• Korean Journal of Agricultural Science
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• v.42 no.3
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• pp.151-158
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• 2015

This study was conducted to know the variation and relationship of rice grain quality and starch pasting properties by transplanting times. Two early maturing rice cultivars which accounted for the most area of early maturing rice cultivar in Chungnam province were used. The experiment was laid out in a split-plot design with 3 replications. The main plot consisted of three transplanting times viz. early (April 25), ordinary (May 25) and late (June 25) with sub-plots containing two cultivars. According to the transplanting times, most of rice grain quality and starch pasting properties showed significant difference and Joami showed higher grain quality than Unkwang in all transplanting times. Especially, rice grain quality was improved when transplanted late, showing high head rice and glossiness of cooked rice due to the lower mean temperature during grain filling stage. Glossiness of cooked rice was positively correlated with head rice ratio, amylose content and setback value, and negatively correlated with chalky rice ratio and protein content. The highest positive and negative correlation were observed between breakdown value and peak viscosity ($r=0.98^{**}$), and breakdown and setback ($r=-0.94^{**}$), respectively. These results provide some information for rice researchers and producers producing cultivars with an improved quality, suggesting that rice quality is highly influenced by temperature at grain filling stage, and transplanting times is crucial in improving rice quality. In addition, starch pasting properties are useful for determining rice quality because rice grain quality and starch pasting properties are dependent on each other.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.68 no.3
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• pp.99-105
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• 2023

Starch characteristics and pasting properties of Tongil-type rice varieties with different amylose content were analyzed. Three different Tongil-type rice varieties and one Japonica-type rice variety were examined for their properties. Tongil-type rice varieties have longer panicles and higher rice yield (721-765 kg per 10a) than Boramchan, a Japonica-type high-yield rice variety. The protein content of the Tongil-type rice variety was higher than that of Boramchan. Japonica-type rice varieties had lower amylose content than Japonica-type rice varieties, except for Amimyeon (Milyang355). Amimyeon had higher protein content than the other varieties, and its amylose content was particularly high at 39.2%. The distribution of starch granule sizes of the four varieties was similar, and the particle size corresponding to D50 was approximately 87.8-81.9 ㎛. The pasting properties of rice flour varied among varieties. The Dasanbyeo and Hanarum2 amylogram patterns were similar. These two varieties had a higher peak viscosity (PV) and lower setback (SB) than Boramchan. In the case of Amimyeon, the hot paste viscosity (HPV), cool paste viscosity (CPV), and SB were significantly higher than those of the other Toingil-type varieties, and the breakdown (BD) was very low, showing pasting properties significantly different from that of the other varieties. The onset (T_o), peak (T_p), and conclusion temperature (Tc) of gelatinization of rice flour from Amimyeon were lower than those of the other tested varieties. In addition, the gelatinization temperature, measured using differnetial scanning calorimetry (DSC), and BD, measured using al rapid visco analyzer (RVA) were low in Amimyeon. Amylose content showed a high positive correlation with pasting time (PTi), HPV, and SB and a negative correlation with PV and BD.

• Korean Journal of Human Ecology
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• v.14 no.6
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• pp.1037-1046
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• 2005

Using three consecutive years' harvested rices and their starches isolated from rice flours by alkaline method, it was found that no significant aging effect on rice flour and starch was observed based on following results. Proximate data of flours or starches showed in similarity, except high level of crude fat in rice flour and rice starch harvested in 2002. In SEM, the surface of aged rice flour had slightly layered shape due to possible abrasion during storage, and that of aged starch showed more smooth and less rigid polygonal shape. X-ray diffraction patterns of flours and starches were all A type, and crystallinity of rice starch harvested in 2000 had the smallest. From tristimulus colorimetry (Hunterlab Color), total color difference ($\Delta$E) calculated from L, a, and b gave less color difference with the darkest in 2002 harvested one among flours and the lightest in 2001 one among starches. WBCs of both 2002 rice flour and starch were the lowest among samples studied. At 80$^{\circ}C$, swelling power and solubility of rice starches harvested in 2000, 2001 and 2002 were 14.35, 9.75; 14.04, 9.6; and 12.49, 8.82, respectively. The highest peak viscosities measured by RVA were shown both in 2001 rice flour and in its starch. Starch and milled rice flour harvested in 2000 had higher hydrolytic $\alpha$-amylase, compared to other flour and starch samples.

