Tae Wha Moon

Seoul National University, Sŏul, Seoul, South Korea

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Publications (54)105.57 Total impact

  • Chang Joo Lee · Tae Wha Moon
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    ABSTRACT: The objective of this study was to investigate the structural characteristics of slowly digestible starch (SDS) and resistant starch (RS) fractions isolated from heat-moisture treated waxy potato starch. The waxy potato starch with 25.7% moisture content was heated at 120°C for 5.3h. Scanning electron micrographs of the cross sections of RS and SDS+RS fractions revealed a growth ring structure. The branch chain-length distribution of debranched amylopectin from the RS fraction had a higher proportion of long chains (DP≥37) than the SDS+RS fraction. The X-ray diffraction intensities of RS and SDS+RS fractions were increased compared to the control. The SDS+RS fraction showed a lower gelatinization enthalpy than the control while the RS fraction had a higher value than the SDS+RS fraction. In this study we showed the RS fraction is composed mainly of crystalline structure and the SDS fraction consists of weak crystallites and amorphous regions. Copyright © 2015 Elsevier Ltd. All rights reserved.
    Carbohydrate Polymers 07/2015; 125. DOI:10.1016/j.carbpol.2015.02.035 · 4.07 Impact Factor
  • Min Ah Kim · Seung Jun Choi · Tae Wha Moon
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    ABSTRACT: This study investigated whether the crystalline structure of the retrograded starch affects the contents of slowly digestible starch (SDS) and resistant starch (RS). When the relative crystallinities were similar, there was no difference in RS content between the retrograded starches with A- and B-type crystallites. However, the SDS content in A-type crystalline structure was constantly higher than B-type, contradicting the observation that the granular starches with B-type crystallites were more enzyme resistant. Therefore, the primary factor that accounts for the digestibility of granular starch is not the crystalline structure, but the granular properties, including the surface pores and the size.
    Journal of the Korean Society for Applied Biological Chemistry 04/2015; DOI:10.1007/s13765-015-0069-z · 0.54 Impact Factor
  • Bo Kyung Kim · Hye In Kim · Tae Wha Moon · Seung Jun Choi
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    ABSTRACT: Starches with high slowly digestible starch (SDS) contents were prepared by treating completely gelatinized waxy corn starch with amylosucrase. The structural properties of the prepared starches were then investigated. The content of SDS increased by up to 38.7% after amylosucrase modification, and the portion of chains with degree of polymerisation (DP) 25–36 increased, while the portion of chains with DP ⩽ 12 decreased. Amylosucrase-modified starches showed a weak B-type crystalline structure. A slight increase in the degree of relative crystallinity was observed with increased reaction time. The thermal properties, including melting temperature and enthalpy, of the amylosucrase-modified starches were higher than for the control starch. Although the amylosucrase-modified starches showed varying structural properties according to reaction time (1–45 h), their digestibilities did not change much after 6 h. By controlling the reaction time of the amylosucrase treatment, a tailored starchy food containing the desired amount of SDS can be produced.
    Food Chemistry 07/2014; 152:113–120. DOI:10.1016/j.foodchem.2013.11.145 · 3.39 Impact Factor
  • HY Song · SY Lee · SJ Choi · KM Kim · JS Kim · GJ Han · TW Moon
    Food science and biotechnology 02/2014; 23(1):23-31. · 0.66 Impact Factor
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    ABSTRACT: Understanding in vitro digestibility and release experiments with starch-entrapped calcium alginate microspheres provide the possibility of controlling starch digestibility in the human gastrointestinal tract. Native and amylosucrase (AS)-treated waxy corn starches (5000 U, 20 000 U, and control) were encapsulated with three different ratios of sodium alginate: 0.5, 0.7, and 1.0%. The slowly digestible and RS fractions of the encapsulated starch were 57.5 and 97.7%, respectively. After cooking, the proportions of these fractions still ranged from 55.7 to 96.1%, depending on the type of starch and concentration of sodium alginate, whereas the un-encapsulated starch contained between 2.9 and 48.3% slowly digestible and RS after cooking. In vitro release was studied in both uncooked and cooked encapsulated samples. When incubated in simulated gastric fluid, the beads swelled and started to float but did not erode, even after thermal treatment. Incubation in simulated intestinal and colonic fluids caused the beads to release starch in both uncooked and cooked starch-encapsulated samples. Encapsulated AS control and native waxy corn starch samples released much more starch than AS-modified starches. The total amount of starch released did not exceed 20% for uncooked samples and 25% for cooked samples.
