In recent years, the functional properties of peptides derived from food proteins have attracted considerable interest. Among them, bioactive peptides that can effectively bind metals have ...application prospects in the improvement of mineral bioavailability, and compensating for the shortcomings of the generally low bioavailability of inorganic mineral supplements. Although a reasonable understanding of structure activity relationship related to the calcium binding of peptides has been gained, physiological connections of peptides as mineral carriers to gastrointestinal uptake needs further research. Hence, this article reviews (1) the development of calcium supplements; (2) inorganic calcium sources and bone calcium; (3) source and acquisition of biologically active peptides; (4) calcium peptide chelation mechanism and structure–activity relationship; and (5) Methods for evaluating calcium bioavailability.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The effects of heat treatment on protein interaction, surface hydrophobicity, protein profile, amino acid composition, and in vitro digestibility of individual rice protein fractions were ...investigated. Heat treatment at 100 °C for 20 min had no negative effect on essential amino acids in rice protein. Surface hydrophobicity increased significantly with the increased heat treatment temperature. Moreover, free-thiol content decreased significantly with increased temperature and time extension. Hydrophobic interactions contributed to the heat-induced interaction of glutelin and prolamin. Intramolecular disulfide linkages participated in the heat-induced interaction of all rice-protein fractions. Heat treatment had no effects on the in vitro digestibility of glutelin, globulin, and albumin. Thus, the heat-induced interactions of glutelin, globulin, and albumin were not related to their digestibility. By contrast, the formation of intramolecular disulfide bonds and hydrophobic interactions in prolamin may reduce its digestibility by strengthening protein bodies-Is.
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CEKLJ, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
This study aims to assess the effect of gamma irradiation on the physicochemical properties and nutrient contents of two different peanut cultivars. The peanuts were treated with 0, 1, 3, 5, and ...10 kGy gamma irradiation doses. The examined physicochemical properties were water activity, fatty acid value (FAV), peroxide value (PV), carbonyl value (CV), malondialdehyde (MDA) content, and lipase activity. The examined nutrient contents were moisture and ash contents, total sugar, protein and fat contents, fatty acid and amino acid composition. Results showed that high irradiation dose (10 kGy) significantly decreased the fat and protein contents and increased the water activity of peanut. However, the moisture and ash contents and total sugar were not affected by irradiation. The FAV, PV, CV, and MDA contents increased depending on the radiation dose. Fatty acid and amino acid composition changed when the irradiation dose increased. Sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis revealed that irradiation did not modify the protein subunits but disrupted the disulfide bonds. Furthermore, lipase activity decreased with the increased irradiation dose. This phenomenon may positively affect peanut quality during storage.
•High-dose irradiation decreased fat and protein contents of peanut.•γ-irradiation accelerated the degree of peanut lipid oxidation.•Peanut amino acids showed a varying sensibility degrees to irradiation.•γ-irradiation may positively affect peanut preservation by inhibiting lipase.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
•SeMet is the dominant Se species in selenized brown rice.•A Se-containing antioxidative peptide was identified from protein hydrolysates.•The peptide SeMet-Pro-Ser could be used as an natural ...food-born antioxidants.
As a further study of Se-containing proteins (Se-Pro) derived from Se-enriched brown rice (Se-BR), this paper aimed to purify and identify Se-containing antioxidative peptides (Se-antioxi-Peps) from Se-Pro hydrolysates. The total Se content in Se-BR was 6.26μg/g DW, and selenocystine, Se-methylselenocysteine, and selenomethionine were identified as the main organic Se species by high-performance liquid chromatography–inductively coupled plasma mass spectrometry. Se-Pro was extracted and hydrolyzed by four types of proteases, and Alcalase was chosen as the optimum enzyme according to the degree of hydrolysis (DH). The hydrolysate with 17.08% DH possessing the highest DPPH radical scavenging activity was separated into five fractions (F1 to F5). Fractions F3 to F5, which had high antioxidative activities, were further separated. Sub-fractions F3-3, F4-2, and F5-1 were chosen to evaluate antioxidative activities and analyze Se species. The Se-antioxi-Pep with the sequence SeMet-Pro-Ser was identified by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
This review summarized and discussed the mechanisms of self-discharge supercapacitors, with a focus on suppressing strategies in terms of electrode, electrolyte, and separator. The remained ...challenges and the promising directions in suppressing the self-discharge of supercapacitors were also presented and summed up.
