• Korean Journal of Food Science and Technology
• /
• v.30 no.5
• /
• pp.1085-1091
• /
• 1998

The purpose of this study was to investigate the rheological properties of surimi gels and imitation crab-leg products by stress-relaxation test and to examine the correlations between stress-relaxation parameters and T.P.A. parameters. The linear viscoelasticity of surimi gels and imitation crab-leg products was observed in the range of the strain of $5{\sim}20%$ at cross-head speed 2.4 mm/sec. The average tensile forces of surimi gels and imitation crab-leg products were similar, 370.4 g and 436.4 g, respectively, but surimi gels showed higher relaxation time and viscous component (17256.1 sec, $1.357{\times}10^{10}$ poise) than those of imitation crab-leg products (6110 sec, $0.519^{\ast}10^{10}$ poise). Estimated tensile force of each exponential term in relaxation test was highly related with hardness, gumminess and chewiness of T.P.A (r=0.93, 0.93, 0.95, p<0.01), the relaxation time of each exponential term was rrelated with cohesiveness (r=0.89, p<0.01) of T.P,A. and the elastic component of exponential term with gumminess, chewiness and hardness (r=0.92, 0.94, 0.93. p<0.01) of T.P.A.. The viscous component of exponential term was related with cohesiveness (r=0.83, p<0.05) of T.P.A.. The degree of texturization was negatively related with the relaxation time and viscous component (r=-0.92, -0.96, p<0.01).

• Food Science and Biotechnology
• /
• v.18 no.4
• /
• pp.1013-1018
• /
• 2009

Several rheological terms were introduced to estimate the properties of cooked noodles with different starch content using tensile tests. Ring-shaped specimens were prepared by connecting both ends of the noodle strip before cooking. Hencky strain and rate, as well as true stress were applied in constant deformation tests. The elastic region on the curves of strain vs. stress was not clearly identified. Strain hardening in the subsequent plastic region was more prominent in low-starch noodles. Elongational viscosities at lower strain rates were used to differentiate noodles with different starch content, representing the dominant effect of protein content in the range of lower strain rates. In stress relaxation tests, the reciprocal of Peleg's constant $K_1$ (initial decay rate) and $K_2$ (asymptotic level) increased and decreased respectively, with an increase in starch content. This indicated that addition of starch contributed to the noodles becoming viscous liquid rather than elastic solid.

• Food Science and Biotechnology
• /
• v.16 no.5
• /
• pp.734-739
• /
• 2007

This study was conducted to observe the quality characteristics of cheonggukjang fermented with new small-seed soybeans ('Agakong') according to the degree of germination of the raw soybeans. The sprouting rate was $8.6{\pm}5.6%$ after 12 hr of germination, but at 24 hr it increased rapidly to $85.4{\pm}4.7%$. We confirmed that the total isoflavone content immediately after soaking was 273.9 mg%, which was at least 3 times greater than for common soybeans; content increased at the start of germination, and increased to 338.4 mg% by 24 hr of germination, but then decreased. The quantity of viscous substance of the cheonggukjang increased in proportion to the degree of germination of the raw soybeans. The levels of amino acids in the cheonggukjang made from non-germinated soybeans, and soybeans germinated 48 hr, were 12.45 and 10.06%, respectively. The isoflavone levels in the cheonggukjang were determined by the degree of germination of the raw soybeans. There were no significant differences between the odor, sweet taste, savory taste, bitter taste, and overall acceptability of the cheonggukjang with different germination times of 0 to 36 hr.

• Preventive Nutrition and Food Science
• /
• v.22 no.3
• /
• pp.223-230
• /
• 2017

The purposes of this study were to produce polysaccharides from red pepper stems using different extraction methods and evaluate their chemical composition, in vitro biological capacities, and rheological properties. Two polysaccharides were extracted from red pepper stems using an autoclave and alkali treatments, and the extracts were named PAU and PAL, respectively. The contents of total phenolics and flavonoids were significantly higher in PAU than those in PAL. PAU exhibited greater scavenging activities on 2,2-diphenyl-1-picrylhydrazyl radicals, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt radicals, superoxide radicals, and nitrite compared to PAL, suggesting that PAU served as better antioxidants. Similarly, in vitro inhibitory abilities against carbohydrate hydrolyzing enzymes of PAU were higher than those of PAL. Steady shear rheological analysis demonstrated that PAU showed higher psuedoplastic shear-thinning behavior compared to PAL. Based on the results from dynamic shear rheological properties, it was found that both samples had predominantly viscous behavior rather than elastic behavior.

• Journal of Microbiology and Biotechnology
• /
• v.11 no.3
• /
• pp.428-434
• /
• 2001

A viscous substance producer strain BS62, which was isolated from conventional Chungkookjang, was examined for its productivity of levansucrase and levan during soybean fermentation at $37{\circ}C$. After one day of cultivation, the enzyme activity reached the highest level, 8 units $ml^{-1}$. Extracts of fermented soybeans were precipitated by ethanol and hydrolyzed by either 0.1 N HCl or invertase, and the hydrolyzates were analyzed using thin layer and ion chromatographies. Fructose was the only sugar detected. This suggest that fructose was derived from the levan produced by the strain BS62 during soybean fermentation. The aerobic, endospore-forming bacterium BS62 was identified as a Bacillus subtilis sp., based on the composition of its cellular fatty acids and phylogeny, which was determined by its 16S rDNA sequence.

