Keum Taek Hwang

Production of γ-aminobutyric acid in black raspberry juice during fermentation by Lactobacillus brevis GABA100

Black raspberry juice was fermented to produce gamma-aminobutyric acid (GABA) using lactic acid bacteria (Lactobacillus brevis GABA 100) at different temperatures (25, 30, or 37 degrees C) and pHs (3.5, 4, 4.5, 5, 5.5, or 6) for 15 days. Concentrations of GABA in the juices were determined during fermentation using HPLC. GABA was produced continuously even if the viable bacterial counts markedly decreased. The fermentation at 30 degrees C generally showed higher production of GABA in the juices than those at 25 and 37 degrees C. The GABA in the juices fermented at 30 degrees C reached the maximum levels on the 12th day. The juices fermented at lower pH and lower temperature showed a lower degradation of monomeric anthocyanins. The results suggest that black raspberry juice can be GABA enriched using lactic acid bacteria.

Policosanol Contents and Composition of Grain Sorghum Kernels and Dried Distillers Grains

ABSTRACT Grain sorghum can be a major source of policosanols, long-chained alcohols, that have beneficial physiological activities. Sorghum dried distillers grains (DDG), a by-product of ethanol production from grain sorghum, contain a large amount of policosanols. Content and composition of policosanols in long-chained lipids extracted from grain sorghum kernels and DDG were determined. Long-chained lipids were extracted using hot hexane or hot ethanol. The major components of the long-chained lipids extracted from grain sorghum kernels, as determined using HPLC, were policosanols (37–44%), aldehydes (44–55%), and acids (4–5%). Long-chained lipids from DDG contained 52% policosanols, 23% aldehydes, 6.4% acids, and 17% wax esters/steryl esters. Composition of policosanols in DDG matched the composition in grain sorghum kernels, as determined by gas chromatography, even though the content of policosanols in DDG was greater than the content in grain sorghum kernels. Policosonal composition ranges were 0–1% ...

EXTRACTION OF LIPIDS FROM GRAIN SORGHUM DDG

Soxhlet and recirculated solvent extraction methods were used to extract lipid materials from grain sorghum DDG. The lipid content in DDG with a moisture content of 6.7% (dry basis) was as high as 9.32% of the dried DDG as determined by Soxhlet extraction with n-hexane. There was a slight increase in the lipid yield from 9.21% to 9.68% when the moisture contents increased from 2.1% to 17.4% (d.b.). Thin-layer chromatography (TLC) analysis showed that the sorghum lipids were composed of triacylglycerols, fatty acids, fatty alcohols, fatty aldehydes, free sterols, wax esters, and steryl esters. A bench-scale recirculated extraction system was used to investigate the extractability of lipid materials from the DDG under various experimental conditions including solvent to solid ratio (2:1 to 5:1), extraction temperature (45°C, 55°C, 68°C), and extraction time (1 to 6 h). The extractability of DDG lipid ranged from 70.3% to 94.5%. At extraction temperatures near the boiling point of n-hexane, a solvent to solid ratio of 3:1, and an extraction time of 4 h achieved the maximum lipid yield. There was no apparent increase in the extraction yield with further increase of the solvent to solid ratio or extraction time. ry-grind ethanol production continues to expand in the United States. More than 1.3 million metric tons of grain sorghum are used annually to pro- duce ethanol, and the number of tons used is ex- pected to increase in the future. Approximately 8.2 kg of dry residual in the form of distillers dried grains (DDG) remains from each 25 kg of grain sorghum used to produce ethanol. The DDG is sold solely as animal feed. Grain sorghum con- tains considerable amounts of lipid materials, including long- chained fatty acids, fatty aldehydes, fatty alcohols (policosonols), triacylglycerols, and other valuable compo- nents such as phytosterols, tocols, and diacylglycerols (Hwang et al., 2002a, 2002b, 2002c; Singh et al., 2003). There is an increasing interest in the components of sorghum lipid such as sterols, tocopherols, and unsaturated fatty acids, as they may play a preventive role in many diseases (Singh et al., 2003). The economic value of sorghum DDG would likely increase if its lipid materials were extracted and further refined to concentrate fatty acids, fatty aldehydes, policoso- nols, phytosterols, tocols, and diacylglycerols. Extraction techniques have been developed to obtain valuable commercial natural products with wide applications in the food, cosmetic, and pharmaceutical industries. Solvent

The Anti‐Obesity Effects of the Dietary Combination of Fermented Red Ginseng with Levan in High Fat Diet Mouse Model