• Korean Journal of Food Science and Technology
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• v.36 no.4
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• pp.568-573
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• 2004

Effects of dry heating and pH on pasting, thermal, and textural properties of corn starch containing soy protein isolate (SPI) were investigated. Samples were prepared by drying corn starch dispersions containing 3% SPI at $40^{\circ}C$ (unheated sample) or additionally heating dried mixtures at $130^{\circ}C$ (heated sample). Pasting properties of starch samples and textural properties of starch gels were measured using Rapid Visco-Analyzer (RVA) and Texture Analyzer (TA), respectively. Effects of SPI addition and dry heating on retrogradation and microstructure of gel samples were investigated using DSC and SEM, respectively. Pasting viscosity of dry-heated samples was significantly higher than that of unheated samples, and at pH 8 compared to pH 6. Dry-heat treatment decreased fracture stress and strain of starch gels containing SPI. No significant effects of dry-heat treatment and pH were observed on retrogradation of starch gels. Addition of SPI retarded starch retrogradation and modified starch gel properties with increased nutritional value. Dry-heat treatment with SPI could be possible method for starch modification.

• Food Science and Biotechnology
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• v.17 no.1
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• pp.52-57
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• 2008

The effects of transglutaminase (TG) on the pasting and rheological properties of different wheat cultivars ('Sharpshooter', 'Russ', and 'AcAriss') blended with barley (40%) or soy (20%) flour were investigated. In the rapid visco-analyzer (RVA) pasting profile, the addition of barley or soy flour to wheat flour samples induced a decrease in peak, trough, final viscosity, breakdown and setback values. However, TG treatment of these blends significantly increased peak viscosity and breakdown (p<0.05). In particular, TG treatment greatly increased the breakdown of wheat flour blended with soy flour, indicating that the cross-linking of proteins through TG may somehow be related to an increase in starch granule rupturing in pastes. Storage (G') and loss (G") moduli of the sample pastes increased with an increase in frequency ($\omega$), while complex viscosity (${\eta}*$) decreased. In all wheat cultivars, G', G", and $\eta$ were decreased by the addition of barley or soy flour, or TG treatment. Results suggest that protein cross-linking by TG can produce unique and improved properties in wheat flours blended with barley or soy flour.

• Korean Journal of Food Science and Technology
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• v.51 no.2
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• pp.109-113
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• 2019

The soft rice varieties, Hangaru and Singil, were developed via mutation breeding using N-methyl-N-nitrosourea treatment to obtain dry-milled rice flours. The physicochemical, morphological, and pasting properties of these starches were compared with those of Seolgaeng and Chuchung starches. Singil starch was found to exhibit the highest amylose content and initial pasting temperature, whereas Hangaru starch exhibited the highest water binding capacity and swelling power. Hangaru starch's granule size at $d_{50}$ was the largest among the four different starch types. Some Seolgaeng, Hangaru, and Singil granules were observed to have a round-faced polygon shape. Furthermore, the crystallinity of all four starch types was type A. The peak, trough, and final viscosities of the soft rice starches were also lower than those of normal starches. Notably, Hangaru starch showed the highest breakdown viscosity, but the lowest total setback viscosity among the four starches. From these results, the starch characteristics of the soft rice flours were discovered to be different based on the rice variety.