    Starch - Starke 01/2014; 66(1-2). DOI:10.1002/star.201300055 · 1.40 Impact Factor
  • Khanh Son Trinh · Seung Jun Choi · Tae Wha Moon
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    ABSTRACT: Debranched water yam starch was subjected to repeated hydrothermal treatment (HTT), and its physicochemical and structural properties and digestion pattern were investigated. The B-type crystalline pattern of raw starch was recrystallized to B- and CA-type patterns by debranching and repeated HTT. The degree of relative crystallinity of debranched starch gradually increased and reached its maximum (43.3%) after five repetitions of HTT. The thermal transition temperatures and melting enthalpy of recrystallized starches increased progressively, reflecting the perfection of their crystalline structure, leading to the accumulation of boiling-stable crystalline structure under repeated HTT conditions. As a result, RS of HTT starches reached a very high level (>92.2%). The boiling-stable RS content depended on the repetition of this treatment and was maximized (81.0%) after five repetitions.
    Starch - Starke 07/2013; 65(7-8):679-685. DOI:10.1002/star.201200149 · 1.40 Impact Factor
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    ABSTRACT: Forty-seven strains of Aspergillus oryzae isolates from Korean nuruks were compared for their brewing characteristics. A. oryzae YI-A6 and YI-A7 showed the highest acid α-amylase, glucoamylase, and carboxypeptidase activities, respectively. Sixteen isolates with high amylolytic or proteolytic enzyme activities were selected for investigation of their rice wine fermentation characteristics. After 12 days of brewing at 15°C, ethanol concentrations were 10.2–14.3% for A. oryzae strains. Fermentation rates were the highest for YI-A7. Most rice wine samples fermented with nuruk strains had lower concentrations of off-flavor compounds than the control did. All mean sensory attribute values significantly differed among samples. Pearson correlation coefficients showed that glucoamylase activity was positively correlated to both ethanol productivity and overall harmony (p<0.01). Thus, glucoamylase activity was identified as the best factor for screening Aspergillus strains for use in rice wine brewing.
    Food science and biotechnology 04/2013; 22(2):425-432. DOI:10.1007/s10068-013-0097-6 · 0.66 Impact Factor
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    ABSTRACT: The preparation and physicochemical characteristics of sweetpotato flour with increased slowly digestible starch (SDS) fraction were investigated under various heat-moisture treatment (HMT) conditions. The optimum conditions for preparing slowly digestible sweetpotato flour established using response surface methodology were moisture content of 22%, temperature of 103°C, and treatment time of 5.8 h. The highest SDS content in heat-moisture treated sweetpotato flour was 57.6%. The relative crystallinity of heat-moisture treated sweetpotato flour decreased, but the X-ray diffraction pattern maintained the A-type. The DSC of the heatmoisture treated flour showed a decreased gelatinization temperature range and gelatinization enthalpy compared with native one. The viscosity profiles and values changed significantly with HMT, resulting in a higher pasting temperature, decrease of the viscosity values, and no breakdown. It indicates that heat-moisture treated sweetpotato flour is more stable at high temperatures and shear rates than native one.
    Food science and biotechnology 04/2013; 22(2). DOI:10.1007/s10068-013-0091-z · 0.66 Impact Factor
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    ABSTRACT: The effects of annealing on the digestibility, morphology, and physicochemical characteristics of four types of granular sweet potato starches [Yulmi (YM), Yeonwhangmi (YHM), sweet potato starch from Samyang Genex (SSPS), and commercial sweet potato starch (CSPS)] were investigated. Annealing was performed at 55°C and 90% moisture content for 72 h. Morphology, the branched chain distribution of amylopectin, and the X-ray diffraction pattern remained unchanged during the annealing process. The slowly digestible starch content in annealed YM, YHM, and SSPS starches increased, but did not change in annealed CSPS. The gelatinization temperatures increased, but the gelatinization temperature range decreased with annealing. The swelling factor and amylose leaching decreased, while the close packing concentration increased. Rapid Visco Analyser analysis revealed that annealed starches possessed thermal stability and higher pasting temperatures. It is suggested that the enhanced packing arrangement formed during annealing impacts the digestibility and physicochemical properties of sweet potato starches.
