Biosynthesis, behavior and fate of volatile organic sulfide in Lentinus edodes (Berk.) upon hot-air drying treatment.

This study elucidated the biosynthesis and changing behaviors of organic sulfide in shiitake mushrooms upon hot-air drying treatment. The changes of aw, moisture migration, contours of taste and flavor, organic sulfide, and 4 key enzyme activities were monitored throughout three drying procedures (CT/ST1/ST2). Results showed that drying rate was related to the moisture migration. Key enzymes of γ-GTase, ASFase and CS lyase were heat-resistant proteases, while C-Dase exhibited low thermal stability with the activity decreased during treatment. A total of 17 organic sulfides were identified and PLS analyses suggested 6 cyclic polysulfides were formed by C-Dase desulfurization, while 5 thioethers generation were related to the thermal cleavage of direct precursors (straight-chain di/tris/tetrasulfonyl esters) and Maillard reaction. These results indicated that ST2 drying procedures had a positive effect on the formation of cyclic polysulfides at the end of drying pried and the achievement of premium flavor qualities.

Selenium biofortification in Pleurotus eryngii and its effect on lead adsorption of gut microbiota via in vitro fermentation.

It is of great significance to develop safe and efficient dietary selenium sources to improve lead toxicity. In this study, selenate, selenite, SeMet and Se-yeast were supplied to investigate the Se biofortification and bioaccessibility in Pleurotus eryngii. The effects of Se-enriched P. eryngii on lead binding bacteria were investigated via in vitro fermentation. With 40 mg/kg Se in the substrate, the total Se contents of P. eryngii treated with selenite and Se-yeast were 145.22 ± 8.00 mg/kg and 90.01 ± 7.01 mg/kg, respectively. Compared with selenite, Se-yeast treatment significantly increased the organic Se proportion in P. eryngii (SeCys2 2.85 ± 0.17%, MeSeCys 2.33 ± 0.21% and SeMet 78.19 ± 1.58%), which led to higher bioaccessibility. With 1 mg/L lead treatment during in vitro fermentation, Se-enriched P. eryngii promoted the growth of Desulfovibrio, which contributed to the increase of gut microbiota lead adsorption. Se-enriched P. eryngii cultivated with Se-yeast could be used as dietary Se sources for lead toxicity improvement.

Effects of selenylation modification on the antioxidative and immunoregulatory activities of polysaccharides from the pulp of Rose laevigata Michx fruit.

Selenylation modification has been widely utilized to improve the activity of polysaccharides and to develop novel sources of selenium (Se) supplements. A purified pulp polysaccharide of Rose laevigata Michx fruit (PPRLMF-2) was selenized into Se-PPRLMF-2 in this study. PPRLMF-2 + Se was formulated by Na2SeO3 according to the Se content of Se-PPRLMF-2. To investigate the effects of selenylation modification on the structure and functions of PPRLMF-2, the characteristics, antioxidative and immunoregulatory activities of PPRLMF-2 before and after selenylation were compared. The results showed that compared with PPRLMF-2, Se-PPRLMF-2 became an irregular fibrous network, and its Mw decreased and C-6 substitution predominated in 13C NMR spectra. Se-PPRLMF-2 significantly increased chemical antioxidant activity and reduced the oxidative damage of erythrocytes, which was not due to Se alone. Se-PPRLMF-2 significantly increased immunomodulatory activity on macrophages, which was related to Se alone. Se-PPRLMF-2 could be a good potential source of antioxidants, immune enhancers and dietary Se supplements.

Comparison of effects on colitis-associated tumorigenesis and gut microbiota in mice between Ophiocordyceps sinensis and Cordyceps militaris.

