• 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.

• 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.

• Proceedings of the Korean Nutrition Society Conference
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• 1999.05b
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• pp.60-61
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• 1999

The present study examined optimal level of mulberry leave powder, and the method of bread-making were proposed to utilize mulbery leave powder by investigating rhelogical properties of dough and sensory evaluation of bread. The difference of amino acids compositions in flour brew were also investigated by fermentation of S. cerevisiae or bifidobacteria. As the % of mulberry leave powder increases absorption rate of dough was steadily increased, but stability and R!E ratio if dough were dramatically decreased more than 1% leave respectively. R!E ratio value, which indicates gas retnetion property of dough, was not obtained at the level 5%. Gelatinization temperature and maximum viscosity temperature showed a tentency of decrease, resulting in easier cooking of dough. The delay of temperature cauesd by addition of mulberry leave powder was overcome by two step bread making, that is, modified straight dough method adding flour brew fermented 16hrs by bifidobacteria. The firmness of bread was progressively dreased as the amount of mulbery leave powder increased. The addition of 2% level of mulberry powder to bread showed no significant difference comparing with control in sensery evaluation. Amino acids compositions of Flour brew fermented by bifidobacteria was superior th that by S. cerevisae nutritionally.onally.

• Korean journal of food and cookery science
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• v.16 no.1
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• pp.1-8
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• 2000

Six Domestic Wheat Tapdong, Eunpa, Kobun, Olgru, Uri, Kumgang cultivars and one standard wheat Dark Northern Spring (DNS) were milled and determined bread-making properties of dough and bread made the wheats. The ash contents of DNS showed 0.54%, on the other hand, domestic wheat flours showed lower contents than DNS, and Kumgang was the lowest. The Protein contents which suggest the flour gluten content showed 11.68% in DNS cultivars, however 13.85% in Kumgang, 12.35% in Eunpa, 12.32% in Kobun. Valorimeter value in Farinograph data for Kumgang, Kobun, Eunpa cultivars which evaluate the dough formation time and stability showed better result than DNS. Resistance rate in Extensograph for Tapdong and Kobun showed higher rate than DNS. Gelatinization temperature in Amylograph for DNS, Tapdong, Eunpa, Kobun, Kumgang revealed 59$\^{C}$, 59$\^{C}$, 58$\^{C}$, 58$\^{C}$, 59$\^{C}$ respectively, but Uri, Olgru cultivars showed upper temperature which suggest the two cultivars was not suitable for bread making. W(gluten strength) in Alveograph data for DNS showed 297, however, 386 for Tapdong, 327 for Kumgang which indicated that the upper domestic wheat cultivars satisfactory the bread-making properties. In the CO$_2$production of straight bread doughs measured with Meissle fermenter for 5hr, Kumgang cultivar showed the highest CO$_2$ as 333 mg per 30 g of dough. The breads prepared with the above domestic wheat flours showed acceptable quality in sensory test for parameters such as volume, color of crust, symmetry of form, crust, evenness, grain, color, texture, aroma, taste, but the bread made DNS seemed to be superior in organoleptic property to the breads made with domestic wheat flours. The sponge dough bread made with Kumgang cultivars showed the best organoleptic quality among the wheat flours tested. These results indicate that the Kumgang seemed to be practical wheat variety for bread-making.

• Korean journal of food and cookery science
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• v.15 no.5
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• pp.500-506
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• 1999

Scanning electron microscopy was used to study changes in granule shape, dough and cooked noodle structure of pea starch-wheat composite flour with 20% and 30% pea starch substitution. The granule shape of pea starch with low swelling power and solubility was oval, irregular and smooth, which had more a deep groove than corn starch and wheat flour. During gelatinization, pea starch after swelling was partially collapsed but it still held its main shape. The dough microstructure of 20% pea starch substitution showed compact structure distributed with more small starch granules than wheat dough and was held in discontinuous network. When cooked, more open filamentous network where starch gelatinization was complete were noticed. Swollen but partially collapsed large starch granules maintaining their shape were appeared in noodle structure after 30 min soaking in soup. In farinograph studies, 20% pea starch substitution to wheat flour showed that MTI value was as same as wheat flour even though stability was slightly decreased so that it was considered that it has proper property of noodle making.

