Deformation and fracture behaviour of wheat starch plasticized with glucose and water

Ollett, A.-L.; Parker, Roger; Smith, Andrew C.

doi:10.1007/bf00544476

Cited by 94 publications

(25 citation statements)

References 9 publications

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“…At high sorbitol concentration (30%), E and s max showed very low values in the water content range of 5±10%. Similar plasticiser effects have been shown for cellulose-based ®lms, 56 pectin/starch ®lms, 57 gluten, 58 starch, 52 pullulan/starch 22 and sodium caseinate/ starch blends. 51 Increases in the¯exural modulus and maximum stress of pullulan and P/S 85:15 ®lms were observed between 2 and 8% water content, whereas the softening effect of water became dominant above this level (Fig 8).…”

Section: Mechanical Properties Of Plasticised Pullulan Filmssupporting

confidence: 65%

Physicochemical properties and application of pullulan edible films and coatings in fruit preservation

et al. 2001

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The effects of water, sorbitol and a sucrose fatty acid ester (SE) on the water sorption behaviour and thermal and mechanical properties of pullulan-based edible ®lms as well as the physiological responses of fruit coated with pullulan have been studied. Incorporation of sorbitol or SE in pullulan ®lms resulted in lower equilibrium moisture contents at low to intermediate water activities (a w ), but much higher moisture contents at a w > 0.75; estimates of monolayer values (within 4.1± 5.9 gH 2 O kg À1 solids) were given by application of the Brunauer±Emmett±Teller (BET) and Guggenheim±Anderson±DeBoer (GAB) models. A single glass±rubber transition (T g ), attributed to the polysaccharide component, was detected by calorimetry and dynamic mechanical thermal analysis (DMTA) at a sorbitol level of 15±30% DM. With both tests the strong plasticising action of water and polyol was evident in the thermal curves, and the T g vs moisture content data were successfully ®tted to the Gordon±Taylor empirical model. Multifrequency DMTA measurements provided estimates for the apparent activation energy of the glass transition in the range of Ä 300±488 kJ mol À1. With largedeformation mechanical testing, large decreases in Young's moduli (tensile and three-point bend tests) were observed as a result of water-and/or polyol-mediated glass-to-rubber transition of the polymeric ®lms. In the moisture content range of 2±8%, increases in¯exural modulus (E) and maximum stress (s max ) with small increases in moisture content were found for ®lms made of pullulan or pullulan mixed with 15% DM sorbitol; a strong softening effect was observed when the water content exceeded this range. Addition of sorbitol increased the water vapour transmission rate of the ®lms, whereas addition of SE had the opposite effect. Application of a pullulan/sorbitol/SE coating on strawberries resulted in large changes in internal fruit atmosphere composition which were bene®cial for extending the shelf-life of this fruit; the coated fruit showed much higher levels of CO 2 , a large reduction in internal O 2 , better ®rmness and colour retention and a reduced rate of weight loss. In contrast, similar studies on whole kiwifruits showed increased levels of internal ethylene, which caused acceleration of fruit ripening during storage.

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Section: Mechanical Properties Of Plasticised Pullulan Filmssupporting

confidence: 65%

Physicochemical properties and application of pullulan edible films and coatings in fruit preservation

et al. 2001

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“…26 Several articles have Compression Molding been published on the mechanical properties of TPS and extruded starches prepared from several starch Starches were mixed with a constant amount of sources, such as maize, wheat, potato, waxy maize, glycerol to give the following composition: starch : and amylomaize starch. [27][28][29][30][31][32][33][34][35] It has been shown that glycerol Å 100 : 30 (w/w on the basis of dry the amount of amylose and amylopectin affects the starch). These premixes were further mixed with crystallinity present in glycerol-containing TPS water to obtain mixtures with water contents in plastics, but no relationships with properties have the range of 8-35% (w/w on the basis of total been reported.…”

Section: Methodsmentioning

confidence: 99%

Structure and properties of compression-molded thermoplastic starch materials from normal and high-amylose maize starches

