• Applied Biological Chemistry
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• v.31 no.3
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• pp.249-254
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• 1988

Physicochemical properties of starches from the rices of Akibare, Samgang and Mahatma and hardness of the cooked rice were examined Water binding capacity and amylose content were heigher in Samgang. Peak viscosity and breakdown were heigher in order of Akibare, Samgang and Mahatma, while consistency and set back were reverse order. Hydrolytic patterns of three starches with 2.2N HCl at $35^{\circ}C$ showed two distinct stages. Hydrolysis extent of Mahatma starch was lower than those of Akibare and Samgang starches. The relative crystallinities of these starches were heigher in order of Mahatma, Akibare and Samgang. Mahatma was more resistant to heat and acid treatments, lower in water binding capacity and harder when it was cooked.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.217-217
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• 2022

Pullulanase (PUL), a debranching enzyme, has been utilized in hydrolyzing the a-1,6 glucosidic linkages in starch, amylopectin, pullulan, as well as related oligosaccharides. It has also been indicated that PUL is a novel indicator of inherent RS (Resistant Starch) formation in rice. In this study, we performed haplotype analysis on 320 bred rice accessions, and additional 54 wild accessions were added to study genetic diversity along with other population-based analyses of the PUL gene. Through these investigations, we summarized a total of 10 functional (non-synonymous) SNPs from 7 different exons on chromosome 4. There were 10 haplotypes, of which only six haplotypes were functional, implicating different subpopulations. Diversity reduction was noticed in temperate japonica (0.0005) compared to the highest one (aus, 0.0154), illustrating their higher genetic differentiation by F_ST-value (0.926). The highest Tajima^ D value was observed in indica (3.6613), indicating PUL gene domestication signature under balancing selection, while the lowest Tajima's D value was found in temperate japonica (-2.2191) which might have undergone under positive selection and purified due to the excess of rare alleles. PCA, population structure, and phylogenetic analyses provide information on the genetic relatedness between and or among the cultivated subpopulations and the wild based on PUL genomic region.

• Korean Journal of Food Science and Technology
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• v.52 no.3
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• pp.220-225
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• 2020

In this study, we investigated the starch characteristics of foxtail millet (FM) and sorghum (SG) cultivars grown in Korea. The amylose contents were 29.42 and 6.42% in the Daname and Samdachal FM cultivars, and 9.09 and 11.11% in the Nampungchal and Sodamchal SG cultivars, respectively. The amylopectin polymerization analysis showed that the highest degree of polymerization (DP) was in the range of DP13-24 for all samples, at approximately 60%. The resistant starch content was very low (<0.10%) among the FM and SG cultivars. The starch gelatinization analysis showed low setback values in the Samdachal and Nampungchal cultivars. The gelatinization enthalpy, calculated based on an endothermic reaction, did not differ significantly between the SG cultivars but was significantly higher in the Samdachal FM cultivars than in the Daname FM cultivars. The results of this study might be used as basic data for the development of FM and SG products.

• Journal of Microbiology and Biotechnology
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• v.25 no.2
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• pp.178-184
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• 2015

This work aims to utilize wastes from the potato starch industry to produce single-cell protein (SCP) with high lysine content as animal feed. In this work, S-(2-aminoethyl)-_L-cysteine hydrochloride-resistant Bacillus pumilus E1 was used to produce SCP with high lysine content, whereas Aspergillus niger was used to degrade cellulose biomass and Candida utilis was used to improve the smell and palatability of the feed. An orthogonal design was used to optimize the process of fermentation for maximal lysine content. The optimum fermentation conditions were as follows: temperature of 40℃, substrate concentration of 3%, and natural pH of about 7.0. For unsterilized potato starch wastes, the microbial communities in the fermentation process were determined by terminal restriction fragment length polymorphism analysis of bacterial 16S rRNA genes. Results showed that the dominant population was Bacillus sp. The protein quality as well as the amino acid profile of the final product was found to be significantly higher compared with the untreated waste product at day 0. Additionally, acute toxicity test showed that the SCP product was non-toxic, indicating that it can be used for commercial processing.