• Korean Journal of Food Science and Technology
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• v.28 no.3
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• pp.573-579
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• 1996

Crosslinked potato starches (XP), from 2,400 to 1,900 anhydroglucose units per crosslinked (AGU/CL), were prepared by reacting with epichlorohydrin. Some of the physicochemical properties of the XPs were then compared with those of native potato and cowpea starches. Crosslinking decreased moisture, protein and ash contents but had no effect on phosphorus content. Water binding capacities of the XPs increased as the degree of crosslinking increased, and that of the XP with 2,100 AGU/CL approached the value of cowpea starch. The absorption maxima of the starch-iodine complex shifted from 594 to 580 nm. Granule size increased slightly and surface appearance of the granule became rough when crosslinked. Both native and crosslinked potato starches showed B type X-ray diffraction pattern, and the relative crystallinity was not affected by crosslinking. Gelatinization temperature and the heat of gelatinization, measured by differential scanning calorimeter (DSC), did not change within the range of crosslinking tested. From X-ray and DSC data, it was concluded that the crosslinking ocurred in the amorphous region of the starch granule.

• Journal of the East Asian Society of Dietary Life
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• v.17 no.6
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• pp.903-910
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• 2007

In order to make acquire a potential use for Opuntia humifusa as a natural functional food material, this study was performed to determine the quality properties of Jeung-pyun made with added Opuntia humifusa, or prickly pear powder. According to an analysis of its major components, we found that the prickly pear powder consisteds of nitrogen-free extracts (71.85%) and crude fiber (11.20%). Greater additions of prickly pear powder had resulted in significantly lower pH in the of Jeung-pyun. According to measurements on the degree of Jeung-pyun gelatinization, by means of ${\beta}$-amylase, greater additions of prickly pear powder led to the higher levels of isolated maltose, indicating that the gelatinization degree of the Jeung-pyun became higher. Also, samples with higher concentrations of prickly pear powder had a tendency toward lower water content, which allowed us to expect a longer storage duration for the Jeung-pyun. In the textural property tests the Jeung-pyun that had less hardness and greater adhesiveness (p<0.05) than the control group as the content of prickly pear powder became higher. Also, the Jeung-pyunhad lower gumminess and chewiness than the control group as the content of prickly pear powder became higher. Therefore, it is possible to prepare relatively soft Jeung-pyun using prickly pear powder. For the color differences of the Jeung-pyun samples, lower L- values, and higher a- and b -values (p<0.05) presented as the addition level of prickly pear powder became higher. According to SEM observations of the Jeung-pyun, the added prickly pear powder addition groups generally showed a smaller and more inconsistent pore size, but higher porosity, than the control group. According to sensory analyses of the Jeung-pyun, the P2 group scored highest for color item, and the P4 group generated the fermented scent. Higher additions content of prickly pear powder led to the lower score, but higher scores for adhesiveness. Finally, the P2 group achieved the highest score for overall taste.

• Journal of the Korean Society of Food Science and Nutrition
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• v.21 no.1
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• pp.101-108
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• 1992

Changes were evaluated in chemical and textural properties of Jeung-pyun (fermented rice cake) altered by the particle size of rice flour, amount of added Tak-ju (Korean traditional unrefined liquor) and sucrose, fermentation time and temperature, and steaming time. Particle size of polished rice flour did not affect the volume expansion during fermentation of rice dough by Tak-ju. The maximum expanded volume was noted in the dough, containing 20% sucrose (rice flour vs sucrose = 5 : 1, w/w), fermented at $35^{\circ}C$ for 3 hours. Any volume expansion was not occurred in rice dough without sucrose. The highest value of reducing power and gelatinization degree were observed in the rice dough with Tak-ju (rice flour vs Tak-ju = 2 : 1, w/v), while the lowest blue value was revealed in that case. Steaming followed after fermentation made the smaller volume of bulk by $45{\sim}50%$ of the initial volume be showed just after fermentation. Jeung-pyun prepared under the conditions could give maximum expanded volume by fermentation showed the best overall quality by sensory and textual properties.

• Journal of the Korean Society of Food Science and Nutrition
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• v.13 no.3
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• pp.268-274
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• 1984

The purpose of this study was to investigate the physico-chemical effects of a potato starch and a purified potato starch under the condition of the microwave heating. They were exposed to the microwave energy in a 950 W, 2,450 MHz oven for 30 through 120 seconds. As the microwave heating time was increased, the contents of moisture and the crude fat of the samples were remarkably decreased irrespective of the starch composition, but on the other hand the contents of crude ash was slightly decreased and the crude protein was almost unchanged. The rings of crystallinity come to gradually changed in the X-ray diffraction pattern, and then the only 1 ring, of which interplanner spacing is wide, is changed strikingly. As the microwave heating time is increased, the starch granules which observed by a scanning electron microscope were broken partially with a special form, and the granules of purified potato starch were broken faster than those of potato starch. With the same condition that the microwave heating time was increased, while the gelatinization temperature comes to fall, the swelling power and the solubility were increased. Besides these, while the gelatinization temperature of the purified potato starch was lower than that of the potato starch, both the swelling power and the solubility of the purified potato starch is higher than those of the potato starch.