• Korean Journal of Food Science and Technology
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• v.32 no.6
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• pp.1291-1297
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• 2000

Particle size distribution, pasting properties by Rapid Visco Analyser, and textural properties of acorn, mungbean and buckwheat starches, which are the basic raw materials for mook, are compared. The major particle size of mungbean starch was $10{\sim}30$ micron, whereas acorn and buckwheat starches were $5{\sim}20$ micron. At the same starch concentration, mungbean starch had the highest peak viscosity, breakdown and setback. Acorn starch showed the lowest peak viscosity and breakdown. The peak viscosity of buckwheat starch was close to that of mungbean, however the trough and final viscosity were comparable to those of acorn starch. At the same peak viscosity, mungbean starch showed the lowest trough and final viscosity and the highest breakdown and setback. Acorn starch was differentiated from buckwheat starch in that the former had the higher value of setback. The textural properties of mungbean starch gel were significantly different from others. The texture of gels from acorn and buckwheat starches revealed that only the hardness and gumminess were different each other. The hardness of starch gels were negatively correlated with trough and final viscosity, and positively correlated with setback.

• Korean Journal of Food Science and Technology
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• v.28 no.1
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• pp.58-65
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• 1996

The effects of sodium carbonate (Na), potassuim carbonate (K) and their mixtures (Na/K=0.7-2.0) on pasting properties by amylograph and mixing properties by farinograph of wheat flour (9.45% protein), and of alkali mixtures (0.16%) on noodle property were examined. The concentrations of alkali used were 0.08%, 0.10% and 0.16% based on flour weight (14% mb). The salt (1.7%) and alkali decreased the initial pasting temperature but increased the amylograph peak viscosity. The peak viscosity increased with the increase of alkali concentration, but the mixing ratio at a fixed concentration had no effect on peak viscosity. The farinograph absorption decreased by salt, but the effect of salt diminished in the presence of alkali. The salt and alkali increased the farinograph stability, of which the former was more pronounced. The effect of alkali alone and mixtures in the presence of salt on amylograph and farinograph were essentially the same regardless the concentrations and mixing ratios. The yellowness and breaking force of dry noodle prepared with salt and alkali was higher than that prepared with salt only. The weight and volume gain of the optimum cooked noodle remained essentially constant, but the shear force and compression force were increased by the alkali.

• Korean Journal of Food Science and Technology
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• v.50 no.2
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• pp.191-197
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• 2018

This study investigated the influence of starch extraction (ST-EX) solutions on the extraction yield and characteristics of Chinese yam (CY) starches from domestic Dioscorea batatas. Ascorbic acid (VitC), $Na_2S_2O_3$, $NaHCO_3$, and $Na_2CO_3$ were used as ST-EX solutions (0.4%, w/v). The extracted CY starches were examined for ST-EX yield, chemical composition, size distribution, X-ray diffraction, solubility, swelling power, gelatinization, and pasting viscosity. The highest ST-EX yield was obtained from $NaHCO_3$, followed by VitC. Lower protein content, relative crystallinity, and gelatinization enthalpy were found in CY starches from alkaline ST-EX solutions ($NaHCO_3$ and $Na_2CO_3$). Size distribution and gelatinization temperature did not generally differ for CY starches from the different ST-EX solutions. Pasting viscosities increased in the order from $Na_2CO_3$ > $Na_2S_2O_3$ > $NaHCO_3$ > VitC ST-EX solutions. Thus, VitC may be most appropriate to extract CY starch from Dioscorea rhizomes, considering its ST-EX yield, total starch content, and variation in pasting viscosity.

