Onion and garlic polysaccharides: A review on extraction, characterization, bioactivity, and modifications.

Allium cepa (onion) and Allium sativum (garlic) are important members of the Amaryllidaceae (Alliaceae) family and are being used both as food and medicine for centuries in different parts of the world. Polysaccharides have been extracted from different parts of onion and garlic such as bulb, straw and cell wall. The current literature portrays several studies on the extraction of polysaccharides from onion and garlic, their modification and determination of their structural (molecular weight, monosaccharide unit and their arrangement, type and position of glycosidic bond or linkage, degree of polymerization, chain conformation) and functional properties (emulsifying property, moisture retention, hygroscopicity, thermal stability, foaming ability, fat-binding capacity). In this line, this review, summarizes the various extraction techniques used for polysaccharides from onion and garlic, involving methods like solvent extraction method. Furthermore, the antioxidant, anticancer, immunomodulatory, antimicrobial, anti-inflammatory, and antidiabetic properties of onion and garlic polysaccharides as reported in in vivo and in vitro studies are also critically assessed in this review. Different studies have proved onion and garlic polysaccharides as potential antioxidant and immunomodulatory agent. Studies have implemented to improve the functionality of onion and garlic polysaccharides through various modification approaches. Further studies are warranted for utilizing onion and garlic polysaccharides in the food, nutraceutical, pharmaceutical and cosmetic industries.

Control over MoSe2 formation with vacuum-assisted selenization of one-step electrodeposited Cu-In-Ga-Se precursor layers.

Cu(In,Ga)Se2 (CIGS) absorbers are prepared by direct current electrodeposition process followed by selenization of precursors. Selenization of electrodeposited layers is performed in a tubular furnace at 550 °C in elemental selenium atmosphere using Ar as carrier gas. The effect of evacuation of tube prior to the selenization on the formation of CIGS absorbers is studied. Characterization of CIGS absorbers reveals that the samples selenized without prior evacuation found to have excess MoSe2 formation at the CIGS/Mo interface leading to bulk cracks in underlying Mo back contact compared to their counterparts. Although the fabricated solar cells using the absorbers, prepared with and without evacuation, are observed to be photoactive, the cells from vacuum-based selenization showed improvement in performance compared to the cells from non-vacuum selenization. The process is further being improved to enhance the efficiency, which can pave way towards environmentally friendly low-cost solar cells.

Preparation and characterization of selenized Astragalus polysaccharide and its inhibitory effect on kidney stones.

Astragalus polysaccharide (APS) was modified using the Na2SeO3/HNO3 method to obtain selenized APS (Se-APS) with a selenium content of 1.75 mg/g. The structure and physicochemical properties of APS and Se-APS were investigated through transmission electron microscopy-energy dispersive spectroscopy mapping, fourier transform infrared spectroscopy, nuclear magnetic resonance, nano-zetasizer analysis, atomic force microscopy, and scanning electron microscopy. APS and Se-APS did not exhibit toxic effects on human kidney proximal tubular epithelial (HK-2) cells and were able to remove hydroxyl and DPPH radicals, alleviate the damage caused by calcium oxalate (CaOx) monohydrate (COM) crystals to HK-2 cells, reduce intracellular reactive oxygen species levels, and restore cell viability and morphology. Both APS and Se-APS could inhibit COM growth, induce calcium oxalate dihydrate formation, and increase the absolute zeta potential of the crystals to inhibit crystal aggregation. However, the ability of Se-APS to regulate CaOx crystals and protect the cells from COM-induced damage was better than that of APS. These results suggested that Se-APS might be a candidate drug for the treatment and prevention of kidney stones.

Structural features, selenization modification, antioxidant and anti-tumor effects of polysaccharides from alfalfa roots.