Soest

Borger

1997

J. Appl. Polym. Sci.

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ABSTRACT:The structural and mechanical properties of compression-molded normal and high-amylose maize starches were studied as a function of processing water content and ageing time. Rubbery thermoplastic starches were produced by compression molding of four maize starches with differences in amylose content and amylopectin structure. Glycerol (30% on the basis of dry starch) and water (between 10 and 35% on the basis of total mass) were used as plasticizers. After processing, the amorphous thermoplastic starch materials crystallized during ageing. The semicrystalline materials contained both E-type and V-type, as well as B-type crystallinity. The properties of the thermoplastic starch materials are dependent on water content during processing, starch source, and ageing time. The normal maize starch materials are highly flexible with elongations between 56 and 104%. The elongations of the high-amylose maize starch materials were between 5-35%. The tensile stress and E-modulus of the normal maize starch materials were in the range of 3.9-6.7 and 27-131 MPa, respectively. The tensile stress and E-modulus of the high-amylose maize starch materials increased from approximately 0.5 to 23 and 5 to 700 MPa, respectively, with increasing water content during processing from 10 to 35%. The differences in mechanical properties of the normal and high-amylose materials were explained by differences in the structure of the amylose and amylopectin structure. It was concluded that both lead to differences in the starch network.

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“…In general, it was observed that the films became more extendible when the concentration of plasticizer and relative humidity conditioning were increased. The reduction of the puncture force and the increasing of puncture deformation were consequences of the incorporation of plasticizers, and to water molecules absorbed by the samples, a common phenomenon of edible films, as has been revealed in other studies Debeaufort & Voilley, 1997;Ollett et al, 1991;Gennadios et al, 1993;Gontard et al, 1993). The significant increase in hydration of the films, produced by increase in relative humidity, caused a swelling of the biopolymer matrix, thus leading to an increase in the mobility of polymer chains.…”

Section: Mechanical Properties Of Cassava Starch Filmsmentioning

confidence: 84%

“…According to Bonilla, Atares, Vargas, and Chiralt (2013), biodegradable polymers based on natural polysaccharides, particularly starch, can be produced at low cost and on a large scale and their applications in food packaging are promising due to their environmental appeal, flexibility, transparency, thermoplastic properties and low cost. Starches from different sources like cassava, potatoes, corn, wheat and rice, natural or modified, have been used in the preparation of coatings (García, Martino, & Zaritzky, 1998) and edible films (Stading, Rindlav-Westling, & Gatenholm, 2001;Forssell, Partanen, Buleon, Farhat, & Myllarinen, 2002;Mali & Grossmann, 2003;Ollett, Parker, & Smith, 1991;Lourdin, DellaValle, & Colonna, 1995). In particular, cassava starch (Manihot esculenta C.) is an important source in some countries like Brazil, which is the largest cassava producing country, as well as in Thailand, Malaysia, InCopyright ©2015 ISEKI-Food Association (IFA) 10.7455/ijfs/4.1.2015.a10 donesia and some regions of Africa (Zhu, 2014;Versino & Alejandra Garcia, 2014).…”

Section: Introductionmentioning

confidence: 99%

Mechanical properties of cassava starch films as affected by different plasticizers and different relative humidity conditions

Lagos¹,

Vicentini²,

Santos³

et al. 2015

IJFS

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The influence of plasticizer type (glycerol and sorbitol), its content (starch:plasticizer ratio of 1:0.15; 1:0.20; 1:0.25 and 1:0.30) and the relative humidity conditions (43, 58, 75 and 85%) on the mechanical properties of cassava starch films was studied. Both plasticizers seemed to integrate homogeneously in the film matrix. The incorporation of different concentrations of plasticizers affected the mechanical properties of the cassava starch films. Plasticizer ratio directly influenced the force values of the films, they showed significant flexibility when the plasticizer proportion was increased in the formulation. Under conditions of low relative humidity, sorbitol produced films more resistant to puncture than glycerol. Qualitatively, all the films were less brittle when the plasticizers were incorporated.

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Deformation and fracture behaviour of wheat starch plasticized with glucose and water

Cited by 94 publications

References 9 publications

Physicochemical properties and application of pullulan edible films and coatings in fruit preservation

Physicochemical properties and application of pullulan edible films and coatings in fruit preservation

Structure and properties of compression-molded thermoplastic starch materials from normal and high-amylose maize starches

Mechanical properties of cassava starch films as affected by different plasticizers and different relative humidity conditions

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