In this study, to evaluate the anti‐obesity effects of fermented red ginseng (FG), levan (L), and their combination (FGL), we investigated their effects on the weights of body, liver and white adipose tissue, lipid profiles, and biomarkers for insulin resistance in high fat diet (HFD)‐induced obese C57BL/6J male mice. Furthermore, the levels of leptin in the serum were measured. FG (150 mg/kg/d), L (100 mg/kg/d), and FGL (150 mg/kg/d of FG plus 100 mg/kg/d of L) were administered orally to mice daily for 11 weeks. After 11 weeks feeding, FGL showed significantly lower body weight and fat mass with decreasing food efficiency ratio than the HFD control mice. In addition, the FGL group was significantly lower in the levels of total cholesterol and fasting blood glucose and score of the homeostatic model assessment of insulin resistance. Furthermore, FGL decreased serum leptin levels compared to the HFD control group. Taken together, FGL showed a significant anti‐obesity effect in HFD‐induced obese mice and prevent insulin and leptin resistance. FGL may be potentially useful for the prevention of obesity. Copyright

HPLC of grain sorghum wax classes highlighting separation of aldehydes from wax esters and steryl esters

This study was performed to develop HPLC methods for determining the composition of grain sorghum wax using a silica column and an ELSD. The method development emphasized separation of aldehydes from wax esters (WE) and steryl esters (SE). Gradient mobile systems using 0.2% (v/v) acetic acid and 0.02% (v/v) methyl tert-butyl ether (MTBE) in hexane and 0.2% (v/v) acetic acid in MTBE or hexane and 0.2% (v/v) acetic acid in MTBE separated aldehydes, acids, and alcohols, as well as minor components such as mixtures of WE and SE, and triacylglycerols (TG). Grain sorghum wax was composed of 46. 3% (w/w) fatty aldehydes, 7.5% fatty acids, 41.0% fatty alcohols, 0.7% hydrocarbons, 1.4% WE and SE, and 0.9% TG, based on HPLC data. The gradient HPLC systems were also useful for compositional analysis of carnauba wax. Carnauba wax contained of 34.3% (w/w) WE, 5.1% fatty acids, undetermined amount of fatty alcohols, and 3.0% TG.

Hydrocarbons detected in irradiated pork, bacon and ham

Hydrocarbons produced by γ-radiation of pork, bacon and ham were analyzed to determine how irradiation affects the production of the hydrocarbons and whether the hydrocarbons can be used for identifying post-irradiation of pork, bacon and ham. Hydrocarbons were determined by a sequential procedure of lipid extraction by hexane, Florisil column chromatography and gas chromatography. Hydrocarbons C17:1, C16:2, C17:2 and C16:3 were detected in pork, bacon and ham irradiated at 0.5 kGy or higher, but not in non-irradiated ones except C17:1. The detection levels in all the irradiated samples were in the order of C16:2, C17:1, C17:2 and C16:3 from the highest to the lowest.

Antioxidant and antiinflammatory activities of cyanidin-3-glucoside and cyanidin-3-rutinoside in hydrogen peroxide and lipopolysaccharide-treated RAW264.7 cells

Cyanidin-3-glucoside (C3G) and cyanidin-3-rutinoside (C3R) are 2 major anthocyanins found in Korean Rubus fruits (blackberries, raspberries, and black raspberries). The antioxidant and antiinflammatory effects of C3G and C3R in RAW264.7 murine macrophage cells were determined. Anthocyanins (5, 10, and 20 μg/mL) significantly (p<0.05) reduced H2O2-induced cytotoxicity in H2O2-stimulated RAW264.7 cells, compared with control cells. Incubation with C3G or C3R significantly (p<0.05) decreased intracellular reactive oxygen species and DNA damage (Hoechst and comet assay), and the cellular ferric reducing antioxidant power also increased, compared with control cells. Nitric oxide production in LPS-stimulated RAW264.7 cells treated with C3G and C3R was reduced by 41.9 and 34.4%, respectively. In addition, LPS-induced prostaglandin E2 production was significantly (p<0.05) inhibited by C3G (51.7%) and C3R (58.6%), compared with LPS-stimulated control cells. Protein expressions of iNOS and COX-2 decreased in cells treated with anthocyanins. Anthocyanins down-regulated NF-κB expression and up-regulated I-κB expression in LPS-treated macrophages.