BACKGROUND: Gut microbiota plays an indispensable role in the treatment of inflammatory bowel disease (IBD) and colitis-associated cancer (CAC). As traditional medicinal fungi, previous studies have shown that Ophiocordyceps sinensis could better maintain intestinal health via promoting the growth of probiotics in vitro compared with Cordyceps militaris. However, the detailed pharmacological activities and clinical efficacy of O. sinensis and C. militaris are still elusive. PURPOSE: We aimed to evaluate the different actions of O. sinensis and C. militaris on colitis-associated tumorigenesis in Azoxymethane (AOM)/Dextran Sulfate Sodium (DSS)-treated mice and explore the potential gut microbiota-dependent mechanisms. METHODS: C57BL/6 mice (Male, 4 weeks old) were used to construct the AOM/DSS-induced CAC mice model. The mice were administered with 0.6 mg/g/d O. sinensis or C. militaris for 12 weeks. It's worth noting that fecal microbiota transplantation (FMT) and antibiotic treatment were used to investigated the complex interactions between the medicinal fungi, gut microbiota and colonic tumorigenesis. RESULTS: O. sinensis treatment significantly increased the body weight and survival rate, reduced the number of colon tumors, improved the damage of colon epithelial tissue, restored the crypt structure and alleviate the colonic inflammation in AOM/DSS-treated mice. RT-qPCR results indicated that O. sinensis partly regulated the Wnt/ß-catenin signaling via alleviating the overexpression of ß-catenin, TCF4 and c-Myc genes in adjacent noncancerous tissues. Compared with C. militaris, O. sinensis showed better anti-tumor activity. Gut microbiota analysis revealed that O. sinensis reversed the decline of gut microbiota diversity and the structural disorder induced by AOM/DSS. Spearman's correlation analysis showed that O. sinensis promoted the growth of Parabacteroides goldsteinii and Bifidobacterium pseudolongum PV8-2, which were positively correlated with the anti-tumor activity and the production of SCFAs. FMT combined with antibiotic treatment showed that horizontal fecal transfer derived from O. sinensis-treated mice improved the intestinal inflammation and alleviated the colitis-associated tumorigenesis, which was consistent with the direct ingestion of O. sinensis. CONCLUSION: O. sinensis could better attenuate colitis-associated tumorigenesis compared with C. militaris. These effects might be at least partially due to the increased abundance of probiotics, especially P. goldsteinii and B. pseudolongum PV8-2.

Polysaccharide from Flammulina velutipes attenuates markers of metabolic syndrome by modulating the gut microbiota and lipid metabolism in high fat diet-fed mice.

Natural biological macromolecules with putative functions of gut microbiota regulation possess the advantage of improving metabolic syndrome (MS). In this research, we aimed to determine the effects of Flammulina velutipes polysaccharide (FVP) (Expt. 1) and fecal microbiota transplantation (FMT) (Expt. 2) on MS-related disorders, gut microbiota structure changes and their underlying mechanisms in a murine model fed with high-fat diet (HFD). In Expt. 1, six-week-old male C57BL/6J mice were fed with a control diet (10% calories from fat) or a high fat diet (45% calories from fat), administered with saline or FVP (0.4 mg per g b.w.) by gavage over a 12-week period. In Expt. 2, mice were fed with a HFD, administered with fecal supernatants from healthy and FVP-fed donor mice for 12 weeks simultaneously. The body mass, blood lipid levels and blood glucose homeostasis of mice were analyzed, and total RNA from mouse liver and adipose tissue were extracted by TRIzol and the lipid metabolism-related gene expressions were calculated by qRT-PCR. Gut microbiota changes were evaluated by high-throughput sequencing. Results indicated that FVP and FMT supplementations showed an attenuation effect on mouse obesity, hyperlipidemia and insulin resistance. Up-regulated expressions of Ampkα1 and Ppara were found both in FVP and FMT treatment groups. Different changes were found in the gut microbiota caused by FVP and FMT, respectively. PICRUSt analysis indicated that compared with FVP supplementation, FMT showed a significant effect on regulating lipid metabolism in HFD-fed mice. The findings from this study indicated that oral administrations of FVP or FMT could significantly attenuate MS-related obesity, hyperlipidemia and insulin resistance in HFD-fed mice, and the beneficial effects may be mediated through lipid metabolism and gut microbiota regulation in different ways. These results improve the understanding of the functional activity of FVP as prebiotics.

Computational study on natural compounds inhibitor of c-Myc.

To screen and identify ideal leading compounds from a drug library (ZINC15 database) with potential inhibition effect against c-Myc to contribute to medication design and development.A series of computer-aided virtual screening techniques were performed to identify potential inhibitors of c-Myc. LibDock from the software Discovery Studio was used to do a structure-based screening after ADME (absorption, distribution, metabolism, excretion) and toxicity prediction. Molecular docking was utilized to show the binding affinity and potential mechanism between ligands and c-Myc. Stability of the ligand-receptor complex was analyzed by molecular dynamic simulation at the end of the research.Compounds with more interactive energy which are confirmed to be the potential inhibitors for c-Myc were identified from the ZINC15 databases. Additionally, those compounds are also anticipated with fewer ames mutagenicity, rodent carcinogenicity, nondevelopmental toxic potential, and tolerant with cytochrome p450 2D6(CYP2D6). Dynamic simulation analysis also revealed that the very compounds had more favorable potential energy compared with 10058-F4(ZINC12406714). Furthermore, we prove that those compounds are stable and can exist in natural conditions.This study demonstrates that the compounds are potential therapeutic inhibitors for c-Myc. These compounds are safe and stable for drug candidates and may play a critical role in c-Myc inhibitor development.