• The Korean Journal of Community Living Science
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• v.23 no.4
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• pp.537-552
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• 2012

This study was conducted to investigate the quality characteristics of cooked rice with cereals frequently consumed in Korea by blending ratio. Seven kinds of cereals, white rice, glutinous barley, brown rice, black rice, glutinous rice, glutinous foxtail millet and proso millet, were chosen for the study. According to the results from rapid viscosity analyzer, glutinous barley had the lowest pasting temperature($66.55^{\circ}C$) and black rice had the highest values in the peak(231.77 RVU), trough(162.25 RVU), final viscosity(295.81 RVU) and set back(64.05 RVU)(p<0.05). Water absorption rate by soaking time for black rice and brown rice was increased only 18.77% and 14.57%, respectively, even after 120 minutes, whereas those of other cereals were increased up to 20.28~39.32% after 50 minutes. The pasting characteristics of white rice blended with cereals tended to be lower than white rice in the peak, trough, and final viscosity. Textural property of cooked white rice blended with black rice, brown rice, and glutinous foxtail millet showed a significantly higher value for hardness than that of cooked white rice only(p<0.05). The most preferred blending ratio of the respective cereals was 25% for glutinous barley, 10% for black rice, brown rice and proso millet, and 5% for glutinous foxtail millet and glutinous rice in the sensory evaluation for overall quality, but there were no significant differences except glutinous barley, brown rice and glutinous foxtail millet.

• Food Science and Biotechnology
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• v.18 no.4
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• pp.991-995
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• 2009

As a principle ingredient in omija-eui, the physicochemical properties of mung bean starch (MBS) paste were investigated and compared to those of rice and corn starch. The amylose and the protein content of MBS were higher than those of rice or corn starch while the total sugar content and the swelling power of MBS were lower. In addition, the clarity of MBS paste was higher than either rice or corn starch paste. Regarding pasting properties, the peak viscosity and cool paste viscosity of MBS were higher than those of either rice or corn starch. During the freeze-thaw cycle, MBS exhibited higher degree of syneresis than corn and rice starch, which decreased with high starch concentration and heating temperature. The paste properties and freeze-thaw stability of MBS showed a potential for improving the quality of omija-eui.

• Korean journal of food and cookery science
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• v.30 no.4
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• pp.385-393
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• 2014

This study investigated both the chemical and antioxidative characteristics of wheat flour added with 10, 20 and 30% immature chalssalbori flour; further, the quality characteristics of bread dough during yeast fermentation were assessed. As the addition rate of chalssalbori flour into wheat flour increased, the DPPH radical scavenging capacity, water absorption index, water solubility index and viscosity were all increased. Moreover, the bread dough with an increased addition rate of chalssalbori flour demonstrated an increased pH, reduced fermentative expansion power and a darker yellowish color. The bread dough added with chalssalbori flour after mixing showed higher hardness, gumminess and adhesiveness, but lower cohesiveness and springiness compared to the control; however, these texture characteristics were changed during fermentation. In the present study, the mixed flour with 10% immature chalssalbori flour conveyed similar pasting characteristics to those of wheat flour; moreover, its bread dough showed higher springiness and fermentative expansion power. Furthermore, a delay effect of starch retrogradation can be expected compared to the control.

• Preventive Nutrition and Food Science
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• v.10 no.3
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• pp.207-213
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• 2005

Molecular structures and functional properties of starches isolated from normal, waxy, and zero amylose barleys were examined. Amylopectins from zero amylose starch had the largest molecular weight $(M_w)$, whereas those from high amylose starch, the smallest. A good correlation between the $(M_w)$ and the radius of gyration $(R_g)$ was observed among amylopectins from various starches, indicating similar polymeric conformation in solution even with the differences in the $(M_w)$. The debranched amylopectin molecules from different types of barley starches exhibited similar profiles, implying that the packing geometry of double helices in the different types of barley starches may be similar. Zero amylose starch showed the highest peak viscosity (326 RVU) in RV A viscograms at lower pasting temperature $(67.6^{\circ}C)$, compared to normal and high amylose starches. Relationship between RVA peak viscosity and amylose content suggested that the presence of amylose inhibited the development of granular swelling of barley starches during cooking. A rapid retrogradation, traced by differential scanning calorimetry (DSC) and strain-controlled rheometry, occurred in the high amylose starch sample during storage, while zero amylose starch showed a very good resistance to retrogradation, indicating excellent storage stability.