• Applied Biological Chemistry
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• v.46 no.3
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• pp.189-194
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• 2003

Rice seeds of 4 cultivars including Whachung-giant embryonic rice and Nampung-giant embryonic rice, as a group of the non-waxy rice cultivars, and Shinsunchal-giant embryonic rice and Whachungchal-giant embryonic rice, as that of the waxy rice cultivars, were germinated at $27^{\circ}C$ for 3 days to compare the changes in some physicochemical properties of the starch granules and the starch-hydrolysing enzyme activities during germination, respectively. ${\alpha}-Amylase$ activity of rices germinated for 3 days found to be higher than that of malt. Especially, Whachung-giant embryonic rice and Shinsunchal-giant embryonic rice were greater in activity than other rice cultivars and possessed the activities double that of malt. In contrast, ${\beta}-amylase$ of germinated rice found to be considerably less active than malt, although the giant embryonic rice group showed prevalent activity as compared o the normal rice group. With the starch granules, the amount of long glucose chains from amylose molecules were reduced in the non-waxy type giant embryonic rices, while the chain length increase was found in the waxy type giant embryonic rices. For the distribution profile of the glucose chain length from amylopectin molecules, we could observed that the chain length with DP (degree of polymerization) ranged 33 to 66 and 14 to 32 increased with the decreasing rate of that above 67 and below 13 regardless of starch waxiness. With non-waxy type of giant embryonic rices, susceptibility for glucoamylase were found to reduce along with germination, however, increase in susceptibility was observed with waxy rice types. In addition, we found the reduction in both initiation and termination temperature, and enthalpy for gelatinization.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.58 no.3
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• pp.226-231
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• 2013

A total 11 Korean rice cultivar was prepared and investigated for its starch and quality characteristics. Amylose content, damaged starch contnent, water contnent, water absorption index (WAI), water solubility index (WSI), particle size and pasting properties of rice flours were measured. The amylose content of waxy, middle waxy and non waxy type domestic normal rice cultivars were 7.09%, 11.69% and 18.58-21.52%, respectively. Moisture content of 11 Korean rice cultivar were 7.19-13.89%. WAI and WSI did not show variations by amylose contents. Sample with high moisture contents was lower damaged starch contents. Particle size of samples was $27.61-189.67{\mu}m$. Final viscosity and pasting temperature of the samples was shown to rage from 45.54 to 313.94 RVA and from 71.03 to $87.98^{\circ}C$, respectively. In this study, results indicated that samples with low moisture contents tend to shown low particle size and high damaged starch contents regardless waxy, middle-waxy, and non waxy type.

• Food Science and Biotechnology
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• v.15 no.2
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• pp.207-213
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• 2006

The effects of gellan gum (from S. paucimobilis), EPS-CB (exopolysaccharide from S. chungbukensis), and a series of commercial gums (arabic gum, xanthan gum, guar gum, deacyl gellan gum), on the swelling, rheological, and pasting properties of non-waxy rice flour dispersions were investigated. The swelling properties of rice flours in gellan or guar gum dispersion after heating were found to have increased with increasing gum concentrations, but the swelling properties of rice flour/other gum systems decreased with increasing concentrations. The rice flour/gum mixtures showed high shear-thinning flow behavior (n=0.14-0.32), and consistency index (K) was higher in guar gum than other gum dispersions. The initial pasting temperatures and peak times increased along with increasing gum concentration. The peak viscosity of rice flour increased in guar gum and deacyl gellan dispersions, and the breakdown and setback viscosity of the rice flour paste was lowest in the xanthan gum system, but remained higher than those of the control. The apparent viscosities of the rice flour/gellan gum mixture pastes were the highest among the tested combinations.