Hot water extraction and chromatographic purification methods were used to extract and purify two polysaccharides (RAPS-1 and RAPS-2) from the roots of alfalfa. Subsequently, RAPS-2 was modified using the HNO3/Na2SeO3 method to obtain Se-RAPS-2. The structural features, antioxidant and in vitro anti-tumor activities of the three polysaccharides were evaluated. The structural analysis revealed that RAPS-1 (Mw = 10.0 kDa) was composed of rhamnose, xylose, arabinose, galacturonic acid, mannose and glucose, whereas RAPS-2 (Mw = 15.8 kDa) consisted of rhamnose, xylose, galacturonic acid, mannose, glucose and galactose. RAPS-1 contained 1 â†’ 2, 1 â†’ 4, 1 â†’ 3, and 1 â†’ 6 or 1 â†’ glycosidic bonds; however, while RAPS-2 lacked 1 â†’ 4 glycosidic linkages. The molecular weight of Se-RAPS-2 was 11.0 kDa less than that of RAPS-2. The results of activities demonstrated that Se-RAPS-2 displayed superior antioxidant activity and inhibitory effect in HepG2 cells than RAPS-1 and RAPS-2.

Effects of Post Anthesis Foliar Application of Sodium Selenite to Soybeans (Glycine max): Lipid Composition and Oil Stability.

This study aimed at determining whether applying selenium to soybean plants affected composition and oil oxidative stability of the seeds. Soybean was cultivated and sodium selenite (Selenite) added by foliar application (0, 200, or 300 g Selenite/Ha). Physical and chemical characterization was performed on the harvested seeds (thousand seed weight, bulk and true densities, fat, fiber, ash, protein, nitrogen free extract and selenium content). Soybean oil was tested in terms of Oxidation Induction Time (OIT), fatty acid, tocopherols, phytosterols, density, refractive index and saponification and iodine values. All seeds showed similar composition: crude fat (around 20%) and crude fiber (from 8.4 to 9.3%). Control seeds and those treated with 200 g Selenite/Ha contained higher protein concentration (37%), compared to the 300 g treatment (35.9%). All seeds showed similar ash content (7%). OIT values for both treatments were slightly lower (from 39.1 to 43.7 min) compared with 45.02 min in the control. Polyunsaturated fatty acids were higher for the 300 g Se/Ha (50.2%) compared with 48.2 to 49.4%of the other treatments. All samples showed similar phytosterols and tocopherols concentrations. Results showed that OIT values maintained an inverse relationship with selenium content, suggesting that foliar fertilization enhanced oil oxidation or acted as a pro-oxidant at the applied rates.

Investigation on the Selenization Treatment of Kesterite Cu2Mg0.2Zn0.8Sn(S,Se)4 Films for Solar Cell.

High-selenium Cu2Mg0.2Zn0.8Sn(S,Se)4 (CMZTSSe) films were prepared on a soda lime glass substrate using the sol-gel spin coating method, followed by selenization treatment. In this work, we investigated the effects of selenization temperature and selenization time on the crystal quality, and electrical and optical properties of CMZTSSe films. The study on the micro-structure by XRD, Raman, X-ray photoelectron spectroscopy (XPS), and energy-dispersive X-ray spectroscopy (EDS) analysis showed that all CMZTSSe samples had kesterite crystalline structure. In addition, the crystalline quality of CMZTSSe is improved and larger Se takes the site of S in CMZTSSe with the increase of selenization temperature and selenization time. When increasing the selenization temperature from 500 to 530 °C and increasing the annealing time from 10 to 15 min, the morphological studies showed that the microstructures of the films were dense and void-free. When further increasing the temperature and time, the crystalline quality of the films began to deteriorate. In addition, the bandgaps of CMZTSSe are tuned from 1.06 to 0.93 eV through adjusting the selenization conditions. When CMZTSSe samples are annealed at 530 °C for 15 min under Se atmosphere, the crystal quality and optical-electrical characteristics of CMZTSSe will be optimal, and the grain size and carrier concentration reach maximums of 1.5-2.5 µm and 6.47 × 1018 cm-3.

