959 resultados para Food science
Resumo:
Dielectric barrier discharge (DBD) air plasma is a novel technique for in-package decontamination of food, but it has not been yet applied to the packaging material. Characterization of commercial polylactic acid (PLA) films was done after in-package DBD plasma treatment at different voltages and treatment times to evaluate its suitability as food packaging material. DBD plasma increased the roughness of PLA film mainly at the site in contact with high voltage electrode at both the voltage levels of 70 and 80 kV. DBD plasma treatments did not induce any change in the glass transition temperature, but significant increase in the initial degradation temperature and maximum degradation temperature was observed. DBD plasma treatment did not adversely affect the oxygen and water vapor permeability of PLA. A very limited overall migration was observed in different food simulants and was much below the regulatory limits. Industrial relevance: In-package DBD plasma is a novel and innovative approach for the decontamination of foods with potential industrial application. This paper assesses the suitability of PLA as food packaging material for cold plasma treatment. It characterizes the effect of DBD plasma on the packaging material when used for in-package decontamination of food. The work described in this research offers a promising alternative to classical methods used in fruit and vegetable industries where in-package DBD plasma can serve as an effective decontamination process and avoids any post-process recontamination or hazards from the package itself.
Resumo:
The similarity between the Peleg, Pilosof –Boquet–Batholomai and Singh–Kulshrestha models was investigated using the hydration behaviours of whey protein concentrate, wheat starch and whey protein isolate at 30 °C in 100% relative humidity. The three models were shown to be mathematically the same within experimental variations, and they yielded parameters that are related. The models, in their linear and original forms, were suitable (r2 > 0.98) in describing the sorption behaviours of the samples, and are sensitive to the length of the sorption segment used in the computation. The whey proteins absorbed more moisture than the wheat starch, and the isolate exhibited a higher sorptive ability than the concentrate.
Resumo:
Vaccinium myrtillus or bilberry fruit is a commonly used herbal product. The usual method of determining the anthocyanin content is a single-wavelength spectrophotometric assay. Using this method, anthocyanin levels of two extracts were found to be 25% as claimed by the manufacturers. When high-performance liquid chromatography (HPLC) was used, however, one extract was found to contain 9% anthocyanins probably not derived from V. myrtillus but from an adulterant. This adulterant was subsequently identified, using HPLC, mass spectroscopy, and nuclear magnetic resonance, as amaranth, that is, 3-hydroxy-4-[(4-sulfo-1-naphthalenyl)azo]-2,7-naphthalenedisulfonic acid trisodium saltsa synthetic dark red sulfonic acid based naphthylazo dye. As described in this study, if deliberate adulteration occurs in an extract, a single-wavelength spectrophotometric assay is inadequate to accurately determine the levels of compounds such as anthocyanins. Detection of deliberate adulteration in commercial samples thus requires the use of alternative, more sophisticated, methods of analysis such as HPLC with photodiode array detection as a minimum.
Resumo:
There is public unease about food-related issues including food additives, food poisoning bacteria and GM ingredients. The public wants evidence of no risks, but all regulators can ever offer is no evidence of risk or evidence of a very small risk. The situation is complex because experts and non-experts can perceive the same risk in vastly different ways. The way in which the food industry manages crises and communicates risks will determine the public acceptance and success of new technologies such as GM foods and nanomaterials. There is a need for the food industry (including regulators and scientific experts) to sharpen up their risk communication skills to ensure that technical innovations are accepted by consumers, and crises such as food recalls do not undermine the public's confidence in the food industry. The AIFST has a key role to play in driving the risk communication process and allaying public unease about food-related issues.
Resumo:
Many food materials exist in a disordered amorphous solid state due to processing. Therefore, understanding the concept of amorphous state, its important phase transition (i.e., glass transition), and the related phenomena (e.g., enthalpy relaxation) is important to food scientists. Food saccharides, including mono-, di-, oligo-, and polysaccharides, are among the most important major components in food. Focusing on the food saccharides, this review covers important topics related to amorphous solids, including the concept and molecular arrangement of amorphous solid, the formation of amorphous food saccharides, the concept of glass transition and enthalpy relaxation, physical property changes and molecular mobility around the glass transition, measurement of the glass transition and enthalpy relaxation, their mathematical descriptions and models, and influences on food stability.
Resumo:
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.
Resumo:
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.
Resumo:
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.
Resumo:
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.
Resumo:
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.
Resumo:
Advocates of ‘local food’ 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.
Resumo:
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.
Resumo:
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 customers’ willingness to pay more for green restaurant practices as well as their intention to visit the restaurant using green practices. Management implications are discussed.