• The Korean Journal of Food And Nutrition
• /
• v.9 no.2
• /
• pp.143-150
• /
• 1996

The studies was carried out to investigate ripening degree and functional properties of EMC produced with pancreatic protease and palatase ML. During production of EMC, the amounts of free amino acid and free fatty acid were increased with increasing the reaction time. The amount of total nitrogen(T-N) and water soluble nitrogen(WSN) were increased with increasing time. EMC had contents of 1.79eA T-N and 0.52o WSN at 60 min of hydrolysis time. SRI and FRI value had also a similar correlationship. On the gel filtration, 2 kinds of soluble proteining capacity was also shown in alkali solution. Furthermore the foaming stability had the same result as that of the solubility. The water absorption of EMC showed the highest level at pH 4.0 and 5.0.

• Applied Chemistry for Engineering
• /
• v.10 no.7
• /
• pp.969-973
• /
• 1999

In this work, we studied the degree of hydrolysis of ion exchanger in $NH_4OH$ solution and sorption characteristics of $NH_3$ by potentiometric titration curves with using carboxylic acid ion exchanger Fiban K-4. We knew that the theoretical pH values agreed with the experimental pH values on the $NH_4OH$ concentrations in various concentrations of supporting electrolyte $(NH_4)_2SO_4$. The sorption values of $NH_3$ using the ion exchanger can be calculated from equivalent sorption curves for various pH. Also, the degree of hydrolysis increased with decreasing concentration of supporting electrolyte and pH. In order to obtain the mono ion form below 0.01 M as the decreasing concentration of supporting electrolyte, the pH values should be increased. From these results, therefore, the concentrations of supporting electrolyte and pH values were determined.

• Korean journal of food and cookery science
• /
• v.9 no.4
• /
• pp.278-283
• /
• 1993

This study was attempted to investigate the effects of enzymatic modification of milk protein with protease on functional properties. The selected functional properties were solubility, emulsifying activity (EA), emulsion stability(ES), foam expansion(FE), and foam stability(FS). These properties were measu-red from pH 3.0 to pH 8.0. The proteases used in this study were iaolated from Meju(fermemted soybean) and had specific activity of 250 units/㎎ protein at pH 7.0, 1600 units of pretense was used for 1gr. of skim milk protein. Skim milk showed 30.5％ degree of hydrolysis for 1 hr. and 36.4% degree of hydrolysis for 3.5 hrs. of protease treatment at pH 7.0. Solubility of native skim milk, control, 1 hr. and 3.5 hrs. groups were 3.37, 3.64, 10.21, 14.34％o at pH 4.0 respcetively. The emulsifying activity of native skim milk, control, 1 hr. and 3.5 hrs. groups were 38.8,42.0,43.0,46.7ft at pH 4.0, respectively. Enzymatic modification resulted in the increase of solubility and emulsifying activity at pH 4.0. However at pH 5.0 emulsifying activity of 1 hr. and 3.5 hr. group were lower than native skim milk and control groups. 1 hr. protease treatment was found to be most effective way of increasing foam expansion at pH 4.0 to 6.0. It was supported that, protease treated skim milk can be used to improve solubility, emulsifying activity, foam expansion at acid pH. meju protease. skim milk, solubility, emulsion, foam.

• Polymer(Korea)
• /
• v.34 no.5
• /
• pp.415-423
• /
• 2010

Poly(vinyl alcohol)(PVA) with high degree of hydrolysis of above 98% was dissolved in dimethyl sulfoxide(DMSO), and the shear viscosity was measured up to $C{\simeq}0.14\;g/mL$ in the semi-dilute solution regime. Next, as probe particle, polystyrene(PS) latex was introduced into this matrix system and its delayed diffusion due to polymer concentration was investigated by means of dynamic light scattering. When the solution viscosity of PVA/DMSO was plotted against the reduced concentration $C[{\eta}]$, which is scaled by the intrinsic viscosity, the molecular weight dependence was strongly appeared at C$[{\eta}]$ >2. Some heterogeneties in polymer solution were considered as its source. Contrary, the diffusion of probe particle in the matrix solution was observed as a single mode motion at whole concentration range but its ratio of its diffusion coefficient at solution to that at solvent, D/Do did not show any molecular weight dependence at all. However, the application limit of the stretched exponential function was disclosed at C$[{\eta}]$ >2.5.

