Koan-Sik Woo

Physicochemical Characteristics of Korean Traditional Wines Prepared by Addition of Sorghum (Sorghum bicolor L. Moench) Using Different Nuruks

This study was carried out to compare the physicochemical characteristics of Korean traditional wines fermented by addition of sorghum (Sorghum bicolor) using different nuruks (SH and BS nuruk). The alcohol contents of the fermented wines ranged from 12.36 to 13.21%. The brix degrees of sorghum wines fermented using SH and BS nuruks were 8.6~17.9Bx and 7.6~20.0Bx on addition ratio, respectively. Wine no addedsorghum using SH and BS nuruks showed pH 3.74 and 3.40, total acidity of 1.40 and 1.51%, and 0.441 and 0.149 of turbidity. With increase of sorghum addition, brix degree, pH, turbidity and L-value decreased whereas total acidity and a-value increased. Total color difference (ΔEab) parameters of wines fermented in 30, 70 and 100% sorghum addition using SH and BS nuruk were 4.33, 6.63 and 26.13, and 4.08, 5.29 and 10.59. Glucose content decreased with increasing amounts of sorghum. Organic acids such as lactic acid and acetic acid were predominantly detected in the fermented wine. Finally, based on sensory evaluations, the wine fermented by BS nuruk showed the best overall quality at 30% sorghum addition.

Effects of Heat Treatment and Extraction Method on Antioxidant Activity of Several Medicinal Plants

We investigated the effects of heat treatment and extraction method on the antioxidant activities of five medicinal plants: Cyperus rotundus, Eucommia ulmoides, Bupleurum falcatum, Achyranthes japonica Nakai, and Akebia quinata. Extraction was performed with only ultrasound, ultrasound after heating at for 2 hours, and reflux extraction with distilled water. The phenolic contents of reflux extraction and ultrasound extraction after heating were higher than only ultrasound extraction, and ultrasound extraction after heating samples was higher than reflux extraction except for Eucommia ulmoides and Cyperus rotundus. Total flavonoid content was higher in reflux and ultrasound extraction after heating samples than only ultrasound extraction, except for Cyperus rotundus. ABTS radical scavenging activity was higher in reflux extraction and ultrasound extraction after heating a sample, than only ultrasound extraction. DPPH radical scavenging activity was higher in reflux extraction except for Achyranthes japonica Nakai and Akebia quinata. The reducing power of ultrasound extraction after heating was higher with Achyranthes japonica Nakai. From the results of this study, we can expect to increase the antioxidant activity of medicinal plant extracts by applying suitable extraction and pretreatment conditions on the type of medicinal plant.

Antioxidant Compounds and Antioxidant Activities of Different Varieties of Foxtail Millet and Proso Millet according to Cultivation Time

Effects of cultivation time on the antioxidant contents and activities of foxtail millet and proso millet were determined. The cultivation times were early-season (ES), normal-season (NS), and late-season (LS), and the cultivated varieties were Hwanggeum-cho (HGC), Cheongcha-cho (CCC), Samdamae (SDM), Gyeongkwan 1 (GK 1), Gyeongkwan 2 (GK 2), Ganghae-cho (GHC), Hwanggeum-gijang (HGG), Manhongchal-gijang (MHCG), Byeoruk-gijang (BRG), Norangchal-gijang (NRG), and Whin-gijang (WG). The total polyphenol, flavonoid, tannin content, and DPPH and ABTS radical scavenging activities of the methanolic extracts of foxtail millet and proso millet showed significant differences according to cultivation variety and time. The highest total polyphenol content of foxtail millet was 29.33 mg of gallic acid equivalent (GAE)/g of sample in GK 1 at LS, whereas that of proso millet was 23.48 mg of GAE/g of sample in BRG at LS. The highest total flavonoid content of foxtail millet was 2.12 mg of catechin equivalent (CE)/g of sample in CCC at ES, whereas that of proso millet was 4.49 mg of CE/g of sample in BRG at LS. The highest total tannin content of foxtail millet was 14.07 mg of tannic acid equivalent (TAE)/g of sample in SDM at LS, whereas that of proso millet was 15.59 mg of TAE/g of sample in BRG at LS. The highest DPPH radical scavenging activity of foxtail millet was 7.71 mg of TE/g of sample in CCC at NS, whereas that of proso millet was 12.66 mg of TE/g of sample in BRG at LS. The highest ABTS radical scavenging activity of foxtail millet was 8.05 mg of TE/g of sample in GK 1 at LS, whereas that of proso millet was 34.46 mg of TE/g of sample in BRG at LS. Generally, HGC, GK 1, and GHC had more beneficial effects at LS than ES or NS, whereas CCC, SDM, and GK 2 had more beneficial effects at NS than ES or LS, and proso millet had more beneficial effects at LS than ES or NS.

