• Food Industry And Nutrition
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• v.9 no.2
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• pp.1-9
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• 2004

• Journal of the Korean Society of Food Culture
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• v.26 no.5
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• pp.521-529
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• 2011

This study evaluated the effects of different levels of malt extract on the hardness, moisture, water soluble starch (WSS) contents, and in vitro starch digestibility (IVSD) of Jeungpyun during storage at room temperature ($25{\pm}1^{\circ}C$) and refrigeration temperature ($4{\pm}1^{\circ}C$). Resistant starch (RS) and soluble starch (non-RS) contents were also evaluated. During storage at both temperatures, hardness increased in Jeungpyuns with the malt extract-added Jeungpyun groups (malt-added Jeungpyuns) exhibiting lower hardness than the control. The rate of retrogradation was faster upon storage at refrigeration temperature. Moisture and WSS contents as well as IVSD of Jeungpyuns decreased, whereas these levels were higher in malt-added Jeungpyuns compared to control. Storage increased RS contents in Jeungpyuns stored for up to 4 days, particularly at $4^{\circ}C$, whereas there was a decrease in RS content after 7 days of storage. However, RS content was lower in malt-added Jeungpyuns compared to control. Soluble starch (SS) contents of Jeungpyuns decreased. However, SS content was higher in malt-added Jeungpyuns than that of control. The reduced hardness and RS content as well as the rate of increase in other parameters of malt-added Jeungpyuns were dependent on the concentration of malt extract. These results reveal that addition of malt extract delayed retrogradation of Jeungpyun, whereas retrogradation possibly increased the content of RS during storage at both temperatures, however, that of RS decreased with increasing level of malt extract, suggesting that the level of malt extract as well as the storage conditions are important for obtaining acceptable texture and retaining the RS content of Jeungpyun, which is known to possess physiological activity.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.214-214
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• 2022

Soluble starch synthases (SSs) elongate α-glucans from ADP-Glc to the glucan nonreducing ends and play a critical role in synthesizing resistant starch in the rice. A total of 10 SSs isoforms were reported in rice, including granules-bound starch synthase I (GBSSI), GBSSII, starch synthase I (SSI), SSIIa (SSII-3), SSIIb (SSII-2), SSIIc (SSII-1), SSIIIa (SSIII-2), SSIIIb (SSIII-1), SSIVa (SSIV-1), and SSIVb (SSIV-2). SSIII proteins are involved in forming the B chain and elongating cluster filling chains in amylopectin metabolism. The functions of SSIIIb (SSIII-1) are less clear as compared to SSs. Here, we sought to shed light on the genetic diversity profiling of the SSIII-1 gene in 374 rice accessions composed of 54 wild-type accessions and 320 bred cultivars (temperate japonica, indica, tropical japonica, aus, aromatic, and admixture). In total, 17 haplotypes were identified in the SSIII-1 coding region of 320 bred cultivars, while 44 haplotypes were detected from 54 wild-type accessions. The genetic diversity indices revealed the most negative Tajima's D value in the temperate-japonica, followed by the wild type, while Tajima's D values in other ecotypes were positive, indicating balancing selection. Nucleotide diversity in the SSIII-1 region was highest in the wild group (0.0047) while lowest in temperate-japonica. Lower nucleotide diversity in the temperate-japonica is evidenced by the negative Tajima's D and suggested purifying selection. The fixation index (F_ST) revealed a very high level of gene flow (low F_ST) between the tropical-japonica and admixture groups (F_ST=-0.21) followed by admixture and wild groups (-0.04), indica and admixture groups (0.02), while low gene flow with higher F_ST estimates between the temperate-japonica and aus groups (0.72), tropical-japonica and aromatic groups (0.71), and temperate-japonica and admixture groups (0.52). Taken together, our study offers insights into haplotype diversity and evolutionary fingerprints of SSIII-1. It provides genomic information to increase the resistant starch content of cooked rice.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.286-286
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• 2017