Preparation of newly identified polysaccharide from Pleurotus eryngii and its anti-inflammation activities potential.

The anti-inflammatory effects of two newly identified Pleurotus eryngii polysaccharides (WPEP, NPEP) were determined in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages in this study. Characterization analysis revealed that molecular weights of WPEP and NPEP were 167 and 274 kDa, and were mainly composed of glucose with ß-type glycosidic linkages. WPEP and NPEP could significantly inhibit LPS-induced inflammatory responses by regulating the production of NO, Protaglandin E2 (PGE2 ), Interleukin-1ß (IL-1ß), Tumor necrosis factor-α (TNF-α), and Interleukin-6 (IL-6). This was through the blocking of the activation of Mitogen-activated protein kinase (MAPK) pathway by inhibiting phosphorylation of p38, extracellular regulation of protein kinases 1/2, and stress-activated protein kinase/jun aminoterminal kinase. Moreover, WPEP and NPEP inhibited NF-κB signaling by reducing nuclear translocation and phosphorylation of p65. Overall, our results, for the first time identified two P. eryngii polysaccharides and demonstrated the related anti-inflammatory effects, which indicated the favorable potential of P. eryngii polysaccharide as specific functional foods. PRACTICAL APPLICATION: This study prepared and characterized newly identified Pleurotus eryngii water-soluble polysaccharide fractions and elucidated the nutritional benefits, mainly the immune response related to anti-inflammatory activities by utilizing lipopolysaccharide (LPS)-stimulated RAW264.7 cells. Collectively, results of this study suggested that the P. eryngii polysaccharide fractions could be considered as potential candidates for exploration in the development of new immunomodulatory agent or functional supplementary foods.

Effects of a ß-type glycosidic polysaccharide from Flammulina velutipes on anti-inflammation and gut microbiota modulation in colitis mice.

Using the Flammulina velutipes polysaccharide (FVP) extracted from our previous study, herein, we investigated the improvement of this starch-free ß-type glycosidic polysaccharide in alleviating dextran sodium sulfate-induced ulcerative colitis (UC) in mice. The absolute and relative abundance of intestinal microbes in the mouse feces were both determined by 16s RNA gene sequencing. The results from the histological analysis indicate that FVP treatment reduced the symptoms of UC, up- or down-regulated the relative gene expression levels in the colon tissue, and enhanced the capacity of metabolic and biogenesis in the UC mice, as predicted by PICRUSt. 11 species of gut microbes including Lactobacillus, Bifidobacterium, and Clostridium associated with UC symptoms were analyzed by correlation analysis. Our findings suggest that FVP can alleviate the UC symptoms in mice by regulating specific gut microbes, improving the understanding of the functional activity of FVPs as prebiotics.

Gastrointestinal fate and antioxidation of ß-carotene emulsion prepared by oat protein isolate-Pleurotus ostreatus ß-glucan conjugate.

ß-carotene has been often used as a hydrophobic nutrient in many functional foods owning to its excellent antioxidant activity. However, the poor orally bioavailability of ß-carotene limits its utilization. To overcome such limitation, a delivery system was designed for the encapsulation of ß-carotene based on oil-in-water emulsion stabilized by oat protein isolate - Pleurotus ostreatus ß-glucan Maillard conjugate. The results showed that such conjugate protected emulsion against environmental stresses by increasing steric and electrostatic repulsion between droplets, mainly manifesting as their smaller particle size and higher surface charge. Additionally, conjugate promoted lipid digestion and formation of mixed micelles, leading to an improved gastrointestinal fate of encapsulated ß-carotene, especially for its in vitro bioavailability. Such effects could enhance the cellular antioxidant activity of encapsulated ß-carotene in Caco-2 cells. Our findings confirmed that Maillard conjugate can structure an emulsion-based delivery system for the encapsulation of hydrophobic ingredients to improve their utilization.

Flammulina velutipes polysaccharides improve scopolamine-induced learning and memory impairment in mice by modulating gut microbiota composition.

