Tiger Nut (Cyperus esculentus L.): Nutrition, Processing, Function and Applications

Protein from tiger nut meal extracted by deep eutectic solvent and alkali-soluble acid precipitation: A comparative study on structure, function, and nutrition

Protein from tiger nut meal (TNP) performance high nutritional value. This study optimized the extraction parameters for TNP (DES-TNP) using deep eutectic solvent, with HBD: HBA = 5:1, Liquid: Solid = 11:1, and the moisture content was 15 %. A comprehensive comparison was conducted with the protein extracted using alkali-soluble acid precipitation (ASAE-TNP). DES-TNP demonstrated significantly higher purity (76.21 ± 2.59 %) than ASAE-TNP (67.48 ± 1.11 %). Density functional theory confirmed the successful synthesis of DES and its strong interaction with TNP. Moreover, DES-TNP and ASAE-TNP were different in structure (microscopic, secondary, and tertiary) and molecular weight distribution. The discrepancy contributed to the different functional properties, DES-TNP exhibiting better solubility, emulsification and foaming properties at pH13 compared to ASAE-TNP. For nutritional properties, DES-TNP and ASAE-TNP exhibited similar amino acid composition and digestibility, but the total amino acid content of DES-TNP was higher. This study presented a novel method for the extraction and comprehensive utilization of TNP.

Physiological adaptation of Cyperus esculentus L. seedlings to varying concentrations of saline-alkaline stress: Insights from photosynthetic performance

Soil salinization effects plant photosynthesis in a number of global ecosystems. In this study, photosynthetic and physiological parameters were used to elucidate the impacts of saline-alkaline stress on Cyperus esculentus L. (C. esculentus) seedling photosynthesis. The results demonstrate that salt stress, alkali stress and mixed salt and alkali stress treatments all have similar bell-shaped influences on photosynthesis. At low concentrations (0-100 mmol L-1), saline-alkaline stress promoted net photosynthetic rate, transpiration rate and water use efficiency in C. esculentus. However, as the treatments increased in intensity (100-200 mmol L-1), plant photosynthetic parameters began to decline. We interpreted this as the capacity of C. esculentus to improve osmoregulatory capacity in low saline-alkaline stress treatments by accumulating photosynthetic pigment, proline and malondialdehyde to counterbalance the induced stress - an adaptive mechanism that failed once concentrations reached a critical threshold (100 mmol L-1). Stomatal conductance, maximum photosynthetic rate and actual photosynthetic rate all decreased with increasing concentration of the stress treatments, and intercellular carbon dioxide showed a decreasing and then increasing trend. These results indicated that when the saline-alkaline stress concentrations were low, C. esculentus seedlings showed obvious adaptive ability, but when the concentration increased further, the physiological processes of C. esculentus seedlings were significantly affected, with an obvious decrease in photosynthetic efficiency. This study provides a new understanding of the photosynthetic adaptation strategies of C. esculentus seedlings to varying concentrations of saline-alkaline stress.

Effect of microwave-assisted treatment on proximate, techno-functional, thermal, structural, and storage properties of TGN (Cyperus esculentus L.) flour

BACKGROUND

The use of the emerging technique of microwave-assisted roasting on TGN (TGN) flour was investigated. Tiger nuts were subjected to microwave irradiation at 450, 600, and 900 W each at 5, 10, and 15 min, and milled to flour. The flours were analyzed for proximate, bioactive, techno-functional, morphological, thermal, and storage effects on their composition. An untreated sample was the control.

RESULTS

The results revealed that microwave treatment significantly (P < 0.05) elicited various modifications in the proximate composition and techno-functional properties. The treatment improved the bioactive composition of phenolic content together with the antioxidant activity of the flour. Progressive microwave treatment of TGNs resulted in flours with darker colors and reduced pasting parameters. Structural modification of starch granules, protein denaturation, and starch-protein complexes occasioned by microwave treatment were evidenced in the functional group analysis, including morphological agglomeration, increased particle size, and thermal properties. Treatment also enhanced the microbiological qualities of flour after 8 weeks of storage.

