• Food Engineering Progress
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• v.15 no.4
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• pp.332-337
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• 2011

Physicochemical properties of hydroxypropylated and cross-linked (HPCL) rice starch were investigated. Dual modification of rice starch was carried out by hydroxypropylation using propylene oxide (2, 6, and 12%) and then crosslinking using phosphorus oxychloride (0.005% and 0.02%). Swelling power of dual-modified rice starch increased at lower temperature (60$^{\circ}C$) than that of native rice starch (70$^{\circ}C$). HPCL rice starch showed slightly lower solubility (1.6-6.1%) than native rice starch (2.2-13.8%). Solubility and swelling power tended to gradually increase with increasing phosphorus oxychloride contents. RVA pasting temperature (66.2-70.8$^{\circ}C$) and peak viscosity (160.6- 171.1 RVU) of HPCL rice starch were lower than that of those of native starch (71.3$^{\circ}C$, 190.4 RVU) and decreased with increasing propylene oxide concentration. DSC thermal transitions of HPCL rice starches shifted to lower temperature and show less amylopectin melting enthalpy (11.8-9.8 J/g) than that of native rice starch (11.9 J/g). Overall, physicohemical properties of HPCL rice starches were highly dependent on hydroxypropylation rather than crosslinking.

• Korean Journal of Food Science and Technology
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• v.53 no.6
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• pp.749-755
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• 2021

The objective of this study was to investigate the physicochemical properties of rice starch extracted from stale rice using alkaline steeping (AKL) and improved enzymatic digestion (iENZ) methods. The crude protein content (0.5-0.7%) of stale rice starch (SRS) was less than 1% by iENZ, but not so when measured by the existing ENZ methods. SRS is an intermediate amylose rice starch. AKL-SRS and iENZ-SRS exhibited typical A-type crystal packing arrangements with similar relative crystallinities. iENZ-SRS showed higher gelatinization onset and peak temperatures with a narrower gelatinization temperature range, compared to those of AKL-SRS, indicating that iENZ annealed SRS. Thus, iENZ-SRS exhibited lower swelling power and solubility, and higher pasting viscosities with delayed viscosity development. Overall, the use of stale rice as a rice starch source could make economical production of rice starch possible, and iENZ may diversify rice starch characteristics, which expands the utilization of rice starch in food and non-food industries.

• Korean Journal of Food Science and Technology
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• v.53 no.6
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• pp.731-738
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• 2021

This study investigated the physicochemical properties of rice starch isolated from broken rice using alkaline steeping (AKL) and enzymatic digestion (ENZ) methods. Broken rice starch (BRS) by AKL and ENZ possessed crude protein contents (0.6-1.4%) acceptable to commercial products of native starch and belonged to an intermediate amylose rice starch. AKL-BRS and ENZ-BRS showed a typical A-type crystal packing arrangement with small variations in their relative crystallinity. ENZ-BRS exhibited higher gelatinization onset and peak temperatures, and a narrower gelatinization temperature range than AKL-BRS, indicating that annealing occurred in ENZ-BRS. Lower swelling power and solubility were generally observed in the ENZ-BRS. ENZ-BRS also showed slower viscosity development, higher peak and trough viscosities, and lower breakdown, final, and setback viscosities, compared to those in AKL-BRS. These results are ascribed to the annealing phenomenon in ENZ-BRS. Overall, BRS from cheap broken rice using AKL and ENZ could contribute to the expansion of rice starch utilization in food and non-food industries.

• Applied Biological Chemistry
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• v.41 no.6
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• pp.421-425
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• 1998

The amylograph pasting properties of flours $(9{\sim}12%,\;db)$ and starches $(7.5{\sim}9.0%\;db)$ of Korean rice cultivars indicated that the flour concentration to give a fixed peak viscosity was higher by 1.32 times compared with starch, regardless the maturity. Only at 12% flour concentration the peak viscosity and breakdown viscosity were differentiated among maturity groups, which suggested that flour may be better tool than starch in characterizing the maturity groups by pasting properties.