Improvement of Biological Activity of Morchella esculenta Protein Hydrolysate by Microwave-Assisted Selenization.

Morchella esculenta protein hydrolysate (MPH) from a valued medicinal and edible fungus M. esculenta (L.) is an excellent material for functional food development. To promote MPH utilization, selenization of MPH was performed by applying a simple and environmentally friendly microwave irradiation procedure. The physicochemical characteristics of selenized MPH (Se-MPH) were investigated by SEM-EDX, FTIR, CD, and amino acid analyzer, and its biological activity were assessed by ABTS, DPPH, H2 O2 scavenging, and reducing power assays, as well as α-glucosidase, α-amylase, and tyrosinase inhibition tests. The results showed that MPH was successfully selenized, Se content in Se-MPH reached 59.0 ± 0.64 mg/g, and amino groups, hydroxyl groups, and sulfur atoms of methionine residues in the MPH molecule may participate in selenization. Furthermore, Se-MPH exhibited significantly enhanced antioxidant, antidiabetic, and tyrosinase inhibitory activities, compared with the native MPH and microwave-irradiated MPH. Thus, the microwave-assisted selenization is a feasible strategy for preparing organic Se and improving the biological activity of MPH. PRACTICAL APPLICATION: In this study, selenized Morchella esculenta protein hydrolysate (Se-MPH) was successfully prepared via conjugation with sodium selenite using the microwave-assisted method. The results showed that Se-MPH, synthesized with the aid of microwave, exhibited favorable selenium content and improved antioxidant, antidiabetic, and tyrosinase inhibitory activities. Therefore, microwave can be employed as an innovative and effective avenue for the production of organic selenium in nutraceutical and functional food industry.

Mycochemical Changes Induced by Selenium Enrichment in P. ostreatus Fruiting Bodies.

The effects of selenium enrichment on the biological efficiency, phenolic compounds, amino acid profile, antioxidant capacity, and cellular antioxidant activity (CAA) were evaluated in Pleurotus ostreatus fruiting bodies (FB) harvested during three sequential flushes. Sodium selenate was used to reach selenium content of 17.5 or 5.8 mg/kg in the sorghum straw substrate. Biological efficiency and total selenium content increased. One of the main differences among treatments was in ergothioneine content, an indicator of oxidative stress that was positively related with valine and isoleucine contents and negatively related to leucine and phenylalanine. Besides ergothioneine, nucleosides derived from adenine and uracyl were the major peaks observed in all treatments, and coumaric and ferulic acids were found in the bound phenolics extract. Selenium enrichment also affected the antioxidant capacity, and particularly the methanolic extract obtained from the second flush of FB cultivated in selenium-enriched substrate (17.5 mg/kg) had the best CAA.

The preparation of three selenium-containing Cordyceps militaris polysaccharides: Characterization and anti-tumor activities.

In the present work, three fractions of selenized Cordyceps militaris polysaccharides (SeCPS) named SeCPS- I, SeCPS- II and SeCPS- III were isolated and purified by ultra-filtration. Their selenium content were measured as 541.3, 863.7 and 623.3µg/g respectively by a graphite furnace atomic absorption spectroscopy. The monosaccharide comformation analysis showed that they were mainly consisted of D-Mannose, D-Glucose, and D-Galactose in mole ratios of 1:7.63:0.83, 1:1.34:0.31 and 1:3.77:0.41 respectively. Their structure characteristics were compared by IFR and NMR spectroscopy. Scanning electron microscopy (SEM) and Congo red (CR) spectrophotometric method were used to investigate their morphological characteristics and conformational transition. SeCPS-II showed the strongest anti-tumor effects judging from the result of in vitro anti-tumor assays against two tumor cell lines (hepatocellular carcinoma HepG-2 cells and lung adenocarcinom A549 cells).