Effects of Soil Organic Matter Contents, Paddy Types and Agricultural Climatic Zone on CH 4 Emissions from Rice Paddy Field

To evaluate the effects of abiotic factors of paddy fields on greenhouse gases (GHGs) emissions from rice paddy fields, CH4 emission amounts were investigated from rice paddy fields by different soil organic matter contents, paddy types, and agricultural climatic zone in Yeongnam area during 3 years. CH4 emission amounts according to soil organic matter contents in paddy field were conducted at having different contents of 5 soil organic matters fields (23.6, 28.7, 31.0, 34.5, and 38.0 g kg -1 ), The highest CH4 emission amount was recorded in the highest soil organic matters plot of 38.0 g kg -1 . High correlation coefficient (r=0.963 ** ) was obtained between CH4 emissions from paddy fields and their soil organic matter contents. According to paddy field types, CH4 emission amounts were investigated at 4 different paddy fields as wet paddy, sandy paddy, immature paddy, and mature paddy. The highest CH4 emissions was recorded in wet paddy (100%) and followed as immature paddy 64.0%, mature paddy 46.8%, and sandy paddy 23.8%, respectively. For the effects of temperature on CH4 emissions from paddy fields, 4 agricultural climatic zones were investigated, which were Yeongnam inland zone (YIZ), eastern coast of central zone (ECZ), plain area of Yeongnam inland mountainous zone (PMZ), and mountainous area of Yeongnam inland mountainous zone (MMZ). The order of CH4 emission amounts from paddy fields by agricultural climatic zone were YIZ (100%) > ECZ (94.6%) > PMZ (91.6%) > MMZ (78.9%). The regression equation between CH4 emission amounts from paddy fields and average air temperature of Jul. to Sep. of agricultural climatic zone was y = 389.7x–4,287 (x means average temperature of Jul. to Sep. of agricultural climatic zone, R 2 =0.906 * )

Development of a waxy gene real-time PCR assay for the quantification of sorghum waxy grain in mixed cereal products

BackgroundWaxy-grain sorghum is used in most of the commercial cereal products in Korea. Worldwide, three waxy mutant alleles have been identified in the sorghum germplasm, and DNA markers for these alleles have been developed to identify the waxy genotype. However, that detection method cannot be used to determine the proportion of waxy content in samples containing both waxy and non-waxy sorghum. This study developed an assay that can be used to detect and quantify the waxy content of mixed cereal samples.ResultsAll Korean waxy-grain sorghum used in this study contained the wxa allele, and one wxa allele-containing individual was also heterozygous for the wxc allele. No individuals possessed the wxb allele. The genotyping results were confirmed by iodine staining and amylose content analysis. Based on the sequence of the wxa allele, three different types of primers (wxa allele-specific, non-waxy allele-specific, and nonspecific) were designed for a quantitative real-time PCR (qPCR) assay; the primers were evaluated for qPCR using the following criteria: analytical specificity, sensitivity and repeatability. Use of this qPCR assay to analyze mixed cereal products demonstrated that it could accurately detect the waxy content of samples containing both waxy and non-waxy sorghum.ConclusionsWe developed a qPCR assay to identify and quantify the waxy content of mixed waxy and non-waxy sorghum samples as well as mixtures of cereals including sorghum, rice and barley. The qPCR assay was highly specific; the allele-specific primers did not amplify PCR products from non-target templates. It was also highly sensitive, detecting a tiny amount (>0.5%) of waxy sorghum in the mixed samples; and it was simple and repeatable, implying the robust use of the assay.

A medium maturing, glutinous foxtail millet (Setaria italica Beauv.) variety 'Samdachal'.

‘Samdachal’ is a foxtail millet variety developed and registered by Department of Functional Crop, NICS, RDA in 2011. This variety was developed through pure line breeding method from Jeju landrace. ‘Samdachal’ is a medium maturing variety having 133 days of growth duration from transplanting to harvesting in Milyang of Korea. The culm length is about 128 cm which is longer culm length than standard variety ‘Hwanggeumejo’. However it is adapted to mechanized cultivation because it is tolerant to lodging in field. The panicle shape is a cylinder type and the length is 28cm. Regarding to the grain, color and endosperm characteristics are grey and glutinous. The Calcium, Magnesium and polyphenol contents in grain are showed higher than standard variety ‘Hwanggeumejo’. The milled yield performance of this variety is about 2.24 MT/ha in local adaptability test from 2010 to 2011. ‘Samdamchal’ would be adaptable to plain area of Korea.