The Qualities of Makgeolli (Korean Rice Wine) Made with Different Rice Cultivars, Milling Degrees of Rice, and Nuruks

This study aimed to characterize and compare makgeolli (a Korean rice wine) made using different raw materials. Five cultivars of rice and wheat flour were used as starch materials for makgeolli and assessed for their moisture, crude lipid, crude protein, and crude dietary fiber content. Overall, wheat flour was higher in crude lipid and crude protein and lower in moisture than rice. Makgeolli characteristics were assessed for pH, total acids, organic acids, free sugars, color and appearance. We found no significant differences in pH and total acids between makgeolli made from rice and wheat flour. In addition, the major free sugar in the makgeolli made from rice and wheat flour was glucose, although the content of total free sugars was lower in the wheat flour makgeolli (67.75 mg/mL) than the rice makgeolli (76.41~84.53 mg/mL). In terms of organic acids content, the total organic acid content was highest in the wheat flour makgeolli, while the major organic acids of the makgeolli made from rice and wheat flour were lactic acid and succinic acid, respectively. There were no significant differences in color values among rice makgeolli, but the rice makgeolli was higher in sensory scores (indicating preference) than the wheat flour makgeolli. As the degree of milling increased, moisture, crude lipid, and crude protein in the rice decreased. Acetic acid in the makgeolli also decreased, while there were no significant differences in pH, total acids, free sugars, color values, and sensory scores (except fruitiness). Traditional nuruk (TN) and cultured nuruk (CN) were compared as fermentation starters. Nuruk is a Korean traditional starter for fermentation of makgeolli and a raw material for makgeolli making. The pH in the makgoelli made with TN and CN were 4.29~4.65 and 4.02~4.23, respectively. Total organic acid content was higher in the TN makgeolli (3.5~6.3 mg/mL) compared to the CN makgeolli (2.3~4.3 mg/mL). The content of free sugars in the makgeolli made with CN was higher (59.44~73.34 mg/mL) than that with TN (56.45~59.75 mg/mL). The Hunter color test showed that makgeolli made with TN was lighter and higher in red and yellow color compared to CN. Overall sensory acceptability was higher in the CN makgeolli compared to the TN makgeolli.

Policosanol Contents and Compositions in Wax-Like Materials Extracted from Selected Cereals of Korean Origin

ABSTRACT Policosanols, long-chained alcohols, have been reported to have beneficial physiological activities. Content and composition of policosanols in wax-like materials extracted from selected cereals of Korean origin were determined. Wax-like materials were extracted using hot hexane. Yields of wax-like materials from unpolished grain sorghum, polished grain sorghum, brown rice, purple rice, wheat, and maize were 223, 37, 33, 61, 10, and 10 mg/100 g of dry kernels, respectively. Policosanol contents, as determined using HPLC, in the wax-like materials from the cereals were 33, 29, 6, 0, and 2% (w/w, db), respectively. Major alcohols in the policosanols from grain sorghum were octacosanol and triacontanol. Docosanol was the major alcohol in the policosanols from brown rice, purple rice, wheat, and maize.

Quality Characteristics of Black Raspberry Wine Fermented with Different Yeasts

Four different yeasts (Fermivin (FM), Saf-instant yeast red (SI), Angest wine active dry yeast (AW) and Angest instant yeast high sugar (AI)) were used for the fermentation of black raspberry wine. The amount of reducing sugars in FM (2.7%) and AI (2.8%) were higher than those in SI (2.4%) and AW (2.5%). The amount of glucose (the major free sugar) was higher in AW (2.57 mg/mL) and AI (2.50 mg/mL) than FM (2.03 mg/mL) and SI (1.75 mg/mL). AW (11.95%) had the highest alcohol content, while SI (11.75%) had the lowest. The pH of FM (pH 3.73) was the lowest, and there were no significant differences in total acidity among the samples. The major organic acid in the wines was citric acid (6.71~8.18 mg/mL) and the amount of organic acids depended on the type of yeasts. The amount of malic acid was highest in SI (2.92 mg/mL), and lowest in AI (1.83 mg/mL). The Hunter color test showed that SI was highest in lightness, redness and yellowness, whereas AI was lowest. There were no differences in turbidity between the samples. There were no significant differences in total phenolic contents (TPC) and total anthocyanin contents (TAC). However, the TPC and TAC of black raspberry wines were higher than those in commercial red wines. The antioxidant activities of wines (determined by ABTS and FRAP) increased in the order of FM, AI, AW and SI. It could not be concluded which yeast is adequate for the fermentation of black raspberry wine because any of the tested yeasts showed the best in all the quality characteristics of the wines.