insights into quinoa's adaptability to drought. In conclusion, considering the thorough evaluation of all the measured parameters, the study suggests using the in-furrow planting method with a 75%WR as the best approach for growing quinoa in arid and semi-arid regions to enhance production and resource efficiency.

QPH-FR: A Novel Quinoa Peptide Enhances Chemosensitivity by Targeting Leucine-Rich Repeat-Containing G Protein-Coupled Receptor 5 in Colorectal Cancer.

Chemoresistance is one of the difficulties in the treatment of colorectal cancer (CRC), and the enhanced stemness of tumor cells is the underlying contributing factor. Leucine-rich repeat-containing G-protein-coupled receptor 5 (LGR5) is a classical marker of CRC stem cells and can be an important potential target for CRC chemotherapy. Quinoa, a protein-rich plant, offers potential as a source of high-quality active peptides. Novelly, the study obtained quinoa protein hydrolysate (QPH) from whole quinoa grains by simulated digestion. In vivo experiments revealed that the tumor volume in the 5-FU+QPH group decreased from 145.90 ± 13.35 to 94.49 ± 13.05 mm3 in the 5-FU group, suggesting that QPH enhances the chemosensitivity of CRC. Further, the most effective peptide QPH-FR from 631 peptides in QPH was screened by activity prediction, molecular docking, and experimental validation. Mechanistically, QPH-FR competitively suppressed the formation of the LGR5/RSPO1 complex by binding to LGR5, causing RNF43/ZNRF3 to ubiquitinate the FZD receptor, thereby suppressing the Wnt/ß-catenin signaling pathway and exerting stemness inhibition. In summary, the study proposes that a novel peptide QPH-FR from quinoa elucidates the mechanism by which QPH-FR targets LGR5 to enhance chemosensitivity, providing theoretical support for the development of chemotherapeutic adjuvant drugs based on plant peptides.

Utilizing ultrasound combined with quinoa protein to improve the texture and rheological properties of Chinese style reduced-salt pork meatballs (lion's head).

This study aimed to investigate the effect of ultrasound treatment times (30 min and 60 min) and levels of quinoa protein (QPE) addition (1 % and 2 %) on the quality of Chinese style reduced-salt pork meatballs, commonly known as lion's head. The water-holding capacity (WHC), gel and rheology characteristics, and protein conformation were assessed. The results indicated that extending the ultrasound treatment time and elevating the quinoa protein content caused conspicuous improvements (P<0.05) in the cooking yield, WHC, textural characteristics, color difference, and salt-soluble protein (SSP) solubility of the meatballs. Furthermore, the structural alterations induced by the ultrasound treatment combined with quinoa protein addition included enhancement in ß-sheet, ß-turn, and random coil structure contents, along with a red-shift in the intrinsic fluorescence peak. Additionally, the storage (G') and loss modulus (G'') of the raw meatballs significantly enhanced (P<0.05), indicating a denser gel structure in parallel with the microstructure. In conclusion, the findings demonstrated that ultrasound combined with quinoa protein enhanced the WHC and texture properties of Chinese style reduced-salt pork meatballs by improving SSP solubility.

Quinoa Polyphenol Extract Alleviates Non-Alcoholic Fatty Liver Disease via Inhibiting Lipid Accumulation, Inflammation and Oxidative Stress.

Recently, the incidence of NAFLD has exploded globally, but there are currently no officially approved medications for treating the condition. The regulation of NAFLD through plant-derived active substances has become a new area of interest. Quinoa (Chenopodium quinoa Willd.) has been discovered to contain a large quantity of bioactive compounds. In this study, we established a free fatty acid (FFA)-induced steatosis model and explored the effects of quinoa polyphenol extract (QPE) on the major hallmarks of NAFLD. The results indicated that QPE significantly reduced intracellular triglyceride (TG) and total cholesterol (TC) levels. Additionally, QPE remarkably elevated the levels of superoxide dismutase (SOD), catalase (CAT) and glutathione (GSH) and lowered levels of malondialdehyde (MDA). Further examination revealed that QPE attenuated intracellular inflammation, which was verified by the reduced levels of pro-inflammatory cytokines. Mechanistically, QPE inhibited fatty acid biosynthesis mainly by targeting de novo lipogenesis (DNL) via the AMPK/SREBP-1c signaling pathway. Moreover, network pharmacology was used to analyze key targets for NAFLD mitigation by ferulic acid (FA), a major component of QPE. Taken together, this study suggests that QPE could ameliorate NAFLD by modulating hepatic lipid metabolism and alleviating oxidative stress and inflammation.

Identifying Core Genes Related to Low-Temperature Stress Resistance in Quinoa Seedlings Based on WGCNA.

