Selenium in rice: Impact on protein content and distribution for enhanced food and feed security in agroclimatic challenges

Countries face exasperating and inclement climate worldwide. Food and feed security could be their paramount life objective. The study aimed to investigate the impact of selenium on the protein content and distribution in different parts of rice. For this purpose, advanced selenium biofortified breeding material developed after generations of breeding efforts was investigated at the field area, rice research institute, Chengdu, China during cropping season 2021-22. The accumulation and distribution of selenium and protein contents were observed in various fractions of selenium-enriched rice (Z3057B) and positive control (727). The correlation studies for selenium and protein quantification leads to the optimization of the breeding material and relevance in virtue. The rice fractions indicated rice embryo retains highest selenium contents, which gradually decreases in succession (other rice parts). The difference in protein content between the embryo and endosperm of Se-enriched rice is significant, while that between embryo and aleurone layer is not obvious. The selenium protein was found with molecular weight of 13.6-122.6 kDa. The protein of each molecular weight is found to bind with selenium, but the binding strength of selenium is negatively correlated with the molecular weight of protein. The 67.5% of the total selenium sticks with protein having molecular weight less than 38.8 kDa. In summary, protein with low molecular weight (13.4 kDa) binds maximum selenium and accounts for highest total protein content (40.76%).

Physicochemical, structural and functional properties of protein isolates and major protein fractions from common vetch (Vicia sativa L.)

Common vetch (CV), a leguminous crop cultivated for green manure and fodder rich in protein and starch, is widespread over much area of the northern hemisphere. Its seeds can be used as a protein source to human consumption. CV protein isolates (CVPI) and major protein fractions (CV albumin protein, CVAP; CV globulin protein, CVGP; CV glutelin protein, CVGTP) from 4 samples were investigated the properties to facilitate full use of protein resources. Protein comprises 27.70 %-32.14 % of the dry CV seed weight, which is mainly composed by CVAP (26.79 %-56.12 %) and CVGP (22.78 %-52.42 %). CVPI, CVAP and CVGP mainly presented 7S and 11S components. CVGTP mainly contained the 11S component. They showed difference in thermal properties and surface hydrophobicity. Circular dichroism data showed that α-helix was their major secondary structure. CVPI and major protein fractions exhibited a U-shape protein solubility. CVPI and CVAP had advantages in emulsifying and foaming properties. This study provided novel insights on unexploited sources of CV proteins with interesting characteristics in terms of potential uses as protein-based foods.

Functional, thermal and structural properties of fractionated protein from waste banana peel

Defatted banana peel powder was fractionated using the Osborne method to extract albumin, globulin, prolamin, and glutelin for physicochemical and functional characterization. The total recovery of protein was ∼89.76%. Albumin was the dominant one in terms of yield (62.4%) and protein content (65.15%) among all the fractions. The mean diameter of albumin (635.05 µm) and glutelin (642.62 µm) were significantly smaller than globulin (726.81 µm) and prolamin (986.45 µm). The highest water (1.86 ± 0.12 g/g), oil (1.97 ± 0.12 g/g) holding capacity, and emulsion capacity (59.27 ± 1.25%) were found for the albumin fraction. In contrast, the glutelin fraction showed the highest foaming capacity (19.13 ± 0.41%) and dispersibility (951.55 ± 3.83 g/kg). The denaturation temperature of protein fractions was found in the range of 30.31-82.08 °C. FTIR confirmed low carbohydrates and protein richness of albumin fraction. XRD revealed the crystalline nature of albumin (65%) and the amorphous nature of other fractions (41-45%). The morphology of all fractions was different, which influenced the functional characteristics.

