Starch-composition, fine structure and architecture
TL;DR: In this paper, a review of the current state of knowledge about starch structure in perspective and integrating aspects of starch composition, interactions, architecture and functionality is presented, and the authors highlight the need to understand in more depth the structure of starch granules and how this complex organisation controls functionality.
About: This article is published in Journal of Cereal Science.The article was published on 2004-03-01. It has received 1436 citations till now. The article focuses on the topics: Starch.
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01 Jan 2009
TL;DR: The CRC Emulsifying Biopolymer (CRCRBP) as mentioned in this paper is an emulsifying biopolymer that can be used for coating and adhesives of soybeans.
Abstract: Introduction. Agar. Starch. Gelatin. Carrageenan. Xanthum Gum. Gellan Gum. Gallactomannans. Gum Arabic. Pectins. Milk Proteins. Cellulosis. Tragacanth and Karaya. Xyloglucan. Curdlan. Glucans. Soluble Soybean Polysaccharide. Bacterial Cellulose. Microcrystalline Cellulose. Gums for Coating and Adhesives.Chitosan Hydrogels. Alginates. Frutafit-Inulin. The CRC Emulsifying Biopolymer.
1,290 citations
TL;DR: This critical review provides insights into the state-of-the-art accomplishments in the chemocatalytic technologies to generate fuels and value-added chemicals from lignocellulosic biomass, with an emphasis on its major component, cellulose.
Abstract: Lignocellulosic biomass is the most abundant and bio-renewable resource with great potential for sustainable production of chemicals and fuels. This critical review provides insights into the state-of the-art accomplishments in the chemocatalytic technologies to generate fuels and value-added chemicals from lignocellulosic biomass, with an emphasis on its major component, cellulose. Catalytic hydrolysis, solvolysis, liquefaction, pyrolysis, gasification, hydrogenolysis and hydrogenation are the major processes presently studied. Regarding catalytic hydrolysis, the acid catalysts cover inorganic or organic acids and various solid acids such as sulfonated carbon, zeolites, heteropolyacids and oxides. Liquefaction and fast pyrolysis of cellulose are primarily conducted over catalysts with proper acidity/basicity. Gasification is typically conducted over supported noble metal catalysts. Reaction conditions, solvents and catalysts are the prime factors that affect the yield and composition of the target products. Most of processes yield a complex mixture, leading to problematic upgrading and separation. An emerging technique is to integrate hydrolysis, liquefaction or pyrolysis with hydrogenation over multifunctional solid catalysts to convert lignocellulosic biomass to value-added fine chemicals and bio-hydrocarbon fuels. And the promising catalysts might be supported transition metal catalysts and zeolite-related materials. There still exist technological barriers that need to be overcome (229 references).
1,123 citations
TL;DR: The structure of the starch granule slowly unravels with new insight into key structural features as discussed by the authors, and the most recent findings for the structure of amylose and amylopectin are reported.
Abstract: Recent developments in methods and instrumentation have contributed to major advances in our understanding of the fine structure of amylose and amylopectin. The structure of the starch granule slowly unravels with new insight into key structural features. Following a brief presentation of the structural features common to all starches, the most recent findings for the structure of amylose and amylopectin are reported. The organization of different types of chains in amylopectin is discussed with a critical review of the 'cluster' model leading to the presentation of alternative models. The locations of molecular components in the starch granule are described according to a progress structural order. The description of the crystalline components is followed by a presentation of their supramolecular arrangements. The crystalline components comprise platelet nanocrystals which have already been identified and characterized, and other less well characterized 'blocklet components'. The location and state of amylose within the granule is also presented. This comprehensive review aims at distinguishing between those structural features that have received widespread acceptance and those that are still under debate, with the ambition of being educational and to provide stimulation for further fundamental investigation into the starch granule as a macromolecular assembly.
1,086 citations
Cites background from "Starch-composition, fine structure ..."
