• Korean Journal of Food Science and Technology
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• v.34 no.4
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• pp.610-616
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• 2002

In order to improve a complicated Cheongju manufacturing process, saccharification process with gelatinized rice flour was employed during a Cheongju fermentation. High sugar content without unsaccharified residue appeared to impede the yeast growth and fermentation. To solve this problem, addition of zeolite to the saccharifying solution containing 20% (w/v) sugar and fed-batch system were employed. These adjustments resulted in a increase of yeast viability and 40% time-saving alterations of fermentation. The Cheongju, having 18% (v/v) of ethanol content and fresh and rich flavor, could be made in 12 days. Yeast cells recovered from the fermentation precipitates could be reused up to four times without any adverse effect on cell viability, alcohol production, and flavor of the product. The complicated conventional brewing process of Cheongju can thus be simplified effectively.

• Korean Journal of Food Science and Technology
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• v.16 no.1
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• pp.11-16
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• 1984

Rheological properties of waxy and non-waxy rice starch solutions were evaluated with a narrow gap rotational and Cannon Fenske viscometers. The gelatinized rice starch solutions containing 0.2-1.0% starch displayed pseudoplastic flow behavior. At higher starch level, degree of pseudoplasticity of waxy rice starch solutions increased, while that of non-waxy rice did not changed apparently. The consistency coefficient (K) of non-waxy rice starch solutions increased with increasing gelatinization temperature, but waxy rice starch solutions remained constant, and in alkaline aqueous solutions both of them showed increasing K values. The value of K increased exponentially with an increase in concentration. The effect of the temperature on the viscosity of the solutions followed Arrhenius' type equation, and the activation energies were in the range of 3.675-3.775 kcal/g-mol that were near to that of pure water. The changes of reduced viscosity with concentration were followed Huggin's equation and the values of intrinsic viscosity and interaction coefficient were 0.78-1.59 dl/g and 0.67-2.75, respectively.

• Korean Journal of Food Science and Technology
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• v.20 no.4
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• pp.470-475
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• 1988

The extrusion-cooking method was used to make gelatinized rice extrudate from rice grits of the Chuchung and the Samgang varieties. The water contents of raw rice grits varied from 15% to 25%, and the physicochemical properties of extrudates were evaluated. Low moisture content showed high expansion ratio in rice extrudate and resulted in some decrease in gelatinization, bulk density and break strength. Increasing the water content to 25% resulted in increase in water absoption index but decrease in water solubility index. With regards to Brabender Amylograph values and rheological patterns, higher moisture content in raw materials revealed stronger pseudoplastic flow behavior with lower viscogram property. Hunter's color values of rice flours extruded at low water content were low in b values. Scanning electron microscopy demonstrated the break-down of starch granules during extrusion.

• Korean journal of food and cookery science
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• v.12 no.1
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• pp.46-53
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• 1996

To investigate physicochemical and cooking properties of parboiled rice, choochung paddy processed to parboiled rice by three methods (PL, PT, PA) milled and examined hydration, cooking qualities and firming rate of cooked parboiled rice. The results were obtained as follows. The longer the steaming time during parboiling the larger EMC of soaked parboiled rice. Water uptake rate constants (k) of all the parboiled rice during soaking except for PT rice were generally increased than those of raw rice. The longer the steaming time during parboiling the greater volume increase rate constants ( $k_{v}$) of parboiled rice samples. The glelatinization temperature of parboiled rice flour by DSC was more increased than that of raw rice flour. Gelatinized entalpy was decreased and gelatinization content (%SG: degree of starch gelatinization) was increased by parboiling process. In cooking tests, parboiled rices were harder than raw rice and softness (reciprocal of hardness) was greater PT30, PA, PL30 in turns the cooking time of the parboiled rice took longer 3-10 min than that of raw rice, PL30 took longer time than anyother rices. Cooking water of parboiled rices could be observed lighter turbidities than that of raw rice. Firming rate constants of cooked rice during storage 24 hours were generally decreased by parboiling-processing. The time constants, reciprocal of firming constants of cooked PL30 rice were 2 times slower than those of cooked raw rice.e.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.6
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• pp.834-841
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• 2020

Laver Pyropia sp. is the most exported seafood in Korea and is one of the most consumed edible seaweeds. The export of laver has been centered on seasoned laver products; of note, laver snack products coupled with rice papers or glutinous rice paste are becoming more popular in Western countries. These laver snacks are manufactured using a deep frying process. Therefore, the frying conditions affect the physicochemical and sensory characteristics of fried laver snacks. In this study, we optimized the deep-frying conditions for laver snacks with gelatinized rice dough using a response surface methodology. The frying temperature (X1, 190-220℃) and frying time (X2, 10-30 sec) were selected as independent variables; the dependent variables were the overall acceptance (Y1, points), hardness (Y2, N), and oil content (Y3, %). The optimal values of the frying temperature (X1) and time (X2) as per the overall acceptance (Y1) were 208℃ and 23.1 sec, respectively. The predicted overall acceptance (Y1=8.0 points), hardness (Y2=98.74N), and oil content (Y3=27.69%), were similar to the experimental values under the optimal conditions. Overall, the acceptance was inversely proportional to hardness; the decrease in hardness caused an increase in the crispiness of the laver snacks.

