Properties of deamidated gluten films enzymatically cross-linked   总被引：8，自引：0，他引：8  

Larré C  Desserme C  Barbot J  Gueguen J 《Journal of agricultural and food chemistry》2000,48(11):5444-5449

Films were prepared at neutral pH from deamidated gluten by casting with or without enzymatic treatment by transglutaminase in the presence of various concentrations of diamines added to the film-forming solution. Variation in the glycerol/deamidated gluten ratio from 0.2 to 0.5 had a major effect on the film mechanical properties, which is characteristic of a plasticizing effect. A ratio of 0.35, producing a tensile strength of 1.14 +/- 0.12 MPa and an elongation at break of 376 +/- 62%, was chosen for most of the enzymatic modifications. The action of transglutaminase with or without the addition of external diamines induced a simultaneous increase in tensile strength and elongation at break of the films but tended to decrease the contact angle between the film surface and a water droplet. The presence of diamines in the film solution affected the elongation at break more than the tensile strength of the films. These diamines, able to react at their two extremities, probably acted as spacers between gluten proteins. The decrease in solubility was related to the formation of high molecular weight polymers in the film. The film properties were unaffected by the type of diamine added as secondary substrate in the transglutaminase reaction.  相似文献   

Evidence of the glycation and denaturation of LTP1 during the malting and brewing process     

Jégou S  Douliez JP  Mollé D  Boivin P  Marion D 《Journal of agricultural and food chemistry》2001,49(10):4942-4949

The influence of malting and brewing processes on the chemical and structural modifications occurring on LTP1 was investigated by mass spectrometry and circular dichroism. Proteins were first purified from malt, and samples were collected at various steps of beer processing performed on two barley cultivars. The levels of LTP1 found in malt were not significantly different from the amounts in barley seed. However, in malt, both LTP1b, a post-translational form of LTP1, and a third isoform named LTP1c were isolated. Moreover, both of these proteins were found to be heterogeneously glycated but still exhibited an alpha-helix structure. Both glycated LTP1 and LTP1b were recovered during mashing. It was also shown that glycated LTP1 was unfolded during heat treatment of wort boiling, which is in agreement with the denatured form previously isolated from beer.  相似文献   

Concentrations of metals (zinc, copper, cadmium, and mercury) in three domestic ducks in France: Pekin, Muscovy, and Mule ducks     

Lucia M  André JM  Bernadet MD  Gontier K  Gérard G  Davail S 《Journal of agricultural and food chemistry》2008,56(1):281-288

The role of different factors such as biological material (tissues, organs) and trophic condition (overfeeding or not) in the metal accumulation was studied in three genotypes of ducks (Pekin, Muscovy, and Mule) under breeding conditions. Results showed that overfeeding decreased the concentration in Cd, Cu, and Zn through the dilution process. In contrast, mercury concentration increased with this method. A relation between lipidic metabolism of genotypes and the distribution of this metal in biological material was found. Domestic ducks were little contaminated, but a low chronic contamination in Cd was observed, probably coming from the food. Due to the low levels of contamination observed in these breeding ducks, they can be considered as a good control for further contamination studies and comparison with accumulation levels recorded in the field. The impact of feeding condition on accumulation showed the importance of taking into account the life cycle of birds before studying their contamination and the impact of pollutants.  相似文献   

基于SIRMOD模型的畦灌入渗参数估算及灌溉模拟   总被引：3，自引：2，他引：3  

郑和祥  史海滨  朱敏  刘宏云  José Manuel Gon?alves 《农业工程学报》2009,25(11):29-34

土壤入渗参数是地面灌溉中制定灌溉制度、评价灌水质量的重要指标。针对现有估算方法存在计算工作量较大、精度不高的现状,根据田间实测资料,利用SIRMOD模型,对小麦畦灌条件下田间土壤入渗参数进行了估算。与用Maheshwari法计算结果较为接近,差异均在2.0%以内。根据估算的土壤入渗参数,应用SIRMOD模型进行了多组合灌溉模拟,在保证灌水质量较高的条件下,得出了在不同亏缺水量时的适宜灌水量和灌水流量,通过田间实例验证表明模拟效果较好。  相似文献   

Oxygen-18 enrichment of planktonic foraminifera due to gametogenic calcification below the euphotic zone     

