Desiccation tolerance of prokaryotes.

Hot air and freeze-drying of high-value foods: a review.

The present study in its form, “Obtaining and evaluating blankets and rubber latex blankets of Shiringa (Hevea brasiliensis), in the district of Chazuta - San Martin was developed in the Faculty of Agroindustrial Engineering, Laboratory of Research and Non-Food Agroindustrial Products Technology, from the National University of San Martin - Tarapoto. This study aimed at evaluating the concentrations of sulfur and new acids that influence the improvement of products derived from blankets and rubber latex blankets, analyzing and comparing the physical characteristics of finished products in color, elasticity and impurity content. The samples were located and extracted from the Bristol Concession Zone at vertices 1 to 4, located in the East between 374182 - 375851 and North 9277492 - 9277511, at the UTM coordinates of the total area requested and concessioned Zone 18, WGS 84 in the Chazuta district. To evaluate the influence of the type of acid and its concentration on the physical and mechanical quality of the blankets, a Randomized Complete Design was performed, with a factorial arrangement (3 * 3) with two factors (type of acid and its concentration) and 3 levels for the acid type factor (citric, formic and acetic) and the concentrations of (1 ml, 3 ml and 5 ml) and, for the rubber latex blankets, a Randomized Complete Design was applied, which analyzes the concentrations of sulfur (0.5%; 1 , 0% and 2.0%). Mechanical properties were measured using a Brookield CT3 model. The concentrations of acetic, formic and citric acids influenced statistically (P <0.01) in the behavior of rubber latex blankets. The treatments T8 (3 ml acetic acid of concentration) and T7 (acetic acid at 1 ml.) presented higher average with respect to mechanical properties, and the T2 and T3 presented physical properties. The sulfur concentrations, considered in this research work, did not influence statistically (P <0.01) on the mechanical properties of the rubber latex blankets. The blankets and rubber latex blankets using different acids (citric, formic, acetic acids) and sulfur concentrations are statistically differentiated in their physical characteristics of color, elasticity and impurities.

Sorbitol- vs Glycerol-Plasticized Whey Protein Edible Films: Integrated Oxygen Permeability and Tensile Property Evaluation

The molecular basis of staling is examined by reviewing what is known about the components of wheat flour, factors that affect staling rate, and the various mechanisms that have been proposed. The conclusion reached is that bread staling is a complex phenomenon in which multiple mechanisms operate. Polymer crystallizations with the formation of supermolecular structures are certainly involved. The most plausible hypothesis is that retrogradation of amylopectin occurs, and because water molecules are incorporated into the crystallites, the distribution of water is shifted from gluten to starch/amylopectin, thereby changing the nature of the gluten network. The role of additives may be to change the nature of starch protein molecules, to function as plasticizers, and/or to retard the redistribution of water between components. Nothing more definite can be concluded at this time.

Bread Staling: Molecular Basis and Control.

Melting and glass transitions of low molecular weight carbohydrates

Water, the most abundant constituent of natural foods, is a ubiquitous plasticizer of most natural and fabricated food ingredients and products. Many of the new concepts and developments in modern food science and technology revolve around the role of water, and its manipulation, in food manufacturing, processing, and preservation. This article reviews the effects of water, as a near-universal solvent and plasticizer, on the behavior of polymeric (as well as oligomeric and monomeric) food materials and systems, with emphasis on the impact of water content (in terms of increasing system mobility and eventual water "availability") on food quality, safety, stability, and technological performance. This review describes a new perspective on moisture management, an old and established discipline now evolving to a theoretical basis of fundamental structure-property principles from the field of synthetic polymer science, including the innovative concepts of "water dynamics" and "glass dynamics". These integrated concepts focus on the non-equilibrium nature of all "real world" food products and processes, and stress the importance to successful moisture management of the maintenance of food systems in kinetically metastable, dynamically constrained glassy states rather than equilibrium thermodynamic phases. The understanding derived from this "food polymer science" approach to water relationships in foods has led to new insights and advances beyond the limited applicability of traditional concepts involving water activity. This article is neither a conventional nor comprehensive review of water activity, but rather a critical overview that presents and discusses current, usable information on moisture management theory, research, and practice applicable to food systems covering the broadest ranges of moisture content and processing/storage temperature conditions.

L Slade

Papers

Beyond water activity: recent advances based on an alternative approach to the assessment of food quality and safety