• Korean Journal of Food Science and Technology
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• v.28 no.1
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• pp.34-39
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• 1996

We examined the effects of crude hemicellulose, alcohol-insoluble hemicellulose, high molecular weight soluble polysaccharide (HMS-P : MW>10 kDa) and low molecular weight souble polysaccharide (LMS-P : MW<10 kDa) fraction isolated from buckwheat (raw, roast and steam) on digestive enzyme activity in vitro. The enzyme activities were measured after the polysaccharides-enzyme mixtures were incubated at $37^{\circ}C$ for 5 min. Crude hemicellulose, alcohol-insoluble hemicellulose and residue lowered ${\alpha}-amylase$ activity, whereas HMS-P and LMS-P had no inhibitory effect. All polysaccharides except LMS-P lowered lipase activity. Crude hemicellulose, alcohol-insoluble hemicellulose, residue and HMS-P showed a marked decrease of trypsin and chymotrypsin activity but LMS-P showed a slight decrease of them.

• Journal of the Korean Society of Food Science and Nutrition
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• v.17 no.1
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• pp.13-17
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• 1988

$HF_1$(1H KOH soluble hemicellulose fraction), $HF_2$(2H KOH soluble hemicellulose fraction) $HF_3$(3H KOH soluble hemicellulose fraction) and $HF_4$(4H KOH soluble hemicellulose fraction) were fractionated from Fuji crude cell wall and purified using Sephacryl S-500 to determine the effects of these hemicellulosic fractions on the Ca- pectate gel formation. By increasing of KOH concentration, from 1 to 4N, hexose peas became higher in led, and molecula weights, especially pentose peaks in high molecular weight. Hemicellulose fractions using gel filtration were composed of $8{\sim}10$ peaks which were $10^4{\sim}143{\times}10^4$ molecular weight. Higher values of hardness, adhesiveness and gumminess were found in low molecular weight than in high molecular weight, also in hexose and uronic acid contained than in hexose contained.

• Korean Journal of Food Science and Technology
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• v.22 no.7
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• pp.738-742
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• 1990

Cell wall components were decreased during maturation and postharvest of persimmon fruits. Contents of pectin and alkali-soluble hemicellulose were increased during maturity, but those of acid-soluble hemicellulose were decreased. Contents of pectin and alkali-soluble hemicellulose were decrease in soft persimmon, whereas acid-soluble hemicellulose was increased remarkably. Cellulose contents were increased during maturation and this tend was notable in soft persimmon. Contents of cell wall polysaccharides per 100g-fresh weight were decreased. Contents of total pectin and insoluble pectin were increased during maturation but decreased in soft persimmon. Content of water-soluble pectin was increased during maturation and postharvest.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.1
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• pp.67-71
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• 1997

Different concentrations of lignin and hemicellulose were preincubated with 0.01$\mu\textrm{g}$ of 2-amino-3-methylimidazo［4, 5-f］quinoline(IQ) at simulated gastrointestinal pH condition s. The Ames Salmonella assay using Salmonella typhimurim TA98 was performed to detect any changes in the mutagenicity of IQ in the presence of lignin or hemicellulose. IQ revealed very weak or no mutagenicity when it was preincubated at pH 2.1. However, there was a dose-dependent inhibition of IQ mutagenicity in tile presence of lignin or hemicellulose at pH 5.4 and 6.6. The antimutagenic activities of fibers were not different from each other. Also, at lower concentrations of fibers, pH 5.4 was more effective in suppressing IQ mutagenicity, while 300$\mu\textrm{g}$ of lignin or hemicellulose significantly reduced the mutagenicity of IQ regardless of pH conditions. These results suggest that at gastrointestinal pH conditions, both soluble and insoluble fibers inhibit mutagenicity of IQ by adsorption. Therefore, a possible mechanism for Protective effect of fibers against cancer is due to their adsorption to mutagens in the gastrointestinal tract, and pH seems to be an important factor in the regulation of interactions between the fiber and mutagens.

• Journal of the East Asian Society of Dietary Life
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• v.14 no.3
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• pp.243-250
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• 2004

The effect of hemicellulose extracted from Shiitake mushroom(Lentinus edodes) on the level of blood sugar and cholesterol in the diabetes-induced rat by streptozotocin(STZ) was investigated. The yield of hemicellulose by extraction process of 5% salt extraction, preparation of alcohol insoluble substance, IN KOH extraction, acid precipitation(pH 3.0), and dialysis was 9.24%. The experimental plots divided to 1% cellulose group(control), 0.5% hemicellulose group(H-l) and 1% hemicellulose group(H-2). The groups were fed for 6 weeks, then continuously fed for 1 week after induction of diabetes by STZ. Feed intakes, weight gain and feed efficiency of the each groups were not significantly different, while water intakes and liver weight of H-2 group were lower than those of control and H-l group. Weight of liver in the H-2 group was significantly lower than those of control and H-l groups. The amounts of feces were 0.32 g/day in the control group, 0.43∼0.44 g/day in the H-l and H-2 groups, while the amounts of urine were 15.28 mL/day in the control group, 10.83∼11.20 mL/day in the H-l and H-2 groups. The content of blood glucose before diabetes induction(fed for 3∼5 weeks) was 111.2-132.6 mg/dL in the control group, not significantly different from others; After diabetes induction, however, the contents were 212.8 mg/dL in the control group, 140.0-144.0 mg/dL in the H-l and H-2 groups, which showed significant difference. Urine glucose contents of H-2 group before and after diabetes induction were lower than those of control and H-l groups. There was no significant difference in the content of neutral lipid between each groups. Total cholesterol contents were 101.6 mg/dL in the control group, 56.∼64.0 mg/dL in the hemicellulose groups. HDL-cholesterol content and atherogenic index of hemicellulose groups were lower than those of control group, respectively. In conclusion, the hemicellulose extracted from Shiitake mushroom represented improving and preventing effects for diabetes.