    Food science and biotechnology 02/2013; 23(1):23-31. DOI:10.1007/s10068-014-0004-9 · 0.66 Impact Factor
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    ABSTRACT: Rice flours were treated using a thermostable 4-α-glucanotransferase (GTase) from Thermus aquaticus for 1, 3, and 48 h. Molecular weight of modified rice starch rapidly decreased within 1 h of reaction, then slowed down. As the reaction proceeded, the proportions of short (<DP 11) and long (>DP 30) branched chains of modified starch increased, whereas the proportion of medium chains decreased. Rice cakes were prepared with native and GTase-treated rice flours (substitution at 5%) and kept for 3 and 21 h. Texture profile analysis indicated significantly increased hardness, adhesiveness, chewiness, and resilience in rice cakes containing treated rice flours. Sensory analysis revealed that the rice cakes containing 48 h-treated flour had significantly increased springiness, hardness, toughness, and adhesiveness during both storage periods. Meanwhile, it displayed the lowest starch-like attribute and crumbliness. These results suggested that the substitution for 48 h GTase-treated rice flour could retard the retrogradation of rice cakes.
    Food science and biotechnology 12/2012; 21(6). DOI:10.1007/s10068-012-0227-6 · 0.66 Impact Factor
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    Chang Joo Lee · Yang Kim · Seung Jun Choi · Tae Wha Moon
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    ABSTRACT: Heat-moisture treatment (HMT) was optimised to increase the formation of slowly digestible starch (SDS) in waxy potato starch, and the structural and physiological properties of this starch were investigated. A maximum SDS content (41.8%) consistent with the expected value (40.1%) was obtained after 5 h 20 min at 120 °C with a 25.7% moisture level. Differential scanning calorimetry of HMT starches showed a broadened gelatinization temperature range and a shift in endothermal transition toward higher temperatures. After HMT, relative crystallinity decreased with increasing moisture level and X-ray diffraction patterns changed from B-type to a combination of B- and A-types. Hollow regions were found in the centres of HMT waxy potato starches. HMT intensity significantly influenced SDS level. This study showed that HMT-induced structural changes in waxy potato starch significantly affected its digestibility and the blood glucose levels of mice who consumed it.Highlights► We applied heat-moisture treatment (HMT) to waxy potato starch. ► Optimal conditions for HMT were established using response surface methodology. ► After HMT, starches with high SDS content were produced. ► HMT waxy potato starch was evaluated for its glucose response in mice.
    Food Chemistry 08/2012; 133(4):1222-1229. DOI:10.1016/j.foodchem.2011.09.098 · 3.39 Impact Factor
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    ABSTRACT: Gelatinized water yam starch was subjected to hydrothermal treatment (25, 30, and 35% moisture content for 1, 8, 16, and 24 h at 100 °C) and characterized by X-ray diffractometry, solid-state ¹³C cross-polarization and magic-angle spinning nuclear magnetic resonance, differential scanning calorimetry, and digestibility analysis. The slowly digestible starch (SDS) content of the starch treated at 30% moisture content for 24 h reached 49.1%, 31.9% higher than that of the control starch. The B-type pattern of native starch was re-crystallized to the A-type by hydrothermal treatment. The SDS content showed negative correlations with T(o), T(p), T(c), and T(r), but showed a positive correlation with melting enthalpy. Furthermore, SDS was positively correlated with hydrothermal reaction time, moisture content, relative crystallinity, and the double-helix proportion. The structural changes in hydrothermally treated water yam starches resulted in the enhancement of SDS. PRACTICAL APPLICATION: The hydrothermally treated water yam starch could be used as a food ingredient for slow-energy supply or dietary fiber.