Blanc PL  Bé AW 《Science (New York, N.Y.)》1981,213(4513):1247-1250

Empty shells of spinose planktonic foraminifera on the seabed are significantly enriched in oxygen-18 as compared with the shells of their living counterparts in surface waters. This enrichment is due to gametogenic calcification, which extracts calcium carbonate from deeper and colder waters as the shell sinks below the euphotic zone. JEAN-CLAUDE DUPLESSY.  相似文献   

Galaxies, human eyes, and artificial neural networks     

Lahav O  Naim A  Buta RJ  Corwin HG  de Vaucouleurs G  Dressler A  Huchra JP  van den Bergh S  Raychaudhury S  Sodré L  Storrie-Lombardi MC 《Science (New York, N.Y.)》1995,267(5199):859-862

The quantitative morphological classification of galaxies is important for understanding the origin of type frequency and correlations with environment. However, galaxy morphological classification is still mainly done visually by dedicated individuals, in the spirit of Hubble's original scheme and its modifications. The rapid increase in data on galaxy images at low and high redshift calls for a re-examination of the classification schemes and for automatic methods. Here are shown results from a systematic comparison of the dispersion among human experts classifying a uniformly selected sample of more than 800 digitized galaxy images. These galaxy images were then classified by six of the authors independently. The human classifications are compared with each other and with an automatic classification by an artificial neural network, which replicates the classification by a human expert to the same degree of agreement as that between two human experts.  相似文献   

Soil organic carbon fractions and humic substances are affected by land uses of Caatinga forest in Brazil     

Uemeson José dos Santos  Gustavo Pereira Duda  Marise Conceição Marques  José Romualdo de Sousa Lima  Eduardo Soares de Souza 《Arid Land Research and Management》2019,33(3):255-273

Caatinga is a Brazilian dry ecosystem that occupies around 1 million km² and is one of the largest tropical dry forests of the world. About 46% of the area that was originally covered has been deforested. Land use can cause pronounced reduction in soil carbon stocks that play a major role in the global carbon cycle. The objective of this study was to improve our understanding of the effect of land use on oxidizable carbon fractions, total carbon stocks and humic substances in different layers of soil in a Brazilian semi-arid region. We analyzed soils from tropical dry forest (TDF), forest succession with Anadenanthera falcata (ANA), with Tabebuia alba (TAB), secondary scrubby regeneration (SCR), and non-irrigated maize (MS). Forests showed larger fractions of more labile carbon, except for TDF. The most recalcitrant fraction of carbon stock, humin fraction stock, with the different land use decreased by 38–53% compared to TDF. Oxidizable carbon fractions, carbon stocks, and humic fraction stocks were able to differentiate the successional land uses and agricultural cover from TDF, mainly in the 0–5?cm layer. Our results show that changes in land use, especially with ANA forest succession, showed a larger labile carbon fraction, indicating easy decomposition and loss. Our results provide an alternative tool for the management of deforested areas in tropical dry caatinga ecosystems. This would contribute to the conservation of dry forest systems and could serve as guideline for sustainable management of agriculturally impacted caatinga areas.  相似文献   

Evaluation of Particle Size Influence on Proximate Composition,Physicochemical, Techno-Functional and Physio-Functional Properties of Flours Obtained from Persimmon (<Emphasis Type="Italic">Diospyros kaki</Emphasis> Trumb.) Coproducts     

Raquel Lucas-González  Manuel Viuda-Martos  José Ángel Pérez-Álvarez  Juana Fernández-López 《Plant foods for human nutrition (Dordrecht, Netherlands)》2017,72(1):67-73

The aim of the work was to study the influence of particle size in the composition, physicochemical, techno-functional and physio-functional properties of two flours obtained from persimmon (Diospyros kaki Trumb. cvs. ‘Rojo Brillante’ (RBF) and ‘Triump’ (THF) coproducts. The cultivar (RBF and THF) and particle size significantly affected all parameters under study, although depending on the evaluated property, only one of these effects predominated. Carbohydrates (38.07–46.98 g/100 g) and total dietary fiber (32.07–43.57 g/100 g) were the main components in both flours (RBF and THF). Furthermore, insoluble dietary fiber represented more than 68% of total dietary fiber content. All color properties studied were influenced by cultivar and particle size. For both cultivars, the lower particle size, the higher lightness and hue values. RBF flours showed high values for emulsifying activity (69.33–74.00 mL/mL), while THF presented high values for water holding capacity (WHC: 9.47–12.19 g water/g sample). The bile holding capacity (BHC) and fat/oil binding values were, in general, higher in RBF (19.61–12.19 g bile/g sample and 11.98–9.07, respectively) than THF (16.12–12.40 g bile/g sample and 9.78–7.96, respectively). The effect of particle size was really evident in both WHC and BHC. Due to their dietary fiber content, techno-functional and physio-functional properties, persimmon flours seem to have a good profile to be used as potential functional ingredient.  相似文献   