The effect of enzymatic pretreatment of chickpea on functional properties and antioxidant activity of alkaline protein isolate

Functional properties and antioxidant activity of protein isolates extracted by alkali from chickpea seed after treatment with cellulase and xylanase cocktail and individual arabinofuranosidase were evaluated. Both enzymatic treatments improved recovery of protein by more than 30%, moreover, arabinofuranosidase enabled higher extraction efficiency - above 93%. Protein extracted after treatment with enzyme cocktail showed improved solubility and oil holding capacity by 14% and 80%, respectively, while water holding capacity was increased by 130% after both applied enzymatic pretreatments. The action of enzyme cocktail was more beneficial for improving emulsifying activity and stability of alkaline isolate by 22% and 31%, respectively. Whipping properties of alkaline protein isolate were significantly improved when both enzymatic pretreatments were applied with foam stability increased by 150%. Protein from extractions with arabinofuranosidase and enzyme cocktail expressed enhanced antioxidant activity by 70% and 110%, respectively. Analysis of protein pattern and structural characteristics indicated differences between investigated isolates.

Efficacy of fermentation parameters on protein quality and microstructural properties of processed finger millet flour

The present study aims to explore the outcome of processing methods such as fermentation; treatments using lemon juice (T1), sodium chloride (T2), lemon juice followed by sodium chloride (T3) and fermentation followed by treatment-T3 on the quality characteristics of processed finger millet flour to develop a specialized low protein food supplement for a protein-related inborn error of metabolic disorders. The clean dirt-free finger millet grains were made into slurry subjected to treatment T1 (FMFT1), T2 (FMFT2), T3 (FMFT3), fermentation for 8-36 h with 4 h intervals using yoghurt as starter culture (FFMF) and fermentation (8-36 h) followed by treatment T3 (FFMFT3). The acidity of the finger millet slurry significantly increased with the increase in fermentation time when compared to control. The IVPD was found to be 89% in FFMF (20 h) sample which was significantly higher than the IVPD of control sample flour (27%). However, the crude protein content (%), the protein fractions and the IVPD of FFMFT3 (8-36 h) samples were found to be lesser than the FFMF (8-36 h) samples. The findings were further ensured by the results of scanning electron microscopic images and FT-IR spectra which showed the morphological and chemical modifications caused by the processing methods. The setback and breakdown viscosity of control (945 cP and 664 cP respectively) approximately reduced to two-third in FFMF (20 h) samples and one-third for FFMFT3 samples (303 cP and 286 cP respectively). From the study, it is evident that the processing method of fermentation followed by treatment-T3 could be utilized in the development of low protein food supplements.

Antimicrobial peptides purified from hydrolysates of kanihua (Chenopodium pallidicaule Aellen) seed protein fractions

The kanihua (Chenopodium pallidicaule Aellen) Andean grain from the Peruvian Altiplano presents proteins of 15% to 19%. The objective was to obtain purified bioactive antimicrobial peptides (AMPs), hydrolyzed with Alcalase and Pepsin-pancreatin sequential system of protein fractions of kanihua varieties Ramis (KR) and Cupi-Sayhua (KS), and hydrolysates with different degrees of hydrolysis (DH) and percentage inhibition (IP) of the growth of E. coli, S. aureus, and C. albicans. To obtain AMPs, nutraceuticals, bio-preservatives, and novel ingredients in food design. The results showed 216 hydrolysates (1%, w/v), only 28 presented significant difference compared to controls (IP ≥ 45%, p ≤ 0.05), 4 AMPs were purified by chromatography, glutelins KS 4 h (1:10) stood out with DH 40% and IP 52% and 70% of S. aureus and C. albicans, respectively (p ≤ 0.05), showed minimum inhibitory concentration (MIC) of 95% for E. coli (p ≤ 0.05), and presented an anionic charge. In conclusion, the simulated digestion in vitro showed higher DH (7%-67%) than Alcalase (13%-54%); the majority were extensive; of 28 hydrolysates with IP ≥ 45% 4 AMPs with important IPs were obtained, and one was anionic.

