다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

The American Society for Testing and Materials (ASTM) is an independent organization devoted to the development of standards.

American Society for Testing and Materials

For a long time polymers have supplied most of common packaging materials because they present several desired features like softness, lightness and transparency. However, increased use of synthetic packaging films has led to a serious ecological problems due to their total non-biodegradability. Although their complete replacement with eco-friendly packaging films is just impossible to achieve, at least for specific applications like food packaging the use of bioplastics should be the future. The aim of this review was to offer a complete view of the state of the art on biodegradable polymer packages for food application.

Biodegradable polymers for food packaging: a review

In this article, several applications of nanomaterials in food packaging and food safety are reviewed, including: polymer/clay nanocomposites as high barrier packaging materials, silver nanoparticles as potent antimicrobial agents, and nanosensors and nanomaterial-based assays for the detection of food-relevant analytes (gasses, small organic molecules and food-borne pathogens). In addition to covering the technical aspects of these topics, the current commercial status and understanding of health implications of these technologies are also discussed. These applications were chosen because they do not involve direct addition of nanoparticles to consumed foods, and thus are more likely to be marketed to the public in the short term.

Applications of nanotechnology in food packaging and food safety: Barrier materials, antimicrobials and sensors

Essential oils are aromatic and volatile liquids extracted from plants. The chemicals in essential oils are secondary metabolites, which play an important role in plant defense as they often possess antimicrobial properties. The interest in essential oils and their application in food preservation has been amplified in recent years by an increasingly negative consumer perception of synthetic preservatives. Furthermore, food-borne diseases are a growing public health problem worldwide, calling for more effective preservation strategies. The antibacterial properties of essential oils and their constituents have been documented extensively. Pioneering work has also elucidated the mode of action of a few essential oil constituents, but detailed knowledge about most of the compounds’ mode of action is still lacking. This knowledge is particularly important to predict their effect on different microorganisms, how they interact with food matrix components, and how they work in combination with other antimicrobial compounds. The main obstacle for using essential oil constituents as food preservatives is that they are most often not potent enough as single components, and they cause negative organoleptic effects when added in sufficient amounts to provide an antimicrobial effect. Exploiting synergies between several compounds has been suggested as a solution to this problem. However, little is known about which interactions lead to synergistic, additive, or antagonistic effects. Such knowledge could contribute to design of new and more potent antimicrobial blends, and to understand the interplay between the constituents of crude essential oils. The purpose of this review is to provide an overview of current knowledge about the antibacterial properties and antibacterial mode of action of essential oils and their constituents, and to identify research avenues that can facilitate implementation of essential oils as natural preservatives in foods.

/pdf/essential-oils-in-food-preservation-mode-of-action-synergies-26gwz54pww.pdf

Essential oils in food preservation: mode of action, synergies, and interactions with food matrix components.

An edible wheat gluten film was developed and effects of gluten concentration, ethanol concentration (ET) and pH of the film-forming solution on various film properties were evaluated using Response Surface Methodology. pH and ethanol concentration had strong interactive effects on film opacity, water solubility and water vapor permeability. A simultaneous variation of ethanol concentration and pH between 32.5% ET, pH 4 and 45% ET, pH 2 resulted in homogeneous and transparent film with relatively low water solubility. The lowest water vapor permeability would be expected with 20% ethanol concentration and pH 6. Mechanical properties were mainly affected by gluten concentration and pH. The most resistant film was obtained at high gluten concentration (12.5%) and pH 5.