• Korean Journal of Food Science and Technology
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• v.11 no.2
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• pp.99-104
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• 1979

Rheolegical and baking properties of blends containing 10, 20 and 30 % of rice flours (Milyang 23, non-waxy and Tongil waxy) with wheat flour were investigated. Milyang-wheat blends showed higher amylograph paste viscosities at all reference points than waxy-wheat blends. Rice-wheat four blends had shorter farinograph stability than f·heat flour; however, the dough development time was similar between two blends. Breads produced from either Milyang-wheat or waxy-wheat flour blends at 10% rice level were acceptable compared with breads produced from wheat flour.

• Korean journal of food and cookery science
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• v.29 no.2
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• pp.193-208
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• 2013

The purpose of this study was to investigate the characteristics and brewing methods of Danyangju, which is one of the traditional single brewed rice liquors using Korean ancient literatures publishes from the 1400's to 1600's. Total 32 Danyangju products and 55 brewing methods were found by reviewing the ancient literatures. Danyangju products could be classified into four groups depending on type of grain used: 1) 13 Danyangju products with non-glutinous rice, 2) 14 products with waxy rice, 3) 4 products with mixture of waxy and nonwaxy rice, and 4) 2 products with barley. In this paper, not only ingredients, formula and utensils needed for preparation of Danyangju, but also brewing characteristics and terminology were reviewed. The findings on Danyangju in this study would be useful to improve the brewing methods and quality of Korean traditional liquors.

• Korean Journal of Food Science and Technology
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• v.27 no.5
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• pp.776-782
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• 1995

The effects of alum$(Al{\cdot}K(SO_4)_2{\cdot}12H_{2}O)$ on the rheological properties of $3{\sim}9%(w/v)$ gelatinized solutions of nonwaxy and waxy rice starches were investigated to evaluate the possibility of utilizing a starch modifying agent. Gelatinized non-waxy and waxy rice starch solutions showed a pseudoplastic flow behavior with yield stress. Pseudoplasticity of two rice starch solutions increased by the addition of alum$(0.05{\sim}1.0%,\;w/w)$. Alum increased the yield stresses and consistency indexes of two rice starches and these values decreased with increasing starch concentration. Also, alum(0.5%, w/w) increased the flow activation energy of gelatinized waxy rice starch solution and activation energy decreased with increasing waxy rice starch concentration in the range of $3{\sim}7%(w/v)$, but for the nonwaxy rice starch, activation energy decreased at starch concentration of 7%(w/v). From the above results, it was found that alum had the possibility of utilizing a modifying agent for the rheological property of gelatinized starch solution.

• Food Science and Preservation
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• v.16 no.2
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• pp.266-275
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• 2009

To develop new high-quality Yakchobugak, features of Lactococcus lactis-fermented waxy rice paste after addition of some colored powdered agro-food products were investigated. Total and reducing sugars of waxy rice paste fermented by lactic acid bacteria were higher than those of control raw waxy rice paste. Total acidity gradually increased as powder concentration rose, being 1.02-1.56% and 0.96-1.87% in samples fermented with Cucurbita maxima and Capsicum annuum powders, respectively; these values were 3-4 times those in rice fermented with other powders. Fermented waxy rice paste viscosities were lower than those of non-fermented samples. The viscosities of samples fermented with Curcuma longa and Opuntia ficus powders were in the range $100-160{\times}10^4$ centipoise($mPa{\cdot}s$), and those of pastes fermented with Robus coreanus and Camellia sinensis extracts were under $40{\times}10^4mPa{\cdot}s$. Hunter color lightness(L) values decreased and yellowness(b) values rose after fermentation. Waxy rice paste fermented with Robus coreanus showed uniform particle size distribution, and many pores, by scanning electron micrography.

