Rice Protein Research Articles

Analysis of Microheterogeneous Glutelin Subunits and Highly Efficient Identification of Selenylation Peptides by In-Gel Proteolysis: Focus on Se-Enriched Rice.

Selenylation of cysteine and methionine thiols through selenate supplements increases the content of selenium-containing amino acids in various agricultural products. This modification results in numerous biological and health benefits. Despite their critical roles in human physiology, methods for high-coverage and efficient identification of selenylation peptides are limited. This study systematically developed a mass spectrometric method to identify selenylation peptides combined with in-gel trypsin proteolysis. In-gel proteolysis identified the two well-separated bands containing rice glutelin. We identified 11 rice glutelin subunits along with 42 selenylation peptides from the glutelin acidic subunits and 30 selenylation peptides from the glutelin basic subunits with high confidence. A comprehensive evaluation disclosed the mapping of selenium-containing rice glutelin subunits. Additionally, the selenylation modification of peptides coexisted with oxidation and iodoacetamide (IAM) alkylation. Moreover, the multidimensional MS criteria validated the results, while spectral statistics revealed the veritable Se/S substitution degree in Se-enriched rice. These findings collectively demonstrated the presence of numerous selenation sites in microheterogeneous glutelin subunits, thereby enhancing our understanding of the seleno-peptidomics of rice proteins. As significant bioactive organic compounds, the identified peptides in this study are promising candidates for a variety of bioactivities, including neuroprotective, anti-inflammatory, antioxidant, hepatoprotective, and immunomodulatory effects.

Nuclear localization sequence of MoHTR1, a Magnaporthe oryzae effector, for transcriptional reprogramming of immunity genes in rice.

Plant pathogens secrete nuclear effectors into the host nuclei to modulate the host immune system. Although several nuclear effectors of fungal pathogens have been recently reported, the molecular mechanism of NLS-associated transport vehicles of nuclear effectors and the roles of NLS in transcriptional reprogramming of host immunity genes remain enigmatic. We previously reported the MoHTR1, a nuclear effector of the rice blast fungus, Magnaporthe oryzae. MoHTR1 is translocated to rice nuclei but not in fungal nuclei. Here, we identify the core NLS (RxKK) responsible for MoHTR1's nuclear localization. MoHTR1 is translocated in the host nucleus through interaction with rice importin α. MoHTR1 NLS empowers it to translocate the cytoplasmic effectors of M. oryzae into rice nuclei. Furthermore, other nuclear effector candidates of the blast pathogen and rice proteins which have RxKK also exhibit nuclear localization, highlighting the crucial role of RxKK in this process. We also unveil the importance of SUMOylation in the stability of MoHTR1 and translocation of MoHTR1 to host nuclei. Moreover, MoHTR1 NLS is essential for the pathogenicity of M. oryzae by reprogramming immunity-associated genes in the host. Our findings provide insights into the significance of plant-specific NLS on fungal nuclear effectors and its role in plant-pathogen interactions.

Virulence effectors encoded in the rice yellow dwarf phytoplasma genome participate in pathogenesis.

Bacteria-like phytoplasmas alternate between plant and insect hosts, secreting proteins that disrupt host development. In this study, we sequenced the complete genome of 'Candidatus Phytoplasma oryzae' strain HN2022, associated with rice yellow dwarf (RYD) disease, using PacBio HiFi technology. The strain was classified within the 16Sr XI-B subgroup. Through SignalP v5.0 for prediction and subsequent expression analysis of secreted proteins in Nicotiana benthamiana and rice (Oryza sativa L.), we identified the key virulence effector proteins RY348 and RY378. RY348, a homologue of Secreted Aster Yellows Phytoplasma Effector 54 (SAP54), targets and degrades the MADS-box transcription factors MADS1 and MADS15, causing pollen sterility. Meanwhile, RY378 impacts the strigolactone and auxin signaling pathways, substantially increasing tillering. These findings offer insights into the interactions between plants and phytoplasmas.