Edible Wheat Gluten Films: Influence of the Main Process Variables on Film Properties using Response Surface Methodology

Le glycerol ameliore l'extensibilite mais reduit la resistance a la rupture, l'elasticite, les proprietes barriere a la vapeur d'eau. L'effet plastifiant est tres dependant de la teneur en eau du film. Au cours de la rehydratation du film de gluten on observe une diminution importante de la resistance a la rupture, de l'elasticite et une augmentation de l'extensibilite et de la transmission de vapeur d'eau, pour des temperatures 5, 30 et 50¼C avec respectivement des teneurs en eau de 30 (0,8 aw), 15 (0,7 aw) et 5% (0,4 aw). Ceci peut-etre correlle a la rupture de liaison polymere-eau ainsi qu'au phenomene de transition vitreuse

Water and Glycerol as Plasticizers Affect Mechanical and Water Vapor Barrier Properties of an Edible Wheat Gluten Film

Aims: To investigate the relation between the chemical structure and the antimicrobial activity of carvacrol, eugenol, menthol and two synthesized carvacrol derivative compounds: carvacrol methyl ether and carvacryl acetate against bacteria, Escherichia coli, Pseudomonas fluorescens, Staphylococcus aureus, Lactobacillus plantarum, Bacillus subtilis, a yeast Saccharomyces cerevisiae and one fungi Botrytis cinerea.



Methods and Results:  The antimicrobial activity was tested in liquid and vapour phases, by both broth liquid and microatmosphere methods, respectively. The same classification of the compound's antimicrobial efficiency was found with both methods. Eugenol and menthol exhibited a weaker antimicrobial activity than carvacrol, the most hydrophobic compound. Carvacryl acetate and carvacrol methyl ether were not efficient, indicating that the presence of a free hydroxyl group is essential for antimicrobial activity.



Conclusions:  The different extents of antimicrobial aroma compounds’ efficiency showed that hydrophobicity is an important factor and the presence of a free hydroxyl group and a delocalized system allows proton exchange.



Significance and Impact of the Study:  This study has identified the importance of the hydrophobicity and the chemical structure of phenolic aroma compounds for antimicrobial activity and may contribute to a most rational use of these compounds as antimicrobial agent.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1472-765X.2006.01938.x

Antimicrobial activity of carvacrol related to its chemical structure

Des films composes comestibles, comprenant d'une part une structure matricielle a base de gluten de ble et d'autre part differents lipides comme barriere a l'humidite, ont ete teste pour leurs permeabilites a la vapeur d'eau, leurs dispersions dans l'eau, leurs proprietes mecaniques et leurs opacites. Les effets des lipides sur les proprietes fonctionnelles de ces films, dependent des caracteristiques des lipides utilises et des interactions lipide-structure matricielle proteique. La cire d'abeille, lipide solide et hydrophobique, est le lipide le plus efficace pour ameliorer les proprietes barrieres de ces films. Mais ces films sont opaques, fragiles et facilement degradables dans l'eau. La combinaison de proteines de gluten de ble avec un ester diacetyl tatarique de monoglycerides, reduit la permeabilite a la vapeur d'eau, augmente la force et maintient la transparence

Edible composite films of wheat gluten and lipids: water vapour permeability and other physical properties

The improvement of the safety and quality of minimally processed foods is of major interest to both the consumer and the food industry and is the topic of an EU-sponsored research project with nine international partners. The project optimizes existing techniques and in addition develops novel technologies to ensure high quality and safe food products. Among the systems studied is Modified Atmosphere Packaging, for which the available packaging film materials are tailored to the specific demands of the food products. A novelty in the project is the development of biodegradable packaging materials that can replace conventional synthetic materials. Additionally, edible coatings that are applied directly on the food surface are designed which create a modified atmosphere. The edible coatings can be furnished with active compounds such as antimicrobials or antioxidants to obtain additional desired effects. Such packagings and coatings may protect very powerfully against microbial spoilage and loss of intrinsic product quality, resulting in a prolonged shelf-life. An overview of the development and application of edible films and coatings is given here, comprising recent results from the EU project with regard to the barrier properties of edible films and the inclusion of active compounds.

Nathalie Gontard

Papers

Edible Wheat Gluten Films: Influence of the Main Process Variables on Film Properties using Response Surface Methodology

Water and Glycerol as Plasticizers Affect Mechanical and Water Vapor Barrier Properties of an Edible Wheat Gluten Film

Antimicrobial activity of carvacrol related to its chemical structure

Edible composite films of wheat gluten and lipids: water vapour permeability and other physical properties

Prolongation of the Shelf-life of Perishable Food Products using Biodegradable Films and Coatings