Quinoa is a nutritious crop that is tolerant to extreme environmental conditions; however, low-temperature stress can affect quinoa growth, development, and quality. Considering the lack of molecular research on quinoa seedlings under low-temperature stress, we utilized a Weighted Gene Co-Expression Network Analysis to construct weighted gene co-expression networks associated with physiological indices and metabolites related to low-temperature stress resistance based on transcriptomic data. We screened 11 co-expression modules closely related to low-temperature stress resistance and selected 12 core genes from the two modules that showed the highest associations with the target traits. Following the functional annotation of these genes to determine the key biological processes and metabolic pathways involved in low-temperature stress, we identified four important transcription factors involved in resistance to low-temperature stress: gene-LOC110731664, gene-LOC110736639, gene-LOC110684437, and gene-LOC110720903. These results provide insights into the molecular genetic mechanism of quinoa under low-temperature stress and can be used to breed lines with tolerance to low-temperature stress.

Modulation of physico-chemical and technofunctional properties of quinoa protein isolate: Effect of precipitation acid.

The typically low solubility and gelation capacity of plant proteins can impose challenges in the design of high-quality plant-based foods. The acid used during the precipitation step of plant protein isolate extraction can influence protein functionality. Here, acetic acid and citric acid were used to extract quinoa protein isolate (QPI) from quinoa flour, as these acids are more kosmotropic than the commonly used HCl, promoting the stabilisation of the native protein structure. While proximate analysis showed that total protein was similar for the three isolates, precipitation with kosmotropic acids increased soluble protein, which correlated positively with gel strength. Microstructure analysis revealed that these gels contained a less porous protein network with lipid droplet inclusions. This study shows that the choice of precipitation acid offers an opportunity to tailor the properties of quinoa protein isolate for application, a strategy that is likely applicable to other plant protein isolates.

Effects of superoxide radical on photosynthesis and K+ and redox homeostasis in quinoa and spinach.

Methyl viologen (MV), also known as paraquat, is a widely used herbicide but has also been reported as highly toxic to different life forms. The mode of its operation is related to superoxide radical (O2.-) production and consequent oxidative damage. However, besides the damage to key macromolecules, reactive oxygen species (ROS; to which O2.- belongs) are also known as regulators of numerous ion transport systems located at cellular membranes. In this study, we used MV as a tool to probe the role of O2.- in regulating membrane-transport activity and systemic acquired tolerance in halophytic Chenopodium quinoa and glycophytic spinach plants. Both plant species showed growth reduction in terms of reduced shoot length, lower shoot fresh and dry weight, photosynthesis rate, and chlorophyll contents; however, quinoa showed less reduction in growth compared with spinach. This whole plant response was further examined by measuring the ion concentration, gene expression of ion transporters, activation of antioxidants, and osmolyte accumulation. We observed that at the mechanistic level, the differences in growth in response to MV were conferred by at least four complementary physiological mechanisms: (1) higher K+ loss from spinach leaves resulted from higher expression of MV-induced plasma membrane-based depolarization-activated K+ efflux GORK channel, (2) higher activation of high-affinity K+ uptake transporter HAK5 in quinoa, (3) higher antioxidant production and osmolyte accumulation in quinoa as compared with spinach, and (4) maintaining a higher rate of photosynthesis due to higher chlorophyll contents, and efficiency of photosystem II and reduced ROS and MDA contents. Obtained results also showed that MV induced O2.- significantly reduced N contents in both species but with more pronounced effects in glycophytic spinach. Taken together this study has shown the role of O2.- in regulating membrane ion transport and N metabolism in the leaves of halophyte vs. glycophyte in the context of oxidative stress tolerance.

Polyunsaturated Fatty Acids in Quinoa Induce Ferroptosis of Colon Cancer by Suppressing Stemness.

Polyunsaturated fatty acids (PUFAs) are essential nutrients for the human body, playing crucial roles in reducing blood lipids, anti-inflammatory responses, and anticancer effect. Quinoa is a nutritionally sound food source, rich in PUFAs. This study investigates the role of quinoa polyunsaturated fatty acids (QPAs) on quelling drug resistance in colorectal cancer. The results reveal that QPA downregulates the expression of drug-resistant proteins P-gp, MRP1, and BCRP, thereby enhancing the sensitivity of colorectal cancer drug-resistant cells to the chemotherapy drug. QPA also inhibits the stemness of drug-resistant colorectal cancer cells by reducing the expression of the stemness marker CD44. Consequently, it suppresses the downstream protein SLC7A11 and leads to ferroptosis. Additionally, QPA makes the expression of ferritin lower and increases the concentration of free iron ions within cells, leading to ferroptosis. Overall, QPA has the dual-function reversing drug resistance in colorectal cancer by simultaneously inhibiting stemness and inducing ferroptosis. This study provides a new option for chemotherapy sensitizers and establishes a theoretical foundation for the development and utilization of quinoa.