Antimicrobial activity of protein-containing fractions isolated from Lactobacillus plantarum NRRL B-4496 culture

The interest in lactic acid bacteria, including Lactobacillus plantarum NRRL B-4496, has increased in recent years as bio-preservatives, due to the production of secondary metabolites capable of inhibiting pathogenic bacteria. The objectives of this study were to evaluate the antimicrobial activity, cytotoxicity and the anti-inflammatory response of L. plantarum NRRL B-4496 cell-free supernatant (CFS). Furthermore, the CFS was fractionated by size exclusion chromatography using Sephadex G-25, and a minimal inhibitory volume test was determined against a panel of pathogenic bacteria. The cytotoxicity and the inflammatory activities of the fractions were evaluated using the human-derived THP-1 cell line. Results of this study indicates that CFS of L. plantarum NRRL B-4496 possesses antimicrobial protein compounds against the pathogen Listeria monocytogenes and showed no toxicity nor a pro-inflammatory response to human macrophages. The obtained results contribute to the development of novel bio-preservatives, L. plantarum cell-free supernatant or its fractions, with a potential use in the food industry.

Selenium toxicity in upland field-grown rice: Seed physiology responses and nutrient distribution using the μ-XRF technique

Selenium (Se) is an essential element for human and animal, although considered beneficial to higher plants. Selenium application at high concentration to plants can cause toxicity decreasing the physiological quality of seeds. This study aimed to characterize the Se toxicity on upland rice yield, seed physiology and the localization of Se in seeds using X-ray fluorescence microanalysis (μ-XRF). In the flowering stage, foliar application of Se (0, 250, 500, 1000, 1500, 2000 g ha^-1) as sodium selenate was performed. A decrease in rice yield and an increase in seed Se concentrations were observed from 250 g Se ha^-1. The storage proteins in the seeds showed different responses with Se application (decrease in albumin, increase in prolamin and glutelin). There was a reduction in the concentrations of total sugars and sucrose with the application of 250 and 500 g Se ha^-1. The highest intensities Kα counts of Se were detected mainly in the endosperm and aleurone/pericarp. μ-XRF revealed the spatial distribution of sulfur, calcium, and potassium in the seed embryos. The seed germination decreased, and the electrical conductivity increased in response to high Se application rates showing clearly an abrupt decrease of physiological quality of rice seeds. This study provides information for a better understanding of the effects of Se toxicity on rice, revealing that in addition to the negative effects on yield, there are changes in the physiological and biochemical quality of seeds.

Season does not have a deleterious effect on proportions of stallion seminal plasma proteins

The mechanism by which the content of the major groups of seminal plasma proteins in stallion semen changes between the breeding and non-breeding seasons remains unknown. Here, we investigated the proportions of non-heparin-binding, phosphorylcholine-binding, and heparin-binding proteins in seminal plasma with the aim of relating them to sperm quality and testosterone levels in good and bad freezer stallions. Only minor variations in the major protein groups were found between the breeding and non-breeding seasons. In the non-breeding season, a higher content of a subset of non-heparin binding proteins as well as of heparin-binding proteins was found. Analysis of semen characteristics revealed a somewhat contrasting picture. While only minor variations in sperm kinematics and sperm morphology were found between seasons, the flow-cytometric measurements of mitochondrial membrane potential and also, to some extent, reactive oxygen species production indicated lower sperm quality in the breeding season. Chromatin integrity and testosterone levels were unchanged between seasons. The results suggest that stallion ejaculates could be used year-round for freezing, since only minor differences in protein composition exist between the breeding and non-breeding seasons, as well as between good and bad freezers. In addition, sperm quality is not impaired during the non-breeding season.