• Korean journal of food and cookery science
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• v.19 no.6
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• pp.783-793
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• 2003

The effects of various kinds of starch (mungbean, potato, corn and a blend of potato and com starch) on the quality characteristics of muhwakwa-pyun were studied according to the storage duration. The sweetness, pH and total acidity of muhwakwa extract were analyzed, as were the Visco/Amylograph viscosity profile and DSC thermodynamic characteristics of starches. For quality characteristics, color difference, instrumental texture characteristics and sensory characteristics were compared. The sweetness of muhwakwa extract was satisfactory but the total acidity was low for Kwa-pyun manufacture. Therefore, its pH was adjusted to 3.4 by adding 10％ citric acid with an amount of 1％ of total liquid. From the Visco/Amylograph viscosity profile and DSC thermodynamic characteristics of starches, a blend of potato and com starch was found to be easy to cook and form a gel but a little more resistant than the other starches in terms of retrogradatin. Lightness (L) and yellowness (b) of Kwa-pyun increased while its redness (a) decreased by the storage. The color became whiter and the clarity decrease regardless of the kinds of starch, which became obvious after 3 days of storage. The hardness, springiness, adhesiveness and cohesiveness tended to decrease with storage, which was weak in a blend starch. The overall acceptability of Kwa-pyun made with a blend of potato and com starch was evaluated as being the best among the samples tested. Therefore, for traditional kwa-pyun manufacture manufacture mungbean starch might be replaced with a blend of potato and corn starch which is less expensive and easily available in the market nowadays.

• Journal of the Korean Society of Food Culture
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• v.22 no.6
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• pp.820-826
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• 2007

Different types of bap(cooked rice) was cooked using barley or/and SoRiTae with rice as the base. Total(TS), rapidly digestible(RDS), slowly digestible(SDS) and resistant(RS) starch fractions were determined. Other physicochemical properties such as moisture, protein, amylose contents, protein digestion in vitro and color values as well as sensory properties of different bap were also investigated. Cooked rice with SoRiTae(RiSo) showed the highest moisture content of 63.9%, whereas other bap showed simillar content ranging from 62.3-63.0%. Crude protein content of RiSo was the highest, while that of cooked rice(Ri) was the lowest(p<0.05). Amylose content of RiBa was the highest, while that of RiSo was the lowest(p<0.05). In in vitro protein digestibility(IVPD), cooked rice with barley and SoRiTae(RiBaSo) was the highest, while Ri was the lowest, showing no significant difference at p<0.05. In starch fractions, as barley or/and SoRiTae were added to rice, a decrease in RDS content and increases in SDS and RS contents were observed. In addition, starch digestion index(SDI), which derived as an indicator of their in vitro starch digestibility and rapidly available glucose(RAG) value, which determined as a predictor of potential glycemic response decreased. A decrease in L value from RiSo and RiBaSo, which comprised of SoRiTae and increases in a and b values in RiSo and RiBa were observed, respectively. All sensory parameters involving color, glossiness, sweet taste, wetness, roughness, hardness and stickiness were shown to be a significant difference except sweet taste among different bap(p<0.05). L value of instrumental characteristic was negatively correlated with color of sensory characteristic and a value was positively correlated. Significant negative correlation was found between RS content and glossiness, however, positive correlation with roughness and hardness, respectively. These results suggested that cooked rice mixed with barley and SoRiTae contain significant RS and SDS contents and may improve diabetes and hyperlipidemia, due to the lowering RDS and RAG, respectively.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.63 no.4
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• pp.304-313
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• 2018