• Korean Journal of Food Science and Technology
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• v.47 no.1
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• pp.6-12
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• 2015

This study was performed to determine the optimal hydrolysis conditions for the production of hydrolysates, including water-soluble dietary fiber from Chinese cabbage, with commercial enzymes. The optimal pH and temperature for hydrolysis of the hemicellulose fraction were pH 5.0 and $40^{\circ}C$, and optimal enzyme concentrations were 45 units and 21 units for Shearzyme plus and Viscozyme L, respectively. The yields of the hydrolysate including the water-soluble dietary fiber from the hemicellulose fraction by Shearzyme plus and Viscozyme L were 22.64 and 24.73%, respectively, after a 72 h reaction. The molecular weight distribution of alcohol-insoluble fiber was characterized by gel chromatography; degradation of hemicellulose increased with increasing reaction time. Our results indicate that the hemicellulose fraction was degraded to water-soluble dietary fiber by enzymatic hydrolysis, and its hydrolysate could be utilized as new watersoluble food materials.

• KSBB Journal
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• v.20 no.4
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• pp.317-322
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• 2005

Various recovery methods were investigated to maximize hemicellulose recovery from lignocellulosic material hydrolyzed by pure water. The pretreatment conditions of water hydrolysis were $170\~180^{\circ}C$ and 1 hour of reaction time. The percentage of hemicellulose solubilized increased as the temperature increased from 170 to $180^{\circ}C$. However, significant decomposition of sugar was observed at temperature of $180^{\circ}C$. From the results of water hydrolysis, the total amount of glucan in solid residue and liquid hydrolyzate was close to the total glucan in the original biomass. For hemicellulose, however, there was a significant difference between both contents. To prove this difference, various recovery methods were proposed. From the total sugar accountability (sugar in liquid + sugar in solid), it was confirmed that hemicellulose recovery in the hydrolyzate was increased if the product including both hydrolyzate and solid residue was physically stimulated by such as heating and ultrasound irradiation. This indicated that, in commercial scale processes that much bigger substrate sizes are used and a sufficient amount of leaching solvent can not be used after pretreatment, a significant amount of oligomers could be trapped in the solid matrix.

• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.257-260
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• 2003

Hemicelluloses, one of the most abundant natural polysaccharides, are comprised roughly in one-fourth to one-third of most plant materials. Hemicelluloses contain mixtures of 50-200 five-carbon sugars(xylose and arabinose) and six-carbon sugars(glucose, galactose, mannose, and rhamnose), plus lesser amounts of the sugar acids(glucuronic acid and galacturonic acid). The kinds of hemicelluloses are A, B, and C. The interesting substance of them is hemicellulose B. However, the prodution level of hemicellulose B is very low. Thus, this study was concentrated on increasing the recovery yield of hemicellulose B from rice bran.

• Applied Biological Chemistry
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• v.30 no.4
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• pp.311-314
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• 1987

High-level yeast inocula was investigated as a means of overcoming the inhibition problem in ethanol fermentation of hemicellulose hydrolyzate. When the inoculum exceeded 25g dry cells/liter, the fermentation proceeded completely to the end within 24 hours. Furfural was taken up by Pachysolen tannophilus and catabolized to furfuryl alcohol. Thus inhibitory effect of furfural component was less adverse toward ethanol production than that of non-furfural components in hemicellulose hydrolyzate. The specific ethanol productivity in the fermentation of hemicellulose hydrolyzate was 14% of that of simulated media containing 41.8g xylose and 2.3g furfural per liter.

• Transactions of the Korean hydrogen and new energy society
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• v.19 no.1
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• pp.56-63
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• 2008

In this study, thermochemical degradation of hemicellulose by Acetone-Solvolysis, the effects of reaction temperature, conversion yield, degradation properties and degradation products were investigated. Experiments were performed in a tube reactor by varying reaction temperature from $200{\circ}C$ to $400{\circ}C$ at 40 min of reaction time. The liquid products from pyrolysis-liquefaction of hemicellulose contained various kinds of ketones. ketones, as 4-methyl-3-penten-2-one, 3-methylene-2-pentanone, 22,6-dimethyl-2, 5-heptadien-4-one, 4-methyl-2-pentanone, 5-methyl-2-hexanone, 3,5,5-trimethyl-2-cyclohexen-1-one, and bezenes. as 1,4-dimethylbenzene, 1-methyl-2-(1-methylethyl)-benzene, 1,4-dimethyl-2-(2-methylpropyl)benzene, 4-secbutyl-ethyl benzene, could be used as high-octane-value fuels and fuel additives. Combustion heating value of liquid products from thermochemical conversion processes of hemicellulose was in the range of $6,680{\sim}7,170cal/g$. After 40min of reaction at $400{\circ}C$ in Acetone-Solvolysis of hemicellulose, the energy yield and mass yield was as high as 72.2% and 41.2g oil/100g raw material, respectively.