• Food Science and Biotechnology
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• v.16 no.5
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• pp.663-674
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• 2007

Starches from different botanical sources differ in the ratio of amylose to amylopectin contents, molecular structures of amylose and amylopectin, granule morphology, and minor-component contents. These structural features result in different gelatinization, pasting, retrogradation properties, and enzyme digestibility of starch granules. In this review, compositions and molecular structures of starches and their effects on the physicochemical properties are summarized and discussed.

• Journal of the Korean Society of Food Culture
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• v.36 no.5
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• pp.484-491
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• 2021

This study investigated the effect of dry heat treatment (DHT) on the physicochemical properties of hard type (HR) and floury type (FR) rice to improve the processing aptitude of rice flour. The rice flour was heated at 130℃ for 0, 2 and 4 hours, and the color value, water absorption index (WAI), water soluble index (WSI), swelling power, solubility, pasting properties, particle shape and the X-ray diffraction were measured. After DHT, the L value of rice flour decreased, and the b value increased. The WAI, WSI, swelling power and solubility of HR and FR increased with the increase of treatment time. The cold viscosity and setback increased, while breakdown decreased. Cracks and lumps formed with fine particles were observed. The X-ray diffraction pattern was A-type, while the diffraction intensity decreased. According to the results of the two-way analysis of variance (ANOVA) test, the hydration and pasting properties were significantly different between HR and FR and were affected by DHT time. The results suggest that the properties of modified rice flour by DHT can be used in the food industry.

• Food Science and Biotechnology
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• v.18 no.4
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• pp.855-860
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• 2009

Physicochemical properties of starches isolated from 3 new potato cultivars developed by Potato Valley Ltd. were investigated and compared to those of starch isolated from 'Superior' being distributed prominently in Korea. Significant differences were observed in physicochemical properties such as granule size, amylose content, phosphorus content, water binding capacity, swelling power, solubility, and in vitro digestibility of starches from different potato cultivars. Thermal properties were evaluated using differential scanning calorimetry (DSC), and onset gelatinization temperatire ($T_o$), peak temperature ($T_p$), and enthalpies of gelatinization (${\triangle}H$) of different potato cultivars ranged as $58.0{\pm}0.3-61.7{\pm}0.4^{\circ}C,\;63.7{\pm}0.2-$ $66.5{\pm}0.0^{\circ}C$, and $15.6{\pm}0.5-17.0{\pm}0.3$ J/g, respectively. Pasting properties were evaluated using a rapid visco analyzer (RVA), and pasting temperature, peak viscosity, and final viscosity of different potato cultivars ranged as $65.0{\pm}0.1-68.9{\pm}0.1^{\circ}C$, $8,163.7{\pm}196.3-9,035.7{\pm}6.4$ cp, and $4,397.7{\pm}166.7-7,025.0{\pm}271.3$ cp, respectively. Especially, 'Gogu valley' starch showed the highest values in the amylose and phosphorus content among tested potato cultivars and higher water binding capacity, swelling power, and solubility than those of other tested starches. And it also showed high pasting temperature, peak viscosity, trough viscosity, and final viscosity as compared to other tested starches.

• Korean journal of food and cookery science
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• v.29 no.6
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• pp.833-839
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• 2013

Separated normal and waxy rice starches were pulverized, and the physicochemical and digestive properties of the starches were determined. The size of both starch granules significantly decreased (less than $8{\mu}m$) after pulverization. For pasting properties, significant decreases of peak and setback viscosity were observed in both of pulverized starches than in native ones. The lower pasting temperature as well as increased solubility and water binding capacity of pulverized starches imply molecular degradation of starch by pulverization. For thermal properties, onset temperature and melting enthalpy significantly decreased after pulverization, especially in normal rice starch, however there was no difference in amylose-lipid complex before andafter pulverization. The slowly digestible and resistant starch portion of normal rice starch increased after pulverization, however, in waxy rice starch, the rapidly digestible portion increased.

