• Journal of Food Hygiene and Safety
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• v.35 no.1
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• pp.83-92
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• 2020

This study investigated the optimal conditions of enzymatic reaction for production of isomaltooligosaccharides (IMO) using rice flour. To manufacture IMO, commercial enzymes (Termamyl 2X, Maltogenase L, Promozyme D2, Fungamyl 800L and Transglucosidase L) were used. The sugar composition and amount of IMO were examined by HPLC with charged aerosol detector (HPLC-CAD) in each manufacturing process. Liquefaction reaction was performed according to different Termamyl 2X concentrations (0.025%, 0.05%, 0.075%, 0.1%) and reaction times (1 h, 2 h). As a result, the reducing sugar content was the highest at 138.26 g/L when 0.075% Termamyl 2X was added for 2 hours. In order to optimize simultaneous saccharification and transglucosylation, experiments on enzyme selection, enzyme concentration and enzyme reaction time were conducted. Reaction with 0.0015% Maltogenase L, 0.05-0.1% Promozyme D2 and 0.1% Tansglucosidase L was effective in decreasing glucose content and increasing content of IMO with a high degree of polymerization. A change in sugar content was observed every 6 hours to determine the optimal reaction time, and the highest IMO was produced after 36 hours of reaction (75.36 g/L). The IMO prepared under optimal conditions showed isomaltose, 35.11 g/L; panose, 11.97 g/L; isomaltotriose, 19.95 g/L; isomaltotetraose, 7.46 g/L; isomaltopentaose, 1.05 g/L at 18 brix and the ratio of IMO in the total sugar was 56.37%.

• KSBB Journal
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• v.5 no.4
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• pp.383-390
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• 1990

Alcoholic distillery waste was utilized as dual purposes to produce citric acid and to reduce the amount of waste to be treated. Enzyme and acid hydrolysis of this waste were studied to suggest effective way of present purpose. Enzymatic hydrolysis of this naked barley alcoholic distillery waste by $\alpha$-and $\beta$-amylase gave glucose as 8g/l concentration at $55^{\circ}C$ for 6 hours, which produced 1g/l citric acid and 5.33g/l mycelial. This waste material hydrolyzed with 25% HCl at $120^{\circ}C$ showed 21.5g/l glucose and produced 1.75g/l citric acid with 4.9g/1 mycelial. The glucose concentration was decreased to 3.44g/l by further 2nd acid hydrolysis because the monosugars were decomposed at prolonged hydrolysis conditions. The addition of 3g/l $NH_4NO_3$ increased the mycelial growth but reduced the amount of citric acid formed. The formation of citric acid was increased at low concentration of manganese ion.

• Korean Chemical Engineering Research
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• v.52 no.1
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• pp.45-51
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• 2014

This is to study the effects of various pretreatment methods of agricultural residue, corn stover, and to compare the feature and pros and cons of each method including dilute sulfuric acid (DSA), soaking in aqueous ammonia (SAA), and ammonia recycle percolation (ARP). In order to convert corn stover to ethanol, various pretreatments followed by simultaneous saccharification and co-fermentation (SSCF) were tested and evaluated in terms of ethanol yield. With 3%, w/w of glucan loading using ARP-, DSA-, and SAA-treated solids, SSCFs using recombinant E. coli strain (ATCC$^{(R)}$ 55124) with commercial enzymes (15 FPU of Spezyme CP/g-glucan and 30 CBU/g-glucan enzyme loading) were tested. In the SSCF tests, 87, 90, and 78% of theoretical maximum ethanol yield were observed using ARP-, DSA-, and SAA-treated solids, respectively, which were 69, 58, and 74% on the basis of total carbohydrates (glucan + xylan) in the untreated corn stover. Ethanol yield of SAA-treated solid was higher than those of ARP- and DSA-treated solids. In addition, SSCF test using treated solids plus pretreated hydrolysate indicated that the DSA-treated hydrolysate showed the strongest inhibition effect on the KO11 strain, whereas the ARP-treated hydrolysate was found to have the second strongest inhibition effect. Bioconversion scheme using SAA pretreatment and SSCF can make the downstream process simple, which is suggested to produce ethanol economically because utilization of hemicellulose in the hydrolysate is not necessary.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.8
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• pp.1278-1282
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• 2014

The objective of this study was to improve the sensory qualities of soymilk. For this purpose, soymilk was prepared by adding different types of rice grain, including cooked, puffed, and saccharified rice. Acceptable products could be obtained by addition of saccharified rice. The addition of saccharified rice had a positive influence on sensory qualities, especially mouth feel. Further, soymilk with saccharified rice was comparable in terms of physicochemical characteristics (pH, soluble solids, and viscosity) with commercial whole-bean soymilk. This result suggests that there are opportunities to develop a new market for soy-milk that incorporates health benefits and traditional beverages.

