Selenium, is an essential trace nutrient in the human diet. The health promoting properties of selenium and its compounds are due to its unique mechanism of incorporation into selenoproteins in which selenium is present as selenocysteine. This review presents the nutritional benefits of selenium by listing and linking selenoprotein function to evidence of health benefits. The classification, function, absorption, metabolism, and bioavailability of selenium and selenoprotein are elaborated. Particularly, the resource and nutrition of several common and selenium-enriched foods are discussed herein. Moreover, the future outlook of selenium and selenoproteins involved in selenium supplementation and food nutrition is also elucidated.
The aim of this study was to evaluate the physicochemical and textural characteristics and volatile compounds of Kazakh dry-cured beef made in China. Two types of Kazakh dry-cured beef were investigated: Kazakh dry-cured beef made with smoking and spices (T1) and without smoking and spices (T2). There were significant (P < 0.05) differences in values of aw, moisture, L*, cohesiveness and chewiness between the two types. A total of 86 volatile compounds were isolated by solid phase microextraction-gas chromatography/mass spectrometry (SPME-GC/MS). Hydrocarbons were the most abundant in T1 products and aldehydes in T2 products. Principal component analysis showed that the first principal component (PC1) was highly related to smoke derivatives—naphthalene, 2-cyclopenten-1-one derivatives, 4-methyl-4-hepten-3-one, acetophenone, 2,3-dihydro-1H-Inden-1-one, 2-furanmethanol, methoxy-phenyl-oxime, furfural, 1-(2-furanyl)-ethanone and phenols—and the second principal component (PC2) to lipid derivatives—straight-chain aliphatic aldehydes, methyl ketone, straight-chain alcohols and 2-pentyl-furan.
Clove bud (Syzygium aromaticum) essential oils (EOs) were extracted by hydro-distillation (HD), steam-distillation (SD), microwave-assisted hydro-distillation (MAHD), and microwave-assisted steam-distillation (MASD) methods. A comparison was made between microwave-assisted extraction and conventional extraction methods in terms of extraction kinetic, chemical composition, eugenol enrichment and antioxidant activity. Significant differences were observed between the ultimate EO yields of HD-based methods (12.98 – 13.94%) and those of SD-based methods (11.54 – 12.71%). Nonetheless, chemical compositions of the four extracted EOs were similar, but significant differences occurred among the quantity of compounds in the EOs. The ratio of eugenol per eugenyl acetate in HD-based methods (8.36 – 11.90%) was higher than those of SD-based methods (5.28 – 5.81%). These differences result from the hydrolysis of eugenyl acetate to eugenol in HD-based methods. Although, there was no significant difference between antioxidant activity of EOs extracted by microwave-assisted extraction methods and conventional-based methods but, accordingly, there were significant differences between HD-based methods and SD-based methods.
Roasted wheat bran flour (RWBF) was fermented by Bacillus subtilis HA to produce bioactive compounds including mucilage and peptides. A moisture content of 60% was optimal for the solid-state fermentation, which exhibited the highest mucilage productivity after 1 day. Adding MSG to the substrate resulted in increased viable cell counts and mucilage and decreased acidity. After 1 day of fermentation, the RWBF containing 5% MSG indicated pH 6.5, mucilage content of 11.5%, consistency index of 5.59 Pa·sn, viable cell counts of 6.25 × 108 CFU/g, 4.0 mg/g tyrosine equivalents, and protease activity of 20 U/g. The total content of free amino acids tended to decrease during the alkaline fermentation, in particular, that of glutamate, indicating that the added MSG was efficiently converted to poly-γ-glutamic acid, with an 80% yield. The proposed solid-state fermentation is an effective approach to produce a highly valuable ingredient from wheat bran.
Whole wheat flour (WWF) contains various kinds of functional ingredients, such as dietary fiber, resistant starch, minerals, etc., and bread containing WWF is in great demand in many countries because of its health benefits. Although dough with WWF often results in lower quality bread, previous studies suggested that this could be improved by the addition of suitable enzymes. This study investigated the effects of WWF substitution and enzyme treatments using α-amylase (AM) and hemicellulase (HC) on bread making qualities. Results showed that the addition of WWF produced dough with low gas retention of dough (GRD) and specific loaf volume (SLV). However, AM and HC drastically improved both GRD and SLV of WWF-substituted dough and bread by degrading damaged starch and hemicellulose. Thus, these results indicated that the treatments with suitable enzymes could drastically improve the bread making qualities of dough made with WWF.
