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Water and the Glass Transition — Dependence of the Glass Transition on Composition and Chemical Structure: Special Implications for Flour Functionality in Cookie Baking
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What is a glass? What is a glass transition? Why is the temperature at which a glass transition occurs (Tg) so important to the processing and storage stability of so many different types of foods? Why is the effect of water as a plasticizer on Tg of such widespread relevance to food products and processes? Why are considerations of non-equilibrium glassy solid and rubbery liquid states in foods, rather than equilibrium phases, more germane to issues of food quality and safety? Why are the kinetics of heat/moisture processes for foods and of deteriorative changes in food systems during storage more often appropriately interpreted in terms of the Williams-Landel-Ferry (WLF), rather than the Arrhenius, equation? What is the ‘food polymer science’ approach, with its central concepts of ‘glass dynamics’ and ‘water dynamics’, and why has this research approach proved so useful to the study of glasses and glass transitions in foods? And why has there been, since the early 1980s, such interest in these questions, and such increasing research activity, especially in the last few years, in this area of food science and technology? These are the questions addressed in this paper.
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... The total and damaged starch contents of the WWFs are presented in Table 2. The damaged starch generated during milling considerably increases the water-holding capacity of the flour, which negatively affects the quality of cookies and crackers [27]. An increase in milling time led to a corresponding increase in both total starch and damaged starch contents, confirming the influence of milling force and work on the physical alteration of starch granules. ...
In this study, we investigated the effects of mortar milling conditions on the quality and noodle-processing suitability of whole-wheat flours (WWFs). The WWFs were milled at varying pestle speeds (50 and 130 rpm) and for varying durations (10, 20, 40, and 60 min) and analyzed to determine their particle size distribution, physicochemical properties, dough-mixing characteristics, antioxidant activities, and noodle-making performance. High pestle speed (Group H) produced significantly smaller particle sizes, higher flour temperatures, greater moisture loss, and increased starch damage compared to that produced at low pestle speeds (Group L). Compared with Group L, Group H exhibited higher water and sodium carbonate solvent-retention capacity (SRC) values, increased pasting viscosities, and greater gluten strength owing to finer particles. Total phenolic content increased with reduced particle size, whereas antioxidant activity (ABTS radical scavenging) exhibited inconsistent trends. Fresh noodle properties varied with milling conditions; finer WWF particles improved dough resistance but reduced extensibility when water was adjusted according to water SRC. Thus, WWF particle size strongly influences flour functionality and noodle quality, which highlights the need for precise milling control. This study demonstrates, for the first time, the applicability of a mortar-type mill for producing WWFs, with implications for enhancing WWF functionality.
... It is possible that the cytoplasm of dried seeds in a glassy state resembles a disordered solid with the physical properties of a liquid state (Buitink and Leprince, 2008). On the other hand, the glassy phase in biological systems preserves the structural integrity of the macromolecules, reduces deleterious reactions and increases the stability of enzymes (Slade and Levine, 1994), which has implications for seed longevity. The desiccation of orthodox seeds causes little cell shrinkage because the dry mass accumulated during maturation occupies the entire cell volume. ...
The early stages of winter wheat (Triticum aestivum L.) seed hydration were monitored in order to improve our understanding of the molecular mechanisms of drought resistance. Investigations were carried out using gaseous phase hydration kinetics, sorption isotherm, and 1H-NMR relaxometry. Hydration kinetics have shown that the mass increase could be fitted with a single exponential function. Two fractions of bound water were distinguished: very tightly bound water, Δm/m0 = 0.082 ± 0.016, and the tightly bound water fraction, Δm/m0 = 0.048 ± 0.033, with a hydration time t h1 = (62 ± 23) h. The standard Dent’s model which was used to fit the experimental data, was successfully applied but only for values of relative humidity smaller than h < 0.9. The sorption isotherm was better fitted using the generalized Dent’s model, with the value of the b parameter equal to 0.947, the mass of the water saturating primary water binding sites equal to ΔM/m0 = 0.0209, and the fraction of unoccupied binding sites at h = 1 equal to 1/b1 = 0.104%. Proton free induction decays regi-stered for dry samples up to hydration level Δm/m0 = 0.128 were better described by the Abragam function, whereas for a higher hydration level the Gaussian function sufficiently described the proton signal of the samples.
... Glass transition concept, as a tool for predicting microbiological, physical and chemical changes that occur during processing or storage of food materials, is a subject of interest for many researchers over the years (Roos and Karel, 1991;Slade and Levine, 1994;Champion et al., 2000;Khalloufi and Ratti, 2003;Rahman, 2006;Sablani et al., 2007;Sablani et al., 2009;Djendoubi et al., 2013;Vásquez et al., 2013). ...
