• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.3
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• pp.414-419
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• 2005

Newly harvested milled rice and stored milled rice for 2 years were steeped at the elevated temperatures of 40, 50, and 60℃ for 2hr, and physicochemical properties of the wet-milled rice flour were investigated. The lightness of rice flour was slightly higher in the newly harvested milled-rice, while yellowness was higher in the stored milled rice. For both newly harvested and stored milled rice, WAI, WSI, and gel consistency increased as steeping temperature increased. The amylograph pasting properties indicated that increasing steeping temperature increased peak viscosity. The differential scanning calorimetry (DSC) results of the rice flour showed that increasing steeping temperature increased onset and peak temperatures, with reduced gelatinization enthalphy, suggesting partial annealing occured. Particle size of rice flour from newly harvested milled rice was larger than that from stored milled rice.

• Korean Journal of Food Science and Technology
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• v.47 no.6
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• pp.793-796
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• 2015

The in-vitro starch digestibility of white and brown rice flours was continuously characterized from a rheological point of view. Specifically, the in-vitro viscosities of the rice digesta samples were monitored under simulated oral, gastric, and intestinal conditions. A trend of decreasing viscosities in all the digesta samples was observed during the in-vitro digestion. After cooking, the brown rice sample exhibited lower viscosity than that of the white rice flour due to the presence of more non-starch components. A similar tendency was observed during the simulated oral and gastric digestions. However, the viscosity crossover between the white and brown rice samples was observed during intestinal digestion. In addition, the amount of glucose released from the brown rice flour was significantly lower than that from the white rice flour. Thus, the slower rate of starch hydrolysis in the brown rice flour could be related to its in-vitro rheological behaviors.

• Korean journal of food and cookery science
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• v.23 no.3 s.99
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• pp.314-320
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• 2007

The objective of this study was to investigate the effect of grain size on the physicochemical properties of rice porridge. Here, the grain size of the rice was classified as whole grain, half grain, and flour by traditional Korean cooking methods. The viscosity of the rice flour porridge was highest for the among the three different grain size porridges. In the amylographs, the increase in viscosity for the whole grain porridge was higher than that of the rice flour porridge during cooling. The soluble solid and reducing sugar contents of the rice porridges increased according to the rice grain size, while the blue value decreased. The SDI (starch digestion index) increased according to the rice grain size. The RDS (rapidly digestible starch) was highest while the SDS (slowly digestible starch) the lowest in the rice flour porridge. The morphologies of the rice porridges were examined by SEM and showed a smoother surface and more exudated gelatinized granules in the rice flour than in the whole grain rice porridge. In conclusion, rice porridges made from the smallest possible grain size such as flour may be helpful for people with weaker digestive systems such as infants, the elderly, and hospital patients.

• Preventive Nutrition and Food Science
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• v.4 no.3
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• pp.180-183
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• 1999

Seaweeds is a rich sources of dietary fibers exerting a number of physiological properties. However, the reported dietary fiber contents of seaweeds are not consistent and vary widely. Also. a limited number of studies on the biological effects of specific seaweeds have been reported. In this study, water-holding capacity, viscosity and antixidantive activity of major dietary seaweeds were measured to assess their physiological effects. Results showed that total dietary fiber contents ranged from 28 to 51% of dried weight, and large proportions of dietary fiber were insoluble fibers. Water-holding capacity was highest in sea mustard being 1310% , while laver, sea tangle, and green laver exhibited 943, 854 and 815%, respectively. The viscosity of seaweed samples was 20 to 40 cP in sea mustard and sea tangle, while laver and green laver possessed much lower values. All seaweed samples revealed a weak, albeit significant electron donating ability. Also, lipid peroxidation was reduced by 7 to 18%. However, there was no difference in antioxidative activity among seaweeds and sample concernations used. These results imply that most commonly used seaweeds possibly exert parts of their physiological effects through their water-holding, gel-forming , and/or antioxidative activities.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.4
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• pp.397-400
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• 1995

Effects of rheological parameters, such as shear rate, temperature, concerntration, salts on the apparent viscosity of chitosan(deacetylation degree: $84\%$, Mw: 267,000) dissolved in acetate buffer(pH 4.5) were investigated. Rheologiral properties of chitosan solution from cuticle of red snow crab (Chinonecetes japonicus) are as follows. $0.5\%$ chitosan in 0.1M acetate buffer (pH 4.5) solution showed Bingham flow having hysteresis loop. It's flow equation was $\sigma=0.757+19.6_\gamma(r^2=0.99)$. The viscosity of chitosan solution is exponentially increased with its concentration, and showed Arrhenius dependence with respect to the temperature $(10^{\circ}C-40^{\circ}C).$ When various salts were added to chitosan solution, the viscosity decreased as the concentration of counterion increased. But the type ot counterions itself does not have any significant effects on the viscosity.