• Applied Biological Chemistry
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• v.29 no.1
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• pp.29-35
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• 1986

Viscosity development pattern, in aqueous sodium hydroxide, of rice starches isolated from various hydration groups of milled rice was investigated. The maximum viscosity and viscosity development rate of Japonica rice starches at a given alkali concentration were loswer than those of J/Indica counterparts. The difference in the viscosity development rate of starches by increment of 0.1N (0.02 meq/g) was greater in J/Indica rice starches in comparison with Japonica ones. Viscosity of rice starch was not correlated to that of rice flour and to hydration rate of milled rice.

• Korean Journal of Food Science and Technology
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• v.25 no.2
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• pp.123-129
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• 1993

Physico-chemical properties of the acetylated and raw starch were Investigated with the chucheongbyeo and samkangbyeo. The solubility and swelling power was increased by acylation reaction. The light transmittance was higher in the acetylated rice starch. The blue value of chucheongbyeo and samkangbyeo rice starches were lowered to 10.9% and 16.0%, respectively, by the acylation reaction. The alkali number was 7.6 in the chucheongbyeo rice starch and 7.2 in the samkangbyeo rice starch, whereas acylated starch in the same orders was 55 and 52, respectively. The hardness, adhesion, cohesion of starch gel was increased by the acylation reaction. The temperature of initial gelatinization of the acetylated chucheongbyeo and samkangbyeo rice starch was shown to $59^{\circ}C\;and\;62^{\circ}C$, respectively, lowering $5{\sim}6^{\circ}C$ in temperature by the acylation. The viscosity as well as by the acylation reaction was raised 38% and 14%, respectively. The rice starch particles were shown to plygonal structure. But it were deformed in the acylated starch, and was completely destroyed in the starch which is by gelatinized for 30 min. at $70^{\circ}C$.

• Food Science and Preservation
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• v.22 no.3
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• pp.353-360
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• 2015

Yakju, a Korean traditional alcoholic beverage, is made from rice and Nuruk. In this study, the fermentation characteristics of Yakju was investigated using rice and rice starch. Ingredients was classified into raw material (rice, rice starch) and starter (enzyme supplements, modified Nuruk, traditional Nuruk, and yellow rice koji) for fermentation. The crude protein content of rice, rice starch, and starter were determined as follows (%): rice 6.69, rice starch 0.44, enzyme supplements 7.84, modified Nuruk 15.29, traditional Nuruk 14.28, and yellow rice koji 7.28. The alcohol content of rice with traditional Nuruk ($20.13{\pm}0.12%$) was higher than other Yakju. The concentration of organic acids of rice starch-based Yakju (389.83~538.34 mg%) was higher than that of rice Yakju (259.27~357.70 mg%). The concentration of nitrogen compound of rice Yakju (498.38~5976.93 ppm) was higher than that of rice starch-based Yakju (600.43~4463.79 ppm). In line with these findings, further studies will be necessary for the quality analysis of the rice, rice starch and fermented starter (enzyme supplements, modified Nuruk, traditional Nuruk and yellow rice koji).

• Korean Journal of Food Science and Technology
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• v.27 no.5
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• pp.757-761
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• 1995

The relationship between the molecular structure of rice starch and the texture of cooked rice was investigated using hot-water soluble rice starch. The structure of hot-water soluble starch bound amylose which was composed of small molecular weight and amylopectin which was composed of chain length of $\overline{DP}\;10{\sim}20$, and the average composition of amylose : amylopectin was 7 : 3. The molecular weight of amylose was the smaller and super long chain of amylopectin was the fewer, the extractable ratio of hot-water soluble rice starch was the higher. And hot-water solubility of rice starch be responsible for molecular structure of starch. On the texture of cooked rice, the extractable ratio of hot-water soluble rice starch was the higher, the hardness was the lower and the adhesiveness was the higher. The results suggest that the molecular structure of rice starch could be responsible for the texture of cooked rice.