CONCLUSION

This study shows that microwave treatment produces excellent physical modifications that lead to improvements in the nutritional, functional, sensory, and color properties, and safety attributes of TGN flour for food application. This is a development that could present opportunities for novel food formulation by the food industry and related industries. © 2024 Society of Chemical Industry.

Radio frequency drying on functional diversity of tiger nut flour: Effects on physicochemical, structural, and rheological properties

Tiger nut (TN) is a valuable nutrient and gluten-free tuber. To achieve high-quality TN flour as functional ingredients in food, it is essential to develop effective drying technologies for TN. Five drying methods including natural drying (Control), hot-air drying (HD), radio frequency single drying (RFSD), RF assisted hot-air drying (RFHD), and RF- vacuum drying (RFVD) were selected and compared to determine their effects on physiochemical, structural, and rheological properties of TN flour. Results showed that RF drying (RFD) significantly improved the hydration, oil-absorbing, and antioxidant activity capacity, especially for RFVD. RFHD exhibited greater color (BI = 13.80 ± 0.05 and C = 10.26 ± 0.05) and reducing sugar content (253.50 ± 2.27 mg d.b.) than RFSD and RFVD. The gelatinization temperature, enthalpy value, and particle size (57.30-269.33 μm) of TN flour were reduced. The structural property results indicated that RFD reduced the relative crystallinity and short-range ordering of the flour, altered protein secondary structure, and caused the damaged microstructure in comparison with Control and HD groups. All sample gels exhibited a weak strain overshoot behavior (type III) under large amplitude oscillations, and RFD resulted in a reduced viscoelastic behavior. RFD could be an effective method to produce functional TN flour.

Potential bioaccessibility and bioavailability of polyphenols and functional properties of tiger nut beverage and its by-product during in vitro digestion

"Horchata de chufa" is a beverage produced from tiger nut tubers, which yields a high amount of by-product. This study explored the functional properties of the Spanish tiger nut beverage (TNB) and its by-product (TNBP) together with the bioaccessibility and bioavailability of polyphenols in vitro. TNB and TNBP were characterized for polyphenols via LC/MS/MS and underwent in vitro digestion (INFOGEST). The total antioxidant capacity (TAC) of all bioaccessible fractions and digestion residues was assessed. Intestinal bioaccessible fractions were tested for the ability to inhibit the activity of digestive enzymes (α-amylase, α-glucosidase, and lipase) and the content of polyphenols, whose bioavailability was assessed in a Caco-2 cell model. Thirteen polyphenols were quantified and found to be more abundant in TNB (603 ± 1.4 μg g-1 DW) than in TNBP (187 ± 1.0 μg g-1 DW). Polyphenol bioaccessibility was higher for TNBP than that for TNB (57% vs. 27%), and despite a similar TAC of the intestinal bioaccessible fractions (10.2 ± 0.1 μmoL vs. 9.2 ± 0.03 μmoL eq. Trolox per g DW for TNB and TNBP, respectively), the different patterns of polyphenols released upon digestion suggested the higher ability of TNBP fraction to inhibit α-glucosidase and lipase. TNBP digestion residue showed higher TAC than TNB. Moreover, TNB polyphenols exhibited over 80% bioavailability, whereas TNBP polyphenols' bioavailability ranged from 62% to 84%. Overall, the findings demonstrated that TNBP maintains a high nutritional value, thus suggesting its possible reuse in innovative, healthy, and sustainable foods.

Tiger nut/coconut dietary intervention as antidotal nutritional remediation strategy against neurobehavioural deficits following organophosphate-induced gut-brain axis dysregulation in mice