Water activity is an important parameter that can be used to predict the stability and safety of food with respect to the most mi-crobiological and biochemical reactions, conditioned by its value. In other words, it describes the degree of the ̎ bound ̎ level of water in the dry material, as well as the indicator of the ability of water to act as a solvent, participant in various biochemical reactions, or growth of different microorganisms. The determination of the minimum value of water activity that allows the growth of certain microorganisms and mechanical and thermal equilibrium of the material with the surroundings, are the most important parameters that characterize the stability of the material. The equilibrium moisture content has fundamental role in food industry and technology from the aspect of design and optimization of drying processes and equipment, design of packing materials for dried products, prediction of quality and stability, as well as for calculation of changes in the moisture content of dried material during its storage. Considering the relationship between these two physical parameters, their interdependence has been shown in this paper. REZIME Vodena aktivnost je klučan parametar za predvidžanje stabilnosti i rok trajanja prehranbenih materijala, iz razloga što su največi broj mikrobioloških i biohemiskih reakcija uslovljene njenom vrednošču. Drugim rečima, ona je pokazatelj za stepena veze vode sa suvim skeletom materijala, kao i pokazatelj sposobnosti vode da reaguje kao rastvarač, da učestvuje u različitim biohemiskim reakcijama ili u razvoju odredzenih mikroorganizama. Poznavanje minimalnu vrednost vodene aktivnosti koja omogučava razvoj od-redzenih mikroorganizama, kao i odnos mehaničke i termičke ravnoteže materijala sa okolinom, su jedni od najvažnijih parametara koji karakterišu stabilnost materijala. Ramnotežni sadržaj vlage ima fundamentalnu ulogu u prehranbenoj industriji i tehnologiji u smislu dizajna i optimizacije procesa i opreme za sušenje, dizajniranje ambalažu za pakovanje sušenog proizvoda, predvidžavanje kvaliteta i stabilnosti materijala, kao i proračun promene sadržaju vlage u sušenom materijalu tokom skladištenja. Obzorim na rela-ciju ove dve fizicke velicine u radu je prikazna njihova medžusobna zavisnost. Ključne reči: vodena aktivnost, ramnotežni sadrzaj vlage, prehranbeni materijali.
... It is important to select food ingredients in a 3D printable state and explore the information of the ingredients [50][51][52][53][54]. Materials treated as spares, such as grinding, denatured starch, and separating proteins, are appropriate for 3D food printing and increase thermal stability. ...
Owing to COVID-19, the world has advanced faster in the era of the Fourth Industrial Revolution, along with the 3D printing technology that has achieved innovation in personalized manufacturing. Three-dimensional printing technology has been utilized across various fields such as environmental fields, medical systems, and military materials. Recently, the 3D food printer global market has shown a high annual growth rate and is a huge industry of approximately one billion dollars. Three-dimensional food printing technology can be applied to various food ranges based on the advantages of designing existing food to suit one’s taste and purpose. Currently, many countries worldwide produce various 3D food printers, developing special foods such as combat food, space food, restaurants, floating food, and elderly food. Many people are unaware of the utilization of the 3D food printing technology industry as it is in its early stages. There are various cases using 3D food printing technology in various parts of the world. Three-dimensional food printing technology is expected to become a new trend in the new normal era after COVID-19. Compared to other 3D printing industries, food 3D printing technology has a relatively small overall 3D printing utilization and industry size because of problems such as insufficient institutionalization and limitation of standardized food materials for 3D food printing. In this review, the current industrial status of 3D food printing technology was investigated with suggestions for the improvement of the food 3D printing market in the new normal era.
Headspace solid-phase microextraction combined with gas chromatography-mass spectrometry, elucidated the intricate interplay between physiochemical properties and aroma profiles in wheat flour specimens.
This chapter begins with liquid and solid vaccine formulation approaches and discusses the advantages and limitations. This is followed by a description of drying mechanisms and an overview of the drying technologies most commonly used in the pharmaceutical industry to stabilize vaccines. Next, traditional freeze drying (lyophilization), spray drying, and emerging alternative drying technologies such as spray freeze drying, supercritical fluid drying, and vacuum foam drying are presented, and their respective advantages and disadvantages are compared. Then, an excursus presents newer ways of delivering dried vaccines, such as air-drying vaccines in a sponge, on membrane fibers, microarray patches, or other substrates. A major focus is on the principle of spray drying based on laboratory-scale experience. After that, the chapter is devoted to the question of when spray drying is a suitable alternative to other drying processes for stabilizing vaccines. Numerous case studies and application examples support the chapter for stabilizing vaccines. Facts and figures highlight the main advantages of spray drying for vaccine stabilization. Finally, the main challenges are critically reviewed and discussed. Throughout the chapter, the reader will find relevant literature references that provide further details on the drying process in question.
Carbon-13 and deuteron spin lattice relaxation times T 1 of concentrated solutions of trehalose and sucrose in heavy water are given as function of temperature. From the temperature dependence of the T 1 ideal glass transitions temperatures T o are derived. For both compounds the T o derived for the disaccharides are at high concentrations larger than the T o of the water molecules.
Granular cold-water-soluble (GCWS) starches were prepared by heating a starch slurry in a mixture of water-polyhydric alcohol (PHA) at atmospheric pressure. Exchanging the liquids with ethanol followed by drying produced GCWS starch. The method was applied to cereal, tuber, root and legume starches and many of their cross-linked and substituted forms to yield products with cold-water solubilities ranging from 70 to 95%. The success of the method depended mainly on the type of starch, PHA, the temperature and the proportions of starch, water and PHA. Aqueous propan-1,2-diol was the medium of choice for converting native and modified starches, although aqueous ethylene glycol, glycerol and any of the four positional isomers of butandiol were also useful. Aqueous butandiol was effective for hydroxypropylated starches and aqueous glycerol for potato starch. Differential scanning calorimetry revealed that heating starch in mixtures of water-PHA (starch/water/PHA = 1·0/1·5/4·5, w/w/w) gave a single gelatinization endotherm that occurred at higher temperature and over a narrower range than the endotherm observed in water alone (starch/water = 1/1·5, w/w). The increase in gelatinization temperature effected by the PHAs correlated negatively with their effect on the swelling and dissolving of amylose in a 1:3 (w/w) mixture of water-PHA.