• Food Science and Biotechnology
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• v.17 no.2
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• pp.234-240
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• 2008

The optimal conditions for the production of branched dextrin from com starch (CSBD) using branching enzyme (BE) were established by investigating the degree of retrogradation of the gelatinized starch. The physicochemical properties of CSBD prepared using the established process were evaluated. It was found that physicochemical properties of com starch were greatly modified by BE treatment. CSBD had a higher dextrose-equivalent value and water solubility than the corresponding control. On the other hand, the viscosities in gelatinized solution and amylose contents of CSBD were lower than those of the control. A high-performance size-exclusion chromatography/multiangle laser light scattering/retractive index (HPSEC/MALLS/RI) system showed that the average molecular weight of CSBD was lower than that of the control. The pasting viscosities of CSBD were stable during the entire temperature cycle. In general, the BE treatment resulted in the retrogradation during storage being lower for CSBD than for the control.

• Journal of the East Asian Society of Dietary Life
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• v.25 no.3
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• pp.440-450
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• 2015

Effects of Doenjang and Chunggukjang on rheological properties of bread flour were investigated based on falling number, RVA, farinogram, colorimeter, rheofermentometer and SEM. The falling number of bread flour was highest among all samples, and mixed flours containing Chunggukjang showed lower falling number than Doenjang. RVA showed that initial pasting temperatures of the control mixed flour of Doenjang and Chunggukjang increased sequentially, whereas peak viscosities were reversed and final viscosities showed similar results. In the farinogram, consistencies and water absorptions decreased with increasing quantity of Doenjang and Chunggukjang. Developments, stabilities, time to breakdowns and farinogram quality numbers of the mixed flour containing Doenjang were higher than those of Chunggukjang and greater addition decreased values. In the rheofermentometer test, height of maximum dough development of mixed flours containing Chunggukjang were lower than that of flours containing Doenjang. Total volumes, retention volumes and retention coefficients of mixed flours containing Doenjang and Chunggukjang were lower compared to the control. For features, SEM showed that mixed flour containing Chunggukjang showed a faded boundary compared to flour containing Doenjang. All of results showed that the various activities of Chunggukjang were more potent than those of Doenjang.

• Korean journal of food and cookery science
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• v.32 no.5
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• pp.531-540
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• 2016

Purpose: To improve the cooking quality of brown rice, newly inbred soft rice cultivars were investigated. Methods: The physicochemical properties of brown rice flour and water absorption patterns and cooking characteristics of brown rice grain were compared to Ilmi white and brown rice. Results: General composition and total dietary fiber contents of five rices were significantly different with higher ash, protein, and total dietary fiber contents in soft brown rice than white rice. The hardness of raw rice grain was higher in Ilmi brown rice than in soft brown rice. The water absorption increased rapidly in 30 min of white rice and in 4-6 h of brown rices. The apparent amylose content of soft brown rice was lower than that of Ilmi rice. The initial pasting temperature and all viscosities were significantly different, but the trend was not similar. The textural properties of hardness and roughness were higher, but adhesiveness, cohesiveness, and stickiness were lower in Ilmi brown rice than white and soft brown rices. In sensory preference test, not only textural properties, hardness, adhesiveness, cohesiveness, stickiness, and roughness, but also color, glossiness, and roasted flavor were higher in soft brown rices. Especially soft brown rice B showed the best cooking quality among all rices. Conclusion: The results of the study suggested that soft brown rice is developed for cooking with high nutritional and functional quality.

• Food Science and Biotechnology
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• v.16 no.5
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• pp.759-764
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• 2007

To investigate the effect of soaking and particle sizes on the properties of rice flour and gluten-free rice bread, wet-milled (WRF, dried at $20^{\circ}C$) and dry-milled rice flours (DRF) were passed through sieves (45 or 100 mesh). Soaking of the rice grains affected the particle size distribution of flour passed through the same size screen. The L and b values of WRF were higher than those of DRF and were not changed with decreasing particle sizes, but DRF increased L and decreased b values. The initial pasting temperatures and setback viscosities of both flours decreased with decreasing particle sizes. The swelling powers at $100^{\circ}C$ increased with decreasing particle sizes in DRF, but maintained in WRF. Starch granules were observed on the surface of flour particles in WRF. The apparent viscosity of WRF paste exhibited 3-5 times higher than that of DRF. Thus, wet milled rice flour with smaller particle sizes (${\phi}<150\;{\mu}m$) showed better properties for making gluten-free rice bread.