• The Korean Journal of Food And Nutrition
• /
• v.13 no.6
• /
• pp.529-533
• /
• 2000

The marsh calm soup was prepared with 2 volumes of boiling water and heated for 0, 5, 10, 30, 60 and 120 minutes. As the boiling time prolonged, water content decreased gradually, while protein content increased. Free amino acid content was the highest with 30 minutes of boiling showing 103.1 mg/100g, and decrease showly thereafter. Among the free amino acids, alanine was the most abundant followed by proline, glutamic acid and glycine. Degree of protein hydrolysis increased as boiling prolonged. In the non-volatile organic acids, succinic acid was the highest(137.08 mg/100g with 30 minutes of boiling), followed by oxalic acid, magic acid and lactic acid. The optimum boiling time for marsh calm soup was evaluated to be 30 minutes.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.35 no.5
• /
• pp.600-605
• /
• 2006

B. subtilis JM3 pretense from naturally fermented anchovy sauce was purified in $40{\sim}60%$ ammonium sulfate fraction. In order to accelerate the fermentation of anchovy sauce,2% and 4% of crude B. subtilis JM3 protease were added to 6 month-fermented anchovy sauces, respectively and then the various quality characteristics such as pH, lactic acid, amino-nitrogen, VBN, browning and hydrolysis degree, VBN, and sensory evaluation were analyzed at different storage times. pH was constant during storage time in all samples, whereas lactic acid contents of anchovy sauces hydrolyzed by 2% and 4% proteases were higher than that of control. The amino-nitrogen and volatile basic nitrogen contents of anchovy sauce with 2% and 4% proteases were twice higher than those of control. Anchovy sauces with 2% and 4% pretense increased the hydrolysis rate by 27% and 32%, respectively. Browning degree of anchovy sauce with 4% was higher than those of 2% and control. Anchovy sauce with 2% and 4% proteases was good in sensory evaluation of color, aroma, and taste attributes.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.35 no.6
• /
• pp.666-670
• /
• 2002

To investigate changes of components in salt-fermented sardine, Sardinops melanostictus sauce during 18 months fermentation, various chemical properties were examined at 2$\~$3 months intervals. The degree of hydrolysis increased sharply until 5 months of fermentation and showed the gentle increasement after that. On the other hand, the contents of total and amino nitrogens, total ATP related compounds increased gradually during 18 months of fermentation. The hypoxanthine and uric acid were abundant in ATP related compounds, ranging from $75\%$ to $87\%$. The contents of inosine+hypoxanthine and uric acid were crossed at 13.9 months of fermentation. After 18 months of fermentation, sauce was rich in free amino acids, glutamic acid, aspartic acid, lysine, alanine, threonine in that order.

• Korean Journal of Food Science and Technology
• /
• v.47 no.6
• /
• pp.772-778
• /
• 2015

Hydrolysis of isolate soybean protein (ISP) using subcritical water (SCW) was conducted to study the feasibility for producing protein hydrolyzate. SCW hydrolysis of SPI suspension (5-15%) was conducted in an electrically heated batch reactor (2 L). The effects of temperature (230 to $270^{\circ}C$) and holding time (10 to 50 min) on the degree of hydrolysis (DH) and the production of amino acids were studied by surface response method. The DH was determined by derivatizing the hydrolyzates with ortho-phthalaldehyde (OPA) solution. It was confirmed that reaction temperature and holding time affected the hydrothermolysis of soybean protein. However, the holding time was less effective on amino acid yield when the temperature was higher than $230^{\circ}C$. In order to achieve optimal yields of amino acids exceeding 43%, the temperature should be within the range between 256 and $268^{\circ}C$ with holding time from 29 to 41 min, respectively. A maximum estimated amino acid yield of 43.5% was obtained at $268^{\circ}C$ for 35 min.

• Korean Journal of Food Science and Technology
• /
• v.20 no.3
• /
• pp.338-343
• /
• 1988

Selected kinetic parameters and degree of hydrolysis(DH) were measured using commercial proteases(trypsin, alcalase and pronase) to study the affinity of these enzymes to 7S and 11S soy proteins. Electrophoretic patterns of the hydrolysates were also investigated. In general, the order of affinity between the proteins and the proteases was 11S(protein-rich fraction)and 7S PRF for unheated proteins, and 7S PRF and 11S PRF for preheated proteins. Substrate inhibition was present at a substrate concentration of 1.5% or higher when preheated protein was used as the substrate. The maximum DH values of alcalase were obtained from 7S PRF(60%) and 11S PRF(80%) at 1 hr hydrolysis, respectively. Trypsin hydrolyses did not affect 11S soy protein but the acidic subunits in contrast to alcalase and pronase hydrolyses which changed almost all subunits. Alcalase hydrolysis induced distinct changes on 2S soy protein.

• Korean Journal of Food Science and Technology
• /
• v.43 no.6
• /
• pp.729-734
• /
• 2011

With the goal of transforming rice protein from an insoluble to a soluble form to increase the industrial utilization of rice wine meal (RWM), RWM was derivatized using commercial proteases and the RWM hydrolysates were characterized. Eight commercial proteases were used individually or in combination for hydrolysis of RWM. The degree of hydrolysis was assessed by determining the soluble protein in supernatant using the Lowry assay, protein in precipitates using a semimicro Kjeldahl procedure, and gravimetrically by the weight difference before and after hydrolysis. Protamex, Alcalase and Protease N proteases were most effective for hydrolysis of RWM. Although these assessment methodologies displayed some variation, they generally showed a similar pattern. When the aforementioned three proteases were simultaneously used to treat RWM, no significant difference was observed between the three assays (p<0.05) indicating an absence of enzymatic synergy.