Dextrinization of Starch with Nitrogen Laser

Gholap, A. V.; Marondeze, L. M.; Tomasik, Piotr

doi:10.1002/star.19930451205

Cited by 18 publications

(7 citation statements)

References 12 publications

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“…The modification of starches by UV radiation could induce the alteration in their main properties [31]. It could promote the faster bound of the molecules of starch with the water, increasing the starch solubility [32] and also decreasing the starch paste viscosity [33], as observed in this study. Similar behaviour regarding RVA profiles was reported in previous studies of treated cassava starches for the pasting temperatures and viscosity peaks [12,20].…”

Section: Resultsmentioning

confidence: 72%

Investigation of the photo-oxidation of cassava starch granules

Hornung

Oliveira

Lazzarotto

et al. 2015

J Therm Anal Calorim

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In this study, the combined and simultaneous actions of H 2 O 2 and UV radiation on cassava starch granules were applied and the thermal, rheological, structural and colour properties were investigated. Samples of native cassava starch were oxidised with standard H 2 O 2 solutions (0.1, 0.2 and 0.5 mol L -1 ) and exposed for 1 h under UV light (UVC radiation with k = 256 nm), with constant stirring. The solutions were subsequently filtered, washed, dried and analysed. The thermogravimetric curves showed similar behaviour, with three main mass losses and an increase in the thermal stability of each sample. The oxidative modification performed caused a strong decrease in the setback and final viscosity parameters (RVA), a gradual decrease in the gelatinisation enthalpy (DSC) and relative crystallinity (XRD) and significant differences in the average roughness of the granules (NC-AFM). The X-ray diffraction powder patterns displayed the ''A'' type for all the starch granules. The colour parameters showed a decrease in the -a* value (trend to green) for all the treated samples.

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Section: Resultsmentioning

confidence: 72%

Investigation of the photo-oxidation of cassava starch granules

Hornung

Oliveira

Lazzarotto

et al. 2015

J Therm Anal Calorim

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“…(This is true even when oxygen is excluded.) See, for example, Merlin & Fouassier 1981, Gholap et al 1993, Fiedorowicz et al 1999, and Bertolini et al 2001 …”

Section: Ultraviolet Irradiationmentioning

confidence: 98%

Physical Modification of Food Starch Functionalities

BeMiller

Huber

2015

Annu. Rev. Food Sci. Technol.

240

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Because, in general, native starches do not have properties that make them ideally suited for applications in food products, most starch is modified by dervatization to improve its functionality before use in processed food formulations, and because food processors would prefer not to have to use the modified food starch label designation required when chemically modified starches are used, there is considerable interest in providing starches with desired functionalities that have not been chemically modified. One investigated approach is property modification via physical treatments, that is, modifications of starches imparted by physical treatments that do not result in any chemical modification of the starch. Physical treatments are divided into thermal and nonthermal treatments. Thermal treatments include those that produce pregelatinized and granular cold-water-swelling starches, heat-moisture treatments, annealing, microwave heating, so-called osmotic pressure treatment, and heating of dry starch. Nonthermal treatments include ultrahigh-pressure treatments, instantaneous controlled pressure drop, use of high-pressure homogenizers, dynamic pulsed pressure, pulsed electric field, and freezing and thawing.

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“…However, with sufficiently high intensity or long exposure time, the destructive nature of UV can cause photo-reactions in starch, like a decrease of chain length which is often accompanied with yellowing and the formation of carbonyl and carboxyl groups along the polymer chains [14,15]. UV light treatment of starch has been reported to bring about changes in some functional properties, such as an increase in water binding capacity and solubility as well as a decrease in the hot paste viscosity [16,17]. UV irradiation has been reported not to alter the crystallinity of starch or its gelatinization enthalpy [18].…”

Section: Introductionmentioning

confidence: 99%

Oxidative Degradation of Thermoplastic Starch Induced by UV Radiation

Quispe¹,

López²,

Villar³

2019

Journal of Renewable Materials

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Among biopolymers, thermoplastic starch (TPS) is a good candidate to obtain biomaterials because of its natural origin, biodegradable character, and processability. Exposure to ultraviolet (UV) radiation causes significant degradation of starch-based materials, inducing photooxidative reactions which result in breaking of polymer chains, production of free radical, and reduction of molar mass. These changes produce a deterioration of TPS mechanical properties, leading to useless materials after an unpredictable time. In this work, changes induced on TPS by UV radiation, analyzing structural properties and mechanical behavior, are studied. TPS was obtained through thermo-mechanical processing of native corn starch in the presence of water (45 % w/w) and glycerol (30 % w/w) as plasticizers. Films were obtained by thermocompression and, before testing, specimens were conditioned to reduce material fragility. Photodegradation process was performed by exposing TPS to 264 h UV radiation in a weathering test chamber. Specimen's weight loss was determined gravimetrically. Chemical changes were studied by Fourier Transform Infrared Spectroscopy (FTIR) and morphological modifications were analyzed by Scanning Electron Microscopy (SEM). Reduction of weight average molar mass was measured by Static Light Scattering (SLS). Changes in mechanical properties were studied from tensile tests. After 96 h exposure, TPS specimens presented a weight reduction of 4-6%, mainly attributed to plasticizers lost by evaporation. SEM observations showed that UV radiation induced morphological changes on TPS, evidenced by an increment of specimens cracking. By FTIR, it was detected the presence of an additional band located at 1726 cm -1 in samples submitted to UV radiation, attributed to the formation of -C=O groups. Weight average molar mass of native starch was in the order of 107 g mol -1 . TPS exposure to UV radiation decreased significantly its molar mass, confirming molecular degradation of the biopolymer. When TPS was exposed during 48 h, it was detected a considerable decrease in elongation at break values (~ 85%), indicating that TPS flexibility was reduced. On the other hand, after 48 h exposure, TPS elastic modulus was 55 times higher than those of the unexposed specimens, evidencing an increase in material rigidity. TPS maximum tensile strength was also increased by UV light, with an increment of ~ 400% after 48 h exposure. Results revealed that starch-based materials can be degraded by exposure to UV radiation, modifying their microstructure and mechanical performance.

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Dextrinization of Starch with Nitrogen Laser

Cited by 18 publications

References 12 publications

Investigation of the photo-oxidation of cassava starch granules

Investigation of the photo-oxidation of cassava starch granules

Physical Modification of Food Starch Functionalities

Oxidative Degradation of Thermoplastic Starch Induced by UV Radiation

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