Pea and rice proteins with gellan gum and monovalent salts for the development of plant-based gels for food applications

Pea and rice proteins with gellan gum and monovalent salts for the development of plant-based gels for food applications

Enhancement of the rice protein solubility using industry-scale microfluidization and pH cycling: A mechanistic study

Enhancement of the rice protein solubility using industry-scale microfluidization and pH cycling: A mechanistic study

Probiotic and Rice-Derived Compound Combination Mitigates Colitis Severity

Background: This study investigated the ability of Enterococcus lactis (E. lactis) and Hasawi rice protein lysate (HPL) to suppress colitis induced by dextran sulfate sodium (DSS) in miceColitis is characterized by inflammation of the colon, and exploring potential therapeutic agents could lead to improved management strategies. Methods: Male mice were subjected to DSS treatment to induce colitis, followed by supplementation with E. lactis and/or HPL. The study assessed various parameters, including disease activity index (DAI) scores, gut permeability measured using FITC-dextran, and superoxide dismutase (SOD) activity in excised colon tissues from both treated and untreated control groups. Results: E. lactis supplementation significantly alleviated DSS-induced colitis, as evidenced by improved DAI scores and enhanced gut permeability. Notably, E. lactis combined with HPL (0.1 mg/108) exhibited superior tolerance to a 0.5% pancreatin solution compared to E. lactis alone. Both E. lactis and the combination treatment significantly increased SOD activity (5.6 ± 0.23 SOD U/mg protein for E. lactis and 6.7 ± 0.23 SOD U/mg protein for the combination) relative to the Azoxymethane (AOM)/DSS group, suggesting a reduction in oxidative stress. Additionally, pro-inflammatory markers were significantly reduced in the group receiving both E. lactis and HPL compared to the E. lactis-only group. Levels of proteins associated with cell death, such as PCNA, PTEN, VEGF, COX-2, and STAT-3, were significantly decreased by 14.8% to 80% following E. lactis supplementation, with the combination treatment showing the most pronounced effects. Conclusions: These findings suggest E. lactis supplementation may be beneficial for colitis, with HPL potential to enhance its effectiveness.

Food freshness and composition evaluated by Colorimetry, TPA, and spectroscopy through ICA-based ComDim: A case study of a peanut-based protein-enriched food

This study aimed to apply Common Components and Specific Weights Analysis (CCSWA or ComDim) to explore the relations between colorimetry (color), Texture Profile Analysis (TPA), and Near-Infrared Spectroscopy (NIR) besides determining which of these techniques is most effective in differentiating the freshness and composition of the studied samples. ComDim-ICA, a recent modification of ComDim based on Independent Components Analysis (ICA) decomposition, was used. This approach was chosen to provide more straightforward and interpretable scores and loadings compared to the classical ComDim, which is based on Principal Components Analysis (PCA). The experiment was performed on a peanut-based food enriched with powdered proteins derived from pumpkin seed, rice, pea, sunflower seed, water lentil (duckweed), flaxseed, soybean, and whey. Measurements (Color, NIR, and TPA) were taken on the day of the food preparation, after seven days, and after fourteen days. The global scores indicated that CC2 carried information regarding freshness, while CC3, CC4, and CC5 were associated with food composition. According to the saliences, NIR and color were the most important techniques for determining food freshness (the most important in CC2). Additionally, in CC3, NIR was responsible for distinguishing lentil and rice proteins from the other protein sources. The best differentiation regarding food composition was found in CC4 and CC5, where colorimetry and TPA were most significant. These findings may encourage new applications of multiblock analysis to elucidate differences in food quality based on diverse evaluation techniques.

Enhances the resistance of rice to lepidopteran pests by fusing the Cry1Ca and Cry2Aa genes with self-cleavage peptide sequence.

