991 resultados para Food Science


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The antibacterial activities of water, ethanol and hexane extracts of five Australian herbs (Backhousia citriodora, Anetholea anisata, Eucalyptus staigerana, Eu. olida and Prostanthera incisa) against seven food-related bacteria (Enterococcus faecalis, Escherichia coli, Listeria monocytogenes, Pseudomonas aeruginosa, Salmonella Enteritidis, Sal. Typhimurium and Staphylococcus aureus) were determined by the microtitre broth microdilution assay. The water extracts of all the herbs displayed no or low antimicrobial activity against all of the bacteria tested with the exception of S. aureus. Relatively high levels of activity (minimum inhibitory concentrations of 125-15.6 mu g ml(-1)) against this pathogen were present in water extracts from all herbs except P. incisa. The ethanol and hexane extracts of all herbs displayed some activity against a number of the bacteria tested, with no one particular herb displaying an obviously higher level or range of activity. Staphylococcus aureus proved to be the most sensitive of the bacteria tested against the solvent extracts with all extracts displaying activity ranging from 125 to 7.8 mu g ml(-1), while E. coli and L. monocytogenes, on the other hand, proved the least sensitive with only five of 15 herb/extract combinations displaying any activity against these pathogens. The extracts of the Australian native herbs examined in this study have potential for application in foods to increase shelf-life or promote safety. (c) 2005 Elsevier Ltd. All rights reserved.

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A new Thermal Mechanical Compression Test (TMCT) was applied for glass-rubber transition and melting analyses of food powders and crystals. The TMCT technique measures the phase change of a material based on mechanical changes during the transition. Whey, honey, and apple juice powders were analyzed for their glass-rubber transition temperatures. Sucrose and glucose monohydrate crystals were analyzed for their melting temperatures. The results were compared to the values obtained by conventional DSC and TMA techniques. The new TMCT technique provided the results that were very close to the conventional techniques. This technique can be an alternative to analyze glass-rubber transition of food, pharmaceutical, and chemical dry products.

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Food refusal can have the potential to lead to nutritional deficiencies, which increases the risk of a variety of communicable and non-communicable diseases. Deciding when food refusal requires professional intervention is complicated by the fact that there is a natural and appropriate stage in a child's development that is characterised by increased levels of rejection of both previously accepted and novel food items. Therefore, choosing to intervene is difficult, which if handled badly can lead to further food refusal and an even more limited diet. Food refusal is often based on individual preferences; however, it can also be defined through pathological behaviours that require psychological intervention. This paper presents and discusses several different types of food refusal behaviours; these are learningdependent, those that are related to a medical complication, selective food refusal, fear-based food refusal and appetiteawareness-autonomy-based food refusal. This paper describes the behaviours and characteristics that are often associated with each; however, emphasis is placed on the possibility that these different types of food refusal can often be co-morbid. The decision to offer professional intervention to the child and their family should be a holistic process based on the level of medical or psychological distress resulting from the food refusal. © 2009 Bentham Science Publishers Ltd.

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This chapter analyses specific trends in food supply chain management. We focus our analysis on information technology and on sustainability. Relevant applications, implementation practices and challenges are examined in the context of contemporary food supply chains. This analysis will benefit supply chain managers, researchers and other stakeholders involved with the food sector. © 2010 Woodhead Publishing Limited All rights reserved.

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The aim of this chapter is to increase understanding of e-business adoption in the food supply chain. In the first part of the paper an analysis of the concept and the context of e-business are presented along with a classification of the various e-business applications based on the dimensions of involvement and complexity. Next emphasis is given to the issue of e-business adoption. In particular an analysis of the factors that influence the adoption process is provided by exploring the specific characteristics of the food industry as well as the potential impact of the use of e-business solutions. These factors are not only related to the company but also to the supply chain of each company and the actual value of e-business applications. The chapter concludes that in many cases e-business is wrongly considered as a sole application and its adoption as mainly an intra-firm issue. Finally future trends are considered and discussed. © 2010 Woodhead Publishing Limited All rights reserved.