Organophosphate poisoning remains a global health crisis without efficacious treatments to prevent neurotoxicity. We examined whether antidotal tiger nut and coconut dietary intervention could ameliorate neurobehavioral deficits from organophosphate dichlorvos-induced gut-brain axis dysregulation in a mouse model. Mice were divided into groups given control diet, dichlorvos-contaminated diets, or dichlorvos plus nut-enriched diets. They were exposed to a DDVP-contaminated diet for 4 weeks before exposure to the treatment diets for another 8 weeks. This was followed by behavioural assessments for cognitive, motor, anxiety-, and depressive-like behaviours. Faecal samples (pre- and post-treatment), as well as blood, brain, and gut tissues, were collected for biochemical assessments following euthanasia. Dichlorvos-exposed mice displayed impairments in cognition, motor function, and mood along with disrupted inflammatory and antioxidant responses, neurotrophic factor levels, and acetylcholinesterase activity in brain and intestinal tissues. Weight loss and altered short-chain fatty acid levels additionally indicated gut dysfunction. However, intervention with tiger nut and/or coconut- enriched diet after dichlorvos exposure attenuated these neurobehavioral, and biochemical alterations. Our findings demonstrate organophosphate-induced communication disruptions between the gut and brain pathways that manifest in neuropsychiatric disturbances. Overall, incorporating fibre-rich nuts may represent an antidotal dietary strategy to reduce neurotoxicity and prevent brain disorders associated with organophosphate poisoning.

A review on the biological and bioactive components of Cyperus esculentus L.: insight on food, health and nutrition

Tiger nut (Cyperus esculentus L.) is a small, tuberous root vegetable that has gained increasing attention in recent years due to its potential health benefits. This review article provides an elaborate overview of tiger nut, including its botany, historical uses, nutritional composition, potential health benefits and traditional medicinal uses. This review article comprehensively discusses the nutritional profile of tiger nut, providing a detailed understanding of its nutrient content. Furthermore, the potential health benefits of tiger nut are thoroughly reviewed, including its effects on digestive health, cardiovascular health, blood sugar control, immune function and other potential therapeutic uses. Scientific articles used for this review were retrieved from ScienceDirect, Google Scholar, PubMed and SciELO databases. Only articles published between 1997 and 2022 were used for research. This review contributes to a better understanding of tiger nut and its prospective uses in functional foods and medicine by combining the available scientific material. © 2024 Society of Chemical Industry.

The Effects of Tremella fuciformis Polysaccharide on the Physicochemical, Multiscale Structure and Digestive Properties of Cyperus esculentus Starch

In this study, we have investigated the effects of Tremella fuciformis polysaccharide (TP) on the pasting, rheological, structural and in vitro digestive properties of Cyperus esculentus starch (CS). The results showed that the addition of TP significantly changed the pasting characteristics of CS, increased the pasting temperature and pasting viscosity, inhibited pasting, reduced the exudation of straight-chain starch and was positively correlated with the amount of TP added. The addition of the appropriate amount of TP could increase its apparent viscosity and enhance its viscoelasticity. The composite system of CS/TP exhibited higher short-range ordered structure and solid dense structure, which protected the crystal structure of CS, but was related to the amount of TP added. In addition, the introduction of TP not only decreased the in vitro digestion rate of CS and increased the content of slow-digestible starch (SDS) and resistant starch (RS), but also reduced the degree of digestion. Correlation studies established that TP could improve the viscoelasticity, relative crystallinity and short-range order of the CS/TP composite gel, maintain the integrity of the starch granule and crystalline structure, reduce the degree of starch pasting and strengthen the gel network structure of CS, which could help to lower the digestibility of CS.

Variability of the Main Economically Valuable Characteristics of Cyperus esculentus L. in Various Ecological and Geographical Conditions

This study includes an assessment of the VIR (Center N.I. Vavilov All-Russian Institute of Plant Genetic Resources) chufa collection, grown in various ecological and geographical conditions of the Russian Federation: "Yekaterininskaya experimental station VIR" in the Tambov region and "Kuban experimental station VIR" in the Krasnodar Region during the years 2020-2021. The main indicators of the economic value of chufa accessions were studied: yield structure and nutritional value (oil, protein, starch, and fatty acid profile). The accessions were grown in regions with different climatic conditions. As a result of the study, the variability of the biochemical and yield characteristics and the correlation between the studied indicators and the factor structure of its variability were established. Of the 20 accessions used in the study, the accessions with the highest protein, starch, oil and unsaturated fatty acid contents were selected, which are the most promising for their use as a raw material to expand the range of regional functional food products, as well as for future breeding efforts in the development of new, promising regional chufa varieties.

