• Microbiology and Biotechnology Letters
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• v.17 no.4
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• pp.277-282
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• 1989

Xanthan gum is a biopolymer produced by Xanthomonas campestris. In xanthan gum fermentation, the fermentation broth changes to highly viscous non-Newtonian fluid as xanthan gum concentration increases. Maximum xanthan gum concentration is limited by high viscosity of the broth since mass transfers of nutrient and oxygen are inhibited. Int this study the mass transfer effects were investigated in batch and fed-batch fermentations at various agitation speeds and by separate oxygen transfer experiments. Xanthan gum production rate was observed to be largely dependent on oxygen transfer coefficient; while cell growth rate was not affected highly by this factor.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.2
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• pp.196-203
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• 2002

Effect of different levels (0 ,0.05, 0.15, 0.25%) of xanthan gum on kakdugi fermentation was investigated by analyzing physicochemical and sensory characteristics during fermentation at 2$0^{\circ}C$. During fermentation, pH was maintained higher, and total acidity and number of lactic acid bacteria, maintained lower in xanthan gum groups, especially in 0.05% addition group than control. Free sugar amount were higher in xanthan gun groups than control, and glucose and fructose which were the major free sugars, decreased rapidly during fermentation, whereas mannitol increased in all samples, especially in xanthan gum groups. Liquid content of kakdugi was smaller in 0.05% xanthan gum group than control. Viscosity of kakdugi liquid decreased rapidly whereas initial viscosity was maintained in xanthan gum groups. Hardness decreased during fermentation, but at the 7th day of fermentation was higher in 0.05% xanthan gum group than control. The result of sensory evaluation shows that there were no significant difference in sour odor, moldy, sour taste and savory taste among samples. Starch taste was higher in 0.15% or 0.25% xanthan gum, but there is no difference in 0.05% group, compared to control. Overall preference until the 5th day of fermentation, xanthan gum group was not significantly different from that of control but at the 7th day of fermentation, 0.05% addition group was significantly higher than control.

• Food Science and Biotechnology
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• v.15 no.3
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• pp.474-477
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• 2006

Dynamic rheological properties of commercial 0.8, 1.0, and 1.2% gums [carboxylmethylcellulose (CMC), guar gum, hydroxypropylmethylcellulose (HPMC), tara gum, and xanthan gum], which can be dissolved in cold water, were investigated by small-deformation oscillatory measurements. Magnitudes of storage (G') and loss (G") moduli increased with increasing concentration of gum solutions except for xanthan gum. Guar gum exhibited greatest G' and G" values among all gums except for G' value at 0.8% concentration. Slopes of G' and G" decreased with increasing concentration of gum solutions except for xanthan gum. Tan ${\delta}$ (G"/G') values decreased with increasing concentration of gum solutions except for xanthan gum. Tan ${\delta}$ values of xanthan gum solutions were much lower than those of other gum solutions, indicating that xanthan gum solutions were predominantly more elastic than viscous.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.3
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• pp.423-427
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• 2002

Xanthan gum (XG) was investigated for use as a thickening and stabilizing agent in kimchi during fermentation at 10$\^{C}$. The mixing ratios of XG to salted Chinese cabbage were 0.1, 0.3 and 0.5%. Quality characteristics of kimchi such as pH, titratable acidity, reducing sugar content and microbial loads were measured. pH and reducing sugar content showed abrupt decreases after 5 day lag time until 20 days, while titratable acidity steadily increased during fermentation. The addition with 0.5% XG retarded the change rates of pH and titratable acidity showing the slowest change. Kimchi samples added with 0.1% and 0.3% XG maintained a higher reducing sugar content during the whole fermentation period of 30 days. Microbial loads showed an abrupt increase from 5 to 10 days, and maintained a nearly same load thereafter. Kimchi sample added with 0.3% XG showed better scores in color, aroma and taste.