Accumulation of two or more Bacillus thuringiensis (Bt) proteins in plant not only improves the resistance to pests and broadens the resistance spectrum of crops, but also delays the development of pest resistance. The self-cleavage peptide sequence was used to link two codon-optimized genes, so as to achieve simultaneous accumulation of two low homologous insecticidal proteins in one plant. The rice transformants accumulating Cry1Ca and Cry2Aa proteins were fed to local lepidopteran pests and the larva mortality in 5 days were 100%. The sum of Cry1Ca and Cry2Aa proteins in leaves of transformants E1C&2A-1 and E2A&1C-18 were 10.60 and 9.55 μg g-1 fresh weight (FW), respectively, and the larva mortality of fall armyworm fed on their leaves for 5 days reached 100%. For the control transformants that expressed one Bt protein, the content of Cry1Ca in leaves of transformant E1CM031 was 14.94 μg g-1 FW, and that of Cry2Aa in leaves of transformant B2A4008S was 11.90 μg g-1 FW, but the larva mortality of fall armyworm fed on leaves of E1CM031 and B2A4008S for 5 days were 77.78% and 52.78%, respectively. Although the total Bt contents in transformants expressing one Bt protein were higher than that of transformants expressing two Bt proteins, the lethality of transformants expressing one Bt protein were obviously lower than that of transformants expressing two Bt proteins. The lethal effect of accumulating both Cry1Ca and Cry2Aa proteins in rice was stronger than that of amassing Cry1Ca or Cry2Aa protein only, which meant there was synergistic effect between Cry1Ca and Cry2Aa proteins. © 2024 Society of Chemical Industry.

Estimation of Rice Protein Content Based on Unmanned Aerial Vehicle Hyperspectral Imaging

Estimation of Rice Protein Content Based on Unmanned Aerial Vehicle Hyperspectral Imaging

Rice Protein Peptides Alleviate Alcoholic Liver Disease via the PPARγ Signaling Pathway: Through Liver Metabolomics and Gut Microbiota Analysis.

Alcoholic liver disease (ALD) is the predominant type of liver disease worldwide, resulting in significant mortality and a high disease burden. ALD damages multiple organs, including the liver, gut, and brain, causing inflammation, oxidative stress, and fat deposition. In this study, we investigated the effects of rice protein peptides (RPP) on ALD in mice with a primary focus on the gut microbiota and liver metabolites. The results showed that administration of RPP significantly alleviated the symptoms of ALD in mice including adiposity, oxidative stress, and inflammation. The KEGG pathway shows that RPP downregulates the liver metabolite of capric acid and the metabolism of fatty acid biosynthesis compared with the MOD group. Mechanistically, RPP downregulated the PPARγ signaling pathway and suppressed the expression of fatty acid biosynthesis genes (FASN, ACC1, ACSL1, and ACSL3). Furthermore, two active peptides (YLPTKQ and PKLPR) with potential therapeutic functions for ALD were screened by Caco-2 cell modeling and molecular docking techniques. In addition, RPP treatment alleviates gut microbiota dysbiosis by reversing the F/B ratio, increasing the relative abundance of Alloprevotella and Alistipes, and upregulating the level of short-chain fatty acids. In conclusion, RPP alleviates ALD steatosis through the PPARγ signaling pathway by YLPTKQ and PKLPR and regulates gut microbiota.

Microencapsulation of a Flaxseed and Avocado Oil Blend: Influence of Octenyl Succinic Anhydride (OSA)-Modified Starch and Rice and Pea Proteins on Powder Characterization and Oxidative Stability

This work investigated the influence of the OSA-modified starch, pea protein, and rice protein combination in the microencapsulation process of a blend of avocado and flaxseed oil (25–75%, w/w) by freeze-drying, focusing on emulsions and powders characteristics and oxidative stability. Four different ratios between the mixture of vegetable proteins (1:1) and the OSA-modified starch were analyzed, using a fixed ratio between the oils blend and the combined encapsulant agents of 1:3. Based on the creaming index, the separation of hydrophilic and hydrophobic phases was not observed. The results demonstrated a tendency to increase the droplet mean diameter with increased protein content (4.71–19.36 μm). An increase in the encapsulation efficiency was verified with the increase in the OSA-modified starch content (51.33–60.32%). Powders presented low moisture content and hygroscopicity, and an oxidative induction time value varying from 0.86 to 1.18 h. The increase in the vegetable protein content increased the powders’ oxidative stability, which could be associated with the antioxidant capacity of rice and pea proteins.

The roles of Magnaporthe oryzae avirulence effectors involved in blast resistance/susceptibility.

