• Korean journal of food and cookery science
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• v.17 no.4
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• pp.309-315
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• 2001

The effects of soaking time of nonwaxy rice and particle size of rice flour on the properties of nonwaxy rice flour after steeping at room temperature were investigated. Nonwaxy rice was soaked at 20$^{\circ}C$ for 0, 1, 12, or 24hr, dried at room temperature and milled. Nonwaxy rice flours were passed through 45 mesh or 100 mesh sieve, and were compared for the properties depending on the particle size and soaking time. The particles of rice flour were separated into 10$\mu\textrm{m}$∼30$\mu\textrm{m}$ and 40$\mu\textrm{m}$∼80$\mu\textrm{m}$ groups, and the amount of large particle size(40$\mu\textrm{m}$∼80$\mu\textrm{m}$) was greater in the flour sieved through 45 mesh than 100 mesh sieve. The protein and ash contents decreased and amylose contents increased as the soaking time increased. The water-binding capacity increased rapidly up to 1 hr of soaking and increased slowly thereafter. The swelling power and the solubility increased with temperature rising in the range of 65$^{\circ}C$∼95$^{\circ}C$, and these two properties increased rapidly up to 12 hr of soaking. Peak viscosity and breakdown of the pastes prepared with 12 hr-soaked nonwaxy rice flour were higher than those with 1 hr-soaked ones, while the setback and viscosity at 95$^{\circ}C$ of 12 hr-soaked ones were lower than 1hr-soaked ones.

• Korean Journal of Food Science and Technology
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• v.39 no.5
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• pp.534-540
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• 2007

In this study, waxy rice starch was chemically modified using phosphorous oxychloride ($POCl_3$, 0.002-0.008%). Then the physicochemical properties of resulting cross-linked waxy rice starches were investigated in order to reduce the steeping time of Yukwa (a Korean oil-puffed rice snack) processing. The swelling powers of the cross-linked waxy rice starch samples were higher than the native waxy rice starch at temperatures above $60^{\circ}C$, and their increases were proportional to the $POCl_3$, concentration. The solubility of the cross-linked waxy rice starch was lower (1.6-3.4%) than the native waxy rice starch (2.7-6.1%). However, the moisture sorption isotherm of the cross-linked waxy rice starch was not significantly different from the native waxy rice starch. The rapid visco analyze. (RVA) pasting temperatures $(65.4-67^{\circ}C)$ of the cross-linked waxy rice starch were lower than those of the native starch $(67^{\circ}C)$. The RVA peak viscosities (287-337 RVU) of the cross-linked waxy rice starch were higher than that of native starch (179 rapid visco units (RVU)), and increased with increasing $POCl_3$ concentration. For the differential scornning calorimeter thermal characteristics, although Tc shifted toward higher temperatures with cross-linking, the To, Tp, and amylopectiin melting enthalpy of the cross-linked waxy rice starch showed no differences compared to the native waxy rice starch. The X-ray diffraction patterns of both the native and cross-linked waxy rice starches showed typical A-type crystal patterns, suggesting that cross-linking mainly occurs in the amorphous regions of starch granules. Therefore, the cross-linking reaction did not change the crystalline region, but altered the amorphous region of the waxy rice starch molecules, resulting in changes of solubility and RVA pasting properties in the cross-linked waxy rice starch. In summary, since cross-linked waxy rice starch has a high puffing efficiency and no browning reaction, it may be applicable for Yukwa processing without a long steeping process.

