• Korean journal of food and cookery science
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• v.6 no.4 s.13
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• pp.33-39
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• 1990

Rice and waxy rice starches were adjusted to 27% of moisture and heated at $100^{\circ}C$ for 16hours, respectively. After the treatment, their gelatinization properties were investigated. The initial gelatinization temperature, obtained by transmittance and amylogram, of Akkibare and Taebaek starches were $60{\sim}65^{\circ}C$ but those of waxy rice and the U.S.A. rice starches were $55{\sim}60^{\circ}C$ and $70{\sim}75^{\circ}C$, respectively. The gelatinization temperatures of heat-moisture treated starches were higher than those of the untreated starches. Viscosities at each temperature and the highest viscosity reduced by some degrees after the treatment. DSC thermograms of all starches showed single endotherm and the gelatinization enthalpies were $2.26{\sim}2.63\;cal/g$. The gelatinization enthalpy tended to decrease after the treatment. Transmittance and viscosity by alkali showed in this order; Akkibare and Taebaek starches>waxy starch>the U.S.A. rice starch. The heat-moisture treated starches increased viscosities in every starch. Transmittance in alkali solution of Akkibare, Taebaek and waxy rice starches decreased. but that of the U.S.A. rice search increased.

• Food Science and Preservation
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• v.24 no.4
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• pp.491-496
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• 2017

Paddy rice is typically stored during postharvest until rice grain is processed into brown rice and milled rice by hulling and milling procedure, respectively. Recently, instead of storing paddy rice, storage of brown rice has been in the spotlight because it is more convenient and economically feasible. Different brown rice cultivars with varying amylose contents including waxy rice, medium-waxy rice, and non-glutinous rice were stored in room temperature storage for four months, and the changes in grain qualities of brown rice were evaluated. Amylose content significantly affected pasting properties in which rice cultivar with higher amylose content showed longer pasting time and higher peak viscosity. Storage also affected pasting viscosities, showing an increase in peak viscosity, but a decrease in breakdown viscosity. The changes in pasting viscosity during storage could be an important starch property for aged brown rice utilization. Waxy brown rice showed the weakest aging property in terms of free fatty acids (FFA) accumulation, whereas non-glutinous rice was more substantial grain quality against aging. The FFA values of two months storage were not significantly different from the initial FFA contents, suggesting that brown rice stored in room temperature for two months could be feasible for direct consumption of brown rice.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.45 no.4
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• pp.221-226
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• 2000

This experiment was designed to assess changes in yield difference between waxy (IWR) and non-waxy (INWR) near isogenic rice by evaluating the translocation and accumulation of assimilates in different parts of the rice plants after heading stage under different fertilizer application. Nitrogen content of culm in both IWR and INWR decreased rapidly from 35 days before heading to flowering time and after then it was maintained constantly, while the nitrogen content of leaf blade was continually reduced. Sugar content of leaf blade in IWR decreased steadly by 10 days after heading, but that in INWR increased 20 days after heading. There was no difference in starch content of culum between IWR and INWR from 35days before heading to heading, but that of culm of IWR increased again after heading. Dry weight of IWR plant was less reduced during ripening as compared with INWR. The dry weight of culm was not significantly different between two isogenic lines.

• Korean journal of food and cookery science
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• v.11 no.5
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• pp.479-486
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• 1995

The reological properties of doughs blended with cereal flours were investigated in the study. The doughs were prepared of wheat flours mixed with 10％, 20%, 30% and 40% ratio of rice flour, waxy-rice flour, brown-rice flour and soybean flour. Amylogram, farinogram, extensogram and SEM were used to measured thier special properties with graphs and photos. The results were obtained as followes; 1. Wheat dough formation after fermantation, showed "stringing" structure of small starch granules on the SEM photo. But the large starch granules contributed little to the structure formation in rice flours dough, and played relatively a little role in the structure formation of blended doughs of waxy-rice, brown-rice and soy- bean flours. 2. The absorption of flour composited rice and brown-rice, was lower than that of the control by Farinograph. It was decreased the farinograph absorption with the increase of replacement ratio of cereal flours. Dough development time of cereal blended flours decreased, but that time of waxy-rice and brown-rice were very similiar. Farinograph stability of rice, waxy-rice, brown-rice and soybean blended flours, had shorter than that of wheat-flour. 3. The results showed that cereal blended flours decreased the resistance to extention (elasticity) without affecting the extensibility in fermented dough by Extensograph. 4. The gelatinization temperature of wheat, rice, waxy-rice, and brown-rice were 55.0$^{\circ}C$, 64.0$^{\circ}C$, 58.0$^{\circ}C$ and 61.0$^{\circ}C$. But that of all cereal blended flours showed 58.0$^{\circ}C$ except 20% or 30% soybean blended flours. According to the amylogram, each maximum viscosity of rice flour and wheat flour was 1760 B.U.,760 B.U.. Soybean composite flours had significantly lowe. amylograph peak viscosity (300 B.U.) than that of the other composite flours (450 B.U.-1100 B.U.).

