Structure Evolution during Gelation at Later Stages of Spinodal Decomposition in Gelatin/Maltodextrin Mixtures

Lorén, Niklas; Altskär, and Annika; Hermansson, Anne‐Marie

doi:10.1021/ma010722q

Cited by 56 publications

(58 citation statements)

References 58 publications

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“…Under appropriate conditions, glucans can undergo phase separation followed by nucleation and the growth of a crystalline structure (Lorén et al, 2001;Ziegler et al, 2005;Biliaderis, 2009). The rate and frequency of formation of stable crystalline nuclei in the chloroplast stroma would depend on factors including glucan concentration, size, and structure as well as background conditions such as the nature and concentration of proteins.…”

Section: Granule Initiation Is Infrequent In Mature Leavesmentioning

confidence: 99%

Control of Starch Granule Numbers in Arabidopsis Chloroplasts

et al. 2011

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The aim of this work was to investigate starch granule numbers in Arabidopsis (Arabidopsis thaliana) leaves. Lack of quantitative information on the extent of genetic, temporal, developmental, and environmental variation in granule numbers is an important limitation in understanding control of starch degradation and the mechanism of granule initiation. Two methods were developed for reliable estimation of numbers of granules per chloroplast. First, direct measurements were made on large series of consecutive sections of mesophyll tissue obtained by focused ion beam-scanning electron microscopy. Second, average numbers were calculated from the starch contents of leaves and chloroplasts and estimates of granule mass based on granule dimensions. Examination of wild-type plants and accumulation and regulation of chloroplast (arc) mutants with few, large chloroplasts provided the following new insights. There is wide variation in chloroplast volumes in cells of wild-type leaves. Granule numbers per chloroplast are correlated with chloroplast volume, i.e. large chloroplasts have more granules than small chloroplasts. Mature leaves of wild-type plants and arc mutants have approximately the same number of granules per unit volume of stroma, regardless of the size and number of chloroplasts per cell. Granule numbers per unit volume of stroma are also relatively constant in immature leaves but are greater than in mature leaves. Granule initiation occurs as chloroplasts divide in immature leaves, but relatively little initiation occurs in mature leaves. Changes in leaf starch content over the diurnal cycle are largely brought about by changes in the volume of a fixed number of granules.Chloroplasts in Arabidopsis (Arabidopsis thaliana) mesophyll cells are generally stated to contain about five starch granules at the end of the light period (Zeeman et al., 2002(Zeeman et al., , 2007, but nothing is known about how this number is determined or the extent of genetic, temporal, developmental, and environmental variation in the number. This is an important limitation in understanding control of starch degradation at night, a process essential for the normal growth of the plant (Gibon et al., 2006;Smith and Stitt, 2007;Stitt et al., 2007;Usadel et al., 2008). The surface area and volume of starch granules in the chloroplast are relevant to the control of starch degradation in two ways. First, surface area can potentially limit the rate of degradation during the night. This limitation is not a major determinant of the rate of degradation in wild-type Arabidopsis leaves in controlled conditions; degradation is near linear through most of the night and consumes almost all of the starch reserves by dawn. If degradation were limited by surface area, the rate would decline with time through the night. However, reductions in starch granule numbers may result in limitation of starch degradation. The starch synthase4 (ss4) mutant of Arabidopsis has only one starch granule per chloroplast. It has a low rate of starch degradation and a low...

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Section: Granule Initiation Is Infrequent In Mature Leavesmentioning

confidence: 99%

Control of Starch Granule Numbers in Arabidopsis Chloroplasts

et al. 2011

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“…Studying these systems close to walls is of practical importance as well since the food industry, for example, extensively uses the properties of both colloids and polymers to induce gelation or creaming [131,132] and walls clearly play an important role, e.g. in confining the products, which has implications for the products' shelf-life.…”

Section: Introductionmentioning

confidence: 99%

“…For example, in the food industry extensive use is made of the properties of polymers, e.g. to invoke gelation [131], and adding these to food suspensions leads effectively to colloid-polymer mixtures [132].…”

Section: Introductionmentioning

confidence: 99%

The interface in demixed colloid–polymer systems: wetting, waves and droplets

Aarts

2007

Soft Matter

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By comparison, the interfacial tension between the coexisting phases has received little attention. Here, we show that the ultralow interfacial tension in fluid-fluid demixed colloid-polymer systems, which is roughly one million times smaller than in ordinary liquids, manifests itself in a wide variety of interface characteristics and processes. Discussed are the interfacial wetting behaviour close to a hard wall, the thermal capillary waves at the free interface and the process of droplet coalescence and breakup. These subjects can be studied in a single experiment by combining modern soft matter chemistry and laser scanning confocal microscopy. This combination allows a further exploration of a broad range of interface issues.

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“…11 Studying these systems close to walls is of practical importance as well. The food industry, for example, extensively uses the properties of both colloids and polymers to induce gelation or creaming 12,13 and walls clearly play an important role, e.g., in confining the products. Furthermore, in the living cell microcompartmentation is often thought to be the result of phase separation, and it is evident that wetting properties play a crucial role in the equilibrium structure of the cell.…”

Section: Introductionmentioning

confidence: 99%

Capillary Length in a Fluid−Fluid Demixed Colloid−Polymer Mixture

Aarts

2005

J. Phys. Chem. B

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We report measurements of the interfacial profile close to a vertical wall in a fluid-fluid demixed colloidpolymer mixture. The profile is measured by means of laser scanning confocal microscopy. It is accurately described by the interplay between the Laplace and hydrostatic pressure and from this description the capillary length is obtained. For different statepoints approaching the critical point the capillary length varies from 50 to 5 µm. These results are compared to theory. The mass density difference ∆F is calculated from the bulk phase behavior, which is described within free volume theory with polymers modeled as penetrable hard spheres. The interfacial tension γ is calculated within a squared gradient approximation. The capillary length is then given through γ/g∆F with g equal to the Earth's acceleration. Predictions from theory are in overall qualitative agreement with experiment without the use of any adjustable parameter.

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Structure Evolution during Gelation at Later Stages of Spinodal Decomposition in Gelatin/Maltodextrin Mixtures

Cited by 56 publications

References 58 publications

Control of Starch Granule Numbers in Arabidopsis Chloroplasts

Control of Starch Granule Numbers in Arabidopsis Chloroplasts

The interface in demixed colloid–polymer systems: wetting, waves and droplets

Capillary Length in a Fluid−Fluid Demixed Colloid−Polymer Mixture

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