Replacing animal proteins with plant proteins: Is this a way to improve quality and functional properties of hybrid cheeses and cheese analogs?

The growing emphasis on dietary health has facilitated the development of plant-based foods. Plant proteins have excellent functional attributes and health-enhancing effects and are also environmentally conscientious and animal-friendly protein sources on a global scale. The addition of plant proteins (including soy protein, pea protein, zein, nut protein, and gluten protein) to diverse cheese varieties and cheese analogs holds the promise of manufacturing symbiotic products that not only have reduced fat content but also exhibit improved protein diversity and overall quality. In this review, we summarized the utilization and importance of various plant proteins in the production of hybrid cheeses and cheese analogs. Meanwhile, classification and processing methods related to these cheese products were reviewed. Furthermore, the impact of different plant proteins on the microstructure, textural properties, physicochemical attributes, rheological behavior, functional aspects, microbiological aspects, and sensory characteristics of both hybrid cheeses and cheese analogs were discussed and compared. Our study explores the potential for the development of cheeses made from full/semi-plant protein ingredients with greater sustainability and health benefits. Additionally, it further emphasizes the substantial chances for scholars and developers to investigate the optimal processing methods and applications of plant proteins in cheeses, thereby improving the market penetration of plant protein hybrid cheeses and cheese analogs.

Structure, nutritional composition, and functionality of xylanase/microwave radiation-pretreated tiger nut

In this study, tiger nut was pretreated with xylanase (Xyl), microwave radiation (MW), and a combination of both (MW + Xyl). The structure, nutritional composition, technofunctional, and antioxidant properties of the pretreated and untreated (control) tiger nut flour (TNF) were investigated. The Fourier transform infrared spectroscopic and X-ray diffractrometric spectra of the control and the pretreated samples are similar; however, there was a slight change in some peaks in the pretreated samples, indicating structural re-organization of macromolecules. Scanning electron microscopic images show reductions of surface erosion and formation of clusters in the MW + Xyl-treated TNF compared to the other pretreated samples. Pretreatment increased the protein, Ca, total phenolic content, and swelling capacity of TNF by 3.71-7.31%, 29.41-32.35%, 4.39-9.65%, and 1.59-6.75%, respectively. Meanwhile, 45.52-58.78% and 11.54-15.38% reductions in fat content and water absorption capacity, respectively, were recorded. Pretreatment of TNF with Xyl and MW + Xyl increased its soluble dietary fiber by 26.84% and 64.34%, respectively; however, a 3.31% reduction was recorded following MW treatment. The highest 2, 2-diphenyl-1-picrylhydrazyl scavenging activity (53.20%) was recorded in the MW + Xyl-treated TNF. These findings proved that pretreating TNF with microwave radiation and Xyl could improve its technological and nutritional qualities, enhancing its applicability in food systems.

Tiger Nut Oil-Based Oil Gel: Preparation, Characterization, and Storage Stability

In this study, Tiger nut (Cyperus esculentus L.) oil-based oleogels were prepared using the emulsion template method with whey protein (WPI; 0.5-2.5% (w/v) and Xanthan gum (XG; 0.1-0.5% (w/v). The microstructure of the oleogels obtained from the high internal phase emulsion (HIPE) and an emulsion after further shearing were observed using an optical microscope and laser confocal microscopy. A series of rheological tests were conducted to evaluate the effect of WPI and XG concentrations on the strength of the emulsion and oleogel. The texture, oil holding capacity, and oxidative stability of oleogels were characterized. The results showed that XG alone could not form oleogel, while the concentration of WPI had more effect than XG. When WPI was at a fixed concentration, the viscoelasticity of HIPE increased with the addition of XG. This was due to the complexation of WPI and XG, forming a stable gel network between the tight emulsion droplets and thus giving it a higher viscoelasticity. With an increase in WPI concentration, the stability and viscoelasticity of the emulsion were increased, and the oil-holding capacity and gel strength of the oleogels were enhanced. Moreover, the addition of XG could significantly enhance the stability and viscoelasticity of the emulsion (p < 0.05), and an increase in the concentration had a positive effect on it. The oleogels showed high gel strength (G' > 15,000 Pa) and good thixotropic recovery when the XG concentration was higher than 0.3% (w/v). WPI (2.0%) and XG (>0.3%) could be used to obtain HIPE with good physicochemical and viscoelastic properties, which in turn lead to oleogels with minimal oil loss, viscoelastic and thixotropic recovery, and temperature stability. Compared with tiger nut oil-based oleogel, tiger nut oil contained more polyunsaturated fatty acids, which were more easily decomposed through oxidation during storage and had lower oxidation stability. This study provides a reference for the preparation of oleogels from food-approved polymers and provides additional theoretical support for their potential application as solid fat substitutes.