<Emphasis Type="Italic">Lupinus albus</Emphasis> Conglutin Gamma Modifies the Gene Expressions of Enzymes Involved in Glucose Hepatic Production <Emphasis Type="Italic">In Vivo</Emphasis>     

Ana E. González-Santiago  Belinda Vargas-Guerrero  Pedro M. García-López  Alma L. Martínez-Ayala  José A. Domínguez-Rosales  Carmen M. Gurrola-Díaz 《Plant foods for human nutrition (Dordrecht, Netherlands)》2017,72(2):134-140

Lupinus albus seeds contain conglutin gamma (Cγ) protein, which exerts a hypoglycemic effect and positively modifies proteins involved in glucose homeostasis. Cγ could potentially be used to manage patients with impaired glucose metabolism, but there remains a need to evaluate its effects on hepatic glucose production. The present study aimed to analyze G6pc, Fbp1, and Pck1 gene expressions in two experimental animal models of impaired glucose metabolism. We also evaluated hepatic and renal tissue integrity following Cγ treatment. To generate an insulin resistance model, male Wistar rats were provided 30% sucrose solution ad libitum for 20 weeks. To generate a type 2 diabetes model (STZ), five-day-old rats were intraperitoneally injected with streptozotocin (150 mg/kg). Each animal model was randomized into three subgroups that received the following oral treatments daily for one week: 0.9% w/v NaCl (vehicle; IR-Ctrl and STZ-Ctrl); metformin 300 mg/kg (IR-Met and STZ-Met); and Cγ 150 mg/kg (IR-Cγ and STZ-Cγ). Biochemical parameters were assessed pre- and post-treatment using colorimetric or enzymatic methods. We also performed histological analysis of hepatic and renal tissue. G6pc, Fbp1, and Pck1 gene expressions were quantified using real-time PCR. No histological changes were observed in any group. Post-treatment G6pc gene expression was decreased in the IR-Cγ and STZ-Cγ groups. Post-treatment Fbp1 and Pck1 gene expressions were reduced in the IR-Cγ group but increased in STZ-Cγ animals. Overall, these findings suggest that Cγ is involved in reducing hepatic glucose production, mainly through G6pc inhibition in impaired glucose metabolism disorders.  相似文献   

Irrigation of paddy soil with industrial landfill leachate: impacts in rice productivity,plant nutrition,and chemical characteristics of soil     

Filipe?Selau?CarlosEmail author  Bruno?Loss?dos?Santos  Robson?Andreazza  Marino?José?Tedesco  Lawrence?Morris  Flávio?Anastácio?de?Oliveira Camargo 《Paddy and Water Environment》2017,15(1):133-144

Treated industrial effluents have high levels of nutrients and dissolved organic matter. The irrigation of rice by flooding can increase nutrient uptake and grain yield. Therefore, this study evaluated the nutrient contents in the shoots and grain of the rice crop and also the chemical of the soil after irrigation of the crop with leachate of the treated industrial effluent. A greenhouse experiment was conducted using pots filled with 20 kg of soil in a randomized block design with three replications. The treatments consisted of control (irrigation with distilled water) and four concentrations of the leachate (25, 50, 75, and 100 %) for irrigation. At the end of the experiment, the nutrient contents in tissues of rice plants, sterility of spikelets, and grain mass were evaluated. Results showed that irrigation with the leachate at 25 % content increased the macro- and micronutrients’ concentrations in the shoot biomass and grain, except for potassium and iron. Irrigation with the industrial leachate decreased tillering and grain yield; however, it increased chlorophyll content, sterility of spikelets, and sodium intake at this leachate concentration. The potassium and sodium levels and the electrical conductivity values of soils irrigated with treated industrial leachate were increased. The use of the treated leachate from industrial effluents is an alternative that reuses the nutritional load, but the volume of leachate should be limited and monitored to prevent the sodicity in the soil and problemsdue to eutrophication.  相似文献