Biochemical and molecular characterization of cowpea landraces using seed storage proteins and SRAP marker patterns

Seven landraces of cowpea [Vigna unguiculata (L.) Walp.] were assessed for genetic variability in total proteins, protein fractions viz. albumins, globulins, prolamins, and glutelins by SDS-polyacrylamide gel electrophoresis and DNA polymorphism using sequence-related amplified polymorphisms (SRAP) markers. The solubility-based protein fractionation data indicated that the salt soluble fraction (globulin) and water-soluble fraction (albumin) proteins were the predominant fractions in cowpea seeds comprising 45-50.3% and 31.2-35.5% of total soluble proteins, respectively. The electrophoretic pattern revealed the molecular heterogeneity among total proteins as well as different protein fractions. The molecular weights of protein bands obtained by SDS-PAGE varied between 10 to 250, 15 to 110, 15 to 150, and 15 to 130 kDa for total proteins, albumins, globulins, and glutelins, respectively. A large number of bands were found common to the various landraces, indicative of their close relationship with one another. However, a few bands distinctive to some specific landraces were also detected, indicating varietal differences. A 34 SRAP primer pair combination generated a total of 1003 amplicons (loci) showed 100% polymorphism with an average of 0.93 polymorphism information content (PIC) value. Landraces displayed an average 0.50 similarity coefficient which clustered the landraces corresponding to their growth habit in main clusters and to their geographical origin in subcultures. Molecular and biochemical analysis were correlated with a medium level (Mantel test, r = 0.56, P < 0.02). These findings revealed that seed proteins and DNA polymorphism provide valuable information regarding the variability among landraces and this information could be utilized for breeding purposes in the enhancement of protein quality and quantity in grain legumes.

Modulating the expression level of secreted Wnt3 influences cerebellum development in zebrafish transgenics

The boundaries of brain regions are associated with the tissue-specific secretion of ligands from different signaling pathways. The dynamics of these ligands in vivo and the impact of its disruption remain largely unknown. Using light and fluorescence microscopy for the overall imaging of the specimen and fluorescence correlation spectroscopy (FCS) to determine Wnt3 dynamics, we demonstrated that Wnt3 regulates cerebellum development during embryogenesis using zebrafish wnt3 transgenics with either tissue-specific expression of an EGFP reporter or a functionally active fusion protein, Wnt3EGFP. The results suggest a state of dynamic equilibrium of Wnt3EGFP mobility in polarized neuroepithelial-like progenitors in the dorsal midline and cerebellar progenitors on the lateral side. Wnt3EGFP is secreted from the cerebellum as shown by measurements of its mobility in the ventricular cavity. The importance of Wnt secretion in brain patterning was validated with the Porcn inhibitor Wnt-C59 (C59), which, when applied early, reduced membrane-bound and secreted fractions of Wnt3EGFP and led to a malformed brain characterized by the absence of epithalamus, optic tectum and cerebellum. Likewise, interference with Wnt secretion later on during cerebellar development negatively impacted cerebellar growth and patterning. Our work, supported by quantitative analysis of protein dynamics in vivo, highlights the importance of membrane-localized and secreted Wnt3 during cerebellum development.

Characterization of grain nutritional quality in wheat

Ten Indian wheat varieties viz. RSP-566, RSP-561, PBW-396, HD-2687, C-306, PBW-175, RSP-81, PBW-550, DBW-17 and WH-542 were characterized for grain nutritional quality parameters viz., macronutrients (viz. starch, protein, protein fractions, sugars, fat), essential elements (calcium, phosphorus, iron and zinc), carotenoids, antioxidant and antinutritional parameters (phytic acid, total phenol, polyphenol oxidase (PPO) and trypsin inhibitor). RSP-561 possessed highest starch content, total protein, albumin, globulin, microelements (iron and zinc) and lowest antinutritional phytic acid and its grain contained second highest values of gluten (gliadin + glutenin), calcium, carotenoids and antioxidant contents and second lowest in antinutritional total phenol, PPO, trypsin inhibitor compositions. HD-2687 showed highest content of albumin, gliadin and total phenol constituents besides highest starch and total protein content. PBW-175 had highest sugar, calcium and carotenoids. However, antinutritional trypsin inhibitor, total phenol and PPO were found lowest in RSP-566, PBW-550 and RSP-81 respectively. The finding of this study concludes that on the basis of overall nutritional status, RSP-561 genotypes can be selected as one of best genotypes.