Tiger nut (Cyperus esculentus L.) oil: A review of bioactive compounds, extraction technologies, potential hazards and applications

Tiger nut is a tuber of a plant native in the Mediterranean coastal countries, which is of great interest in food industry due to its richness in carbohydrates, lipids, starches, minerals, etc. Recent studies have focused on the analysis of the phytochemical composition of tiger nut, including six essential nutrients, polyphenols, and the extraction of proteins, starches, and phenolic compounds from the by-products of tiger nut milk 'horchata'. Few works were focused on the possibility of using tiger nut oil, a nutritious oil comparable to olive oil, as an edible oil. Therefore, this review discussed some extraction technologies of tiger nut oil, and their effects on the properties of oil, such as bioactive compounds, oxidative stability and potential hazards. The information on the emerging applications of tiger nut oil was summarized and an outlook on the utilization of tiger nut oil by-products were also reviewed.

Exogenous melatonin enhances the tolerance of tiger nut (Cyperus esculentus L.) via DNA damage repair pathway under heavy metal stress (Cd2+) at the sprout stage

Heavy metal (HM) stress is a non-negligible abiotic stress that seriously restricts crop yield and quality, while the sprout stage is the most sensitive to stress and directly impacts the growth and development of the later stage. Melatonin (N-acetyl-5-methoxytryptamine), as an exogenous additive, enhances stress resistance due to its ability to oxidize and reduce. However, few reports on exogenous melatonin to tiger nuts under HM stress have explored whether exogenous melatonin enhances plants' resistance to heavy metals. Here, "Jisha 2″ was used as material, with a stress concentration of 5 mg/L and 100 μmol/L of CdCl2 to explore whether exogenous melatonin enhances plant resistance and molecular mechanism. The result revealed that stress limits growth, while melatonin alleviated the sprout damage under stress from the phenotypes. Moreover, stress-enhanced reactive oxygen species (ROS) accumulation and membrane lipid peroxidation, while melatonin-increased ROS reduce damage via the analysis of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) and malondialdehyde (MDA) content, hydrogen peroxide (H2O2), superoxide anion (O2-), and Electrolyte leakage (El). Further results indicated that HM leads to DNA damage while exogenous melatonin will repair the damage by analyzing random amplified polymorphic DNA (RAPD), DNA cross-linking, 8-hydroxy-20-deoxyguanine level, and relative density of apurinic sites. Furthermore, gene expression in the DNA-repaired pathway exhibited similar results. These results applied that exogenous melatonin released the hurt caused by HM stress, with DNA repair and ROS balance serving as candidate pathways. This study elucidated the mechanism of melatonin's influence and provided theoretical insights into its application in tiger nuts.

Effects of sprouting duration on the nutrient, functional, and phytochemical properties of tiger nut flour, and the sensory properties of bread made thereof

