• Korean Journal of Human Ecology
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• v.3 no.1
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• pp.88-99
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• 2000

This study was perfomed to search for how properties of the starch viscosity appear in different qualities, when acetic acid is added. For this study, corn starch which belongs to A-type. Potato starch to B-type. and sweet potato starch to C-type were chosen as an experimental material. which was added to acetic acid controlled as pH 4.0, 4.5, and 5.0 at the time of before and after heating. After that, the viscosity properties of each starch was analyzed using Amylogram and Brookfield viscometer. As a result. the viscosity was shown high in an order of potato. sweet potato, and corn starch. According to addition of acetic acid. tile viscosity appeared to be low. The viscosity differences of before and after heating when the acid is added were shown as follows : Amylogram shows that the lower the pH is. the lower the viscosity is when the acid is added before-heating. In case the acid is added before-heating, gelatinization temperature, consistency and setback was increased. but breakdown decreased. In case the acid is added after-heating, the viscosity goes down at soon as it is added meanwhile consistency and setback was decreased. but breakdown increased. Such properties of the viscosity show a conspicuous variation in an order of potato. sweet Potato. and corn starch. Brookrield viscometer shows that the lower the apparent viscosity is. the lower pH is at the time of before-heating when the acid is added. In case of after-heating, when the acid is added. the apparent viscosity shows a higher inclination than that of before-heating in corn starch and sweet potato starch.

• Preventive Nutrition and Food Science
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• v.4 no.3
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• pp.175-179
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• 1999

To develop a production method for modified starches with less pollution, pH adjustment and gamma irradiation were applied to commerical corn starch. Blue values were significantly decreased , while alkali number, optical transmittance and solubility markedly increased when gamma irradiation was applied to pH 2 adjusted corn starch. Water binding capacity and swelling power at pH 5 were the highest among the samples. Gelatinization viscosity was considerably affected by gamma irradiation and pH of the starch. Gamma irradiation of pH 2 adjusted starch showed the lowest peak viscosity and the best cooling stability among the tested samples . Therefore, the production of modified starch with low viscosity as well as with sufficient viscosity stability seems feasible by controlling the pH of the starch and gamma irrdiation.

• Korean Journal of Food Science and Technology
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• v.33 no.2
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• pp.195-199
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• 2001

A study was carried out to establish a detection method for irradiated black pepper using amylograph characteristics. The maximum viscosity, viscosity at $93^{\circ}C$, viscosity after 15 min at $93^{\circ}C$, viscosity at $45^{\circ}C$, viscosity after 30 min at $45^{\circ}C$, and viscosity after 60 min at $45^{\circ}C$ decreased with increasing irradiation doses, but initial pasting temperatures, maximum viscosity temperatures, breakdown, setback, and consistency did not show great changes. The high correlation coefficients $(R^2>0.97)$ were shown between irradiation doses and amylograph characteristics except for breakdown $(R^2>0.75)$, setback $(R^2>0.88)$ and consistency $(R^2>0.31)$. These results suggest that detection of irradiated black pepper is possible using amylograph characteristics.

• The Korean Journal of Food And Nutrition
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• v.12 no.2
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• pp.204-208
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• 1999

In order to obtain data for use of algin in drink making process solution properties of algin have been investigated at various condition of algin concentration temperature pH and various food additives. At same revolution velosity viscosities of algin were increased as algin concentration raised. Algin solution showed dilatnat type flow in concentration of 0.25% to 0.4% but pseudoplastic type flow in above 0.5% showed dilatant type flow in concentration of 0.25% to 0.4% but pseudoplastic type folw in above 0.5% A maximum viscosity of algin was observed at pH 5.5 and its viscosities were also decreased as the tem-perature increased and heating at 8$0^{\circ}C$ above. Organic acids affected on the viscosity of algin with pH dependently and gel formed in pH below 3.0 Sweetners have no effect to the viscosity of algin. How-ever addition of NaCl and KCL upto 1.0% decreased a little its viscosity and CACl2 MgCl2 and FeCl3 increased the viscosity of algin Glutamic acid decreased the viscosity of algin.

• Journal of Oral Medicine and Pain
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• v.39 no.3
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• pp.90-95
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• 2014

Purpose: To investigate viscosity and wettability of hyaluronic acid (HA) solutions according to supplementation of lysozyme and/or peroxidase, and different ionic strength and pH conditions. Methods: Solutions containing HA were prepared using distilled deionized water (DDW) and simulated salivary buffer (SSB) in different conditions. Different concentrations of hen egg-white lysozyme and bovine lactoperoxidase was added into HA solutions. HA solutions with antimicrobials in different ionic strength and pH conditions were prepared. Viscosity was measured using cone-and-plate digital viscometer at six different shear rates and wettability on acrylic resin and Co-Cr alloy was determined by contact angle. Results: The viscosity values of HA dissolved in DDW were decreased in order of HA, HA containing lysozyme, HA containing peroxidase, and HA containing lysozyme and peroxidase. The viscosity values for HA in DDW were decreased as the concentration of lysozyme and/or peroxidase increased. However, the viscosity values for HA in SSB showed no significant changes according to the concentration of lysozyme and/or peroxidase. The viscosity values of HA solutions were inversely proportional to ionic strength and pH. The contact angle of HA solutions showed no significant differences according to tested surface materials, addition of lysozyme and/or peroxidase, and different ionic strength and pH conditions. Contact angles on acrylic resin by HA solutions in all tested conditions were much higher than those by human saliva. Conclusions: The rheological properties of HA supplemented with lysozyme and/or peroxidase in different ionic strength and pH conditions were objectively confirmed, indicating the possibility of HA with lysozyme and/or peroxidase as main components in the development of effective saliva substitutes.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.4
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• pp.487-491
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• 1995