Flammulina velutipes polysaccharides (FVP) have been proved to be effective in improving learning and memory impairment in mice. However, their underlying mechanism remains unclear. The aim of this study was to investigate the relationship between memory improvement and gut microbiota regulation of FVP. The results showed a significant decrease in the relative abundances of Clostridia and Bacilli but a significant increase in Bacteroidia, Erysipelotrichia and Actinobacteria in the FVP-treated group versus the control group. Fecal microbiota transplantation of mice with 'FVP microbiota' derived from FVP-fed mice resulted in improved learning and memory function compared to colonization with 'common microbiota' derived from control individuals. FVP and 'FVP microbiota' significantly increased the numbers of platform crossings and the swimming distance of mice in the probe test and decreased the escape latency and total swimming distance of mice in the hidden platform test. Moreover, FVP and 'FVP microbiota' regulated cytokines, such as IL-1ß, TNF-α, IL-6 and IL-10, suggesting a mechanism involving the suppression of neuroinflammation. This study indicated that the regulation of the gut microbiome may have a causal role in improving scopolamine-induced impairment of learning and memory.

Polyphenols-rich extract from Pleurotus eryngii with growth inhibitory of HCT116 colon cancer cells and anti-inflammatory function in RAW264.7 cells.

Edible mushrooms are rich sources of bioactive components. In this study, a polyphenol-rich extract, designated as PPEP, was isolated from an edible mushroom, Pleurotus eryngii. Using ultra high performance liquid chromatograph combined with triple time-of-flight mass spectrometry (UPLC-TOF/MS/MS), gallic acid monohydrate, 3-(3,4-dihydroxyphenyl)-propionic acid, methyl gallate, syringic acid, ellagic acid and catechin were identified in PPEP. This phenolic-rich extract PPEP exhibited anti-inflammatory effect in lipopolysaccharide-stimulated RAW264.7 macrophages by inhibiting the overproduction of pro-inflammatory mediators including nitric oxide (NO) and reactive oxygen species (ROS). It was demonstrated that the anti-inflammatory effects of PPEP were associated with the inhibition of iNOS expression, suppression of p-IκB protein expression and inhibition of NF-κB and IκB mRNA expression. Next, the inhibitory effect of PPEP against human colon cancer cells was also determined. PPEP suppressed cell proliferation of human colon cancer HCT116 cells in a dose- and time-dependent fashion, while it showed no inhibitory effect on normal human colonic myofibroblasts CCD-18Co cells at the same tested concentrations (0-200 µg mL-1). Moreover, PPEP induced cell cycle arrest and led to extensive cellular apoptosis in human colon cancer cells, which was associated with the downregulation of cell cycle-related signaling protein, e.g. cyclin B and cyclin E, and the upregulation of apoptosis-related signaling protein caspase-3 and cleaved caspase-3. Overall, our results provided a basis for using PPEP as a promising preventive agent against inflammatory disease and colon cancer.

Enrichment of Bread with Nutraceutical-Rich Mushrooms: Impact of Auricularia auricula (Mushroom) Flour Upon Quality Attributes of Wheat Dough and Bread.

Edible mushrooms contain a variety of bioactive molecules that may enhance human health and wellbeing. Consequently, there is increasing interest in fortifying functional foods with these nutraceutical-rich substances. However, incorporation of mushroom-based ingredients into foods should not adversely affect the quality attributes of the final product. In this study, the impact of incorporating powdered Auricularia auricula, a widely consumed edible mushroom, into bread products was examined. The rheological and structural properties of wheat dough and bread supplemented with 0% to 10% (w/w) A. auricula flour were measured. Supplementation of wheat doughs with A. auricula flour increased the peak viscosity and enhanced their water holding capacity. Rapid viscosity analysis showed that peak and final viscosities of the blended flour (wheat flour with A. auricula flour) were higher than wheat flour alone. However, dough stability and elastic modulus were reduced by blending wheat flour with A. auricula flour. SEM observation showed that doughs with up to 5% (w/w) A. auricula flour had acceptable gluten network microstructure. Characterization of the quality attributes of bread indicated that incorporation of A. auricula flour at levels >5% negatively impacted bread volume, height, texture, and appearance.

Evaluation of anti-fatigue property of the extruded product of cereal grains mixed with Cordyceps militaris on mice.