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Supercapacitors are one of the most promising energy storage devices in the fields of vehicle transportation, flexible electronic devices, aerospace, etc. However, the existed self-discharge that is the spontaneous voltage decay after supercapacitors are fully charged, brings about the wide gap between experimental studies and practical utilization of supercapacitors. Although eliminating the self-discharge completely is not reachable, suppressing the self-discharge rate to the lowest point is possible and feasible. So far, the significant endeavors have been devoted to achieve this goal. Herein, we summary and discuss the possible mechanisms for the self-discharge and the underlying influence factors. Moreover, the strategies to suppress the self-discharge are systemically summed up by three independent but unified aspects: modifying the electrode, modulating the electrolyte and tuning the separator. Finally, the major challenges to suppress the self-discharge of supercapacitors are concluded and the promising strategies are also pointed out and discussed. This review is presented with the view of serving as a guideline to suppress the self-discharge of supercapacitors and to across-the-board facilitate their widespread application.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
A series of coupled static-dynamic loading tests is carried out in this study to understand the effect of slightly dynamic disturbance on the rocks under high static stress. The acoustic emission ...(AE) and digital image correlation (DIC) techniques are combined to quantitatively characterize the damage and fracturing behaviors of rocks. The effects of three influencing factors, i.e. initial static stress, disturbance amplitude, and disturbance frequency, on the damage and fracturing evolution are analyzed. The experimental results reveal the great differences in AE characteristics and fracturing behaviors of rocks under static loads and coupled static-dynamic loads. Both the Kaiser effect and Felicity effect are observed during the disturbance loading process. The crack initiation, stable and unstable propagation in the highly-stressed rocks can be triggered by cyclic disturbance loads, and more local tensile splitting cracks are found in the rocks subjected to coupled static-dynamic loads. The damage and fracturing evolution of rocks during cyclic disturbances can be divided into two stages, i.e. steady and accelerated stages, and the increase rate and proportion of each stage are greatly affected by these influencing factors. High initial static stress, low disturbance frequency, and high disturbance amplitude are considered to be adverse factors to the stability of the rocks, which would induce a high increase rate of the steady stage and a high proportion of the accelerated stage within the whole disturbance period. Based on the two-stage damage evolution trend, a linear-exponential damage model is employed to predict the instability of the rocks under coupled static-dynamic loads.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Peanut, an important oil crop worldwide, is highly susceptible to oxidative damage during storage due to its high level of fats and unsaturated fatty acids which will affects its nutritional value ...and agricultural importance. Therefore, it is significantly important to research the physicochemical properties changes of peanuts during storage. Peanuts belong to two varieties were stored at various temperatures (15°C, 25°C, and 35°C) for 320 days. Peroxide value (PV), carbonyl value (CV), and malondialdehyde (MDA) content of oil extracted from peanuts were determined every 80 days to evaluate lipid oxidation degree. Proximate composition (fat, protein, total sugar, moisture, and ash), fatty acid, and amino acid compositions were also assessed. All samples exhibited increased CV and MDA contents during storage. The PV of peanuts increased continuously when stored at 15°C and 25°C, but the PV increased firstly and then decreased sharply when stored at 35°C. Storage significantly affected the contents of lipids, proteins, total sugars, and moisture in peanuts but did not influence the ash content. In general, the fatty acid and amino acid compositions changed significantly during storage at different temperatures. High temperatures lead to a high degree of lipid oxidation and nutrient loss. The results above of this study can provide a theoretical basis for the actual storage and preservation of peanuts.
Peanut belong to two varieties was stored at various temperatures for 320 days. Peroxide value, carbonyl value, and malondialdehyde contents in oil extracted from peanuts were determined every 80 days to evaluate lipid oxidation degree. Proximate composition, fatty acid, and amino acid compositions were also assessed.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Milk processing technologies for the control of cow’s milk protein allergens are reviewed in this paper. Cow’s milk is a high nutritious food; however, it is also one of the most common food ...allergens. The major allergens from cow’s milk have been found to be β-lactoglobulin, α-lactalbumin and caseins. Strategies for destroying or modifying these allergens to eliminate milk allergy are being sought by scientists all over the world. In this paper, the main processing technologies used to prevent and eliminate cow’s milk allergy are presented and discussed, including heat treatment, glycation reaction, high pressure, enzymatic hydrolysis and lactic acid fermentation. Additionally, how regulating and optimizing the processing conditions can help reduce cow’s milk protein allergenicity is being investigated. These strategies should provide valuable support for the development of hypoallergenic milk products in the future.
Summary
Changes in lipid oxidation and quality of brown rice stored at different temperatures were investigated. Fatty acid value (FAV), peroxide value (POV) and carbonyl value (CV) of brown rice ...were determined every 45 day for 270 day. Volatile compounds in seven samples stored for 0, 135 and 270 day were also identified. Relationships between volatile compounds and oxidative indices were analysed. Results revealed that the FAV, POV and CV of brown rice significantly increased (P < 0.05) with prolonged storage. Samples stored at low temperatures showed lower FAV, POV and CV than those stored at high temperatures. Brown rice stored under different conditions produced similar volatiles. Based on the principal component analysis of the volatiles, the first two principal components explained 58.20% of the variance. Volatiles of PC1 were correlated with FAV, POV and CV and can be used as an index to assess the quality of stored brown rice.
Changes in lipid oxidation of brown rice stored at different temperatures. Principal component analysis of volatile compounds in brown rice, and correlation analysis between volatile compounds and fatty acid value, peroxide value, and carbonyl value.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Selenium-rich rice has become one of the effective ways to increase people's selenium intake. Selenium-containing proteins have higher antioxidant properties, which may lead to selenium-rich brown ...rice (Se-BR) having better storage stability than ordinary brown rice (BR). By measuring the peroxidation value, fatty acid value, carbonyl value and protein secondary structure, it was found that Se-BR had higher oxidation resistance stability than BR. The biological function of the differential proteins (DEPs) between ordinary brown rice stored for 0 days (BR-0) and 180 days (BR-6) as well as Se-rich brown rice stored for 0 days (Se-0) and 180 days (Se-6) was investigated by using iTRAQ. A total of 237, 235, 113 and 213 DEPs were identified from group A (BR-0/BR-6), group B (Se-0/Se-6), group C (BR-0/Se-0) and group D (BR-6/Se-6), respectively. Kyoto Encyclopedia of Genes and Genomes analysis showed that the DEPs were mainly enriched in glucose metabolism, tricarboxylic acid cycle, fatty acid biosynthesis and degradation, glutathione metabolism, sulfur metabolism, peroxisome and other metabolic pathways. This study provides theoretical support for the study of protein oxidation kinetics and storage quality control of brown rice during storage.
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