• Korean Journal of Food Science and Technology
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• v.17 no.5
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• pp.350-354
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• 1985

For the purpose of studying the possibility to use the barley as a raw material in vinegar manufacturing process, several factors related to the fermentation of acetic acid were investigated. The optimum quantity of sweet liquor prepared by koji method in medium was 30-40%. When koji of A. oryzae, commercial enzyme products and malt were used for the saccharification of the barley, the production rates of acetic acid during log period were 0.056%/hr, 0.025%/hr, 0.03896/hr and lag period were 22 hours, 48.5 hours and 25 hours, respectively. These results indicate that the saccharifying method using koji of A. oryzae is superior to that by the commercial enzyme products or malt for the acetic acid fementation. The optimum initial acidity was 2% and the proper initial ethanol degree were 4-6% in metium. In a submerged culture process using a jar fermentor, lag period was 15 hours, and acetic acid fermetation period was about 45 hours. In the sensory test of barley vinegar and commercial vinegar of the market, barley vinegar was superior to the vinegar in market with respect to tastes.

• Journal of Life Science
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• v.26 no.8
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• pp.976-982
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• 2016

Seaweed has high growth rate, low land usage, high CO₂ absorption and no competition for food resources. Therefore, the use of lignin-free seaweed as a raw material is arising as a third generation biomass for bioethanol production. Various pretreatment techniques have been introduced to enhance the overall hydrolysis yield, and can be categorized into physical, chemical, biological, enzymatic or a combination. Thermal acid hydrolysis pretreatment is one of the most popular methods to attain high sugar yields from seaweed biomass for economic reasons. At thermal acid hydrolysis conditions, the 3,6-anhydro-galactose (AHG) from biomass could be converted to 5-hydroxymethylfurfural (HMF), which might inhibit the cell growth and decrease ethanol production. AHG is prone to decomposition into HMF, due to its acid-labile character, and subsequently into weak acids such as levulinic acid and formic acid. These inhibitors can retard yeast growth and reduce ethanol productivity during fermentation. Thus, the carbohydrates in seaweed require effective treatment methods to obtain a high concentration of monosaccharides and a low concentration of inhibitor HMF for ethanol fermentation. The efficiency of bioethanol production from the seaweed biomass hydrolysate is assessed by separate hydrolysis and fermentation (SHF). To improve the efficiency of the ethanol fermentation of mixed monosaccharides, the adaptation of yeast to high concentration of sugar could make simultaneous utilization of mixed monosaccharides for the production of ethanol from seaweed.

• Korean Chemical Engineering Research
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• v.51 no.3
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• pp.335-341
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• 2013

Ammonia circulation reactor (ACR) was devised for the effective pretreatment of corn stover. This method is designed to circulate aqueous ammonia continuously so that it can reduce the chemical and water consumption during pretreatment. In this study, ammonia pretreatment with various reaction conditions such as reaction time (4~12 hour), temperature ($60{\sim}80^{\circ}C$), and solid:liquid ratio (1:3~1:8) was tested. Chemical compositions including solid remaining after reaction, lignin and carbohydrates were analyzed and enzymatic digestibility was also measured. It was observed that as reaction conditions become more severe, lignin removal was significantly affected, which was in the range of 47.6~70.6%. On the other hands, glucan and xylan losses were not substantial as compared to that of lignin. At all tested conditions, the glucan loss was not changed substantially, which was between 4.7% and 15.2%, while the xylan loss varied, which was between 7.4% and 25.8%. With (15 FPU-GC220+30 CBU)/g-glucan of enzyme loading, corn stover treated using ammonia circulation reactor for 8~12 hours resulted in 90.1~94.5% of 72-h glucan digestibility, which was higher than 92.7% of $Avicel^{(R)}$-101. In addition, initial hydrolysis rate (at 24 hour) of this treated corn stover was 73.0~79.4%, which was shown to be much faster than 69.5% of $Avicel^{(R)}$-101. As reaction time increased, more lignin removal and it was assumed that the enhanced enzymatic digestibility of treated biomass was attributed to the lignin removal.