• Korean journal of food and cookery science
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• v.27 no.6
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• pp.745-754
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• 2011

To improve the textural properties of gluten free rice flour based products, the physicochemical and pasting properties of extruded non-waxy rice flours using extruder were investigated. The high yielding Tongil type rice variety, Hanarum was used. Hanarum rice flour was prepared by dry milling from soaked and dried rice grain. The operation conditions of twin screw extruder were 250 rpm of screw speed, $160^{\circ}C$ of barrel temperature, and 24, 27, and 30% of moisture content. Hanarum extruded rice flour (HERF) were lower in crude lipid and ash contents, but higher in crude protein than Hanarum rice flour (HRF). The color values of HERF showed significantly different (p<0.05) with different moisture contents. Water binding capacities, apparent amylose contents, and damaged starch of HERF were higher than those of HRF. Moisture contents affected water binding capacities of HERF. Solubility increased with increasing heating temperature and solubilities of HERF differed significantly (p<0.05). X-ray crystallinity was changed after extrusion cooking and that of HERF showed sharp peaks at $2{\theta}=18-20^{\circ}$. The pasting viscosities of HERF kept lower values (~ 10 RVU) constantly.

• Journal of Applied Biological Chemistry
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• v.51 no.6
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• pp.277-284
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• 2008

The objective of this study was to investigate the effect of soaking time on physicochemical properties of waxy rice, waxy rice flour and waxy rice starch. Waxy rice (WR), waxy rice flour (WRF), waxy rice starch (WRS) were soaked at $18^{\circ}C$ for 14 days and dried at $40^{\circ}C$. Dried samples were grounded and sieved using 180 mesh. Physicochemical properties of the three samples, such as swelling power, solubility, moisture sorption isotherms and pasting properties using rapid visco analyzer (RVA) and crystal pattern using X-ray diffractometer were determined. In all samples, soaking time greatly influenced moisture sorption isotherms but no typical pattern was shown. Swelling power was not greatly changed by soaking time in the three samples. Solubility increased with increasing soaking time in all three samples, indicating that some soluble particles were exuded during soaking. In RVA pasting properties, WR and WRF showed a similar pattern, while WRS showed different pasting properties, suggesting that rice protein plays a significant role in pasting properties. X-ray diffraction patterns of all three samples showed typical A-type crystal pattern suggesting that soaking did not affect crystalline region of samples.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.spc1
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• pp.292-296
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• 2006

Three rice cultivars of Goami2 (G2), Ilpumbyeo (IP), and Baegjinju (BJJ) of which physicochemical properties are significantly different, were blended by a simplex-lattice mixture design. The effect of blending those rice cultivars on pasting and texture properties were observed. Rapid Visco Analysis (RVA) indicated that the onset gelatinization temperature of pure blend of G2 rice $(83.80{\pm}0.07^{\circ}C)$ was higher than that of IP $(68.08{\pm}0.01^{\circ}C)$ and BJJ $(68.08{\pm}0.04^{\circ}C)$. Increasing G2 rice resulted in lower peak and breakdown viscosity, and adhesiveness and cohesiveness, whereas higher setback viscosity and hardness. Pasting and texture properties of IP and BJJ indicated that G2 rice has quite different physical characteristics compared to IP and BJJ. Thus, it is expected that blending those three rice cultivars can be used to formulate a desirable rice blend on purpose, furthermore to promote the consumption of G2 rice, which has higher indigestible carbohydrate contents.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.1
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• pp.1-8
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• 1999