Phytopathogens represent an ongoing threat to crop production and a significant impediment to global food security. During the infection process, these pathogens spatiotemporally deploy a large array of effectors to sabotage host defense machinery and/or manipulate cellular pathways, thereby facilitating colonization and infection. However, besides their pivotal roles in pathogenesis, certain effectors, known as avirulence (AVR) effectors, can be directly or indirectly perceived by plant resistance (R) proteins, leading to race-specific resistance. An in-depth understanding of the intricate AVR-R interactions is instrumental for genetic improvement of crops and safeguarding them from diseases. Magnaporthe oryzae (M. oryzae), the causative agent of rice blast disease, is an exceptionally virulent and devastating fungal pathogen that induces blast disease on over 50 monocot plant species, including economically important crops. Rice-M. oryzae pathosystem serves as a prime model for functional dissection of AVR effectors and their interactions with R proteins and other target proteins in rice due to its scientific advantages and economic importance. Significant progress has been made in elucidating the potential roles of AVR effectors in the interaction between rice and M. oryzae over the past two decades. This review comprehensively discusses recent advancements in the field of M. oryzae AVR effectors, with a specific focus on their multifaceted roles through interactions with corresponding R/target proteins in rice during infection. Furthermore, we deliberated on the emerging strategies for engineering R proteins by leveraging the structural insights gained from M. oryzae AVR effectors.

Influence of Brown Rice, Pea, and Soy Proteins on the Physicochemical Properties and Sensory Acceptance of Dairy‐Free Frozen Dessert

ABSTRACTFat and protein derived from milk are prime ingredients in a frozen dessert such as ice cream conferring multiple desirable functionalities. However, this frozen dairy dessert is not suitable for individuals having lactose intolerance, cow milk allergy, or vegans. Hence, the study aimed to formulate dairy‐free frozen desserts using plant oils and plant proteins and compare their physicochemical characteristics and sensory acceptance against an ice cream containing milk fat and milk protein. Results indicated that the types of protein significantly influenced the physicochemical properties and sensory acceptance of the frozen dessert samples. Frozen desserts containing brown rice, pea, and soy protein showed greater resistance to melting (0.29, 0.12, and 0.19%/min vs. 1.95%/min), but they scored lower in sensory quality than ice cream made with milk protein; although they remained at an acceptable level. When compared among the plant proteins, the physicochemical characteristics of frozen desserts containing brown rice, pea, and soy protein varied because of the differences in the respective protein composition. Frozen dessert with brown rice protein showed higher overrun (47.50% vs. 40.78% and 37.8%), lower hardness (20.02 N vs. 22.24 and 26.37 N), and higher melting rate (0.29%/min vs. 0.19 and 0.12%/min) than frozen desserts containing soy and pea protein. Additionally, the brown rice protein frozen dessert received lower sensory acceptance than soy and pea protein frozen desserts. In summary, brown rice, pea, and soy proteins showed potential to be used as viable alternatives to milk protein for dairy‐free frozen dessert applications.

Improved qualities of cod-rice dual-protein gel as affected by rice protein: Insight into molecular flexibility, protein interaction and gel properties

Blending plant-based proteins with animal-based proteins to achieve adequate dietary protein intake is a strategy to address dietary deficiencies in the elderly. This research systematically investigated the effect of the ratio of cod protein/rice protein (21:0, 21:1.5, 21:3, 21:4.5, 21:6, 21:7.5, and 21:9) on the gelation properties of dual-protein gels and the underlying dual-protein interaction mechanisms. The results indicated that the myosin heavy chain (MHC) of cod and the glutelin in rice protein are primarily linked by hydrogen bonds, particularly involving Tyr residues, as evidenced by molecular docking and fluorescence quenching results. The addition of rice protein in cod protein promoted α-helix transforming into β-sheet, β-turn and random coil of the original protein solution, which was significantly correlated with molecule flexibility increasing. The decrease in the dual-protein particle size, and rice protein uniformly distributed in a cod protein-based gel network, which promoted the compactness and density of the gel structure. It was found that the hardness and springiness of 21:6 cod-rice protein gel increased by 73.96% and 17.28% compared to single cod gel, respectively. This study provides theoretical basis to the mechanism of dual-protein interaction affecting gel properties from the molecular level.