The influence of sprouting on tiger nut's (TN) nutritional, functional, and phytochemical quality was examined, and the flour used for bread making to evaluate the feasibility as a functional ingredient. TN was sprouted and sampled at 3 days intervals for 12 days, dried and milled into flour and analyzed. Subsequently, 25% of wheat flour (WF) was replaced with the 9 days-sprouted TN flour for bread. Sprouting for 9 days increased the protein content from 9.19 ± 0.04 to 9.79 ± 0.15 g/100 g dry matter (DM), fiber from 6.75 ± 0.16 to 9.27 ± 0.44 g/100 g DM, and ash from 2.34 ± 0.10 to 2.70 ± 0.06 g/100 g DM but decreased fat content from 26.10 ± 0.18 to 23.18 ± 0.43 g/100 g DM and soluble sugar from 33.13 ± 1.25 to 23.75 ± 1.44 °Bx. We observed increases in the polyphenols (94.16 ± 6.43-214.23 ± 6.98 mg GAE/100 g) and ascorbic acid (26.66 ± 0.17-65.13 ± 0.19 mg AE/100 g) and decreases in the cyanogenic glycosides (273.79 ± 0.37-231.54 ± 3.53 mg/100 g) and oxalates (19.04 ± 1.14-5.65 ± 0.93 mg/100 g) contents. Sprouting decreased the particle size and increased the water retention and swelling power of TN flour. WF bread was described as stretchy, sweet, and creamy, whereas sprouted TN bread was brown, nutty, and wheat-like. Consumer acceptance for the sprouted TN bread was comparable to WF bread, showing the possible application in bread making. PRACTICAL APPLICATION: The outcome of the study could help to exploit the nutri-functional and phytochemical benefits of sprouted TN in the baking industry for producing acceptable products. This would enhance the utility of TN for food in regions where TNs grows.

Tiger Nut Milk's Antiviral Properties against Enveloped and Non-Enveloped Viruses: Effect of Concentration and Adding Sugar

The global COVID-19 pandemic has warned scientists of the requirement to look for new antimicrobial compounds to prevent infection by this type of viral pathogen. Natural compounds are becoming a promising avenue of research thanks to their renewable, biodegradable, and non-toxic properties. In this work, tiger nut milk's (TNM) antiviral properties, with and without sugar, were studied against enveloped and non-enveloped viruses. The antiviral properties of TNM were evaluated at different concentrations. The antiviral tests showed that TNM is antiviral against the enveloped bacteriophage phi 6, which is commonly used as a surrogate for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), although it did not have any antiviral effect against the non-enveloped bacteriophage MS2. We also found that adding sugar to this natural drink can improve its antiviral properties against enveloped viruses and render it antiviral against non-enveloped viruses like bacteriophage MS2. The antiviral activity of TNM depends on the TNM concentration. TNM is a natural bioproduct that could help to fight against viral infections and protect against a wide range of viral illnesses. These results confirm that the typical sweetened drink made from tiger nut extract and sugar (known as horchata in Spain) possesses broad-spectrum antiviral properties.

Analysis of oil synthesis pathway in Cyperus esculentus tubers and identification of oleosin and caleosin genes

The tubers of the widely distributed Cyperus esculentus are rich in oil, and therefore, the plant is considered to have a high utilization value in the vegetable oil industry. Oleosins and caleosins are lipid-associated proteins found in oil bodies of seeds; however oleosins and caleosins genes have not been identified in C. esculentus. In this study, we performed transcriptome sequencing and lipid metabolome analysis of C. esculentus tubers at four developmental stages to obtain the information on their genetic profile, expression trends, and metabolites in oil accumulation pathways. Overall, 120,881 non-redundant unigenes and 255 lipids were detected; 18 genes belonged to the acetyl-CoA carboxylase (ACC), malonyl-CoA:ACP transacylase (MCAT), β-ketoacyl-ACP synthase (KAS), and fatty acyl-ACP thioesterase (FAT) gene families involved in fatty acid biosynthesis, and 16 genes belonged to the glycerol-3-phosphate acyltransferase (GPAT), diacylglycerol acyltransferase 3 (DGAT3), phospholipid:diacylglycerol acyltransferase (PDAT), FAD2, and lysophosphatidic acid acyltransferase (LPAAT) gene families playing important roles in triacylglycerol synthesis. We also identified 9 oleosin- and 21 caleosin-encoding genes in C. esculentus tubers. These results provide detailed information on the C. esculentus transcriptional and metabolic profiles, which can be used as reference for the development of strategies to increase oil content in C. esculentus tubers.