• Proceedings of the KAIS Fall Conference
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• 2010.11b
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• pp.1014-1016
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• 2010

우리나라 쌀 생산량은 해마다 증가되고 있으나, 1인당 쌀 소비량은 급격히 감소되고 있는 수급 불균형을 이루고 있다. 특히 충청남도는 최근 6년간 전국 쌀 생산량 1위를 차지해 오고 있어서 쌀 소비의 확대방안이 더욱 절실히 요구되고 있는 지역적 특성을 지니고 있다. 취반용 쌀 소비량 확대만으로는 쌀 소비량 증대에 한계점이 있으므로, 소비자의 요구에 맞는 고 기능성, 간편식으로 다양한 기호성을 지닌 쌀 가공식품 형태의 개발이 필요하게 되었다. 이러한 요구에 적합한 제품개발로 쌀을 이용한 쌀국수를 개발하고자 하였으며, 이러한 쌀국수 제품개발은 쌀을 이용한 제품개발은 또다른 시도가 되어 쌀 소비촉진이 향상될 것으로 기대된다. 기능성 쌀국수 개발을 위하여 천연물 중 연잎 소재를 첨가하였다. 연잎은 차와 사찰음식을 대표하는 소재중 하나이다. 연잎에는 비타민 C와 섬유소가 매우 풍부하다. 이러한 성분은 미용식품으로써의 응용이 가능하며, 식이 섬유소는 배변작용에도 도움이 될 수 있다. 또한 항산화제인 quercetin이 다량 함유되어 있다. 이 quercetin은 플라보이드 배당체이며, 우리 몸의 세포의 노화를 유발하는 유해 활성 산소를 제거하는 기능을 가지고 있다. 따라서 이러한 유해 활성산소를 억제하는 것이 항산화 활성이 높은 연잎을 이용하여 고 기능성 쌀가공품 제품 개발이 가능할 것으로 기대한다. 쌀가루 50%를 기준으로하여 연잎가루는 3% 첨가하였으며, 전분의 종류를 달리하여 최종 제품을 개발한 결과, texture analyser로 물성을 측정한 결과 타피오카 전분과 쌀가루 혼한 쌀국수의 물성이 좋은 결과를 나타내었다. 관능검사 결과도 타피오카 전분과 쌀가루 혼합 쌀국수가 소비자들의 기호도가 높은 선호도를 나타내었고, 감자전분과 밀가루는 다소 낮은 선호도를 나타내었다. 본 연구를 기초로 하여 쌀제품 개발시 쌀의 가공적성 및 기능성 소재의 첨가 비율 확립하고, 연잎과 같은 쌀국수에 첨가 가능한 다양한 기능성 소재 발굴 및 첨가 가능성을 제시하고자 하였다.

• Applied Biological Chemistry
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• v.33 no.1
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• pp.1-7
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• 1990

Starch samples of rice and glutinous rice starches were adjusted to 27 % of moisture and heated at $100^{\circ}C$ for 16 hours, respectively. After the treatment, their physicochemical properties were investigated. The granule shapes of all the starches were polygonal and they became slightly bigger in their sizes after the treatment. All their X-ray diffraction patterns were A types. The specific gravity of the starches decreased to 1.03-1.09 by the treatment. The water binding capacity of rice starches increased, while that of glutinous counterparts slightly decreased. Almost no change in the amount of amylose included was found. Swelling power and solubility were increased with the increase of temperature. At a certain temperature, however, the solubility of the treated starches increased when the swelling power decreased. The initial gelatinization temperatures of Akkibare, Yongmun, and Taebaek starches were $60{\sim}65^{\circ}C$ but those of glutinous rice starch and U.S.A. rice starch were $55{\sim}60^{\circ}C$ and $70{\sim}75^{\circ}C$, respectively, as measured by transmittance. The gelatinization temperature of the treated starches was higher than that of the untreated starches.