• Ecology and Resilient Infrastructure
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• v.8 no.3
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• pp.135-142
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• 2021

Biopolymers have been known as eco-friendly soil strengthening materials and studied to apply levees. However, the effect of biopolymer on vegetation is not fully understood. In this study, we analyzed the root growth of Camelina sativa L. (Camelina) when the xanthan gum was amended to soil in Aluminum (Al) stress conditions. Amendment of 0.05% xanthan gum increased root growth of Camelina under Al stress conditions. Under the Al stress condition, expression of aluminum activate malate transporter 1 (ALMT1) gene of Camelina root was induced but showed a lower level of expression in xanthan gum amended soil than non-amended soil. Additionally, the binding capacity of xanthan gum with Al ions in the solution was confirmed. Using morin staining and ICP-OES analysis, the Al content of the roots in the xanthan gum soil was lower than in the non-xanthan gum soil. These results suggest that xanthan gum amended soils may reduce the detrimental effects of Al on the roots and positively affect the growth of plants. Therefore, xanthan gum is not only an eco-friendly construction material but also can protect the roots in the disadvantageous environment of the plant.

• Geomechanics and Engineering
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• v.12 no.5
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• pp.831-847
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• 2017

Conventional geotechnical engineering soil binders such as ordinary cement or lime have environmental issues in terms of sustainable development. Thus, environmentally friendly materials have attracted considerable interest in modern geotechnical engineering. Microbial biopolymers are being actively developed in order to improve geotechnical engineering properties such as aggregate stability, strength, and hydraulic conductivity of various soil types. This study evaluates the geotechnical engineering shear behavior of sand treated with xanthan gum biopolymer through laboratory direct shear testing. Xanthan gum-sand mixtures with various xanthan gum content (percent to the mass of sand) and gel phases (initial, dried, and re-submerged) were considered. Xanthan gum content of 1.0% sufficiently improves the inter-particle cohesion of cohesionless sands 3.8 times and more (up to 14 times for dried state) than in the untreated (natural) condition, regardless of the xanthan gum gel condition. In general, the strength of xanthan gum-treated sand shows dependency with the rheology and phase of xanthan gum gels in inter-granular pores, which decreases in order as dried (biofilm state), initial (uniform hydrogel), and re-submerged (swollen hydrogel after drying) states. As xanthan gum hydrogels are pseudo-plastic, both inter-particle friction angle and cohesion of xanthan gum-treated sand decrease with water adsorbed swelling at large strain levels. However, for 2% xanthan gum-treated sands, the re-submerged state shows a higher strength than the initial state due to the gradual and non-uniform swelling behavior of highly concentrated biofilms.

• Food Industry
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• s.45
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• pp.32-37
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• 1978

자연에서 얻어지는 고무질로서는 여러 가지 종류의 것이 많으나 한천, 알긴산염, 카라기난(Carrageenan), 퍼셀라란(furcellaran)등은 해조로부터 추출되며 Pectin, arabic gum, karaya gum, tragacanth gum, ghatti gum, guargum, 메뚜기콩고무(Locust been gum), 사이리엄고무(psyllium seed gum)등은 식물로부터 추출된다. 특히 이외에도 미생물에서 분비되는 고무질인 다당(多糖)으로는 dextran, curdlan, pullulau, 잔산고무(Xanthan gum)등도 최근에 알려진 고무질이다. 여기에서는 미생물이 생산하는 고무질인 다당(多糖)인 Xanthan gum이 새로히 식품첨가물로 지정되었기에 Xanthan gum의 발견내역, 성질, 생산과 응용면을 소개한다.

