• Food Science and Preservation
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• v.24 no.4
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• pp.491-496
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• 2017

Paddy rice is typically stored during postharvest until rice grain is processed into brown rice and milled rice by hulling and milling procedure, respectively. Recently, instead of storing paddy rice, storage of brown rice has been in the spotlight because it is more convenient and economically feasible. Different brown rice cultivars with varying amylose contents including waxy rice, medium-waxy rice, and non-glutinous rice were stored in room temperature storage for four months, and the changes in grain qualities of brown rice were evaluated. Amylose content significantly affected pasting properties in which rice cultivar with higher amylose content showed longer pasting time and higher peak viscosity. Storage also affected pasting viscosities, showing an increase in peak viscosity, but a decrease in breakdown viscosity. The changes in pasting viscosity during storage could be an important starch property for aged brown rice utilization. Waxy brown rice showed the weakest aging property in terms of free fatty acids (FFA) accumulation, whereas non-glutinous rice was more substantial grain quality against aging. The FFA values of two months storage were not significantly different from the initial FFA contents, suggesting that brown rice stored in room temperature for two months could be feasible for direct consumption of brown rice.

• Korean Journal of Food Science and Technology
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• v.52 no.1
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• pp.31-39
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• 2020

The effects of heat-moisture treatment (HMT) on the functional properties of high amylose rice starches (HARSes) purified from Korean rice varieties (A-type Goami and Singil and B-type Dodamssal and Goami2) were investigated. HMT was accomplished with moisture contents of 18 and 27% and heated at 100℃ for 16 h. While the amylose content, swelling power and solubility decreased after HMT, the water binding capacity and resistant starch (RS) content increased with increasing moisture content after HMT. The X-ray diffraction patterns of all HARSes did not change after HMT, but a decrease in the intensity of peak at 2θ=5° was observed in B-type HMT HARSes. While the starch granules aggregated after HMT, their shape and size remained unchanged. B-type HARSes exhibited higher gelatinization temperatures and lower pasting viscosities than A-type HARSes following HMT. The results, thus, suggest that while the crystalline intensity of B-type Dodamssal and Goami2 rice starches did not change after HMT, the RS content, water binding capacity, and pasting temperatures of all HARSes increased with increasing moisture content after HMT.

• Korean Journal of Food Science and Technology
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• v.40 no.6
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• pp.603-610
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• 2008

The principal objective of current study was to evaluate the potential of near infrared reflectance spectroscopy (NIRS) as a non-destructive method for the prediction of the amylose and protein contents of un-hulled and brown rice in broad-based calibration models. The average amylose and protein content of 75 rice accessions were 20.3% and 7.1%, respectively. Additionally, the range of amylose and protein content were 16.6-24.5% and 3.8-9.3%, respectively. In total, 79 rice germplasms representing a wide range of chemical characteristics, variable physical properties, and origins were scanned via NIRS for calibration and validation equations. The un-hulled and brown rice samples evidenced distinctly different patterns in a wavelength range from 1,440 nm to 2,400 nm in the original NIR spectra. The optimal performance calibration model could be obtained by MPLS (modified partial least squares) using the first derivative method (1:4:4:1) for un-hulled rice and the second derivative method (2:4:4:1) for brown rice. The correlation coefficients $(r^2)$ and standard error of calibration (SEC) of protein and amylose contents for the un-hulled rice were 0.86, 2.48, and 0.84, 1.13, respectively. The $r^2$ and SEC of protein and amylose content for brown rice were 0.95, 1.09 and 0.94, 0.42, respectively. The results of this study suggest that the NIRS technique could be utilized as a routine procedure for the quantification of protein and amylose contents in large accessions of un-hulled rice germplasms.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.04a
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• pp.42-42
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• 2019

This study was carried out to build a database system for amylose and protein contents of rice germplasm based on NIRS (Near-Infrared Reflectance Spectroscopy) analysis data. The average waxy type amylose contents was 8.7% in landrace, variety and weed type, whereas 10.3% in breeding line. In common rice, the average amylose contents was 22.3% for landrace, 22.7% for variety, 23.6% for weed type and 24.2% for breeding line. Waxy type resources comprised of 5% of the total germplasm collections, whereas low, intermediate and high amylose content resources share 5.5%, 20.5% and 69.0% of total germplasm collections, respectively. The average percent of protein contents was 8.2 for landrace, 8.0 for variety, and 7.9 for weed type and breeding line. The average Variability Index Value was 0.62 in waxy rice, 0.80 in common rice, and 0.51 in protein contents. The accession ratio in arbitrary ranges of landrace was 0.45 in amylose contents ranging from 6.4 to 8.7%, and 0.26 in protein ranging from 7.3 to 8.2%. In the variety, it was 0.32 in amylose ranging from 20.1 to 22.7%, and 0.51 in protein ranging from 6.1 to 8.3%. And also, weed type was 0.67 in amylose ranging from 6.6 to 9.7%, and 0.33 in protein ranging from 7.0 to 7.9%, whereas, in breeding line it was 0.47 in amylose ranging from 10.0 to 12.0%, and 0.26 in protein ranging from 7.0 to 7.9%. These results could be helpful to build database programming system for germplasm management.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.56 no.4
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• pp.293-298
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• 2011