We conducted to compare the characteristics of rice flours according to the different milling processes. Five rice varieties (Oryza sativa L.) with different amylose content were prepared by wet and dry milling processes. The moisture contents of wet-milled rice flours (WMR) was mostly three-time higher than those of dry-milled flours (DMR). Water absorption index (WAI), water solubility index (WSI) and swelling power (SP) increased in proportion to temperature ($50-90^{\circ}C$). WAI, WSI, SP of DMR showed higher value than those of WMR. Baeokchal (BOC) which is waxy rice cultivar was significantly high level of WSI. Pasting properties of DMR except BOC cultivar resulted in higher peak viscosity, trough viscosity, final viscosity and Setback. The levels of resistant starch in the four cultivars except Dodamssal (DDS) were under 1% irrespective of Milling processes, whereas the resistant starch contents of DMR and WMR in DDS was 9.18 and 6.27, respectively. Damaged starch content of WMR were less than those of DMR, moreover, negative correlation was observed between amylose content and damaged starch of rice cultivars. These results suggest that the properties of rice flour varied depending on the milling methods and varieties, and it could be a reference for selecting the appropriate processing purposes.

• Korean journal of food and cookery science
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• v.32 no.3
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• pp.253-260
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• 2016

Purpose: To develop fat-free dressing containing a resistant starch (RS) as a dietary fiber, the viscosity and stability of various type RSes prepared from wheat, maize, potato, rice, waxy rice, and amaranth starches were investigated by using Brookfield viscometer. The shape of RS granule in the dressing during storage was also observed. Methods: The viscosity of fat free dressing with different retrograded RS3 (RS3V) prepared from waxy rice starch with 0.1% lemon vinegar and ascorbate mixed solution had higher RS3 that was maintained constant during storage. Annealing and heating prior to cross-linking, and heating after cross-linking increased RS level of RS4 type starches. Results: The viscosities and stabilities of dressings with RS were different depending on starch sources and RS preparation conditions. The heated RS4 (HRS4) increased in viscosity and stability with RS4 addition. Especially the fat-free dressings with HRS4 prepared from rice and waxy rice starches maintained stability regardless of separation after one month storage with only 7% separation after 6 month storages. The shape of RS4 granule in acidic medium of dressing did not change until 6 months. Conclusion: In this study, RS4 made by the rice and waxy rice starches showed high viscosity and maintained stability of the fat-free dressings during storage.

• Korean Journal of Food Science and Technology
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• v.49 no.1
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• pp.1-7
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• 2017

Molecular structure, physicochemical properties, and in vitro digestibility of starch from Korean rice cultivars for special uses (Baegjinju 1, Hanareum, Deuraechan, and Goami 4) were investigated. The starch from Baegjinju 1 had the lowest amylose content (9.7%) and Hanareum, Deuraechan, and Goami 4 had intermediate amylose (20-25%) contents. Baegjinju 1 had a lower proportion of short amylopectin branch chains than the other rice starches. Hanareum had the lowest relative crystallinity and the highest intensity ratio of $1047cm^{-1}/1022cm^{-1}$ among the rice starches. The starch from Goami 4 had a higher pasting temperature and lower gelatinization enthalpy than the other rice starches. Peak viscosity of rice starch from Baegjinju 1 was substantially higher than peak viscosity of other rice starches. Rice starch from Baegjinju 1 had significantly higher rapidly digestible starch content and lower resistant starch content than other rice starches, whereas there was no significant difference in resistant starch content among the rice starches.

• Journal of Microbiology and Biotechnology
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• v.3 no.2
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• pp.95-98
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• 1993

This study was carried out to isolate and characterize the mutant strains of Schwanniomyces castellii NRRL Y-2477. Mutants were prepared with the treatment of ethyl methane sulfonate. 2-deoxy-D-glucose resistant mutants were isolated and two mutants were selected based on their high production of amylolytic enzymes and their ability to ferment starch. The mutants selected had higher a-amylase and glucoamylase activities than the wild type strain from several other carbon sources. Especially, it was revealed that mutant strain M-9, when cultured in the presence of glucose as a sole carbon source, shows relatively high activities of a-amylase and glucoamylase compared to those of the wild type strain. In result, this mutant strain can be considered as a constitutive producer of amylolytic enzymes. To compare the ethanol production ability of wild type strain and of mutant strains selected, an alcohol fermentation was carried out using 100 g/l soluble starch. Mutant strain M-9 did not improve the direct alcohol fermentation of starch, despite its excellent amylolytic activities performance. On the other hand, mutant strain M-6 produced 37.9 g/l (4.8%, v/v) ethanol by utilizing about 82% of substrate.

