• KSBB Journal
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• v.24 no.4
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• pp.361-366
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• 2009

Response surface methodology (RSM) was used for optimization the fraction conditions of xylose from pepper stem with dilute sulfuric acid. The independent variables were acid concentration in the range of 1.134 to 2.866%, reaction temperatures in the range of 142.68 to $177.32^{\circ}C$, and hydrolysis time in the range of 6.34 to 23.66 min. were studied. The dependent variables were xylose yield from pepper stem, and the production of by-products, for example, furfural, acetic aicd, HMF etc. Experimental results had a good match with statistical result. The maximum xylose yield obtained in this experiment was 71% concentration.

• Clean Technology
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• v.17 no.1
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• pp.31-36
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• 2011

All types of ${\gamma}-Al_2O_3$ such as acidic, neutral and basic forms were chemically modified with (3-mercaptopropyl) trimethoxysilane (3-MPTMS) and oxidized by 30 wt% $H_2O_2$ solution. As a result, sulfonic acid modified ${\gamma}-Al_2O_3$ catalysts were obtained. Their formation was achieved more easily by treating 1M HCl solution. Their catalytic performance was tested by dehydration reaction of D-xylose to furfural. The sulfonic acid modified ${\gamma}-Al_2O_3$ catalysts showed high conversion (>90%) of D-xylose, and the selectivity to furfural was increased with the amount of sulfonic acid anchored on the catalyst.

• Microbiology and Biotechnology Letters
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• v.47 no.4
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• pp.530-535
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• 2019

Diverse types of nuruks (traditional Korean fermentation initiators) were examined in order to isolate thermotolerant yeast strains capable of utilizing xylose as a carbon source. Among twenty yeast strains that grew at 46℃, MBY/L1597 showed a notably higher specific growth rate than other strains. This strain was identified as Millerozyma farinosa. While the control strain M. farinosa KCTC27412 (= CBS7064) did not show xylose reductase (XR) activity and apparent growth at 46℃, M. farinosa MBY/L1597 exhibited XR activity of 4.98 ± 0.49 U/mg protein when NADPH was used as a cofactor. M. farinosa MBY/L1597 cultured at 46℃ produced (9.87 ± 1.00 g/l) xylitol from 20 g/l xylose, corresponding to approximately 50% yield. M. farinosa MBY/L1597 was deposited at the Korean Collection for Type Cultures as KCTC27797.

• Clean Technology
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• v.16 no.2
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• pp.95-102
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• 2010

Sulfonic acid (-SO3H) functionalized mesoporous silica containing HMS, SBA 15(S15), MCM 41(M41) were synthesized by post-synthesis and co-condensation method. Their catalytic performance is tested by dehydration reaction of D-xylose to furfural. As a result, good conversion and selectivity was obtained using water as an environmentally friendly solvent. Additionally, increased amounts of sulfuric acid in catalysts resulted in improved conversion of D-xylose. All of the acid-functionalized mesoporous silica showed higher selectivity than other solid acids such as ${\gamma}-Al_{2}O_{3}$ and zeolite.

• Journal of Applied Biological Chemistry
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• v.57 no.4
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• pp.307-312
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• 2014

Chocolate is restricted for obese and diabetic patients due to high in sugar contents. We investigated shell-chocolate fillings with low calorie content and low glycemic indexes using alternative sweeteners such as tagatose and xylose and adding coffee grounds. Chocolate filling was made with sugar, cacao and butter in the original recipe. Sugar was substituted with tagatose or xylose and 3% coffee ground was added in each chocolate filling and substituted for 3% of the cocoa. Water retention and spreadability of the chocolate filling was significantly higher in the tagatose+coffee ground group in comparison to the sugar. In the chromaticity test, chocolate filling made with tagatose was darker in comparison to that made with sugar: brightness (L) was lower and redness (a) and yellowness (b) were higher than the sugar filling. Sensory evaluation revealed that chocolate filling made with tagatose had high score in 4 categories such as taste, smell, texture of foreign substance, overall acceptance. After consuming 60 g of the chocolate with different fillings, blood glucose levels of subjects at 1 and 2 h were significantly lower in the tagatose and tagatose+coffee ground groups than the other groups. In conclusion, using tagatose as the sweetener in chocolate filling has a beneficial effect on lowering blood glucose levels and increasing water retention, spreadability and sensory scores. Coffee ground did not have additive effect on quality of chocolate filling and blood glucose levels. These results indicate that shell chocolate made with tagatose can be used as a snack for diabetic patients.