Physical and structural characteristics of four local barnyardgrass flour and starch were investigated. Amylose content ranged from 6.9 to 12.5%. The BP 3563 and BP 3606 were low amylose lines, and the BP 3592 and BP 3610 showed very low amylose lines. Peak viscosities of four barnyardgrass collections BP-3563, BP-3592, BP-3606, and BP-3610 ranged 264 to 2397. All barnyard grass lines displayed an A-type X-ray diffraction pattern showing the strong diffraction peak at around $2{\theta}$ values $15^{\circ}$, $17^{\circ}$, $18^{\circ}$ and $23^{\circ}$, and a small peak at $20^{\circ}$ $2{\theta}$. Scanning electron microscopy revealed that the starch granule sizes ranged $5.5-12.5{\mu}m$ in diameter showing polygonal and rarely spherical in shape with round edges and some pores at the surface. Starch crystallinity of BP 3563, BP 3592, BP 3606, and BP 3610 was 23.9, 25.0, 24.7, and 25.5%, respectively.

• Korean Journal of Soil Science and Fertilizer
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• v.51 no.1
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• pp.61-70
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• 2018

This study was carried out to review and compare crop cultivations upon chemical properties of paddy soil and qualitative characteristics of rice in Sejong-city from a point of view of farming extension to rice farmers and to utilize the result of the study as a basic guideline for precise agricultural practice. The pH in soils of Sejong was about 6.1-6.6 and had no difference with an average pH of paddy soils in Chung-Nam with pH 6.1. However, the average of organic matter, calcium (Ca) and available silicate in Sejong was lower than the average of them in Chung-Nam. The yields of rice were higher in 2010 than in 2011 and 2012, and the protein contents of rice were the highest in 2011 while the lowest water contents of rice in 2011. The protein contents upon regions were the highest in 2011 with 6.1%, and the amylose contents were the highest in Yeondong-myun, Jeoneu-myun, and Yeonseo-myun in 2010 while Kumnam-myun and Jeondong-myun were the highest in 2012. With the increase of precipitation, the protein content level in rice was increased while the amylose content level tended to decrease. Correlations between the chemical properties of paddy soil and the quality of rice and between level of organic matter in soil and amylose contents were negative (r = -0.507), and the correlation between the moisture contents and amylose contents (r = 0.419) and between the water contents and whiteness (r = 0.485) were positive. Because the quantity and quality of rice yield is determined by the soil characteristics, the consultation to farmers for the proactive soil analysis and for the maintenance of stable level of pH, organic matter and available silicate based on historical results of analysis is highly recommended. Also, the analysis on the effect of the weather and the soil characteristics affecting the quality and quantity of rice would be another good way.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.53 no.3
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• pp.285-291
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• 2008

This study was performed to find out starch properties of rice grains in three varieties with different amylose content, Ilpumbyeo (non-waxy), Goami2 (high amylose), and Hwasunchalbyeo (waxy rice). There was no difference among physico-chemical characteristics of rice grains, but Goami 2 showed $2{\sim}3$ folds higher crude fat (1.36%) than Ilpumbyeo. Pasting properties of RVA showed the highest values of maximum viscosity, breakdown, and final viscosity in Ilpumbyeo. A similar chain length distribution of amylopectin was found in Ilpumbyeo and Hwasunchalbyeo, indicating that DP 12 had the highest distribution. Goami 2 had the highest distribution in DP 14, and showed the lower percent (14.1%) than other rice cultivars. Thermal properties of DSC showed that the values of Tc and Tp of Hwasunchalbyeo were similar to Ilpumbyeo, whereas a slightly higher Tc was observed. The absorbtion enthalpy was also the highest (11.1 mJ/mg) in Hwasunchalbyeo. Goami 2 showed higher To, but the lowest enthalpy (6.52 mJ/mg) compared to Ilpumbyeo (7.92 mJ/mg). Retrogradation properties, which were measured with the gelatinized rice sample used for DSC, and stored in $4^{\circ}C$ during 6 days, indicated that retrogradation absorbtion peak was the first peak at $52.6{\sim}55.2^{\circ}C$, and the second peak above $95^{\circ}C$. Retrogradation enthalpy of Goami 2 was the highest value (5.12 mJ/mg).