• Food Science and Biotechnology
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• v.14 no.1
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• pp.32-38
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• 2005

Effects of acid and ${\alpha}$-amylase on resistant starches including retrograded RS3 and cross-linked RS4 prepared from normal maize starch were investigated. Acid and ${\alpha}$-amylase hydrolytic patterns of RS3 were similar, while those of native starch and RS4 differed. Acid hydrolysis rate of RS3 was markedly higher at initial stage, then slowly decreased up to 20 days, whereas that of RS4 increased continuously. The sizes of acid- and ${\alpha}$-amylase-treated RS3 residues decreased, but those of RS4 remained unchanged. X-ray patterns of all treated residues did not change; however, the peak intensities increased. Swelling power of RS3 increased to 150% at $95^{\circ}C$, whereas that of RS4 differed depending on the treatment condition. Swelling power of acid-treated RS4 residue increased markedly, but that of ${\alpha}$-amylase-treated one remained constant. Gel filtration chromatography profiles of untreated RS3 and RS4 residues were similar, whereas that of acid-treated RS4 residue was different from them. RS showed different hydrolytic behavior by acid and ${\alpha}$-amylase depending on the type, and susceptibility of RS3 was higher than that of RS4.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.273-273
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• 2022

The increasing number of Westernized eating patterns based on wheat flour in Korea has led to an increase in the rate of diseases such as obesity and diabetes, which has become a social problem. Wheat consumption is increasing due to changes in eating habits, but domestic wheat has low price competitiveness and has stagnated recently, so it is necessary to secure new resources to differentiate from imported wheat. Resistant starch, a newly created resource in domestic wheat, can act as a prebiotic similar to dietary fiber in the body, inducing microbial changes in the gut and having beneficial effects on metabolic syndrome. Wheat research on resistant starch was carried out based on the breeding of high amylose. A genome-wide association study (GWAS) was used to perform SNP identification and expression analysis related to wheat amylose through phenotype and genotype. 561 wheat core collection gene sources were investigated for amylose content in wheat, and related genes were extracted and analyzed. In the GWAS analysis, the model formulas BLIMK, FarmCPU, GLM, MLM, and MLMM were used to derive results such as QQ plots and Manhattan plots through phenotypic data. Among these models, BLAST was conducted to find the association between the SNPs identified using FarmCPU and genes related to starch, and 15 were found. Using the identified markers, it becomes easier to develop and browse related wheat cultivars according to their amylose content.

• Korean Journal of Food Science and Technology
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• v.32 no.2
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• pp.328-334
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• 2000

A study was conducted to investigate the effect of ACAMS(Autoclaved-cooled amylomaize VII) and ACNMS(Autoclaved-cooled normal maize starch) containing resistant starch(RS) on ASW (Australian wheat flour) rheology and noodle quality. The water absorption in farinograph increased with the addition of ACAMS and ACNMS, but the dough stability decreased with the addition. The ACNMS added flours showed the highest initial pasting temperature and the lowest peak viscosity in RVA. The addition of ACAMS and ACNMS were not effective on the weight and volume of cooked noodles during cooking time for 5 min. However, as the cooking time increased, noodle weight and volume were the highest in control(no RS added flour) and the lowest in ACNMS added flours. Noodle texture was evaluated using rheometer. The hardness of RS(ACAMS, ACNMS) added noodles was higher than that of control. Cohesiveness was significantly different between control and ACAMS added noodles, but the cohesiveness of ACNMS added noodles was similar to other noodles. The elasticity of ACNMS added noodles in sensory test was lower than that of control but the smoothness and overall acceptibility were higher.