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

American Society for Testing and Materials

There is a special reason for reviewing this book at this time: it is the 50th edition of a compendium that is known and used frequently in most chemical and physical laboratories in many parts of the world. Surely, a publication that has been published for 56 years, withstanding the vagaries of science in this century, must have had something to offer. There is another reason: while the book is a standard fixture in most chemical and physical laboratories, including those in medical centers, it is not as frequently seen in the laboratories of physician's offices (those either in solo or group practice). I believe that the Handbook can be useful in those laboratories. One of the reasons, among others, is that the various basic items of information it offers may be helpful in new tests, either physical or chemical, which are continuously being published. The basic information may relate

Handbook of Chemistry and Physics

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.

Perspectives for chitosan based antimicrobial films in food applications

Statistical Databases

Starch films exhibits low poor water barrier and poor mechanical properties due to its great hygroscopicity, fragility and brittleness. These properties can be influenced by different factors such as composition, processing conditions and storage of the films. In this work, the effect of gelatin and ester of fatty acids (E-471) addition on the mechanical and barrier properties of cassava starch films, containing glycerol as plasticizer, was analysed in both newly prepared films and those stored for 5 weeks. Microstructural analysis of the films was also studied by using SEM (Scanning electron microscopy) and AFM (Atomic force microscopy). The addition of gelatin into cassava starch film formulation improved mechanical properties and ester incorporation significantly (p<0.05) reduced the water vapour permeability of composite films. Storage time affected mechanical behavior of films, increasing stiffness and resistance and reducing their stretchability. Microstructural observations corroborated the good compatibility among both polymers (starch and gelatin) to form the film matrix and the scarce effect of ester addition in the improvement of functional properties. SEM micrographs showed compact structure of pure films. Composite films presented a more heterogeneous surface than the pure films but a good compatibility among the polymers (no separation). The E-471 integrates differently depending on the matrix: in pure starch films is included in the continuous network as amylose-lipid complexes; in composite films (50S-50G), the formation of lipid aggregates distributed throughout the film matrix can be observed.

Mechanical, barrier and microstructural properties of films based on cassava starch gelatin blends: effect of aging and lipid addition

The authors acknowledge the financial support provided by Ministerio de Economia y Competividad (Project AGL2013-42989-R).

/pdf/biopolymers-carrying-essential-oils-or-their-compounds-for-lgrrl7ehow.pdf

Biopolymers Carrying Essential Oils, or their Compounds, for Food Antimicrobial Packaging

The overall purpose of this paper was to examine the microstructure of oil-in-water low fat emulsions (300 g/kg) containing skim milk powder and locust bean gum as emulsifiers/stabilizers, and to correlate the microstructural features with their rheological behaviour. Eight samples were analysed, where composition was changed within a certain range for each component. All of these showed a strong thixotropic character and yield stress. The microstructure of the samples was analysed by transmission electron microscopy. Micrographs showed casein micellar aggregates in the continuous phase of the emulsion. Also, the presence of a network structure, probably associated with protein–polysaccharide macromolecular entanglements, was evident. This macromolecular interaction also appears at the oil–water interface, where an adsorbed macromolecular multilayer surrounds the oil droplets. This feature was in agreement with a higher consistency and stability detected with increased gum and milk concentration in the emulsions. As locust bean gum is a nonionic polymer, protein–polysaccharide interactions could be favoured by the low pH of the samples within the isoelectric range of caseins, and by the high level of the ionic strength, which could exert an additional neutralizing effect on the ionic groups of proteins.

Microstructure of Oil-in-water Low-fat Emulsions Containing Skim Milk Powder and Locust Bean Gum

The preservation and shelf-life of formulations of the biocontrol agent Candida sake CPA-1 and starch derivatives as a function of water activity (aW) were studied in terms of the physical stability of the products and cell viability. Formulations of biocontrol products (BCPs), based on combinations of potato starch and pre-gelatinised potato starch (F1 and F2) or maltodextrines (MD) (F3) containing cell protectants, were obtained by fluidised-bed drying. The carriers and the formulated products were stored at 20°C under different aW conditions. The water sorption and water plasticization behaviour of the different products were analysed through the water sorption isotherms and glass transition temperatures (Tg). Likewise, the viability of C. sake over time was determined as a function of the aW. The solubility of the products was also assessed. Although formulations stored at 20°C and low aW (≤ 0.33) exhibited a better shelf-life, a significant decrease in cell survival ratio after 180 storage da...

Amparo Chiralt

Papers

Mechanical, barrier and microstructural properties of films based on cassava starch gelatin blends: effect of aging and lipid addition

Biopolymers Carrying Essential Oils, or their Compounds, for Food Antimicrobial Packaging

Microstructure of Oil-in-water Low-fat Emulsions Containing Skim Milk Powder and Locust Bean Gum

Stability of biocontrol products carrying Candida sake CPA-1 in starch derivatives as a function of water activity

Properties of PLA films with cinnamic acid: effect of the processing method