Evaluation of a Sustainable Production of Encapsulated Chili Pepper Powder (Capsicum pubescens) through Convective and Vacuum Drying

Throughout the world, chili and chili powders are spices of considerable economic importance. Rocoto (Capsicum pubescens R. & P.) is a chili pepper used in Andean cuisine. Fresh chili is perishable and therefore it is convenient to protect the capsaicin, color and other bioactive compounds through preservation methods such as encapsulation. The present study systematically evaluates the technical and environmental aspects of producing encapsulated Rocoto red chili powder using three different wall materials—maltodextrin, rice protein and rice flour—in conjunction with two drying methods, namely convection drying and vacuum drying. Our technical objectives focused on developing an encapsulated product with high heat and vibrant red color, key attributes that significantly influence consumer purchasing behavior. In addition, the study aimed to mitigate the loss of polyphenols, flavonoids and antioxidant activity. After identifying the optimal conditions for each wall material and drying process, a comprehensive environmental assessment was conducted to identify the most efficient and sustainable production methods. The results demonstrate that rice flour encapsulation (20%) in conjunction with hot air drying (40 °C) represents the most efficacious method for the preservation of chili powder’s pungency. This approach resulted in a mere 24% reduction in Scoville units while maintaining the powder’s vibrant red coloration. This method not only preserved key bioactive compounds, including capsaicin, polyphenols and flavonoids, but also significantly enhanced the antioxidant capacity of the product. From an environmental perspective, this approach offers significant sustainability benefits, reducing the overall environmental impact by approximately 72% compared to vacuum drying of unencapsulated chili. The use of rice flour as an encapsulant aligns with sustainability goals, making it the most efficient option for balancing product quality and environmental performance.

Selenium-containing peptides as effective alleviators for low-level lead induced neural damage

The TSeMMM and SeMDPGQQ, two selenium-containing peptides derived from Se-enriched rice protein hydrolysates, have previously been demonstrated to show neuroprotective properties against high-dose lead exposure. However, the potential toxicological effects of these functional peptides on low-dose lead-induced neurotoxicity remain poorly understood. The present study aimed to investigate the protective mechanism of two selenium-containing peptides in mitigating low-dose Pb2+-induced damage in HT22 cells. Results showed that treatment with 40 μmol/L Pb2+ significantly reduced cell viability and increased apoptosis, both of which were alleviated by 40 μmol/L TSeMMM and SeMDPGQQ treatment. Furthermore, two peptides exhibited antioxidant potentials by reducing reactive oxygen species levels to 32.19% and 79.29% of the model group, respectively. They also enhanced antioxidant enzyme activities and mitigated oxidative stress through activation of the Keap1/Nrf2 pathway. Additionally, two peptides improved mitochondrial function by elevating mitochondrial membrane potential, ATP production while dramatically reducing reactive oxygen species levels. Interestingly, TSeMMM exhibited superior neurointerventional effects compared to SeMDPGQQ. The RNA sequencing analysis revealed that TSeMMM modulated gene expressions related to oxidative stress and neuroprotective function. The study provides insights into the protective mechanism underlying selenium-containing peptides for mitigating neuronal damage.

Fermented plant-based beverage supplemented with uvaia (Eugenia pyriformis) pulp: an innovative and pioneering approach to diversify plant-based diet product market

Over the years, there has been an increase in demand for plant-based foods as alternatives. In line with this, this work explores the production and in vitro digestion of a fermented plant-based beverage (FPBB) produced with pea and rice proteins and 0% (FPBB-C), 5% (FPBB-5), and 10% (FPBB-10) uvaia pulp through lactic fermentation with Lacticaseibacillus rhamnosus GG. The in vitro gastrointestinal digestion process was conducted to assess the bioaccessibility of L. rhamnosus GG, total phenolic content (TPC), and antioxidant activity before and after simulating the gastrointestinal conditions. After 48 h of digestion, highly viable L. rhamnosus GG cells remained throughout the gastrointestinal system. FPBB-C (106.89%) and FPBB-5 (109.38%) exhibited higher survival rates than FPBB-10 (102.20%), indicating that these beverages have a higher prebiotic action potential. Compared with the non-digested samples, after 48 h of digestion, all samples exhibited a significant increase in TPC. The same behavior occurs for the antioxidant activity of FPBB-C, FPBB-5, and FPBB-10 by DPPH (4.06, 3.96, and 8.44 mg TEAC mL−1), ABTS (10.28, 11.06, 11.97 mg TEAC mL−1), and FRAP method (917.02, 863.87, and 1983.23 mg TEAC mL−1). Thirteen compounds were identified and quantified in uvaia pulp by HPLC-DAD-ESI-MS, particularly epigallocatechin gallate, quercetin-3-rhamnose, and quercetin-3-glucoside. Isorhamnetin was the main phenolic compound detected in the colon, assumably due to the conversion of quercetin-3-glucoside by the probiotic cells. In conclusion, as all counts were above 9 log CFU g−1, the FPBB formulations containing pea, rice protein, and uvaia pulp become a promising vehicle for carrying L. rhamnosus GG.