• Food Science and Biotechnology
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• v.14 no.2
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• pp.233-237
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• 2005

Rheological properties of acorn flour-guar gum mixtures (4% w/w) at different guar gum concentrations (0, 0.2, 0.4, 0.6, and 0.8% w/w) were evaluated in steady and dynamic shear. The acorn flour-guar gum mixtures at $25^{\circ}C$ showed high shear-thinning flow behavior (n= 0.20-0.27). Consistency index (K), apparent viscosity (${\eta}_{a,100}$), and Casson yield stress (${\sigma}_{oc}$) increased with the increase in guar gum concentration. Within the temperature range of $25-70^{\circ}C$, the {\eta}_{a,100}$ of mixtures obeyed the Arrhenius relationship with high determination coefficient ($R^2=\;0.974-0.994$). Activation energy values (5.37-6.77 kJ/mole) of acorn flour dispersions in the mixtures with guar gum (0.2-0.8%) were much lower than that (12.5 kJ/mole) of acorn flour dispersion (0% guar gum). Storage modulus (G'), loss modulus (G"), and complex viscosity (${\eta}^*$) increased with the increase in guar gum concentration. Dynamic rheological data of 1n (G', G") versus ln frequency (w) of guar gum-acorn flour mixtures had positive slopes with G' greater than G" over most of the frequency range, indicating that they exhibited weak gel-like behavior.

• Journal of the Korean Society of Food Culture
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• v.25 no.2
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• pp.225-231
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• 2010

The principal objective of this study was to evaluate quality characteristics of dried noodles when different concentrations of lotus leaf powder (LLP) were added to the wheat flour, thereby determining which noodle recipe was preferred. The cooking quality, mechanical texture properties, and viscosity were measured, and then a sensory evaluation was conducted with the prepared noodles. The gelatinization points of the composite LLP-wheat flours were shown to have an increased, viscosity at $95^{\circ}C$ after 15 minutes. As measured via amylograph, the maximum viscosity values of those samples were decreased as the LLP content was increased. As well, when increased amounts of LLP were added, both the L and a values were reduced, whereas the b value was increased. The color values, weight and volume of the cooked noodle increased, as did the turbidity of the soup. With regard to the textural characteristics, the LLP additive increased hardness and cohesiveness, and reduced adhesiveness and springiness. Overall, according to the results of our sensory evaluation, the noodles prepared with 5% LLP were preferred over the other noodles.

• Food Science and Biotechnology
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• v.18 no.4
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• pp.900-903
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• 2009

An oat gum was extracted from whole seeds of a drought harvested oat (Avena sativa). Oat gum presented a ${\beta}-glucan$ content of 65%(w/w) and an intrinsic viscosity of 141 mL/g. Gelling capability of oat gum at different concentrations was investigated. Gel hardness increased from 0.08 to 0.25 N as the oat gum concentration changed from 5 to 10%(w/v). Whippability, foam stability, emulsion stability, and reduced viscosity of oat gum at different pH were also investigated. Oat gum whippability was maximum at pH 7 (146%), while the higher foam and emulsion stability values were found at pH 9 (88 and 96%, respectively). The gum reduced viscosity increased from 715 to 958 mL/g as the pH changed from 7 to 9. Oat gum shows great potential as a gel forming, thickening, and stabilizing agent.

• Food Science and Preservation
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• v.31 no.2
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• pp.199-209
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• 2024

This study explored how temperature, time, and moisture content affect the rheological properties (apparent viscosity, flow behavior index, and consistency coefficient) of stored tomato and pepper purees. These purees were prepared with moisture contents of 85%, 90%, and 95% (w/v) using the hot-break method and tested over 6 days at 2-day intervals and temperatures of 5℃, 10℃, and 15℃. Results displayed distinct ranges for apparent viscosity, consistency coefficient, and flow behavior indices: tomato puree (2,519.9-4,324.6 mPa·s, 258.0-550.6 mPa·Sn, 1.80-0.48) and pepper puree (2,105.6-4,562.0 mPa·s, 268.4-580.4 mPa·Sn, 0.22-0.48). The temperature and storage time had significant (p≤0.05) effects, but moisture content did not affect these properties. Flow behavior and consistency coefficients demonstrated relative variation with apparent viscosity, indicating pseudoplastic behavior. Optimal processing and storage conditions were identified within specific ranges: 13.21-14.42℃ for 2 days with 92.22-94.23% (w/v) moisture content for pepper, and 8.42-11.77℃ for 2-6 days with 85% (w/v) moisture for tomato.

• Korean journal of food and cookery science
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• v.24 no.2
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• pp.206-211
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• 2008

This study investigated the feasibility of manufacturing a low-sugar wild vine jam by examining viscosity, water content, and pH, as affected by sugar and pectin content. The jams were prepared by adding various amounts of sucrose, glucose, or fructose (1.89 M, 2.34 M, 2.63 M, or 2.92 M) and/ or pectin (0%, 0.3%, 0.5%, 0.8%, or 1%) to wild vine juice and heating at $90^{\circ}C$ for 3 hrs. A higher viscosity was shown for the jam manufactured with sucrose as compared to those made with glucose or fructose, and the greater the sucrose level the higher the viscosity of the jam. The jam with 50% reduced sugar content showed a similar viscosity to the control jam, which contained only 2.92 M sucrose, when the sugar was co-added with pectin at 0.5% for the low sucrose jam, and at 0.8% for the low glucose or low fructose jams, respectively. The water content of the low sucrose jam was lower than that of the low glucose or low fructose jams, and adding pectin had no significant effect on the water content of the low sugar jam. The pH levels of the jams were not significantly different, regardless of the type and concentration of sugar, temperature, or pectin addition, and ranged between 3.6 and 3.8. Overall, the results clearly show that wild vine jam with 50% reduced sugar content and having the same viscosity as control jam, can be manufactured when pectin and sugar are added together.