BACKGROUND: Fatigue is a biological phenomenon that involves a feeling of extreme physical or mental tiredness that could potentially cause some severe chronic diseases. Recently, diet therapy has provided a new alternative to alleviate physical fatigue. In our previous study, addition of Cordyceps militaris (C. militaris) into an extruded product was shown to provide high nutrition and unique flavors; however, little is known whether this product has some scientific evidence regarding anti-fatigue property. The purpose of this study was to evaluate the anti-fatigue effects of extruded products of cereal grains (EC) and EC mixed with C. militaris (ECC). METHODS: The mice were divided into seven groups: one group received distilled water (Control group, n = 20), and the other groups received different dosages of EC (5, 10 and 20 g/kg body weight, n = 20 per group) or of ECC (5, 10 and 20 g/kg body weight, n = 20 per group) solution in water. All of the mice were administered with distilled water, EC or ECC continuously for 30 days by gavage and the anti-fatigue activity was evaluated using a weight-loaded swimming test, along with assessments of fatigue-related indicators. The mode of fighting fatigue was investigated by determining changes in exercise endurance and biochemical markers, including exhaustive swimming time, lactate dehydrogenase (LDH), blood lactic acid (BLA), creatine kinase (CK), blood urea nitrogen (BUN), malondialdehyde (MDA), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), catalase (CAT), and hepatic and muscle glycogen levels. RESULTS: EC and ECC prolonged the swimming endurance time of mice compared to the control. The content of BLA at high dose of ECC group (20 g/kg) was significantly lower than that in the negative control group. CK, BUN and MDA levels were significantly reduced by treatment with EC and ECC compared to the negative control, while the low and middle dose of EC had no significant effect on MDA levels. Additionally, only the middle and high dose of EC (10, 20 g/kg) could significantly decrease the BUN level. EC and ECC treatments increased glycogen, LDH, SOD, CAT and GSH-Px levels. Low and middle dose of EC had no significant effects on muscle glycogen. Moreover, low dose of EC could increase the level of SOD but it was not statistically significant. Compared to the EC treatment groups, ECC demonstrated the efficacy of anti-fatigue potential, particularly at a high dose of ECC, the best performance in relieving fatigue. CONCLUSIONS: These results suggest that EC and ECC could prevent exercise-induced fatigue in mice and ECC provided a better effect. In addition, C. militaris in ECC might play a crucial role in the anti-fatigue activity of ECC.

Immunopotentiation of Pleurotus eryngii (DC. ex Fr.) Quel.

ETHNOPHARMACOLOGICAL RELEVANCE: Pleurotus eryngii (DC. ex Fr.) Quel has been collected from the wild, cultivated and used in traditional medicines to treat various disorders and diseases since antiquity. In traditional Chinese medicine, the powdered fruiting bodies of Pleurotus eryngii were used for immunostimulation, skin-care, wound-healing, cancer and lumbago treatment. In the current study, we investigated the antiproliferative activity of Pleurotus eryngii powder on A549, BGC-823, HepG2 and HGC-27 cancer cells and its immunomodulating activity on macrophage, RAW 264.7 cells based on its active compound. MATERIALS AND METHODS: A novel bioactive protein (PEP) was extracted from Pleurotus eryngii fruiting bodies powder and purified on DEAE-52, CM-52 and Superdex 75 column chromatographies using an ÄKTA purifier. Its cytotoxicity on A549, BGC-823, HepG2, HGC-27 and RAW 267.4 cell lines was then evaluated using MTT, alamar blue (AB), trypan blue (TB), neutral red (NR), lactate dehydrogenase (LDH), Annexin V FITC/PI and morphological change assays. Moreover, lysosomal enzyme activity, pinocytosis, nitric oxide (NO) and hydrogen peroxide (H2O2) production assays were used to examine immunomostimulatory activity of PEP on RAW 267.4 cells. RESULTS: Based on high performance gel permeation chromatography (HPGPC), Fourier transform infrared (FT-IR) and nuclear magnetic resonance (NMR) analyses, the isolated protein (PEP) had a molecular weight of 63 kDa, a secondary (α-helical) structure and was mainly composed of arginine, serine and glycine. PEP significantly (P<0.05) inhibited A549, BGC-823, HepG2 and HGC-27 tumor cells proliferation dose-dependently with an IC50 range of 36.5 ± 0.84 to 229.0 ± 1.24 µg/ml. Contrarily, PEP stimulated the proliferation of macrophages. CONCLUSION: Pleurotus eryngii fruiting bodies powder has a potential application as a natural antitumor agent with immunomodulatory activity, proposedly, by targeting the lysosomes of cancerous cells and stimulating macrophage-mediated immune responses.