Gluten, whey protein concentrate and kaolinite mixtures were irradiated at microwave oven for different period of time. Based on these powders, ternary gluten, whey protein, kaolinite biopolymer composites were obtained by dispersing in water and heating for 30 min at 80°C. Produced biopolymer composites were dried in a thermostatic cabinet. The optimal irradiation time was determined by measuring small strain rheological properties using an oscillatory rheometer. The mixture of gluten and whey protein concentrate produced several times stronger gels than the singular proteins. It suggests that microwave heating propagated interactions between gluten and whey proteins. The biggest hardness was noted for composites obtained from powders irradiated for 30 s. SEM and elements mapping showed good dispersion of kaolinite particles in the gluten/whey protein matrix. Dry-heating of the mixed gluten, whey protein and kaolinite at 30 s caused interactions (probably mostly disulphide bridges) between unfolded protein molecules. Longer irradiation time than 30 s probably led to highly crosslinked network which negatively affected the properties of bioplastics.
The aims of this study were to investigate the antioxidant and anti-inflammatory effects of extracts from fruits of Ziziphus jujuba Mill. cv. jinsixiaozao Hort (ZJMH) and its active chemical constituents. For antioxidant activity, reducing power, DPPH and β-carotene bleaching inhibition assay were used. Ethyl acetate extract exhibited the strongest antioxidant potential in all the models. For anti-inflammatory activity, petroleum ether extract showed the strongest inhibition (32.86%) against carrageenan-induced paw edema, which also displayed potent anti-inflammatory activity against xylene-induced ear edema (41.52%). The contents of phenolic acids, flavonoids, triterpenes, anthocyanins, triterpenoid saponins of different extracts were also observed. Moreover, seven compounds were first isolated from petroleum ether extract and showed considerable anti-inflammatory activity, especially alphitolic acid and stigmasterol. The results showed that ZJMH can be a natural antioxidant and anti-inflammatory agent.
Physical properties, flavor characteristics and antioxidant properties of the red mature peppers of Shimatogarashi (Capsicum frutescens) were compared to Takanotsume peppers (Capsicum annuum) as the control. Compositions of organic acids and capsaicinoids differed between the peppers. Malic acid was the prevalent organic acid in Shimatogarashi, while citric acid was prevalent in Takanotsume. Shimatogarashi had higher capsaicin and dihydrocapsaicin contents compared to Takanotsume. In terms of volatile compound compositions, the prevalent compounds in Shimatogarashi and Takanotsume peppers were hexanal and 10s,11s-himachala-3(12),4-diene, respectively. Overall, Shimatogarashi peppers were brightly colored, highly pungent with a fresh and fruity aroma, while Takanotsume peppers were dark red, moderately pungent with a warm and herbaceous aroma. As suggested by their total phenolic content and ORAC, Shimatogarashi peppers showed higher antioxidant activity compared to Takanotsume peppers.
In this study, we investigated the relationship between the size of food pieces generated by chewing and the taste intensity during mastication, using cubic gels of two sizes made from agarose of different molecular weights. The intensities of both sweetness and saltiness increased to peak intensity and then decreased with increasing number of chewing cycles, irrespective of the gel sample size and of the molecular weight of agarose gels used. The suppression of sweet taste release was strong with high molecular weight agarose gels with a large pre-ingestion size. In the large pre-ingestion size gel, agarose of higher molecular weight required larger differences in gel fragment size for perception of significant differences in the sweetness intensity than agarose of lower molecular weight. The sodium chloride concentration eluted from agarose gel and the perception of taste was positively correlated in the early stage of mastication, but negatively correlated in the late stage.