The objective of this study was to investigate the resistance starch(RS) content and in vitro hydrolysis index of roasted rice flours for low GI food development. This study used intermediate and high amylose rice varieties containing resistant starch. The intermediate amylose rice varieties 'Ilmi' and high amylose rice varieties, 'Goami4' and 'Dodamssal' were tested. The crude fat and crude protein contents of the rice cultivars ranged 2.12~3.08% and 6.2~7.63%, respectively. The RS and amylose contents of Dodamssal and Goami4 were higher than those of Ilmi. RS content of Ilmi was not significantly different before and after roasting treatment. The RS content of Goami4 before roasting was significantly higher than that of Dodamssal, but the RS content of Dodamssal was higher than that of Goami4 at temperatures above $210^{\circ}C$ of roasting. The soluble starch decreased after roasting in Goami4 and Dodamssal. Starch hydrolysis index (HI) and expected glycemic index (GI) were higher in order of Imi, Goami4 and Dodamssal regardless of roasting treatment. The sensory evaluation showed high scores in Dodamssal for color, flavor, bitter taste, bitter taste, sweet taste and sweetness at $240^{\circ}C$ for 10 min and $210^{\circ}C$ for 30 min. The results of this study indicate that Dodamssal was suitable varieties for powder meal with low GI.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.62 no.3
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• pp.184-192
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• 2017

Rice flours from five rice (Oryza sativa L.) varieties with different amylose content were prepared by both wet and dry milling processes. The moisture content of wet-milled rice flours (WMR) was approximately three-times higher than that of dry-milled rice flours (DMR). Water absorption index (WAI), water solubility index (WSI), and swelling power (SP) increased in proportion to temperature. The WAI, WSI and SP values of DMR were higher than those of WMR. Baeokchal (BOC), which is a waxy rice cultivar, had a significantly high WSI value. Pasting properties of DMR, except for the BOC cultivar, resulted in an increase in peak, trough, final, and setback viscosities. The levels of resistant starch in four cultivars, except for Dodamssal (DDS), were under 1%, irrespective of the milling process, whereas the resistant starch contents of DMR and WMR in DDS were 9.18% and 6.27%, respectively. In vitro digestibility of WMR was higher than that of DMR, and the estimated glycemic index of the rice flour varieties ranged from 57.6 to 81.3. Damaged starch content of WMR was less than that of DMR; in addition, a negative correlation was observed between the amylose and damaged starch contents of WMR. These results suggest that the properties of rice flour vary depending on the milling method and flour variety, and could be a reference for selecting the appropriate processing method.

• Food Engineering Progress
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• v.14 no.3
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• pp.263-270
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• 2010

An alkalophilic microorganism named DK-2386, which produces xylanase, was isolated from soil of Taejo-mountain, Cheonan-si, Chungnam, Korea. The isolated strain was characterized as Gram-positive, with size of 0.4${\times}$2.5 ${\mu}$m, spore forming, anaerobic, catalase positive, possessed with hydrolysis abilities of casein, starch, sodium carboxy methyl cellulose, and xylan, reduction of nitrate to nitrite, resistant against lysozyme, urease positive, and motility positive. The color of culture broth was reddish yellow. The strain DK-2386 was identified as Bacillus agaradhaerens by whole cell fatty-acid composition analysis and 16S rDNA sequence analysis. However, it was not identical to Bacillus agaradhaerens 40952 obtained from the Korean Culture Center of Microorganism in its colour of culture broth. Therefore, we have named the newly isolated strain as Bacillus agaradhaerens DK-2386.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.300-300
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• 2022

Wheat (Triticum spp.) is an important source of food worldwide and the focus of considerable efforts to identify new combinations of genetic diversity for crop improvement. In particular, wheat starch composition is a major target for changes that could benefit human health. Starches with increased levels of amylose are of interest because of the correlation between high amylose content and elevated levels of resistant starch, which has been shown to have beneficial effects on health for combating obesity and diabetes. In this study, high amylose wheat germplasms from other countries were collected and cultivated in Korea, and then the content of amylose was evaluated, we examined amylose content in 614 wheat germplasm. Furthermore, amylose content was validated using several milling processes such as roller, hammer, and grinding mill. As a result, the amylose content distribution was divided into five groups. The range of the amylose levels in whole wheat flour was 18.3% to 29.6%. In addition, the mutant lines were screened for high amylose, and two mutant lines (WX-1046 and WX-1074) exhibited a comparable amylose content to Keumkang whole wheat (19.6%). It has been established that high amylose indicated SS IIa null and necessitate GBSS. Based on these findings, it may be helpful to develop high amylose wheat germplasm and production techniques, particularly in Korea.