• KOREAN JOURNAL OF CROP SCIENCE
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• v.54 no.1
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• pp.13-23
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• 2009

To intensively analyze and examine the changes in palatability of cooked rice and structural properties of rice grains influenced by increased nitrogen topdressing during the panicle formation and ripening stage, a series of experiments were carried out using three japonica rice cultivars with contrasting rice quality characteristics. The protein content of brown rice increased maximally up to $35{\sim}47%$ of that in standard N6 plot with the increase in nitrogen topdressing fertilizer during 20 days before heading to 10 days after flowering. The high-yielding rice cultivars showing poor palatability of cooked rice revealed larger increase in protein content of rice grains by increased nitrogen topdressing. Under the same nitrogen level of 15 kg per 10a with nitrogen topdressing at 3 kg/10a, high-yielding rice cultivars, Yumehikari and Reihou showed the significant increase in protein content of brown rice when topdressing was applied at 10 days after flowering as compared with when it was applied at 30 days after transplanting. Although the variation in amylose content of milled rice as affected by nitrogen topdressing level was relatively small, it decreased within 1% with the opposite tendency against increased protein content of brown rice by increased nitrogen topdressing. The total score of sensory evaluation was higher in the order of Hinohikari < Yumehikari < Reihou in panel test. It decreased significantly by increased amounts of nitrogen topdressing during 20 days before heading to 10 days after flowering when nitrogen level was higher than 12 kg/10a. The more poor palatable rice cultivar in panel test revealed the larger decreasing in total score of sensory evaluation by higher nitrogen topdressing rates. All sensory evaluation components were largely affected by the change in protein content of brown rice rather than amylose content of milled rice. The influence of protein content to palatability of cooked rice was larger in poor-palatable rice than in high-palatable rice. The protein content decreased drastically from outer layer to inner layer of rice grains, while the amylose content increased on the contrary. The high-palatable rice exhibited higher distribution of protein content on bran layer but lower distribution of protein content on the layer of polished rice as compared with the poor-palatable rice. Especially, the high-palatable rice showed also significantly lower distribution of amylose content on the outer layer of polished rice as compared with the poor-palatable rice.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.60 no.4
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• pp.448-457
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• 2015

Developing rice lines with various amylose contents is necessary to diverse usages of rice in terms of raw materials for processed food production, and thereby to promote rice consumption in Korea. A rice mutant line, 'Namil(SA)-dull1' was established through sodium azide mutagenesis on 'Namil', a non-glutinous Korean Japonica rice cultivar. Namil(SA)-dull1' had dull endosperm characteristics and the evaluated amylose content was 12.2%. A total of 94 F2 progenies from a cross between 'Namil(SA)-dull1' and 'Milyang23', a non-glutinous Tongil-type rice cultivar, was used for genetic studies on the endosperm amylose content. Association analyses, between marker genotypes of 53 SSR anchor markers and evaluated amylose contents of each 94 F2:3 seeds, initially localized rice chromosome 6 as the harboring place for the modified allele(s) directing low amylose content of 'Namil(SA)-dull1'. By increasing SSR marker density on the putative chromosomal region followed by association analyses, the target region was narrowed down 0.94 Mbp segment, expanding from 28.95 Mbp to 29.89 Mbp, on rice chromosome 6 pseudomolecule. Among the SSR loci, RM7555 explained 84.2% of total variation of amylose contents in the $F_2$ population. Further physical mapping on the target region directing low amylose content of 'Namil(SA)-dull1' would increase the breeding efficiency in developing promising rice cultivars with various endosperm characteristics.

• Food Science and Biotechnology
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• v.18 no.1
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• pp.118-123
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• 2009

In order to find out the effect of low level of starch acetylation on physicochemical properties of potato starch, amylose content, digestibility of raw and gelatinized starch, thermal properties, pasting properties, and the swelling power of native and acetylated potato starches were measured. The amylose content was significantly lower in acetylated starch than in their counterpart native starches. Though a tendency in the decrease in digestibility of raw starch was observed with starch acetylation, acetylation did not alter the proportion of readily digestible starch (RDS), slowly digestible starch (SDS), and resistant starch (RS) of both raw and gelatinized potato starches. No clear increase in the swelling power was observed, however, the peak and onset gelatinization temperatures and the enthalpy required for starch gelatinization decreased with starch acetylation. Peak and breakdown viscosities were reduced due to acetylation of potato starch while final viscosity and set back were increased.