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Advocates of â˜local foodâ claim it serves to reduce food miles and greenhouse gas emissions, improve food safety and quality, strengthen local economies and enhance social capital. We critically review the philosophical and scientific rationale for this assertion, and consider whether conventional scientific approaches can help resolve the debate. We conclude that food miles are a poor indicator of the environmental and ethical impacts of food production. Only through combining spatially explicit life cycle assessment with analysis of social issues can the benefits of local food be assessed. This type of analysis is currently lacking for nearly all food chains.

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Food safety is critical to the success of restaurants. Yet current methods of controling foodborne illness are inadequate, including time and temperature control, safe food handling procedures, good employee hygiene, cleaning and sanitizing techniques, and Hazard Analysis and Critical Control Points (HACCP) plan. Several barriers to food safety in restaurants are identified and recommendations for management are suggested.

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Solid waste disposal is a major concern today. This study seeks to identify the current practices and attitudes of managers of independent food services toward solid waste management and the characteristics of food services which were most likely to be involved with a solid waste management program

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Providing meals to passengers on aircrafts requires a complex logistical system if it is to be done sucessfully. Variations to that system are required if special meals, such as kosher ones, are to be provided since it entails unique system challenges. The authors discuss service requirements, the challenges they pose to the inflight meal service logistical system, and some of the ways in which these challenges are met.

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The current exploratory study was designed to determine the impact that green restaurant practices may have on intention to visit a restaurant and willingness to pay more because of those green practices. The study analyzed a convenience sample of 260 surveys from customers in fast food restaurants and 501 surveys from customers in upscale casual restaurants in the Midwestern United States (U.S.) in order to determine if there were differences in the perception of guests regarding these types of restaurants and their green practices. The findings showed that upscale casual restaurant customers believed they are knowledgeable at a higher level than the fast food restaurant customers about green restaurant practices, have a higher mean rating on the importance of environmental record and recycling in restaurants, and believed that restaurants should use local products when they can. In both groups of customers, there was a positive relationship between green practices utilized at home and customersâ willingness to pay more for green restaurant practices as well as their intention to visit the restaurant using green practices. Management implications are discussed.

