• Korean journal of food and cookery science
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• v.28 no.1
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• pp.51-55
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• 2012

This study was conducted to investigate the physicochemical properties of citrus peel extracts with different hot water extraction and enzymatic hydrolysis conditions. Enzymatic hydrolysis was also employed using Viscozyme L and results were compared with that of optimized hot water extract. Hot water extraction was performed under different parameters; the sample to solvent ratio(1:20, 1:15, 1:10), extraction time(2, 4 hrs), extraction temperature(85, $95^{\circ}C$) and enzymatic hydrolysis(0, 1%) and the subsequent extracts were used for determining their physicochemical properties, such as total yield, total phenolics, total flavonoids, and electron donating ability (EDA). With the increase in the sample to solvent ratio and extraction time, total yield, total phenolics, total flavonoids and EDA increased. But extraction temperature did not significantly affect the hot water extract. As hot water extract was hydrolyzed by the enzyme, total yield and active ingredients increased rapidly. In the result of total yield, total phenolics, total flavonoids and EDA, the activity of enzyme-treated extract was higher than those of enzyme-untreated extract. Based upon the overall hot water extraction efficiency, it was found that 20 times volume or 120 min at a time at $95^{\circ}C$ after enzyme treatment was optimal.

• Applied Chemistry for Engineering
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• v.25 no.6
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• pp.619-623
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• 2014

The acid hydrolysis and enzymatic saccharification were carried out for the production of cellulosic ethanol. The possibility of bio-energy production from tangerine peel and apple and watermelon rind was evaluated by determining the optimum production condition. The optimum conditions for the production of cellulosic ethanol from fruit peel were as follows: the sulfuric acid concentration and reaction time of acid hydrolysis for the ethanol production from an apple rind were 20 wt% and 90 min, respectively. The concentration of sulfuric acid for tangerine peel and a watermelon rind at the hydrolysis time of 60 min were 15 wt% and 10 wt%, respectively. A viscozyme was proven as the best conversion for the ethanol production when using enzymatic saccharification from fruit peels. The optimum enzymatic saccharification time for tangerine peel and apple and watermelon rind were 60, 180, and 120 min, respectively.

• Preventive Nutrition and Food Science
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• v.10 no.1
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• pp.11-16
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• 2005

Enzymatic hydrolysis of dark muscle of skipjack was optimized by using response surface methodology. Three factors of independent values were pH (4.2 to 9.8), time (0.6 to 3.4 hrs) and temperature (34℃ to 76℃), and independent values were optical density and brix. The optimum conditions for enzymatic hydrolysis were pH 7.0 to 8.0, 55℃ and 3 hrs. The headspace volatile compounds of reaction flavors using the enzymatic hydrolysate, cysteine and xylose were identified by using the combination of a canister system, gas chromatography and mass selective detector. Among 67 compounds, we identified 8 sulfur-containing compounds and 7 furans which were thought to be highly related to meat-like flavors.

• Microbiology and Biotechnology Letters
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• v.19 no.4
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• pp.377-382
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• 1991

Reef tallow was hydrolyzed with lipase under the conditions of liquid state and solid state. Lipase OF 360 was used for that purpose, and the lipase had the maximum activity when the olive oil was used as a substrate at pH 6 and $37^{\circ}C$. Beef tallow was dispersed by an agitator to perform a liquid enzymatic reaction. Water content, reaction temperature, and enzyme amount were varied as parameters affecting hydrolysis percentage. Ninety three percents of tallow were hydrolyzed at the following conditions: water content 80% w/w, temperature $37^{\circ}C$, and enzyme amount 200 unitlg tallow. In order to conduct a solid phase enzymatic reaction, sonication was employed for pretreating tallow with the enzyme solution. Molten tallow was sonified with the enzyme solution, and solidified by lowering temperature. And then hydrolysis reaction proceeded at $30^{\circ}C$. Sonication intensity and time were varied to control hydrolysis percentage. Optimum values of the intensity and the time were found to exist since the hydrolysis percentage did not increase further according to the increases of the intensity and the time.

• Food Science of Animal Resources
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• v.35 no.3
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• pp.350-359
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• 2015

This review focuses on the enhanced functional characteristics of enzymatic hydrolysates of whey proteins (WPHs) in food applications compared to intact whey proteins (WPs). WPs are applied in foods as whey protein concentrates (WPCs), whey protein isolates (WPIs), and WPHs. WPs are byproducts of cheese production, used in a wide range of food applications due to their nutritional validity, functional activities, and cost effectiveness. Enzymatic hydrolysis yields improved functional and nutritional benefits in contrast to heat denaturation or native applications. WPHs improve solubility over a wide range of pH, create viscosity through water binding, and promote cohesion, adhesion, and elasticity. WPHs form stronger but more flexible edible films than WPC or WPI. WPHs enhance emulsification, bind fat, and facilitate whipping, compared to intact WPs. Extensive hydrolyzed WPHs with proper heat applications are the best emulsifiers and addition of polysaccharides improves the emulsification ability of WPHs. Also, WPHs improve the sensorial properties like color, flavor, and texture but impart a bitter taste in case where extensive hydrolysis (degree of hydrolysis greater than 8%). It is important to consider the type of enzyme, hydrolysis conditions, and WPHs production method based on the nature of food application.