Cytotoxicity and apoptotic effects of tea polyphenol-loaded chitosan nanoparticles on human hepatoma HepG2 cells.

Tea polyphenols have strong antioxidant and antitumor activities. However, these health benefits are limited due to their poor in vivo stability and low bioavailability. Chitosan nanoparticles as delivery systems may provide an alternative approach for enhancing bioavailability of poorly absorbed drugs. In this study, tea polyphenol-loaded chitosan nanoparticles have been prepared using two different chitosan biomaterials, and their antitumor effects were evaluated in HepG2 cells, including cell cytotoxicity comparison, cell morphology analysis, cell apoptosis and cell cycle detection. The results indicated that the tea polyphenol-loaded chitosan nanoparticles showed a branch shape and heterogeneous distribution in prepared suspension. MTT assay suggested that tea polyphenol-loaded chitosan nanoparticles could inhibit the proliferation of HepG2 cells, and the cytotoxicity rates were increased gradually and appeared an obvious dose-dependent relationship. Transmission electron microscope images showed that the HepG2 cells treated with tea polyphenol-loaded chitosan nanoparticles exhibited some typical apoptotic features, such as microvilli disappearance, margination of nuclear chromatin, intracytoplasmic vacuoles and the mitochondrial swelling. In addition, the tea polyphenol-loaded chitosan nanoparticles had relatively weak inhibitory effects on HepG2 cancer cells compared with tea polyphenols. Tea polyphenols not only induced cancer cell apoptosis, but also promoted their necrosis. However, tea polyphenol-loaded chitosan nanoparticles exhibited their antitumor effects mainly through inducing cell apoptosis. Our results revealed that the inhibition effects of tea polyphenol-loaded chitosan nanoparticles on tumor cells probably depended on their controlled drug release and effective cell delivery. The chitosan nanoparticles themselves as the delivery carrier showed limited antitumor effects compared with their encapsulated drugs.

[Determination of mineral elements in two grades of three green tea varieties by ICP-AES].

Green tea, a traditional healthy drink, has various necessary nutrients. A study was carried out on the contents of mineral elements such as Ni, Ba, Fe, Mn, Cr, Mg, Ca, Cu and Al in two grades of three green tea varieties by ICP-AES. The difference in contents of mineral elements between green teas was studied. The results indicated that there are different contents of mineral elements among varieties and grades of green tea. A basis for consumption, varieties identification and grades judgment was provided by the study.

Synthesis, characterization and cytotoxicity studies of chitosan-coated tea polyphenols nanoparticles.

Chitosan nanoparticles (CS-NPs) were prepared by ionic gelation method using carboxymethyl chitosan and chitosan hydrochloride as carriers of tea polyphenols. The characteristics of chitosan-coated tea polyphenols nanoparticles (CS-TP NPs) were determined by using transmission electron microscopy (TEM) and FT-IR spectroscopy. It was found that the synthesized CS-TP NPs were non-spherical in shape with an average size of 407±50nm. Meanwhile, the drug content and encapsulation rate of the nanoparticles was 8-16% and 44-83%, respectively. These CS-TP NPs also demonstrated sustained release of tea polyphenols in PBS. The antitumor of CS-TP NPs towards HepG2 cancer cells was investigated. The result showed that CS-TP NPs retained significant antitumor activities.

Distribution and in vitro availability of selenium in selenium-containing storage protein from selenium-enriched rice utilizing optimized extraction.

Selenium (Se) distribution in Se-enriched rice and optimization of extraction for Se-containing protein were studied. Se availability in Se-containing protein product was simulated using an in vitro gastrointestinal digestion. The results showed that Se was predominately found as organic Se, whereas inorganic Se comprised only 2.85% of the total Se. The glutelin fraction contained the largest amount of Se, approximately 31.3% of the total Se in the rice gain. Utilizing orthogonal analysis, the optimum extraction conditions were selected at a volume to weight of 20:1, 0.08 M NaOH, an extraction time of 3 h, and at a temperature of 35 degrees C. A Se-containing rice protein product with 83.5% protein and 9.09 microg g(-1) Se was sequestered using the optimal extraction method. This rice protein product with high molecular weight Se-containing protein can readily be digested to low molecular weight peptides and selenomethionine (52.3% of total Se in protein extract).