• Applied Biological Chemistry
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• v.34 no.4
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• pp.379-385
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• 1991

Morphological changes of starch granules from 12 different varieties of rice were examined by scanning electron microscopy during heating at 2.5% (w/v) concentration. Rice starch granules proceeded through a similar pattern of progressive morphological changes daring heating, regardless of variety. Rice starch granules began to swell radially in the initial stage of gelatinization and then undergo radial contraction and random tangential expansion to form complex structures in the latter stage of gelatinization temperature range. At higher temperatures, starch granules softened and melted into thin flat discs, and then stretched into thin filaments to form three-dimensional networks. These progressive morphological changes were reflected in the changes of swelling power, solubility and amylograph viscosity of starch. During the transition of melting or softening, swelling power, solubility and amylograph viscosity increased rapidly. The time of loss of granular structure of starch depended on gelatinization temperature range. The ratio of amylose to amylopectin was largely responsible fur the rate of melting or softening and the fineness of a three-dimensional filamentous network above the gelatinization temperature range. Therefore, both the gelatinization temperature range and amylose content of starch affect the rate of cooking, and amylose content of starch affects the final texture of cooked starch paste.

• Korean Journal of Food Science and Technology
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• v.35 no.4
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• pp.545-550
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• 2003

The effect of ${\beta}-glucan$ on gelatinization of barley starch was studied. By the rapid visco-analyzer measurement, gelatinization of starch became rapid and viscosity increased largely on the RVA pattern by addition of ${\beta}-glucan$ to starch. The results of differential scanning calorimeter showed that molecular structure of starch was getting stabilized through shifting up of gelatinization temperature and increase in enthalpy by addition of ${\beta}$-glucan. X-ray diffraction pattern also showed the same results as differential scanning calorimeter. But it was revealed that addition of ${\beta}$-glucan to starch didn't affect characteristics such as microscopic observation, solubility, swelling power, and iodine binding properties during gelatinization of starch.

• Korean Journal of Food Science and Technology
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• v.25 no.4
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• pp.400-403
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• 1993

Gelatinization degrees of torn and waxy corn starches in the low-moisture environment were determined by DSC thermogram and enzymatic analysis, the results were compared each other As the moisture content increased from 20% to 70%, the enthalpy of endothermic peak of starch increased linearly in DSC thermograms. When the moisture content exceeded above 70%, the DSC enthalpy of starch remained constant in DSC thermogram. The enthalpies for gelatinization of corn and waxy corn starches were 3.23 cal/g and 4.2 cal/g, respectively. When gelatinization degrees of starches were measured by enzymatic analysis, the gelatinization degree increased linearly as the moisture content increased from 20% to 80%. A linear correlation between DSC and enzymatic analysis was obtained only when the moisture content was under 70%.

• Journal of the Korean Society of Food Science and Nutrition
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• v.29 no.1
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• pp.1-5
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• 2000

Physicochemical properties and gelatinization patterns of purple-fleshed sweet potato starch were studied. Shape of starch granule was round and polygonal, X-ray diffraction pattern was Ca-type. Amylose content was 14.4% which was lower than that of other sweet potato starch. Water binding capacity was 82.54%, swelling power and solubility at 8$0^{\circ}C$ were 27.94% and 15.35%, respectively. Initial temperature of gelatinization was 72$^{\circ}C$ using Brabender/Visco/Amylograph, consistency and setback were lower than those of other sweet potato starch. The peak temperature and enthalpy determined by DSC were 68.1$^{\circ}C$, 1.24cal/g, respectively. The transmittance of starch dispersions in alkaline solutions increased with NaOH concentration up to 0.17N, and then changed slowly at 0.19N or above. The apparent viscosities were similar to the transmittance of starch dispersions in alkaline solutions, but drastically increased above 0.21N.

• Korean Journal of Food Science and Technology
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• v.26 no.5
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• pp.638-643
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• 1994

Gelatinization and retrogradation properties of modified starches which were prepared by steeping sweet potato at $40^{\circ}C$ for 2, 4, 7 and 10 days were investigated. The peak temperature of gelatinization and enthalpy of untreated starch by DSC were $53.9^{\circ}C\;and\;1.32\;cal/g$, respectively, but those of modified starch were increased by steeping. In gelatinization by alkali, starches with 2, 4 and 7 day steeping showed higher viscosities than untreated starch, whereas the viscosities of starches with 10 day steeping decreased. The clarities in paste decreased during storage in all starches and decreased in starches with steeping. The degrees of retrogradation by ${\alpha}-amylase-iodine$ method were higher in starches with steeping than untreated starch. The enthalpy of retrograded starches by DSC increased by steeping except 4 day steeping starch. The sweet potato extract containing sugar inhibited the retrogradation of starch paste and the degree were higher in residual starches than in untreated starch.