Exploration of changes in rheological and spectral properties of rice protein inks before and after 3D printing

The aim of this work was to understand the effect of the printing process on food inks by applying the chemometric approach to analyze the rheological and spectral properties of rice protein. Rice protein was printed under two conditions (speed: 35 and 50 mm/s, layer height: 1.5 and 1.2 mm, and nozzle diameter: 1.7 and 1.2 mm). Infrared spectroscopy and oscillatory tests at 1 Pa between 0.1 and 10 Hz were performed before and after printing. PCA and k-means analysis of rheological and spectral data identified patterns and significant differences. The analysis revealed that 3D printing affects rheological properties, reducing structural stiffness and modifying the relationship between elastic and viscous behavior. Spectral vibrations associated with NH, CH3, O-H, and C=O functional groups indicated significant structural changes due to the printing process. These results suggest that the printing process influences food inks' rheological and structural properties.

Genome-Wide Association Study Reveals Marker–Trait Associations for Heat-Stress Tolerance in Sweet Corn

Sweet corn (Zea mays var. rugosa Bonaf.) is a crop with a high economic benefit in tropical and subtropical regions. Heat tolerance analysis and heat-tolerant gene mining are of great significance for breeding heat-resistant varieties. By combining improved genotyping using targeted sequencing (GBTS) with liquid chip (LC) technology, a high-density marker array containing 40 K multiple single polynucleotide polymorphisms (mSNPs) was used to genotype 376 sweet corn inbred lines and their heat-stress tolerance was evaluated in the spring and summer of 2019. In general, plant height, ear height and the number of lateral branches at the first level of the male flowers were reduced by 24.0%, 36.3%, and 19.8%, respectively. High temperatures in the summer accelerated the growth process of the sweet corn, shortening the days to shedding pollen by an average of 21.6% compared to the spring. A genome-wide association study (GWAS) identified 85 significant SNPs distributed on 10 chromosomes. Phenotypes in the spring and summer were associated with the 21 and 15 loci, respectively, and significant phenotypic differences between the two seasons caused by the temperature change were associated with the 49 SNP loci. The seed setting rate (SSR) was more susceptible to heat stress. An annotation analysis identified six candidate genes, which are either heat shock transcription factors (Hsfs) or heat shock proteins (Hsps) in Arabidopsis and rice (Oryza sativa), and these candidate genes were directly and indirectly involved in the heat-resistant response in the sweet corn. The current findings provide genetic resources for improving the heat-stress tolerance of sweet corn by molecular breeding.

Phenotypic Analysis and Gene Cloning of Rice Floury Endosperm Mutant wcr (White-Core Rice).

The composition and distribution of storage substances in rice endosperm directly affect grain quality. A floury endosperm mutant, wcr (white-core rice), was identified, exhibiting a loose arrangement of starch granules with a floury opaque appearance in the inner layer of mature grains, resulting in reduced grain weight. The total starch and amylose content remained unchanged, but the levels of the four component proteins in the mutant brown rice significantly decreased. Additionally, the milled rice (inner endosperm) showed a significant decrease in total starch and amylose content, accompanied by a nearly threefold increase in albumin content. The swelling capacity of mutant starch was reduced, and its chain length distribution was altered. The target gene was mapped on chromosome 5 within a 65 kb region. A frameshift mutation occurred due to an insertion of an extra C base in the second exon of the cyOsPPDKB gene, which encodes pyruvate phosphate dikinase. Expression analysis revealed that wcr not only affected genes involved in starch metabolism but also downregulated expression levels of genes associated with storage protein synthesis. Overall, wcr plays a crucial role as a regulator factor influencing protein synthesis and starch metabolism in rice grains.