• Preventive Nutrition and Food Science
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• v.20 no.3
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• pp.183-189
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• 2015

In the present study, an optimum protease was selected to hydrolyze the egg white liquid protein for the antioxidant peptides. Alcalase treatment yielded the highest amount of ${\alpha}$-amino groups (15.27 mg/mL), while the control (no enzymatic hydrolysis) showed the lowest amount of ${\alpha}$-amino groups (1.53 mg/mL). Alcalase also gave the highest degree of hydrolysis (DH) value (43.2%) and was more efficient for egg white liquid hydrolysis than the other enzymes. The Alcalase hydrolysate had the highest radical-scavenging activity (82.5%) at a concentration of 5.0 mg/mL. The conditions for enzymatic hydrolysis of egg white liquid with Alcalase were selected as substrate : water ratio of 2:1. Five percent Alacalse treatment did not show significant (P>0.05) increases of DH and ${\alpha}$-amino nitrogen content after 24 hhydrolysis. Thirty two hour-hydrolysis with 5% Alcalase is sufficient to make antioxidative egg white liquid hydrolysate from egg white liquid. DPPH and ABTS radical-scavenging activities were significantly (P<0.05) higher after enzymatic digestion. These results suggest that active peptides released from egg-white protein are effective radical-scavengers. Thus, this approach may be useful for the preparation of potent antioxidant products.

• Biotechnology and Bioprocess Engineering:BBE
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• v.3 no.1
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• pp.35-39
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• 1998

An enzymatic process was developed to produce protein hydrolysater form defatted soya protein. Various unit operations were tried, and the effects of pre- and post-treatments on the product characteristics such as degree of hydroylsis (DH), free amino acid content (%FAA) and average molecular weight (MW) were investigated. The use of acid washes showed no difference in %DH. Increasing pH during pre-cooking gave lower %DH. Alkaline cooking made too much insoluble protein, thus the protein yield was too small. A better hydrolysis with more acceptable taste was obtained when the combination of Neutrase/Alcalase/Flavourzyme was used in place of Alcalase/Flavourzyme combination; Untoasted defatted soya was more effective on the proteolysis than toasted one. The MW of the evaporated and spray dried product was higher than that of undried product, due to precipitation of low-solubility components. When ultrafiltration and the product concentration carried out the product separation by reverse osmosis, the solubility and the taste of the product were improved. The difference between enzyme hydrolysate and acid hydrolysate was significant in free amino acid composition, especially in tyrosine, phenylalanine, glutamine and asparagine.

• Journal of the Korean Wood Science and Technology
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• v.21 no.3
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• pp.53-60
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• 1993

Substrates used were hardwood-Suwon poplar-(Populus alba${\times}$glandulosa L.) and softwood-pitch pine-(Pinus rigida M.). And these substrates were steam exploded then treated with sodium chlorite at 75$^{\circ}C$ with occasional stirring in order to obtain samples which had different lignin contents and crystallinity. And then this resulting samples incubated with a commercial cellulase derived from Trichoderma ressei. The contents of Klason lignin were decreased as the increasing of the ratio of sodium chlorite in the two species. The effect of hardwood was more effective than that of softwood in the same ratio of sodium chlorite. The minimum contents of Klason lignin were 0.8% and 5.1% respectively. And the crystallinities of cellulose were increased very little as increasing of the ratio of sodium clorite. The hydrolysis extent of the two species were increased as the increasing of delignification. Especially, the hydrolysis extent of hardwood was more higher than that of softwood. The maximum hydrolysis extent were 89.8% and 71.1%, respectively.

• Korean Chemical Engineering Research
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• v.54 no.1
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• pp.70-74
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• 2016

In this study, the effects of citrate buffer pretreatment conditions (solid-to-liquid ratio, reaction temperature, pH and concentration of buffer) on enzymatic hydrolysis of E. intestinalis for total reducing sugar (TRS) production were investigated. As a results of the citrate buffer pretreatment, a 5.40% hydrolysis yield was obtained under conditions including 1:10 solid-to-liquid ratio, 0.25 M citrate buffer (pH 3.5) at $140^{\circ}C$ for 60 min. The maximum hydrolysis yield of 18.68% was obtained to enzymatic hydrolysis after pretreatment. This result is 1.81 times higher than that of control.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.46 no.6
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• pp.1-7
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• 2014

Dissolving part of xylan and lignin in lignocellulosic biomass by base can be used as pretreatment technique. Cork oak was pretreated with sodium hydroxide solution and the pretreatment effects were evaluated with two critical factors - NaOH concentration and pretreatment temperature. Some of xylan and lignin were removed by base pretreatment. At $90^{\circ}C$ and 13% NaOH pretreatment, 22.0% of lignin and 78.8% of xylan removed by base treatment. Enzymatic hydrolysis of cork oak which was pretreated at higher temperature or concentration was further improved. After pretreatment of cork oak with 13% NaOH at $90^{\circ}C$, the conversion rate of cellulose to fermentable sugars were reached up to 91.3%. At ethanol fermentation with enzymatic hydrolysate from different pretreatment conditions, all enzymatic saccharification liquids were well fermented by Saccharomyces cerevisiae.