• Applied Biological Chemistry
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• v.27 no.1
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• pp.52-54
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• 1984

Ethanol fermentation from the chemically gelatinized starchy material was examined. The critical concentration of sodium hydroxide solution for gelatinization was dependent on the species of starch; 0.4M for potato and 0.6M for tapioca at room temperature. For alcohol fermention the starchy material was gelatinized by addition of sodium hydroxide solution, neutralized by sulfuric acid, and then yeast was added. The amount of $CO_2$ evolved during ethanol fermentation indicates that non-fermentable material was not produced from the starch by chemical gelatinization. In ethanol fermentation of potato and tapioca starch no significant difference was observed between the thermal and the chemical gelatinization.

• Food Science and Biotechnology
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• v.14 no.4
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• pp.470-473
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• 2005

Starch was isolated from turnip (Brassica rapa L.), and to elucidate the structure-function relationship its structural and physical properties were characterized. Morphological structure of the starch was analyzed by SEM (Scanning Electron Microscopy). Most of the starch granules were spherical in shape with diameter ranging from 0.5-10mm. Apart from larger granules ($<10\;{\mu}m$) which dominated the population size of turnip starch, significant amount of small ($0.5-2\;{\mu}m$) and mid-size granules (${\sim}\;{\mu}m$) were also detected. It was revealed that presumably, erosion damages occurred due to the attack of amylase-type enzymes on the surface of some granules. Branch chain-length distribution was analyzed by HPAEC (High-Performance Anion-Exchange Chromatography). The chain-length distribution of turnip starch revealed a peak at DP12 with obvious shoulder at DP18-21. The weight-average chain length ($CL_{avg}$) was 16.6, and a large proportion (11.8%) of very short chains (DP6-9) was also observed. The melting properties of starch were determined by DSC (Differential Scanning Calorimetry). The onset temperature ($T_o$) and the enthalpy change (${\Delta}H$) of starch gelatinization were $50.5^{\circ}C$ and 12.5 J/g, respectively. The ${\Delta}H$ of the retrograded turnip starch was 3.5 J/g, which indicates 28.2% of recrystallization. Larger proportion of short chains as well as smaller average chain-length can very well explain relatively lower degree of retrogradation in turnip starch.

• Journal of Dairy Science and Biotechnology
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• v.26 no.2
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• pp.45-49
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• 2008

We studied the feasibility of monitoring and controlling the manufacturing process of an infant formula with rice starch by testing in-process samples using rheology. We used DSC to first determine the gelatinization temperature of the rice starch, a key ingredient of this product. With this characteristic temperature and the process design known, rheological measurements were conducted on the in-process samples for detecting the presence and extent of gelatinization and retrogradation of rice starch; in-process samples were collected from the carbohydrate tank, after the homogenizer, and the finished product tank. The correlation between the rheological measurements on these samples and manufacturing performance proved that rheology is a very sensitive tool for monitoring the structural development of this infant formula during main process, and their influence on sterilization efficiency. We observed that the lower degree of gelatinization during main process, a shorter residence time in the finished product tank, and using caustic flush rather than clean-in-place additively lead to higher sterilization efficiency. These findings can be utilized for a rational design and analysis of the manufacturing process for infant formulas containing rice starch.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.1
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• pp.17-24
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• 1997

The effects of steeping on the physicochemical and gelatinization characteristics of glutinous rice flour and its starch were studied. Steeping conditions were 1 day at 25"C,7 days at 2iC and 7 days at 35"C. Crude protein, lipid and ash content were decreased br steeping. It was observed with scanning electron microscopy that endosperm cell wall of glutinous rice flour was diminished by steeping. Although morphology of the glutinous rice starch granules was not affected, the size was decreased by steeping. Density and water binding capacity(WBC) of glutinous rice flour and its starch were changed by steeping. X-ray diffraction pattern of glutinous rice starch was A type and was not affected by steeping. Swelling power of glutinous rice flour and its starch was increased but solubility was decreased by steeping. In Brabender amylographic examination, peak viscosity of untreated glutinous rice flour was very low and increased enormously by steeping resulting in the similar Brabender viscosity pattern to its starch. The gelatinization temperature examined by X-ray diffractometry was lowered by steeping. And the degree of gelatinization under the conclusion temperature increased with increasing of steeping Period and temperature.mperature.

• Korean Journal of Food Science and Technology
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• v.19 no.5
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• pp.435-440
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• 1987

Gelatinization properties of heat-mositure treated potato and sweet potato starches were investigated. Water-binding capacity of starch was increased by heat-mositure treatment, which was more pronounced in sweet potato starch. Blue value was not affected by the treatment. Amylograph viscosities were decreased by heat-mositure treatment, which was more pronounced in potato starch. Critical concentration of NaOH for gelatinization of starch increased as moisture level increased. Gel volume of starch upon KSCN gelatinization was higher in potato starch. Gelatinized starches showed Binghamapseudoplastic behavior. Consistency index and yield stress were drastically decreased upon heat-moisture treatment.