...1 to 200 mm depending on their botanical origin [1–5]....
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TL;DR: In this paper, the authors describe the current understanding of starch structure that is relevant to its functionality in foods and nutrition, and describe how amylose influences packing of amylopectin into crystallites and the organization of the crystalline lamellae within granules, which is important for properties related to water uptake.
758 citations
TL;DR: It is proposed that in the face of environmental stochasticity, large, long-lived trees may require larger C investments in storage pools as safety margins than previously recognized, and that an important function of these pools may be to maintain hydraulic transport, particularly during episodes of severe stress.
Abstract: Research on the degree to which carbon (C) availability limits growth in trees, as well as recent trends in climate change and concurrent increases in drought-related tree mortality, have led to a renewed focus on the physiological mechanisms associated with tree growth responses to current and future climate. This has led to some dispute over the role of stored non-structural C compounds as indicators of a tree's current demands for photosynthate. Much of the uncertainty surrounding this issue could be resolved by developing a better understanding of the potential functions of non-structural C stored within trees. In addition to functioning as a buffer to reconcile temporal asynchrony between C demand and supply, the storage of non-structural C compounds may be under greater regulation than commonly recognized. We propose that in the face of environmental stochasticity, large, long-lived trees may require larger C investments in storage pools as safety margins than previously recognized, and that an important function of these pools may be to maintain hydraulic transport, particularly during episodes of severe stress. If so, survival and long-term growth in trees remain a function of C availability. Given that drought, freeze-thaw events and increasing tree height all impose additional constraints on vascular transport, the common trend of an increase in non-structural carbohydrate concentrations with tree size, drought or cold is consistent with our hypothesis. If the regulated maintenance of relatively large constitutive stored C pools in trees serves to maintain hydraulic integrity, then the minimum thresholds are expected to vary depending on the specific tissues, species, environment, growth form and habit. Much research is needed to elucidate the extent to which allocation of C to storage in trees is a passive vs. an active process, the specific functions of stored C pools, and the factors that drive active C allocation to storage.
660 citations
Cites background from "Starch-composition, fine structure ..."
...The dynamics of starch deposition and utilization follows the ‘onion model’, whereby starch is deposited in successive layers to form a starch granule, and degradation upon demand proceeds from outer to inner layers (Tester et al. 2004)....
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References
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Book•
01 Jan 1965
TL;DR: Starch: Chemistry and Technology, Second Edition as discussed by the authors focuses on the chemistry, processes, methodologies, applications, and technologies involved in the processing of starch, including the history and future expectation of starch use, economics and future of the starch industry, and the genetics and physiology of starch development.
Abstract: Starch: Chemistry and Technology, Second Edition focuses on the chemistry, processes, methodologies, applications, and technologies involved in the processing of starch. The selection first elaborates on the history and future expectation of starch use, economics and future of the starch industry, and the genetics and physiology of starch development. Discussions focus on polysaccharide biosynthesis, nonmutant starch granule polysaccharide composition, cellular developmental gradients, projected future volumes of corn likely to be used by the wet-milling industry, and organization of the corn wet-milling industry. The manuscript also tackles enzymes in the hydrolysis and synthesis of starch, starch oligosaccharides, and molecular structure of starch. The publication examines the organization of starch granules, fractionation of starch, and gelatinization of starch and mechanical properties of starch pastes. Topics include methods for determining starch gelatinization, solution properties of amylopectin, conformation of amylose in dilute solution, and biological and biochemical facets of starch granule structure. The text also takes a look at photomicrographs of starches, industrial microscopy of starches, and starch and dextrins in prepared adhesives. The selection is a vital reference for researchers interested in the processing of starch.
2,002 citations
TL;DR: This review will focus first on the present understanding of the structures of amylose and amylopectin and their organization within the granule, and then on the biosynthetic mechanisms explaining the biogenesis of starch in plants.