• The Korean Journal of Food And Nutrition
• /
• v.27 no.2
• /
• pp.274-279
• /
• 2014

The objective of this study was to investigate the fermentation characteristics of cheonggukjang made with smoked soybeans. The study found that the amino nitrogen content and pH of cheonggukjang made with smoked soybean (CSS) were significantly elevated compared to that of cheonggukjang made with non-smoked soybeans (CNS). On the other hand, the moisture content of CSS was significantly lower when compared to that of CNS. Moreover, there were no significant differences in the viscous substance content between CNS ($5.8{\pm}0.2%$) and CSS ($5.6{\pm}0.3%$). In terms of colour, the L and b values of CSS were higher than that of CNS, whereas the a value of CNS was higher than that of CSS. Hence, it was confirmed that the total isoflavone contents in CSS ($1,624.6{\pm}53.2{\mu}g/g$) were higher than that in CNS ($1,590.6{\pm}59.3{\mu}g/g$). In both CSS and CNS, the content of genistin was highest followed by glacitin and daidzein. Also, the number of aerobic bacteria in CNS ($8.1{\pm}0.4\;log\;cfu/g$) was higher than that in CSS ($7.3{\pm}0.3\;log\;cfu/g$). Taken together, a smoking process can useful for the development of new cheonggukjang products.

• Food Science of Animal Resources
• /
• v.44 no.4
• /
• pp.885-898
• /
• 2024

Ovomucin (OM), which has insoluble fractions is a viscous glycoprotein, found in egg albumin. Enzymatic hydrolysates of OM have water solubility and bioactive properties. This study investigated that the immunostimulatory effects of OM hydrolysates (OMHs) obtained by using various proteolytic enzymes (Alcalase^®, bromelain, α-chymotrypsin, Neutrase^®, pancreatin, papain, Protamax^®, and trypsin) in RAW 264.7 cells. The results showed that OMH prepared with pancreatin (OMPA) produced the highest levels of nitrite oxide in RAW 264.7 cells, through upregulation of inducible nitric oxide synthase mRNA expression. The production of pro-inflammatory cytokines such as tumor necrosis factor-α and interleukin-6 were increased with the cytokines mRNA expression. The effect of OMPA on mitogen-activated protein kinase signaling pathway was increased the phosphorylation of p38, c-Jun NH2-terminal kinase, and extracellular signal-regulated kinase in a concentration-dependent manner. Therefore, OMPA could be used as a potential immune-stimulating agent in the functional food industry.

• Korean Journal of Food Science and Technology
• /
• v.39 no.6
• /
• pp.676-680
• /
• 2007

This research was conducted to investigate the changes in quality characteristics of cheonggukjang made with 24-hr germinated soybeans during fermentation. Our study confirmed that the pH of the 24-hr germinated soybeans was 6.7, and the value increased as fermentation progressed. The amount of viscous substances in the cheonggukjang produced with the 24-hr germinated soybeans constantly increased to 5.89% at 36 hr of fermentation, and then remained unchanged. Free sugars (raffinose, sucrose, glucose, and fructose) rapidly decreased with the fermentation process. The levels of free amino acids in the 24-hr germinated agakong and the 48-hr fermented cheonggukjang were 391.0 and 10,994.8 mg%, respectively. Glutamic acid content was highest, followed by aspartic acid, lysine, leucine, and proline. The ratio of glutamic acid to total free amino acids at 48-hr of fermentation was 18.0%. Finally, it was confirmed that the sensory evaluation score of the 24-36 hr fermented cheonggukjang, made with the 24-hr germinated soybeans, was superior to that of the 24 and 48-hr fermented cheonggukjang.

• Food Science and Biotechnology
• /
• v.14 no.6
• /
• pp.813-817
• /
• 2005

We investigated the effect of a viscous substance from chongkukjang (chongkukjang mucilage) on immunohistochemical reactions in rat gastrointestinal (GI) tracts, Rats fed a steady diet of chongkukjang mucilage showed an increase in the immunoreactive densities of gastrin and serotonin in the pyloric region of their stomachs and duodenal villi, The number of gastrin and serotonin immunoreactive cells was significantly higher in the experimental group than in the control group. Feeding on dietary chongkukjang mucilage increased the immunohistochemical densities of $CD4^+$ and $CD8^+$ lymphocytes in the mucosa and submucosa of the rats' gastroduodenal region. The universal nitric oxide synthase (uNOS)-immunoreactive neurons and nerve fibers were strongly stained in the vascular walls of the submucosa and myenteric plexus in rats fed the test diet. The results indicate that the intake of chongkukjang mucilage could increase mucosal immune activity, gastrointestinal motility, and blood circulation in the GI tract.

• The Korean Journal of Food And Nutrition
• /
• v.28 no.6
• /
• pp.1004-1010
• /
• 2015

This study was conducted to investigate the changes in the physicochemical characteristics and antioxidant activity of cheonggukjang with the addition of walnuts. The pH of cheonggukjang did not change significantly with the addition of walnut. But the water content decreased significantly. Walnut addition to the soybean was expected to have a positive effect because the number of Bacillus subtilis was not reduced. The viscous substance content was significantly decreased when more than 20% of walnut was added to cheonggukjang. The addition of walnut made the color darker. The flavonoid and polyphenol content was sharply increased in proportion to the walnut addition and the DPPH radical scavenging activity of cheonggukjang also increased. Altogether, it was found that the addition of walnut had a positive influence on the cheonggukjang by increasing the antioxidant activity.