• Journal of Applied Biological Chemistry
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• v.50 no.4
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• pp.234-238
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• 2007

The effects of ultra-fine pulverization on the physicochemical properties of rice starch (RS) were investigated using a high impact planetary mill. After pulverization, RVA characteristics, peak viscosity, break down, and set back values of RS decreased from 274.75 to 9.42 RVU, 214.46 to 6.17 RVU, and 87.80 to 17.00 RVU, respectively. The pasting properties also changed significantly. X-Ray diffractogram revealed RS had four A-type peaks, which disappeared after pulverization. The peak temperature and gelatinization enthalpy of RS using differential scanning calorimetry (DSC) were 13.99 J/g at $75.14^{\circ}C$, whereas the pulverized RS (PRS) had two peaks, 0.13 J/g at $63.88^{\circ}C$ and 1.23 J/g at $101.24^{\circ}C$. DSC measurement showed the retrogradation degree of PRS was lower than that of RS after storage at 4 and $25^{\circ}C$. The enzymatic (${\alpha}$-amylase) digestibilities of RS and PRS were 72.7 and 77.3%, respectively.

• Food Science and Biotechnology
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• v.16 no.6
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• pp.902-909
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• 2007

Granular maize starch was treated with Thermus scotoductus 4-${\alpha}$-glucanotransferase (${\alpha}$-GTase), and its physicochemical properties were determined. The gelatinization and pasting temperatures of ${\alpha}$-GTase-modified starch were decreased by higher enzyme concentrations. ${\alpha}$-GTase treatment lowered the peak, setback, and [mal viscosity of the starch. At a higher level of enzyme treatment, the melting peak of the amylose-lipid complex was undetectable on the DSC thermogram. Also, ${\alpha}$-GTase-modified starch showed a slower retrogradation rate. The enzyme treatment changed the dynamic rheological properties of the starch, leading to decreases in its elastic (G') and viscous (G") moduli. ${\alpha}$-GTase-modified starch showed more liquid-like characteristics, whereas normal maize starch was more elastic and solid-like. Gel permeation chromatography of modified starch showed that amylose was degraded, and a low molecular-weight fraction with $M_w$ of $1.1{\times}10^5$ was produced. Branch chain-length (BCL) distribution of modified starch showed increases in BCL (DP>20), which could result from the glucans degraded from amylose molecules transferred to the branch chains of amylopectin by inter-/intra-molecular transglycosylation of ${\alpha}$-GTase. These new physicochemical functionalities of the modified starch produced by ${\alpha}$-GTase treatment are applicable to starch-based products in various industries.

• Korean journal of food and cookery science
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• v.31 no.6
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• pp.696-702
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• 2015

Rice dumpling shells were prepared with different levels of hydrocolloids, such as hydroxypropyl methyl cellulose (HPMC), and potato starch. After steaming, the physical, sensory, and cooking properties of the shells were measured. Increasing the amount of potato starch decreased the pasting temperature and increased the peak viscosity. With the addition of hydrocolloids, water absorption and cooking loss for the rice dumpling shells decreased significantly. For the textural properties, the rice dumpling shells with hydrocolloids showed lower hardness and higher springiness than the control, and especially, 10% potato starch and 3% HPMC addition (P10H3) improved the texture of the rice dumpling shells the most. The sensory results seemed to be affected more by the addition of potato starch than HPMC, and over 15% addition of potato starch significantly decreased the quality of the rice dumpling shells. By addition of adequate amount of hydrocolloids (3% HPMC and 10% potato starch), the sensory quality of rice dumpling shells can be effectively improved.