1,839 citations
26 May 2006
TL;DR: Alistair M. Stephen and Shirley C. Cui as mentioned in this paper proposed a method for the detection of polysaccharides in foods, and showed that the method can be applied in the field of agriculture.
Abstract: Introduction, Alistair M. Stephen and Shirley C. Churms Starch: Structure, Analysis, and Application, Henry F. Zobel and Alistair M. Stephen Modified Starches, Otto B. Wurzburg Starch Hydrolysates, Paul H. Blanchard and Frances R. Katz Cellulose and Cellulose Derivatives, Donald G. Coffey, David A. Bell, and Alan Henderson Galactomannans and Other Cell Wall Storage Polysaccharides in Seeds, Michael J. Gidley and J.S. Grant Reid Agars, Norman F. Stanley Gelling Carrageenans, Lennart Piculell Alginates, Kurt Ingar Draget, Storker T. Moe, Gudmund Skjak-Braek, and Olav Smidsrod Inulin, Anne Franck Pectins: Structure, Functionality, and Uses, J.A. Lopes da Silva, and M.A. Rao Bacterial Polysaccharides, V.J. Morris Gums and Mucilages, Peter A. Williams, Glyn O. Phillips, Alistair M. Stephen, and Shirley C. Churms Chitosans, Kjell M. Varum and Olav Smidsrod Polysaccharides in Food Emulsions, George A. van Aken Polysaccharide Rheology and In-Mouth Perception, K. Nishinari Phase Behavior in Mixed Polysaccharide Systems, Vladimir Tolstoguzov Dietary Fiber, Andrew Chesson Genetic Engineering and Food Crops, Jennifer A. Thomson Detection and Determination of Polysaccharides in Foods, Yolanda Brummer and Steve W. Cui Index
1,579 citations
Journal Article•
TL;DR: In this paper, a method was developed for measuring the volume of water absorbed by starch granules heated in excess water, based on the observation that blue dextran dye (molecular weight 2 X 106) will dissolve in supernatant and interstitial water but not in the intragranular water.
Abstract: A method was developed for measuring the volume of water absorbed by starch -granules heated in excess water, based on the observation that blue dextran dye (molecular weight 2 X 106) will dissolve in supernatant and interstitial water but not in the intragranular water. Swelling curves of wheat and normal and waxy barley and maize starches, determined by measuring the swelling factor (swollen volume/initial volume of airdried starch) at various temperatures up to 850C, were characterized by an initial phase of slight swelling, a second phase of rapid swelling, and a final stage of maximum swelling (not observed with high-gelatinizing starches or if granules disintegrated). With wheat starch, swelling began at 45-500C and continued to 850C; loss of birefringence and a large decrease in gelatinization enthalpy attributed to dissociation of crystalline Gelatinization in the narrowest sense is the thermal disordering of crystalline structures in native starch granules, but in the broader sense it includes related events such as swelling of the granules and leaching of soluble polysaccharides (Atwell et al 1988). Gelatinization temperature (GT) and enthalpy (AH) are conveniently measured by differential scanning calorimetry (DSC), and this aspect has received much attention in recent years because it is experimentally convenient and precise. However, in most food systems the actual temperature at which starch gelatinizes is less important than those properties that depend on swelling, such as pasting behavior and rheological properties of the partially or fully swollen starch granules. The properties of the starch-water system will, of course, be different if the swollen granules are dispersed mechanically to give a uniform gel. Historically, starch swelling has been studied by simple methods that do not distinguish between intragranular water and intergranular or interstitial water (Leach et al 1959), and the precision of measurements was not particularly good. This paper describes an improved method for measuring only intragranular water and hence the true swelling factor at a given temperature, based on the observation that blue dextran (Mr 2 X 106) does not penetrate swollen granules. The effects of amylopectin (AP), amylose (AM), and lipids on swelling behavior were then investigated using the blue dextran method. MATERIALS AND METHODS
1,523 citations