Chromosome-scale Genome Assembly of the Yellow Nutsedge (Cyperus esculentus)

The yellow nutsedge (Cyperus esculentus L. 1753) is an unconventional oil plant with oil-rich tubers, and a potential alternative for traditional oil crops. Here, we reported the first high-quality and chromosome-level genome assembly of the yellow nutsedge generated by combining PacBio HiFi long reads, Novaseq short reads, and Hi-C data. The final genome size is 225.6 Mb with an N50 of 4.3 Mb. More than 222.9 Mb scaffolds were anchored to 54 pseudochromosomes with a BUSCO score of 96.0%. We identified 76.5 Mb (33.9%) repetitive sequences across the genome. A total of 23,613 protein-coding genes were predicted in this genome, of which 22,847 (96.8%) were functionally annotated. A whole-genome duplication event was found after the divergence of Carex littledalei and Rhynchospora breviuscula, indicating the rich genetic resources of this species for adaptive evolution. Several significantly enriched GO terms were related to invasiveness of the yellow nutsedge, which may explain its plastic adaptability. In addition, several enriched Kyoto Encyclopedia of Genes and Genomes pathways and expanded gene families were closely related with substances in tubers, partially explaining the genomic basis of characteristics of this oil-rich tuber.

Analysis of Lhc family genes reveals development regulation and diurnal fluctuation expression patterns in Cyperus esculentus, a Cyperaceae plant

Sixteen Lhc genes representing 13 phylogenetic groups were identified from the full-length transcriptome of tigernut, exhibiting development regulation and diurnal fluctuation expression patterns in leaves. Nuclear encoded light-harvesting chlorophyll a/b-binding (Lhc) proteins play indispensable roles in oxygenic photosynthesis. In this study, we present the first transcriptome-based characterization of Lhc family genes in tigernut (Cyperus esculentus L.), a Cyperaceae C₄ plant producing oil in underground tubers. A number of 16 Lhc genes representing 13 phylogenetic groups identified from the full-length tigernut transcriptome are equal to that found in both Carex littledalei (another Cyperaceae plant) and papaya, slightly more than 15 members present in both rice and jatropha, but relatively less than 18, 20, and 21 members present in sorghum, cassava, and Arabidopsis, respectively. Nevertheless, nearly one-vs-one orthologous relationship was observed in most groups, though some of them are no longer located in syntenic blocks and species-specific expansion was frequently found in Lhcb1. Comparative genomics analysis revealed that the loss of two groups (i.e., Lhca2 and Lhca5) in C. littledalei is species-specific, sometime after the split with tigernut, and the expansion of Lhcb1 was mainly contributed by tandem duplication as observed in most species. Interestingly, a transposed duplication, which appears to be shared by monocots, was also identified in Lhcb1. Further transcriptome profiling revealed a predominant expression pattern of most CeLhc family genes in photosynthetic tissues and enhanced transcription during leaf maturation, reflecting their key roles in light absorption. Moreover, qRT-PCR analysis revealed an apparent diurnal fluctuation expression pattern of 11 dominant CeLhc genes. These findings not only highlight species-specific evolution of Lhc genes in the Cyperaceae family as well as the monocot lineage, but also provide valuable information for further functional analysis and genetic improvement in tigernut.

The Potential Neuroprotective Effect of Cyperus esculentus L. Extract in Scopolamine-Induced Cognitive Impairment in Rats: Extensive Biological and Metabolomics Approaches

The aim of the present study is to investigate the phytochemical composition of tiger nut (TN) (Cyperus esculentus L.) and its neuroprotective potential in scopolamine (Scop)-induced cognitive impairment in rats. The UHPLC-ESI-QTOF-MS analysis enabled the putative annotation of 88 metabolites, such as saccharides, amino acids, organic acids, fatty acids, phenolic compounds and flavonoids. Treatment with TN extract restored Scop-induced learning and memory impairments. In parallel, TN extract succeeded in lowering amyloid beta, β-secretase protein expression and acetylcholine esterase (AChE) activity in the hippocampus of rats. TN extract decreased malondialdehyde levels, restored antioxidant levels and reduced proinflammatory cytokines as well as the Bax/Bcl2 ratio. Histopathological analysis demonstrated marked neuroprotection in TN-treated groups. In conclusion, the present study reveals that TN extract attenuates Scop-induced memory impairments by diminishing amyloid beta aggregates, as well as its anti-inflammatory, antioxidant, anti-apoptotic and anti-AChE activities.