• Journal of the East Asian Society of Dietary Life
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• v.26 no.5
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• pp.457-465
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• 2016

Effects of soaking time on the physicochemical and structural characteristics of waxy rice flours and starches purified from flours using the alkaline steeping method were investigated. Korean cultivar Sinseonchal waxy rice was washed and soaked in tap water (1:2 w/w) and stored at room temperature for 15 days. On each day of soaking for 0, 1,2 3, 5, 10, and 15 days, pH of soaking water was measured and rice grains were dried, ground, and passed through 100 mesh sieve. The pH was reduced to 3.90 by day 5 and increased to 4.60 by day 15. The protein and ash contents, swelling powers and solubilities of flours and starches decreased with increasing soaking time. The water-binding capacities increased while trends were not similar to soaking time. The flour particle size distribution ranged from two to four peaks with increasing soaking times. Starch granule size decreased with increasing soaking time. The peak, trough, and final viscosities of flours and starches showed similar trends until 10 days and 15 days, respectively. The starches presented higher viscosities than the flours. The branch chain length distributions of amylopectin of starches showed an increaseed DP6~12 portion and decreased DP13~24 portion with increasing soaking time of waxy rice grains.

• Food Engineering Progress
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• v.23 no.4
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• pp.290-296
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• 2019

Rice in Korea is a highly valuable food resource that serves both as staple food and ingredient in various processed edibles. This study was conducted to explore pre-treatment methods for rice that result in good saccharification upon production of rice beer. When rice was subjected to fine grinding, steeping, roasting, gelatinizing, or puffing prior to saccharification with malt, wort containing puffed rice had the highest soluble solid content (°Bx). Upon production of wort without the addition of any enzymes for liquefaction or saccharification, the addition of 30% rice resulted in the highest soluble solid content (°Bx). Production of beer containing 10, 20, or 30% of either roasted or puffed rice showed that wort containing 30% puffed rice had the highest soluble solid content (15.4 °Bx) with good saccharification. The resulting beer likewise exhibited higher alcohol content (5.0-5.4%) than the beer that had roasted rice added, without the turbidity and with less bitterness. Therefore, rice puffing was considered a beneficial processing method to enhance rice saccharification and to facilitate both the production of fine quality beers and rice beer containing puffed rice.

• Korean Journal of Food Science and Technology
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• v.30 no.3
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• pp.562-568
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• 1998

Rice (Dongjin-byeo) added with black rices (Chindo and Suwon-415) was cooked and the changes of texture and color of this cooked rice were investigated by texture analyser and color & color difference meter. The hydration time to come to the equilibrium condition was at least 11 hr in black rices. The optimum ratio of water to cooked rice added with black rice was 1.6 (ratio of water to rice) and the hardness of cooked rice added with 5% Chindo black rice was $5.66\;kg_f$. Regardless of ratio of water to rice, Hunter a value increased as the ratio of black rice addition to rice increased, while L value decreased. The color elution rate of Suwon 415 was 4 times greater than that of Chindo black rice. The pH of the steep water of Suwon 415 at $20^{\circ}C$ during 120 min decreased from pH 6.40 to pH 6.16 as the steeping time increased. The optimum heating time by microwave oven of cooked rice added with black rice was between $90{\sim}120\;sec$ to recover the original texture after cold storage treatment of 7 days.

• Journal of Applied Biological Chemistry
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• v.62 no.3
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• pp.219-228
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• 2019

This study summarized processing factor (PF) by the stage of rice and barley processing based on JMPR reports from 2006 to 2016. We compared PF of 17 pesticides in rice products during the processing of rice grain, husked rice, polished rice, hulls, bran and cooked rice. Among the 17 pesticides, 12 pesticides except for 5 pesticides such as acephate, methamidophos, glufosinate, quinclorac and sulfoxaflor mostly decreased in pesticides when rice grain processed into brown rice. Pesticides tended to be partially reduced when processed from husked rice to polished rice. However, hulls and bran produced during the milling process were concentrated. Acephate and others, 5 pesticides are systemic pesticides, and pesticides are penetrated into foods, and a large amount of pesticides was not removed during the milling process. The remaining pesticide residues in polished rice were mostly removed after processing into cooked rice, and trace amounts of pesticide residues remained. In the comparison of 23 pesticides PF during the processing of barley products (pearl barley, flour, short, malt, beer, hulls and bran). Most of the pesticide except for 4 pesticide (ethephon, pyraclostrobin, penthiopyrad, sulfoxaflor), which are systemic pesticides, decreased during the process of pearl barley production out of the barley grain. The pesticide in the malt, which was made by steeping pearl barley was concentrated but when processed into beer, pesticide was remained only in trace amounts.