• Food Science and Biotechnology
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• v.16 no.1
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• pp.146-149
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• 2007

Dynamic rheological properties of hot pepper-soybean paste (HPSP) mixed with xanthan gum were evaluated at different gum concentrations (0.3, 0.6, and 0.9%) and fermentation times (12 and 24 week). Magnitudes of storage (G') and loss moduli (G") in the HPSP-xanthan gum mixture systems increased with an increase in frequency ($\omega$), while complex viscosity (${\eta}^*$) decreased. G' values were higher than the G" values over most of the frequency range (0.63-63 rad/sec), and were frequency-dependent. The dynamic moduli (G', G", and ${\eta}^*$) of the HPSP-xathan mixtures were lower than those of the control (0% gum). The differences between the dynamic moduli values at 12-week and 24-week fermentation decreased with increasing gum concentration, showing that xanthan gum can be used to stabilize and improve the viscoelastic rheological properties of HPSP. The G' value of the HPSP-xathan mixtures increased with an increase in gum concentration from 0.3 to 0.9%, whereas the G" decreased. The ability of xanthan gum to increase the elastic properties in the HPSP-xanthan mixture systems seemed to be the result of the incompatibility phenomena existing between xanthan gum and glutinous rice starch.

• Geomechanics and Engineering
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• v.33 no.2
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• pp.121-131
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• 2023

Clay sedimentation has been widely analyzed for its application in a variety of geotechnical constructions such as mine tailing, artificial islands, dredging, and reclamation. Chemical flocculants such as aluminum sulfate (Al₂(SO₄)₃), ferric chloride (FeCl₃), and ferric sulfate (Fe(SO₄)₃), have been adopted to accelerate the settling behaviors of clays. As an alternative clay flocculant with natural origin, this study investigated the settling of xanthan gum-treated kaolinite suspension in deionized water. The sedimentation of kaolinite in solutions of xanthan gum biopolymer (0%, 0.1%, 0.5%, 1.0%, and 2.0% in a clay mass) was measured until the sediment height was stabilized. Kaolinite was aggregated by xanthan gum via a direct electrical interaction between the negatively charged xanthan gum molecules and positively charged edge surface and via hydrogen bonding with kaolinite particles. The results revealed that the xanthan gum initially bound kaolinite aggregates, thereby forming larger floc sizes. Owing to their greater floc size, the aggregated kaolinite flocs induced by xanthan gum settled faster than the untreated kaolinite. Additionally, X-ray computed tomography images collected at various depths from the bottom demonstrated that the xanthan gum-induced aggregation resulted in denser sediment deposition. The findings of this study could inspire further efforts to accelerate the settling of kaolinite clays by adding xanthan gum.

• Journal of the Korean Society of Food Culture
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• v.24 no.5
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• pp.540-551
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• 2009

This study was conducted to investigate the quality characteristics of mungbean starch gels containing various hydrocolloids (carrageenan, locust bean gum and xanthan gum) during room temperature storage ($25^{\circ}C$ for 24, 48 and 72 hours). Carrageenan and xanthan gum reduced the pasting viscosity of mungbean starch, whereas the locust bean gum increased the viscosity. The melting characteristics, as assessed by DSC, showed that carrageenan and xanthan gum delayed gelatinization of mungbean starch and the locust bean gum had no effect on this property. The lightness (L) of the gels with the locust bean gum was similar to that without the additive during storage, whereas that with carrageenan and xanthan gum was higher than that without the additive. Hardness, chewiness and gumminess of the gels with the locust bean gum was higher than that without the additive during storage, whereas that with carrageenan and xanthan gum was lower than that without the additive. The rupture stress, rupture strain and rupture energy of the gels with carrageenan and xanthan gum was lower than that without the additive during storage, whereas that with the locust bean gum was similar to that without the additive. In the sensory evaluation, springiness and cohesiveness of the gels with carrageenan and xanthan gum were lower than those without the additive, whereas springiness, brittleness and hardness of the gels with the locust bean gum were higher than those without the additive. In addition, the overall acceptability of the gels with the locust bean gum improved. The above results showed that carrageenan and xanthan gum lowered the quality characteristics of the mungbean starch gel and the locust bean gum improved them. Thus, the addition of 0.5% locust bean gum is an appropriate method for improving the quality characteristics of mungbean starch gel.