• Korean Journal of Food Science and Technology
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• v.46 no.4
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• pp.470-476
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• 2014

This study was performed to evaluate the quality characteristics and antioxidant activity of sikhe prepared using various concentrations of hot water extracts roasted coffee ground residue (CR-sikhe; 0.2, 0.4, 0.6, 0.8, and 1.0%). The pH increased with increasing CR concentration. The reducing sugar content after 5 h saccharification was the highest when 0.8% CR extract was used. Total polyphenol and flavonoid contents increased in a concentration-dependent manner reaching maximum levels when 1.0% CR-extract was used. The antioxidant activities of CR-extracts were higher than that of the control and increased dose-dependently. The CR-0.6 showed the best taste (4.28), color (4.56), flavor (4.08), and overall acceptability (4.28). After 10 day of storage at $4^{\circ}C$, the total cell count in CR-sikhe was approximately 1-2 log cycle, which was less than that in the control.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.9
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• pp.1211-1218
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• 2007

The aim of this study was to compare the fermentability and characteristics of fermented broths for white ginseng, red ginseng and extruded white ginseng at $110^{\circ}C$ (A), $120^{\circ}C$ (B) and $130^{\circ}C$ (C). The scanning electron microphotograph of B and C was uniform aircell distribution, but A had increased pore size and exploded some aircell's wall. Saccharification rate constant of C was the highest (10.123 $mg/mL·hr^{1/2}$). Fermentation temperature was $27^{\circ}C$ for 30 days and the cultivation was fixed with Saccharomyces cerevisiae, Aspergillus usamii, and Rhizopus japonicus. The pH of red ginseng fermented broth was 3.79, which was the highest among the fermented samples. The fermented broth of B had the highest acidity (4.46%). The fermented broth of A had the highest reducing sugar content in ginseng suspensions (32.36 mg/mL). In ginseng fermented broths, reducing sugar content was decreased rapidly during the initial 5 days and alcohol content was increased during the initial 5 days. On the fifth day, the fermented broth of C showed the highest alcohol content (5.20%).

• Applied Biological Chemistry
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• v.47 no.1
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• pp.78-84
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• 2004

In order Nuruk to improve the quality of millet wine, a traditional Jeju cereal wine, yeasts and molds were isolated from 35 kinds of Nuruk collected nationwide. Isolated strains were screened for saccharification of starch and brewing of millet wine. Fermentation characteristics of millet wine with different types of Nuruk were also investigated. The average number of microbial populations in the Nuruk were $6.4{\times}10^5{\sim}4.5{\times}10^7\;cfu/g$ for molds and $1.4{\times}10^4{\sim}7.7{\times}10^7\;cfu/g$ for yeasts. Among the 169 strains of molds and 103 strains of yeasts, 16 strains were screened for saccharifying activity on starch as a substrate, and one yeast strain was screened for the brewing of millet wine. A8-3, supposed as Aspergillus sp., showed the highest enzyme activities of glucdamylase, ${\alpha}-amylase$ and xylanase while B23-3 strain, supposed as Rhizopus sp., showed the highest saccharifying activity. A10-4, supposed as Saccharomyces sp., showed the highest level of weight loss from $CO_2$ evolution, sugar and alcohol tolerance during fermentation. When the Nuruk was made after inoculation with the selected strains, saccharifying activity was higher for the co-cultivation of A8-3 and B23-3 than individual cultivation of each strain. Similar saccharifying activities were shown in both disc-type and pellet-type Nuruk. It was suggested that pellet-type Nuruk could improve fermentation yield. The collected Nuruk consisted of $10{\sim}13%$ moisture, $55{\sim}70%$ total sugar, $10{\sim}18%$ crude protein, $0.2{\sim}1.0%$ crude fat and $1.8{\sim}2.1%$ ash. The Nuruk made in this study was composed of $12{\sim}15%$ moisture, $61{\sim}71%$ total sugar, $15{\sim}20%$ crude protein, $0.4{\sim}1.5%$ crude fat and $1.1{\sim}1.5%$ ash.