• Culinary science and hospitality research
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• v.23 no.3
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• pp.137-146
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• 2017

This study was conducted to examine the sensory quality characteristics of Hobakjook (pumpkin porridge) samples prepared with 0%, 4%, 8%, 12%, 16% of waxy rice powder and non-waxy rice powder. The moisture content and spreadability decreased with the addition of waxy and non-waxy rice powder, while total soluble solid and viscosity increased with the addition of rice powder (p<0.001). The lightness (L-values) of Hobakjook significantly increased with the addition of both rice powder, but the yellowness (b-values) decreased. In the attribute difference test of sensory evaluation, yellowness, gloss, pumpkin flavor, sourness, smoothness and intensity of after-taste were amount-dependently decreased with the addition of both rice powders. However, sweetness, savory flavor, astringency, gelatinized rice flavor, and viscosity significantly increased as the amount of rice powder increased. The rankings of overall acceptance by consumers were 12% > 16% > 8% > CON (0%) & 4% for Hobakjook samples with waxy rice powder, while 8% & 12% > 16% > CON(0%) & 4% for Hobakjook samples with non-waxy rice powder. However, there was no significant preference between waxy rice powder and non-waxy rice powder.

• Applied Biological Chemistry
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• v.27 no.3
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• pp.198-203
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• 1984

Ethanol fermentation of chemically gelatinized starch and uncooked raw starch was nested with various starchy materials. Starches were gelatinized by 5.4% NaOH and neutralized by sulfuric acid. The patterns of $CO_2$ evolving and the ethanol yield for the chemically gelatinized starch resemble those obtained with thermally gelatinized starch. The alcoholic fermentation of raw starch was carried out by the simultanous saccharification-fermentation using a commercial glucoamylase and yeast. Ethanol yield from uncooked rice starch fermentation was highly comparable to that from cooked one. $CO_2$ evolving rates of the uncooked starches of corn, barley, tapioca and sweet potato were lower than those of the cooked starches. However, the final ethanol yields were similar or slightly lower, depending on the types of starch.

• Korean journal of food and cookery science
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• v.23 no.3 s.99
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• pp.314-320
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• 2007

The objective of this study was to investigate the effect of grain size on the physicochemical properties of rice porridge. Here, the grain size of the rice was classified as whole grain, half grain, and flour by traditional Korean cooking methods. The viscosity of the rice flour porridge was highest for the among the three different grain size porridges. In the amylographs, the increase in viscosity for the whole grain porridge was higher than that of the rice flour porridge during cooling. The soluble solid and reducing sugar contents of the rice porridges increased according to the rice grain size, while the blue value decreased. The SDI (starch digestion index) increased according to the rice grain size. The RDS (rapidly digestible starch) was highest while the SDS (slowly digestible starch) the lowest in the rice flour porridge. The morphologies of the rice porridges were examined by SEM and showed a smoother surface and more exudated gelatinized granules in the rice flour than in the whole grain rice porridge. In conclusion, rice porridges made from the smallest possible grain size such as flour may be helpful for people with weaker digestive systems such as infants, the elderly, and hospital patients.

• Korean journal of food and cookery science
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• v.13 no.4
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• pp.384-389
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• 1997

Attempts were made to improve gelatinization, saccharification and panfrying processes for mass production of Nochi, a kind of traditional Korean rice cake. Gelatinization of waxy rice powder with 20-55% of moisture content were completed within a minute at 120$^{\circ}C$ or above by using the extrusion cooker. Among enzymes tested for liquefaction and saccharification of the gelatinized rice, in place of malt, BAN (0.53%)+${\beta}$-amlyase (4.27%) was the most suitable enzymes for the production of Nochi. Panfrying process of Nochi was drastically shortened by heating Nochi dough for 1 minute in a microwave oven and subsequently panfrying at 150$^{\circ}C$ for 7 minutes.

• Applied Biological Chemistry
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• v.28 no.2
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• pp.106-109
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• 1985

Gelatinization of Japonica(30 varieties) and J/Indica(22 varieties) rice flours in 0.2N NaOH was examined. J/Indica rice flours were easily gelatinized and showed higher viscosities at all reference points than Japonica counterparts. Viscosity development rate was not correlated with protein or amylose content. Only J/Indica rice varieties showed positive correlation between hydration rate and viscosity development rate.