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现今商海中,新技术的应用是件既困难又危险的事情.不利用新技术的优势会导致市场丧失,但动手太早又有可能是投资了一项不成熟的技术,或者使企业面临巨大的财务压力.  相似文献   

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There is growing scientific evidence that the health, well-being and the attractiveness of the skin are strongly influenced by nutrition. Consumers recognize this and have supported the creation of a global cosmeceuticals market estimated in 2010 at $27.2 billion. Early in 2011, the US Department of Health and Human Services and Department of Agriculture issued the Dietary Guidelines for Americans, 2010. Twelve vitamins and nine minerals were recognized as essential. The minerals include calcium, copper, iron, magnesium, phosphorus, selenium, zinc, potassium and sodium. Although the topical benefits of several minerals such as zinc, magnesium and iron are recognized and, in some cases, approved by the FDA, the topical benefits of the others to the skin are largely unexplored and unexploited. This review attempts to summarize what has been published in the literature on the interactions of the eight of the nine essential elements with the skin.  相似文献   

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The reaction behaviour of monosaccharides in the Maillard reaction is well investigated. Amadori compounds, for instance, form deoxyhexosuloses which are responsible for the formation of volatile flavour substances and melanoidins. These intermediates can be quantified by a trapping reaction with o‐phenylendiamine as stable quinoxalines. However the reaction behaviour of oligo and polymeric carbohydrates in non‐enzymatic browning reactions are hardly known. Therefore maltooligosaccharides and in some cases starch were used together with glycine as model substances to investigate the Maillard reaction mechanism of oligo and polysaccharides. In quasi waterfree reaction systems oligosaccharides form α‐dicarbonyl compounds via a “peeling off” mechanism. The Maillardreaction with the amino compound starts at the reducing end of an α‐glucane residue and results in the formation of 1,4‐dideoxyhexosulose. This is the main α‐dicarbonyl compound found by trapping reaction with o‐phenylendiamine during thermally induced degradation of maltooligosaccharides. The thermal reaction of maltooligosaccharides is accompanied by transglycosylations leading to formation of branched carbohydrate structures and by dehydrations forming anhydrosugars. The reaction mechanism which is responsible for degradation of oligomeric carbohydrates in aqueous model systems differs significantly from pathways mentioned above for water free reaction conditions. As the main α‐dicarbonyl compound 3‐deoxypentosulose is formed which can be proved also by trapping reactions. Under aqueous reaction conditions the formation of other α‐dicarbonyls plays only a marginal role in the Maillard reaction of oligomeric carbohydrates. In an aqueous system transglycosylation and dehydration of maltooligosaccharides are not important.  相似文献   

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News on the Maillard reaction of oligomeric carbohydrates: a survey.   总被引:1,自引:0,他引:1  
L W Kroh  A Schulz 《Die Nahrung》2001,45(3):160-163
The reaction behaviour of monosaccharides in the Maillard reaction is well investigated. Amadori compounds, for instance, form deoxyhexosuloses which are responsible for the formation of volatile flavour substances and melanoidins. These intermediates can be quantified by a trapping reaction with o-phenylendiamine as stable quinoxalines. However the reaction behaviour of oligo and polymeric carbohydrates in non-enzymatic browning reactions are hardly known. Therefore maltooligosaccharides and in some cases starch were used together with glycine as model substances to investigate the Maillard reaction mechanism of oligo and polysaccharides. In quasi waterfree reaction systems oligosaccharides form alpha-dicarbonyl compounds via a "peeling off" mechanism. The Maillard reaction with the amino compound starts at the reducing end of an alpha-glucane residue and results in the formation of 1,4-dideoxyhexosulose. This is the main alpha-dicarbonyl compound found by trapping reaction with o-phenylendiamine during thermally induced degradation of maltooligosaccharides. The thermal reaction of maltooligosaccharides is accompanied by transglycosylations leading to formation of branched carbohydrate structures and by dehydrations forming anhydrosugars. The reaction mechanism which is responsible for degradation of oligomeric carbohydrates in aqueous model systems differs significantly from pathways mentioned above for water free reaction conditions. As the main alpha-dicarbonyl compound 3-deoxypentosulose is formed which can be proved also by trapping reactions. Under aqueous reaction conditions the formation of other alpha-dicarbonyls plays only a marginal role in the Maillard reaction of oligomeric carbohydrates. In an aqueous system transglycosylation and dehydration of maltooligosaccharides are not important.  相似文献   

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A review of the current literature concerning the role played by metallic elements present in wine is presented. The aim is to show the importance of these elements in the entire wine-making process, mainly through their influence on the organoleptic properties of wine. The study takes into consideration the individual stages of the process such as fertilization, fermentation and aging and also deals with other interesting aspects related to hygiene and dietetic properties, as well as the possibility of differentiating wines according to their metal contents.  相似文献   