Starch was isolated from nine Korean sweet potato varieties(Shinmi, Seangmi, Yulmi, Shinyulmi, Sunmi, Jeungmi, Mokpo 26, Mokpo 29, and Mokpo 30) and analysed in its physicochemical properties in comparison with a commercial sweet potato starch(Kumokanyu) imported from China. Protein content in the isolated starch was highest(1.1%) in Mokpo 29 and lowest(0.3%) in Kumokanyu, whereas lipid content was equally less than 0.2%. Pasting analysis by Rapid Viscoanalyser(RVA) showed that Yulmi starch had the lowest pasting temperature(70.2oC) whereas Kumokanyu did the highest one (74.3oC). Under a differential scanning calorimetry(DSC), however, Kumokanyu showed the lowest onset temperature(61.8oC) and enthalpy(42.0 J/g) for crystal melting. Shinyulmi showed the highest peak viscosity of the starch paste, but shear thinning was significant like commercial potato starch. Kumokanyu, however, displayed the least peak visicosity but good shear stability. With the starch gels prepared at 4oC, Mokpo 29 showed the highest hardness, whereas Shinyulmi did the lowest one. Against repeated freeze thawing treatments, the starch gel of Kumokanyu was most stable, and among the Korean varieties, Yulmi, Shinyulmi, Jeungmi and Mokpo 26 had good stability. According to the chain distribution analysis, Shinyulmi and Mokpo 29 consisted of larger quanitites of shorter amylopectin chains than Kumokanyu, potato and corn starches.

• Korean journal of food and cookery science
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• v.32 no.4
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• pp.524-530
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• 2016

Purpose: The properties of starch and starch gel prepared from a newly inbred sweet potato, Daeyumi were compared to the properties of starch and starch gel prepared from Sinyulmi which is a well known mealy type sweet potato. Methods: The starch was isolated by using the alkaline steeping method. Physicochemical, pasting, and thermal properties, and crystallinity were measured. The texture properties of starch gel (10%, w/w) were examined. Results: The amylose contents of Daeyumi and Sinyulmi starches were 25.57% and 22.59%, respectively. The initial pasting temperature of Daeyumi starch was significantly higher than that of Sinyulmi starch (p<0.05), but other paste viscosities were not different. The peak and conclusion temperatures of Daeyumi starch were higher than those of Sinyulmi starch by differential scanning calorimetry. The shape of Daeyumi starch gel was more clear and rigid than the shape of Sinyulmi starch gel. The surface and the upper side of Daeyumi starch gel were smoother than the surface and the upper side of Sinyulmi starch gel. Hardness and gumminess were higher in Daeyumi starch gel than in Sinyulmi starch gel. The crystallinity types of Daeyumi and Sinyulmi starches were $C_b$ and A types, respectively, but starch gels showed an amorphous type. Conclusion: Therefore, it is suggested that Daeyumi starch would have better physicochemical properties and higher quality of starch gel than Sinyulmi starch.

• Korean journal of food and cookery science
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• v.27 no.2
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• pp.19-29
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• 2011

Sweet potato powders made from eight Korean varieties, including purple-fleshed, orange-fleshed, and commercial dry type sweet potatoes, were investigated for physicochemical and pasting properties to develop processed food. Crude protein and lipid contents of Shinjami and Borami were higher than those of other varieties. The lightness value of raw sweet potato flesh was the highest value in Shinchunmi, and the lowest in Shinjami. Using the color difference (${\Delta}E$), color similarities compared to the white plate occurred in the following order; purple-fleshed > orange-fleshed > commercial dry type sweet potatoes. Total and damaged starch contents were significantly different (p<0.05). Total starch content of sweet potatoes was higher in commercial dry sweet potatoes (61.89-70.46%), particularly Shinchunmi (70.46%) but lower in orange-fleshed sweet potato (48.87 and 49.53%, respectively). Water binding capacity of Yeonwhangmi, swelling power and solubility of Shinyulmi were the highest values (174.70, 25.54 and 87.49%, respectively) among them (p<0.05). But oil absorptions of Shinyulmi and Shinchunmi showed lower values (97.08 and 97.54%, respectively). All sweet potato powders had an A type x-ray diffraction pattern. The initial pasting temperatures of sweet potato powders ranged from 69.50 to $75.95^{\circ}C$ and the amylolytic enzyme in sweet potato powder lowered pasting viscosity.