RNA-Seq Analysis Demonstrates Different Strategies Employed by Tiger Nuts (Cyperus esculentus L.) in Response to Drought Stress

Drought stress, an important abiotic stress, has affected global agricultural production by limiting the yield and the quality of crops. Tiger nuts (Cyperus esculentus L.) are C4 crops in the Cyperaceae family, which have high-quality wholesome ingredients. However, data on mechanisms underlying the response of tiger nuts to drought stress are few. Here, the variety of Jisha 1 and 15% polyethylene glycol (PEG; a drought stress simulator) were used to study the mechanisms of stress response in tiger nuts. Our evaluation of the changes in physiological indicators such as electrolyte leakage (El), malondialdehyde (MDA), hydrogen peroxide (H₂O₂), superoxide anion (O₂⁻) and activities of reactive oxygen species (ROS) showed that 12 h was the most suitable time point to harvest and analyze the response to drought stress. Thereafter, we performed transcriptome (RNA-Seq) analysis in the control (CK) and stress treatment groups and showed that there was a total of 1760 differentially expressed genes (DEGs). Gene Ontology (GO) analysis showed that the DEGs were enriched in abscisic acid (ABA) terms, and pathways such as starch and sucrose metabolism (ko00500), phenylpropanoid biosynthesis (ko00940) and plant hormone signal transduction (ko04075) were significantly enriched in the Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. In addition, quantitative real-time PCR (qRT-PCR) analysis of the DEGs demonstrated an upregulation of ABA and lignin content, as well as enzyme activities in enriched pathways, which validated the RNA-Seq data. These results revealed the pathways and mechanisms adopted by the tiger nuts in response to drought stress.

Fabrication of benzoyl chloride treated tiger-nut fiber reinforced insect repellent hybrid composite

An insect repellent composite containing tiger nut particulate fibre, waste low density polyethene (LDPE) and castor oil alkyd resin was fabricated. Canarium schweinfurthii gum was used as insect repellent compound and maleic anhydride as compatibilizer. The tiger nut chaff was subjected to benzoylation using benzoyl chloride to increase the fibre-matrix interaction. The compound and composition was then moulded with LDPE as dual matrices for excellent physico-mechanical properties (pressed for 5 min, 130 °C and 25 bar and cured). The 10 wt.% treated composite exhibited a minimum water absorption of ~ 0.085%, optimal chemical resistance for both acids (HCl and H₂SO₄) and bases (NaOH and KOH) and no effect on thickness. Density measurement showed the lowest value of ~ 0.0096 g/cm³ for the treated fibre composite. However, the tensile strength, flexural stress, hardness and impact load were improved up to 35.08 Mpa, 456.3 Mpa, 95 and 730 J/m respectively with treated composites. Insect repellent tests against termites and cockroaches show repellent activity with time intervals. FTIR and SEM analysis showed fibre modification achieved.

Cyperus (Cyperus esculentus L.): A Review of Its Compositions, Medical Efficacy, Antibacterial Activity and Allelopathic Potentials

Cyperus (Cyperus esculentus L.) is an edible perennial grass-like plant, which propagates exclusively with underground tubers. Its tubers are rich in starch (20-30%), fat (25-35%), sugar (10-20%), protein (10-15%) and dietary fiber (8-9%). In addition, the tubers also contain alkaloids, organic acids, vitamins (C and E), steroids, terpenoids and other active components. The contents of oleic acid and linoleic acid in Cyperus oil are very high, which have important medicinal value and health-promoting properties. Most of the extracts from the tubers, stems and leaves of Cyperus have allelopathic potential and antibacterial, antioxidant and insecticidal activities. In recent years, the planting area of Cyperus has increased significantly all over the world, especially in China and some other countries. This paper presents the current status of Cyperus and the recent trend in research in this area. Published reports on its nutritional contents, active ingredients, medicinal efficacy, antibacterial activity and allelopathic potential were also reviewed.