The aim of this study was to evaluate the anti-prediabetic effect of 6-O-caffeoylsophorose (CS) isolated from red vinegar in prediabetic spontaneously diabetic Torii (SDT) rats. The effect of CS on glucose uptake in rat skeletal muscle L6 myotubes was also investigated. By the supplementation of CS at a dose of 100 mg/kg/day for 8 weeks to 8-week-old SDT rats, impaired glucose tolerance in 12- and 16-week-old rats was improved in CS group, along with promoted insulin secretion. In a glucose uptake study using 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]-2-deoxyglucose (2-NBDG), > 50 µM CS stimulated uptake of 2-NBDG and translocation of glucose transporter 4 (GLUT4) to the plasma membrane. In CS-treated L6 cells, western blot analysis showed phosphorylation of AMP-activated protein kinase (AMPK) but not of Akt. Consequently, we concluded that CS showed an in vivo anti-prediabetic effect, and promoted GLUT4 translocation in L6 myotubes possibly through the activation of the AMPK signaling pathway.
Petal extracts of the edible flowers of two typical cultivars, Aboukyu and Enmeiraku, of Japanese Chrysanthemum spp. (Chrysanthemum morifolium Ramat. forma esculentum Makino) were analyzed for their bioactive characteristics, including neuroprotective and neurotrophic-like activity in relation to the chemical profile of phenolic components. Phenolic components of petals differed significantly between the Aboukyu and Enmeiraku cultivars. The level of luteolin, an antioxidant polyphenol that possesses neurotrophic and neuroprotective activities, was higher in Enmeiraku than in Aboukyu. Extracts of Enmeiraku protected neuroblastoma SH-SY5Y cell viability against oxidative stress-induced injury in a concentration-dependent manner (12.5 – 100 µg/mL). By contrast, the neuroprotective effect of Aboukyu extracts was biphasic and was weakened at concentrations > 25 µg/mL. Individually, the Aboukyu and Enmeiraku extracts only slightly induced neurite outgrowth; however, in combination with nerve growth factor, the extracts acted synergistically to induce full neurite outgrowth in PC12 cells. Our findings suggest that differences in the neuroprotective effect of Aboukyu and Enmeiraku extracts are attributable to differences in the composition of the constituent phenolic compounds.
Hydrolyzed leather protein (HLP), which is collagen extracted from leather scraps, was intentionally added into dairy products by some illegal dairy producers and has caused food safety scares in China. In this study, near-infrared (NIR) spectroscopy and chemometric analysis were employed to detect HLP adulteration in infant formula. Infant formula adulterated with HLP powder can be well discriminated from authentic samples by using soft independent modelling of class analogy (SIMCA) method. Furthermore, partial least squares regression (PLS) and support vector regression (SVR) models were developed, optimized and compared for quantitative analyses of HLP adulteration concentrations. The SVR modelling method has demonstrated a better predicted capacity than PLS, and a relatively high (7.42) ratio of prediction (RPD) can be achieved. NIR spectroscopy coupled with the chemometric analysis technique could be a useful tool for simple, rapid, economical and non-destructive detection of HLP adulteration in dairy products.
The anti-inflammatory effects of two phlorotannins identified in the brown alga Eisenia arborea, i.e., 6,6′-bieckol and 6,8′-bieckol, were previously determined in vitro. Here we investigated the in vivo effects of these phlorotannins in mice. In ICR mice, ear swelling was induced by three sensitizers: arachidonic acid, 12-O-tetradecanoylphorbol-13-acetate (TPA) and oxazolone (OXA). Swelling was suppressed after the two phlorotannins were applied to the mouse ears. In particular, compared with epigallocatechin gallate, a typical natural inhibitor, the phlorotannins had a significantly greater effect on OXA-induced ear swelling (6,6′-bieckol, p < 0.05; 6,8′-bieckol, p < 0.01). This is the first report to confirm the anti-inflammatory effects of 6,6′-bieckol and 6,8′-bieckol in vivo.
Singlet oxygen absorption capacity (SOAC) is an assay method used to evaluate the singlet oxygen quenching capacity. We evaluated the precision of the SOAC assay method in an inter-laboratory validation study using 3 antioxidant solutions and 3 food extracts. This study involved 14 participating laboratories, with data sets from 8 successfully participating laboratories subjected to statistical analysis. In accordance with the harmonized protocol, this study showed that the intermediate precision relative standard deviation (RSDint) and the reproducibility relative standard deviation (RSDR) ranged from 3.4 to 9.9%, and from 6.2 to 14.0%, respectively, and the HorRat values ranged from 0.87 to 1.97. Therefore, the SOAC assay method was validated by this inter-laboratory study in accordance with the internationally harmonized protocol.