• 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.

• Food Science and Biotechnology
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• v.16 no.6
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• pp.943-947
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• 2007

The acid modification of waxy rice starch was conducted to improve the yugwa production process. The intrinsic viscosity, paste viscosity, and differential scanning calorimetry characteristics of acid modified starch were measured, and bandaegi and yugwa prepared from acid modified starch were evaluated. The intrinsic viscosities of acid thinned starches were 1.48, 1.27, 1.15, and 0.91 mL/g after reaction times of 1, 2, 3, and 4 hr, respectively. The gelatinization enthalpy was reduced from 16.3 J/g in native starch to 15.8, 15.3, 14.7, and 14.5 J/g in acid thinned starches as the time of acid thinning increased. The peak viscosity and final viscosity decreased with increasing the time of acid thinning, but the pasting temperature was slightly increased in acid thinned starches. The hardness of bandaegi from acid thinned starches under high pressure greatly decreased relative to the control, typical yugwa. Yugwa from acid thinned starch under high pressure maintained a homogeneous structure containing tiny and uniform cells similar to that of native waxy rice starch used for typical yugwa. Acid thinning under high pressure appears to be a good alternative to the existing steeping process for better yugwa quality.

• Korean Journal of Food Science and Technology
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• v.38 no.3
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• pp.385-391
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• 2006

Physicochemical properties of hydroxypropylated waxy rice starches were investigated to reduce steeping-time of yukwa (Korean oil-puffed rice snack) processing. Swelling power of hydroxypropylated waxy rice starch increased at relatively higher temperature $(60^{\circ}C)$ than native waxy rice starch $(70^{\circ}C)$. Solubility of hydroxypropylated waxy rice starches increased with increasing propylene oxide content. Pasting temperature $(66.3-66.9^{\circ}C)$ and peak viscosity (216-232 RVU) of hydroxypropylated waxy rice starch were higher than those of native starch (179 RVU) and increased with increasing propylene oxide content. DSC thermal transitions of hydroxypropylated waxy rice starches shifted toward higher temperature. Amylopectin melting enthalpy of hydroxypropylated waxy rice starch (8.4-9.2 J/g) was similar to native starch (9.0 J/g). X-ray diffraction patterns of native and hydroxypropylated waxy rice starches showed typical A-type pattern with no significant differences between them, suggesting hydroxypropylation only affected amorphous region. Results suggest hydroxypropylated waxy rice starch is not applicable for yukwa due to low puffing efficiency and dark color.

• Food Science and Preservation
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• v.14 no.3
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• pp.276-280
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• 2007

This study investigated the physicochemical properties of traditional Olbyeossal(Korean-style parboiled waxy rice) and other rices(dried cooked rice, germinated brown rice, and waxy brown rice). Olbyeossal had a moisture content of 12.7% a crude fat level of 1.0%, a crude ash content of 0.9%, and a crude protein value of 6.3%. The color values were 58.63(L value), 0.83(a value) and 21.73(b value). The water adsorption index(WAI) of Olbyeossal was 6.2g/g after 40 min steeping at room temperature, which was much higher than the WAI of the other rices. The hardness of Olbyeossal(10.5 kgf) was higher than those of other rices($7.5{\sim}8.9$ kgf). The initial pasting temperatures of Olbyeossal, dried cooked rice(DCR), germinated brown rice(GBR) and waxy brown rice(WBR) were $39.5^{\circ}C,\;43.5^{\circ}C,\;65.0^{\circ}C,\;and\;64.5^{\circ}C$, respectively. The breakdown and total setback viscosities of Olbyeossal(70 B.U., 50 B.U.) and WBR(10 B.U., 30 B.U.) were lower than those of DCR(120 B.U., 275 B.U.) and GBR(142 B.U., 340 B.U.).