    Journal of Food Science 05/2012; 77(6):C574-C582. DOI:10.1111/j.1750-3841.2012.02703.x · 1.79 Impact Factor
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    ABSTRACT: The structural properties and digestibility of slowly digestible hydrothermally treated potato starch (SDS) were investigated. The potato starch with 20, 30 or 40% moisture content was heated at 100 °C for 30 min, and then kept at 30 °C or 70 °C for 12 h. The sample with 30% moisture content, heated and kept at 30 °C, produced the highest SDS content (37.5%). The modified products were analysed with scanning electron microscopy, X-ray diffraction, and differential scanning calorimetry (DSC). The cross-section showed a large hollow area and X-ray patterns were altered from B- to a mixture of B- and A-type. DSC of the heated samples demonstrated a broader gelatinisation temperature range compared with the heated-and-stored samples. In vivo glucose responses with mice correlated with the in vitro starch digestibility experiments. This study showed that structural changes during hydrothermal treatment of potato starch significantly affected digestibility and blood glucose levels in mice.
    Carbohydrate Polymers 02/2011; 83(4):1879-1886. DOI:10.1016/j.carbpol.2010.10.057 · 4.07 Impact Factor
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    ABSTRACT: This study investigated the technical feasibility of coating type 4 resistant starch (RS4) onto rice with the edible polymers locust bean gum (LBG) and agar. The coating solutions were prepared using LBG, agar, and a mixture of LBG and agar at three concentrations (0.01%, 0.1% and 1%). The raw milled rice was soaked in the prepared coating solutions, rolled in RS4 powder and dried. Microscopic observation revealed that the RS4 coating on the rice surface with 0.1% and 1% LBG–agar mixture had a resistance to washing and cooking and covered the whole surface of the rice with good adherence. The thickness of the RS4 coating on the rice surface with 0.1% and 1% LBG–agar mixture was approximately 74 and 233 μm, respectively. Compared with uncoated rice and rice mixed with RS4, the RS4-coated rice showed lower starch digestibility, a decreased glucose response and a slower rate of blood glucose decrease.
    International Journal of Food Science & Technology 12/2010; 45(12):2612 - 2621. DOI:10.1111/j.1365-2621.2010.02434.x · 1.35 Impact Factor
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    ABSTRACT: Enzymatic modification by amylosucrase (AS) from Neisseria polysaccharea was used on waxy rice, normal rice, waxy corn, normal corn, waxy potato, and normal potato starches to prepare the starches with a high content of slowly digestible starch (SDS) fraction. The AS-treated starches contained similar amounts of resistant starch, decreased rapidly digestible starch, and increased SDS compared to controls. After the AS treatment, the SDS contents increased by approximately 25% in waxy starches but about 8% in normal starches. The yields of the insoluble fraction of waxy starches were about 15% higher than those of normal starches. The branch chain length was increased by DP 13–19. The AS-treated starches showed a B-type X-ray diffraction pattern, 5–9 J/g for retrogradation enthalpy, 88–89 °C for peak temperature, and much larger moduli for their gels compared with raw starches.
    Carbohydrate Polymers 09/2010; 82(2):489-497. DOI:10.1016/j.carbpol.2010.05.017 · 4.07 Impact Factor
  • Sang-Jun Lee · Tae Wha Moon · Jaehwan Lee
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    ABSTRACT: The explosive puffing process may provide characteristic physicochemical properties in red ginseng. The effects of explosive puffing on the changes of volatiles in red ginseng were investigated using headspace-solid phase microextraction (HS-SPME)-gas chromatograph (GC) with a mass selective detector (MS). Formation of porous structures and smaller pieces were clearly observed on the surface of puffed red ginseng by scanning electron microscopy. Total volatiles in puffed red ginseng increased by 87% compared to those in red ginseng. Hexanal, Delta-selinene, and beta-panasinsene were major volatiles in red ginseng, whereas aristolene, beta-panasinsene, and calarene were main volatiles in puffed red ginseng. Puffing process decreased volatiles from lipid oxidation including aldehydes, ketones, and 2-pentylfuran and increased terpenoids in red ginseng. Selective ion monitoring (SIM) mode for GC/MS results showed that 2-furanmethanol and maltol were present at the concentrations of 0.20% and 0.24%, respectively, in red ginseng and 5.86% and 3.99%, respectively, in puffed red ginseng. The explosive puffing process increased 2-furanmethanol and maltol in puffed red ginseng significantly (P < 0.05) with the changes of microstructures.