• Korean Journal of Food Science and Technology
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• v.51 no.3
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• pp.214-220
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• 2019

Four rice varieties (Boseogchal for waxy, Baegjinju for medium-waxy, and Seolgaeng and Haiami for non-waxy) were milled to 2% degree of milling (DOM), and physicochemical and sensory properties of 2% milled rice (2% MR) were compared to those of brown rice (BR). No significant differences in the approximate compositions of BR and 2% MR were observed, whereas the grain color of 2% MR was slightly brighter than that of BR. For all varieties, water absorption ratio of BR was significantly increased by milling. The pasting properties of rice varied significantly depending on the variety, but there was no significant difference in peak and through viscosities between BR and 2% MR. Analysis of the texture of cooked rice showed that milling to 2% DOM caused a significant decrease in hardness, but an increase in adhesiveness and stickiness. Cooked Seolgaeng 2% MR scored significantly higher in the sensory evaluation than the corresponding BR. These results suggest that 2% DOM would be useful for improving the sensory properties of cooked non-waxy rice.

• Korean journal of food and cookery science
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• v.29 no.1
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• pp.29-36
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• 2013

The present study was conducted to supply more scientific information for standardization of preparation method of Gyungdan and to determine the standard for manufacturing procedure adapted with mechanically impacting technology (MIT) for mass production. The optimum preparation condition for non-waxy Gyungdan adapted with MIT was 35% of water, 0.5% of wheat flour (w/w of soaked rice), and mechanically impacting for 10 min at 450 rpm. In the present study, standardization of manufacturing procedure for merchandizing of Gyungdan was established with width, weight, and height. Average of Gyungdan adapted with MIT at 90 rpm (stuffing speed) and 46.58 Herz (cutting speed) is 18.3 g of weight, 28.4 mm of height, and 32.4 mm of width. Hardness, as a main parameter of texture profile, of Gyungdan was maintained lower than 100 g up to 3 days at the storage of $20^{\circ}C$ and up to 70 days at the storage of $-20^{\circ}C$. And, it was performed to develop rice cake as meal-replacement adapted with MIT and sub-ingredients such as strawberry, pumpkin, and mugwort. Gyungdan prepared under controlling manufacturing condition of MIT was supplemented with 0-1.6% of sub-ingredients, respectively. In sensory tests, the best substitute ratios of strawberry, pumpkin, and mugwort were 1.6%, 0.8%, and 1.6%, respectively. With the results above, not-harden Gyungdan supplemented with sub-ingredients and various stuffs can be expected to application for wheat-substitute meal-replacement.

• Korean journal of food and cookery science
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• v.12 no.2
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• pp.186-192
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• 1996

Retrogradation of non-waxy rice (NWR) and waxy rice (WR) cakes (45% moisture) stored at 5$^{\circ}C$, $25^{\circ}C$ and -2$0^{\circ}C$ was studied by differential scanning calorimetry (DSC) and enzymatic ($\beta$-amylase-puuulanase) method. With DSC, endotherms did not appear with rice cakes stored at room ($25^{\circ}C$) and deep freezing (-2$0^{\circ}C$) temperatures but did with samples stored at low temperature (5$^{\circ}C$), showing accelerated retrogradation by low temperature. Onset temperature (To) and peak temperature (Tp) did not change under 14 days at 5$^{\circ}C$ but enthalpy values ($\Delta$H) increased rapidly within one day and increased steadily until 5th day of storage, then equilibrated. Higher $\Delta$H were obtained with WR cakes than NWR cakes. It was suggested that more amylopectin recrystallization occured with WR than NWR. Degrees of gelatinization of rice cakes determined by enzymatic method increased in the following order: 5$^{\circ}C$ < $25^{\circ}C$ < -2$0^{\circ}C$. In contrast with DSC results, dogrees of gelatinization of NWR cakes, were relatively lower than that of WR cakes. However, increased retrogradation extents (melting enthalpies) caused reduced enzyme susceptibilities to $\beta$-amylase-pullulanase system, among NWR or WR cakes stored at 5$^{\circ}C$. The degrees of retrogradation of rice cakes stored at 5$^{\circ}C$ were higher than those stored at $25^{\circ}C$ and -2$0^{\circ}C$ without regard to the kind of rice. The higher sensitivity of the enzymatic method was obtained than that of DSC method when the degrees of retrogradation of rice cakes were determined during storage under this experiment conditions.