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Nephrocalcinosis is a common disorder in female rats. Various etiological factors are involved in the pathogenesis, e.g. sex, age, genetical and dietary factors. Dietary phosphorus concentration appears to be of crucial importance in the induction of nephrocalcinosis. The pathological changes in calcinotic kidney tissue are described. Possible mechanisms underlying nephrocalcinogenesis are discussed. Phosphorus concentration within the proximal tubule may be the major determinant of nephrocalcinogenesis.  相似文献   

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Summary A review of the current literature concerning the role played by metallic elements present in wine is presented. The aim is to show the importance of these elements in the entire wine-making process, mainly through their influence on the organoleptic properties of wine. The study takes into consideration the individual stages of the process such as fertilization, fermentation and aging and also deals with other interesting aspects related to hygiene and dietetic properties, as well as the possibility of differentiating wines according to their metal contents.
Die Bedeutung der metallischen Elemente im Wein. Eine Literaturübersicht
Zusammenfassung Eine Untersuchung über die Rolle der metallischen Elemente im Wein wurde abgeschlossen. Das Ziel dieser Untersuchung war, die Bedeutung der Elemente bei der Herstellung des Weines, hauptsächlich ihren Einfluß auf die sensorischen Eigenschaften, zu beweisen. In erster Linie wurden bei dieser Arbeit die verschiedenen Phasen der Weinherstellung, wie Düngung, Gärung oder Altern, betrachtet, um schließlich auch andere interessante Aspekte, z. B. hygienische und diätische oder die mögliche Differenzierung der Weine aufgrund ihrer metallischen Elemente zu behandeln.
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A sampling campaign from 21 sites in Italy was conducted: 15 species from fishery and three species from aquaculture, for a total of 40 determinations, were considered. A careful sample preparation preceded the instrumental analysis that was carried out by means of GC–ECD and GC–MS. Good laboratory practice was achieved by the participation in proficiency tests, by the use of certified reference materials and by applying other directives recommended by international organisations. Concentrations measured in this work were compared with a TDI proposed by some international bodies: for a person weighing 70 kg one-third of the samples from fishery, when consumed, lead to exceed this TDI if the average fish daily consumption per capita is considered. Based on the data obtained here some hypotheses on environmental spreading and influence of PCBs on human health are made. Some suggestions about the preparation of fish for consumption are also given.  相似文献   

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PURPOSE: Collective kitchens are community-based cooking programs in which small groups of people cook large quantities of food. They have developed over the past 20 years, and hundreds of groups have been formed across the country. However, collective kitchens described in the literature vary considerably in structure, purpose, and format. The purpose of this review is to synthesize research on this topic. METHODS: Articles and theses were collected through searches of major databases, and synthesized to improve understanding of current information, and of continuing gaps in the knowledge of collective kitchens in Canada. RESULTS: The limited published research on collective kitchens suggests that social and learning benefits are associated with participation. Some indication exists that participants also find the food cooked to be high quality, culturally acceptable, and acquired in a manner that maintains personal dignity. Whether collective kitchens have an impact on food resources as a whole is unclear, as research has been limited in scale. CONCLUSIONS: The role of collective kitchens in community building and empowering participants often is noted, and bears further investigation. Dietitians and nutritionists have a unique opportunity to facilitate the health promotion and food security benefits of collective kitchens.  相似文献   

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Research concerning the benefits derived from dietary polyphenols, a significant class within the family of phytonutrients, has increased considerably in the last decade. Prior to the late 1990s, the nutritional spotlight focused on the antioxidant capabilities of carotenoids, vitamins, and minerals. More recently, however, research has emerged in strong support of the antioxidant capacity of polyphenols and their role in the prevention and/or treatment of certain cancers, diabetes, cardiovascular diseases, and inflammation. Polyphenols are categorized according to the nature of their carbon skeleton, ranging from basic phenolic molecules to highly complex compounds, such as flavonoids, the most common and widely studied of all phenolic compounds. The most prevalent phenolic acids include ellagic acid, gallic acid, tannic acid, and capsaicin.  相似文献   

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Ready-to-eat foods at retail and catering establishments were randomly sampled at the point of sale for a period of 15 months. During this period, 4,469 food samples were examined for the presence of Campylobacter with the use of plate-based methodology. A range of different ready-to-eat food types, all of which have the potential to be contaminated with the organism, were examined. No viable Campylobacter cells were detected in any of the foods during the survey. There is no evidence that the foods examined in this study represent a risk to the consumer. Although these foods may be a vehicle for infection if cross-contamination occurs, other sources need to be investigated as causes of enteric infection caused by Campylobacter.  相似文献   

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