Effects of pH and molecular weight on the intrinsic viscosity of carboxymethyl chitin (CM-chitin) in dilute regime were studied. When the prepared CM-chitin was dissolved in 0.1M NaCl solution at $30^{\circ}C$, the intrinsic viscosity, molecular weight and degree of substitution of CM-chitin were 1.23dl/g, 15,500 and 0.62, respectively. The lower intrinsic viscosity $([\eta])$ of CM-chitin was showed at the lower pH than 7.0 and the higher pH (>7.0) did not result in any increase in intrinsic viscosity. Intrinsic viscosity decreased from 3.1dl/g to 2.55d1/g in water at $25^{\circ}C$ and from 15,500 to 12,600 as molecular weight for 20min of sonication treatment. The Mark-Houwink constant K and v of CM-chitin in water at $25^{\circ}C$ were $3.48\times10^-4$ and 0.94, respectively. So intrinsic viscosity could be expressed using molecular weight as followed equation; $[\eta]=3.48\times10^{-4}M^{0.94}$, consistent with random roil behaviour.

• Journal of Oral Medicine and Pain
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• v.17 no.2
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• pp.87-97
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• 1992

The purpose of this study is to investigate the age-and sex-related changes in the pH of resting saliva, viscosity, microorganisms and immunoglobulin A of stimulated whole saliva, and to investigate their correlations. The 120 healthy subjects were included in this study and the author used cone-and plate digital viscometer for viscosity, MSB agar for Streptococcus mutans, SL Rogosa agar for lactobacilli, and single radial immunodiffusion technique for immunoglobulinA. The obtained results were as follows : 1. There was no significant difference in pH, viscosity, Streptococcus mutans lactobacilli and immunoglobulin A of the saliva between males and females. 2. The viscosity values of stimulated whole saliva showed the increasing pattern with aging. 3. DMFS (or dmfs) rate was not correlated with pH, viscosity, Streptococcus mutans, lactobacilli and immunoglobulin A of the saliva. 4. There was a significant difference in the concentration of immunoglobulin A between the group under 10 and groups above 10. 5. The viscosity values of stimulated whole saliva showed the increasing pattern with decreasing of the number of Streptococcus mutans.

• Journal of Conservation Science
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• v.27 no.3
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• pp.261-268
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• 2011

Traditional paste materials and additives for investigation were selected through careful literature survey. We used the immersed glutinous rice flour, soybean as a traditional paste materials and a yellow wax, alum, and lime as additives. The effect of additives on viscosity, pH, adhesive strength, flexibility, antibacterial activities, mildew resistance, and conservation properties were examined. It was found that there was a relationship between the properties(viscosity, pH, and adhesive strength) and the characteristics of additives. Alum increased flexibilty but decreased viscosity, adhesive strength, and pH. Yellow wax deceased flexibilty, viscosity, adhesive strength, and pH. Lime increased flexibilty, viscosity, adhesive strength, and pH. The conservation properties increased by adding all additive. The present work was therefore carried out with the objective of offering the base datum for keeping traditional papers and textiles using traditional paste.

• Korean Journal of Food Science and Technology
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• v.16 no.4
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• pp.423-428
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• 1984

Changes in viscosity of soymilk were evaluated as affected by solid concentration, temperature, pH and sugar addition. Soybeans were soaked, ground with boiling water, and filtered followed by boiling for 30 min for soymilk preparation. It was found that viscosity increased exponentially as solid concentration increased while the raise of temperature caused exponential decrease in it. A minimum viscosity was ovserved at pH 6.5 in the range of pH 5.0-8.0. The effects of solid concentration and pH on viscosity were reduced as the measuring temperature increased. Addition of sucrose up to 9% showed little effect on viscosity with showing a tendency of increase.

• Korean journal of food and cookery science
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• v.4 no.1
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• pp.17-26
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• 1988

The polysaccharide produced by pseudomonas elodea, Gellan gum, was rheologically characterized, compared with agar. Rheological properties were determined from the change in the value of intrinsic viscosity with the pH and salt concentration. At the range of pH 2∼ll and salt 0∼0.16M KC1, the intrinsic viscosity of Gellan gum ranged from 8.8 to 21.2dl/g and agar ranged from 1.97 to 11.46d1/g. In the absence of salt, the intrinsic viscosity of Gellan gum increased as the pH of solution increased up to neutral pH then decreased slightly at alkaline pH, whearas the intrinsic viscosity of agar increased as the pH of solution increased up to pH 9 then decreased slightly. Intrinsic viscosity of Gellan gum and agar decreased with an increase in salt concentration. The chain stiffness parameter for the Gellan gum was 0.033. The overlap parameter of Gellan gum and agar were 0.047g/dl and 0.087g/dl, respectively. Gellan gum and agar were shear rate dependent or pseudoplastic. The yield stress and proportionality constant of Gellan gum increased slightly as the concentration increase, on the other hand, the shear index of Gellan gum showed a maximum at 0.75g/dl and gradually decreased as the concentration increase. The apparent viscosity of Gellan gum and agar decreased as the temperature increase. A lower concentration of the divalent cations calcium and magnesium is required to obtain maximum gel strength than for the monovalent cations sodium and potassium.