    Journal of Food Science 03/2010; 75(2):C147-51. DOI:10.1111/j.1750-3841.2009.01461.x · 1.79 Impact Factor
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    ABSTRACT: The structural characteristics of citric acid-treated rice starch, which was subjected to autoclaving and stored at a high temperature under acidic conditions, were investigated by high performance anion-exchange chromatography, multi-angle laser-light scattering, X-ray diffraction, differential scanning calorimetry (DSC), nuclear magnetic resonance, and scanning electron microscopy. The citric acid-treated rice starch contained chains of different lengths (DP 7−70) and had an A + V type polymorphism. The DSC thermogram of acid-treated rice starch showed a broad endothermic peak, which indicated that the structure of the acid-treated rice starch contained a number of double helices with various melting temperatures. Microscopic observation showed that the internal structure of the acid-treated starch displayed more or less spherical lumps that could be composed of short chains and amylose–lipid complex. The digestive properties of acid-treated rice starch were altered by heat processing such as cooking and autoclaving because crystalline regions were converted to amorphous regions or lamellae.
    Carbohydrate Polymers 10/2009; 78(3):588-595. DOI:10.1016/j.carbpol.2009.05.017 · 4.07 Impact Factor
  • Ki Woo Kim · Seung Jun Choi · Tae Wha Moon
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    ABSTRACT: Charging artifacts and surface features of corn starch granules were investigated by scanning electron microscopy. Three types of industrial waxy corn starch granules with different levels of moisture content (0, 10.3, and 24.2%) were prepared and subjected to both secondary electron imaging and backscattered electron imaging. There were no significant charging artifacts in secondary electron images at 3 or 5 kV. However, imaging at higher magnifications and accelerating voltages much lower than 3 kV ranging from 0.1 to 1 kV did not show well-resolved structures. At higher accelerating voltages than 5 kV, charging was manifested as excessive brightness at specific areas and alteration of bright and dark lines in the direction of the raster pattern in secondary electron images of all the types of specimens tested. As the accelerating voltage increased up to 30 kV in secondary electron images, the charging also increased. Meanwhile, no charging was detected in all the backscattered electron images taken at different accelerating voltages. As the accelerating voltage increased in backscattered electron images, the resolution increased with less depth of focus. Consistent results were found in all the types of corn starch granules assayed in this study. These results suggest that a simple and rapid morphological analysis of moisturized starches can be performed by backscattered electron imaging without considerable heat drying of starches. Concomitantly, it allows for imposing a higher accelerating voltage to ensure better image resolution, facilitating morphological characterization of diverse starch granules as they are in native states.
    Micron 12/2008; 39(8):1160-1165. DOI:10.1016/j.micron.2008.05.007 · 2.06 Impact Factor
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    ABSTRACT: Reaction conditions were optimized to increase the content of resistant starch in adlay starch using esterification with glutaric acid, and the physicochemical properties of the prepared glutarate starches were investigated. Different amounts of glutaric acid (0.1–0.5g/g starch, dry weight basis) were reacted with adlay starch at various temperatures (70–130°C) and reaction times (3–9h). The resistant starch levels increased with increased glutaric acid content, reaction temperature, and reaction time. The color difference was mainly affected by reaction time. The highest resistant starch content (RS 66%) was obtained using conditions of 0.4g glutaric acid/g starch, 115°C, and 7.5h, with a color difference of 10.24. After digestion with α-amylase and amyloglucosidase, the water-soluble fraction of glutarate starch had more oligosaccharides than high-amylose maize starch (RS 43%). FT-IR and solid-state NMR detected carbonyl groups in the glutarate starch, indicating the formation of cross-linkages through esterification. The granular structure of the glutarate starches was not destroyed and they retained birefringence. After heating with an excess of water, the granules kept their shape but lost their birefringence. The glutarate starches had low solubility in both cold and hot water, and the resistant starch contents were unchanged after heating due to the restriction of swelling by cross-linking. The glutarate starches had a similar chain-length distribution to raw starch, indicating that acid hydrolysis took place at branching points in the amorphous region. Furthermore, the glutarate starches possessed a weaker crystalline region, more diverse double helical chains, and lower enthalpy than raw starch.
    Carbohydrate Polymers 11/2008; 74(4):787-796. DOI:10.1016/j.carbpol.2008.04.043 · 4.07 Impact Factor
  • Food science and biotechnology 08/2008; 17(4):705-712. · 0.66 Impact Factor