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Lactic acid bacteria expolysaccharides (LAB-EPS), in particular those formed from sucrose have the potential to improve food and beverage rheology and enhance their sensory properties potentially replacing or reducing expensive hydrocolloids currently used as improvers in food and beverage industries. Addition of sucrose not only enables EPS formation but also affects organic acid formation, thus influencing the sensory properties of the resulting food/beverage products. The first part of the study the organoleptic modulation of barley malt derived wort fermented using in situ produced bacterial polysaccharides has been investigated. Weisella cibaria MG1 was capable to produce exopolysaccharides during sucrosesupplemented barley malt derived wort fermentation. Even though the strain dominated the (sucrose-supplemented) wort fermentation, it was found to produce EPS (14.4 g l-1) with lower efficiency than in SucMRS (34.6 g l-1). Higher maltose concentration in wort led to the increased formation of oligosaccharide (OS) at the expense of EPS. Additionally, small amounts of organic acids were formed and ethanol remained below 0.5% (v/v). W. cibaria MG1 fermented worts supplemented with 5 or 10% sucrose displayed a shear-thinning behaviour indicating the formation of polymers. This report showed how novel and nutritious LAB fermented wort-base beverage with prospects for further advancements can be formulated using tailored microbial cultures. In the next step, the impact of exopolysaccharide-producing Weissella cibaria MG1 on the ability to improve rheological properties of fermented plant-based milk substitute plant based soy and quinoa grain was evaluated. W. cibaria MG1 grew well in soy milk, exceeding a cell count of log 8 cfu/g within 6 h of fermentation. The presence of W. cibaria MG1 led to a decrease in gelation and fermentation time. EPS isolated from soy yoghurts supplemented with sucrose were higher in molecular weight (1.1 x 108 g/mol vs 6.6 x 107 g/mol), and resulted in reduced gel stiffness (190 ± 2.89 Pa vs 244 ± 15.9 Pa). Soy yoghurts showed typical biopolymer gels structure and the network structure changed to larger pores and less cross-linking in the presence of sucrose and increasing molecular weight of the EPS. In situ investigation of Weissella cibaria MG1 producing EPS on quinoa-based milk was performed. The production of quinoa milk, starting from wholemeal quinoa flour, was optimised to maximise EPS production. On doing that, enzymatic destructuration of protein and carbohydrate components of quinoa milk was successfully achieved applying alpha-amylase and proteases treatments. Fermented wholemeal quinoa milk using Weissella cibaria MG1 showed high viable cell counts (>109 cfu/mL), a pH of 5.16, and significantly higher water holding capacity (WHC, 100 %), viscosity (> 0. 5 Pa s) and exopolysaccharide (EPS) amount (40 mg/L) than the chemically acidified control. High EPS (dextran) concentration in quinoa milk caused earlier aggregation because more EPS occupy more space, and the chenopodin were forced to interact with each other. Direct observation of microstructure in fermented quinoa milk indicated that the network structures of EPS-protein could improve the texture of fermented quinoa milk. Overall, Weissella cibaria MG1 showed favorable technology properties and great potential for further possible application in the development of high viscosity fermented quinoa milk. The last part of the study investigate the ex-situ LAB-EPS (dextran) application compared to other hydrocolloids as a novel food ingredient to compensate for low protein in biscuit and wholemeal wheat flour. Three hydrocolloids, xanthan gum, dextran and hydroxypropyl methylcellulose, were incorporated into bread recipes based on high-protein flours, low-protein flours and coarse wholemeal flour. Hydrocolloid levels of 0â5 % (flour basis) were used in bread recipes to test the water absorption. The quality parameters of dough (farinograph, extensograph, rheofermentometre) and bread (specific volume, crumb structure and staling profile) were determined. Results showed that xanthan had negative impact on the dough and bread quality characteristics. HPMC and dextran generally improved dough and bread quality and showed dosage dependence. Volume of low-protein flour breads were significantly improved by incorporation of 0.5 % of the latter two hydrocolloids. However, dextran outperformed HPMC regarding initial bread hardness and staling shelf life regardless the flour applied in the formulation.

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Nanotechnology is a multidisciplinary science that is having a boom today, providing new products with attractive physicochemical properties for many applications. In agri/feed/food sector, nanotechnology offers great opportunities for obtaining products and innovative applications for agriculture and livestock, water treatment and the production, processing, storage and packaging of food. To this end, a wide variety of nanomaterials, ranging from metals and inorganic metal oxides to organic nanomaterials carrying bioactive ingredients are applied. This review shows an overview of current and future applications of nanotechnology in the food industry. Food additives and materials in contact with food are now the main applications, while it is expected that in the future are in the field of nano-encapsulated and nanocomposites in applications as novel foods, additives, biocides, pesticides and materials food contact.

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Antioxidant enzymes (catalase and peroxidase) and carotenoids (lutein and â-carotene) are often used as biomarkers of metal contamination of water and agricultural soils. In this study, the effects of heavy metals present in irrigation water on the aforementioned carotenoids of potatoes (Solanum tuberosum L.) and carrots (Daucus carota L.), cultivated in a greenhouse and irrigated with a water solution including different levels of Cr(VI) and Ni(II) were investigated. These results were compared to the levels of the same metabolites that had been assessed in market-available potato and carrot samples. The findings indicated that the levels of the examined metabolites on the treated with Cr and Ni samples, resemble the levels of the same parameters in the market samples, originating from polluted areas. Therefore, the antioxidant enzymes, catalase and peroxidase, and the carotenoids, lutein and â-carotene, could be handled as indicators of heavy metal pollution.