• Preventive Nutrition and Food Science
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• v.14 no.3
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• pp.233-239
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• 2009

The effects of guar gum (GG) and xanthan gum (XG) at different concentrations (0, 0.2, 0.4, and 0.6% w/w) on the rheological properties of Korean waxy rice starch (WRS) pastes were evaluated under both steady and dynamic shear conditions. The flow properties of WRS-gum mixtures were determined from the rheological parameters of the power law model. The addition of GG and XG to WRS resulted in an increase in the apparent viscosity ($\eta_{a,100}$) and consistency index (K) values obtained from power law model. The flow behavior index (n) values of the WRS-XG mixtures decreased with an increase in gum concentration while there was only a marginal difference between n values for the WRS-GG mixtures. Dynamic moduli (G', G", and $\eta^*$) values in the WRS-gum mixture systems also increased with an increase in gum concentration. WRS-XG mixtures had higher dynamic moduli and lower tan $\delta$ (ratio of G"/G') values than WRS-GG mixtures, indicating that the higher dynamic rheological properties of WRS-XG can be attributed to an increase in the viscoelasticity of the continuous phase in the starch-gum mixture systems, which was due to the higher viscoleastic properties of XG compared to GG. The dynamic ($\eta^*$) and steady shear ($\eta_a$) viscosities of the WRS-XG paste at a 0.2% gum concentration followed the Cox-Merz superposition rule.

• 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.

• Korean Journal of Food Science and Technology
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• v.24 no.4
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• pp.347-352
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• 1992

Physicochemical properties of native and defatted nonwaxy(Dongjin byeo) and waxy(Sinseunchalbyeo) rice starches were investigated. The granule shapes of rice starches were polygonal and X-ray diffraction patterns were A types, but relative crystallinity was decreased by defatting. The amylose content of defatted starches slightly increased, but water binding capacity of defatted starches decreased. Swelling power and solubility of starches increased with the increase of temperature, at each temperature increased by defatting. Transmittance of Dongjinbyeo and Sinseunchalbyeo starch suspensions showed a rapid increase at $60{\sim}65^{\circ}C$, $55{\sim}60^{\circ}C$ respectively. The initial pasting temperature by amylograph of Dongjinbyeo and Sinseunchalbyeo starches were $66^{\circ}C$ and $64^{\circ}C$, respectively. The gelatinization temperature of defatted starches was higher than that of the nondefatted starches. Dongjinbyeo starch decreased peak viscosity and breakdown by defatting, but Sinseunchalbyeo starch unchanged.

• Korean journal of food and cookery science
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• v.30 no.6
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• pp.716-725
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• 2014

Gelatinization properties and the molecular structure of Korean waxy rice starchesisolated from two japonica types, Sinseonchal, and Dongjinchal, as well as an indica type, Hangangchal 1 were investigated. Sinseonchal is preferred cultivar for making Korean traditional rice cakes and cookies. Sinseonchal starch was the highest in crude protein, amylopectin, damaged starch contents, and water binding capacity among the cultivars tested. The initial pasting temperature ($72.75^{\circ}C$), peak (360.54 RVU), breakdown (162.21 RVU) and setback (30.83 RVU) viscosities of Sinseonchal had the highest values (p<0.05). Onset and peak temperatures by differential scanning calorimeter were also the highest in Sinseonchal. The molecular weight of Sinseonchal amylopectin was 5.46 107higher than those of the other cultivars, but its peak height and area were the lowest among them. The amylopectin peak by HPSEC showed a shoulder in the lower molecular weight portion and its relative area decreased in the following order; Sinseonchal > Dongjinchal > Hangangchal 1. On the branch chain length distribution of amylopectin, the proportion of DP13-24 and DP25-36 showed reverse trends, with higher japonica type amylopectin in DP13-24.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.5
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• pp.770-774
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• 2002

The effect of mixing ratio of materials and their retort processing conditions on the physical properties and preference of oyster porridge were investigated. Rice gave adequate viscosity (about 800 cp) to the porridge as it was used 10～12% level and half of it was ground. Potato starch, waxy corn starch, and Perfectamyl AC showed small variation in viscosity unrelated to the temperature, that was a good condition for high quality porridge. Especially, waxy corn starch had a good property for retort porridge because its viscosity was maintained high during the processing and decreased to preferable one after processing. Purity CSC, modified starch gave gum-like texture and didn't cause water-separation much after freezing and thawing treatment of the porridge. Therefore, it was good for enhancing the physical property of the porridge as a co-additive of waxy corn starch when it was used at quarter level of waxy corn starch. Xanthan gum increased dispersibility of materials and it was useful for stabilizing physical quality of the porridge without affecting preference when it was used below 0.2% concentration. As a result, the optimal material-mixing ratio was determined as rice 10% (50% of it was ground), waxy corn starch 1.5%, Purity CSC 0.5%, xmthan gum 0.2%, salt 0.3%, and water 87.5%. Oyster's porridge, retort processed with this recipe, showed stable physical property after 6 month storage at room temperature.

• Journal of the Korean Society of Food Science and Nutrition
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• v.22 no.5
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• pp.596-602
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• 1993

The Characteristics of Shinsunchalbyeo(Japonica) and Hangangchalbyeo($J{\times}Idica$) starches including physicochemical properties, differential scanning calorimetry(DSC) and enzymatic digestion of lintnerized starches were investigated. Degree of hydrolysis of Hangangchalbyeo starch with 2.2N HCI for 48hr was higher than that of shinsunchalbyeo starch. Absorbance at ${\lambda}_{max}$ 680nm, and ${\lambda}_{max}$ of iodine stained starch decreased upon acid treatment. But water binding capacity, swelling power and solubility considerably increased as hydrolysis progressed. Relative crystallinity of two starches increased with acid treatment, and that of Shinsunchalbyeo starch was higher than that of Hangangchalbyeo starch. DSC data continuously decreased for lintnerization periods, and those of Shinsunchalbyeo starch. DSC data continuously decreased for lintnerization periods, and those of Shinsunchalbyeo starch have higher than those of Hangangchalbyeo starch. The onset temperature of starch by DSC continuously decreased by treatment, but conclusion temperature increased until 24hr and then decreased. The enthalpy for gelatinization decreased for both starches. Degree of hydrolysis of lintnerized Shinsunchalbyeo starch with glucoamylase was slightly higher than that of Hangangchalbyeo starch.