新型微生物多糖结冷胶的特性及其应用研究

结冷胶是一种新型微生物多糖，具有很多其他食品胶不具有的优点，如凝胶形成能力强，透明度高，耐酸耐热性能好等。本文介绍了结冷胶的特性，生产技术以及在食品工业中的应用。     

高酰基结冷胶(HA)特性的研究进展

高酰基结冷胶是美国Kelco公司开发的一种新型微生物多糖,它是由少动鞘脂单胞菌（Sphingomonas paucimobilis）经有氧发酵产生的。高酰基结冷胶是集凝胶剂、稳定剂、悬浮剂于一身的多功能亲水性胶体,具有热可逆性、高持水性、良好的复配性等优良特性,因此在食品工业中逐步展现广阔的应用前景。本文综述了高酰基结冷胶的结构、凝胶机理及其特性,并对其应用前景作了探讨。     

高品质亲水胶体,服务中国本土市场——访斯比凯可亚太区业务发展、战略及市场总监卜力知

记者:与食品工业中用到的其他胶体相比,结冷胶的性能有哪些优越性?具体可以应用在哪些方面? 卜力知:结冷胶是斯比凯可公司于20世纪80年代开发的一种微生物食用胶,以Kelcogel品牌出名.这种多功能亲水胶体以极少用量用于各种饮料中做悬浮剂,可以节省成本,增加生产效益.结冷胶的独特性在于通过形成一种流体网络凝胶进行悬浮,同时保持清爽的口感.     

高酰基结冷胶对乳清分离蛋白热诱导凝胶特性的影响

蛋白质-多糖凝胶具有良好的稳定性和机械强度,在稳定和传递生物活性物质、营养强化剂方面的应用前景广阔。该研究以乳清分离蛋白、高酰基结冷胶为原料制备热诱导混合凝胶,分析高酰基结冷胶对乳清分离蛋白-高酰基结冷胶混合凝胶的凝胶强度、保水性及显微结构等,揭示乳清蛋白-高酰基结冷胶凝胶形成机理。结果表明,高酰基结冷胶促使蛋白质巯基暴露从而使凝胶形成稳定结构,提高混合凝胶的凝胶强度和保水性,且随着高酰基结冷胶含量增加而显著增大,其质量浓度为4 g/L时,复合凝胶的凝胶强度最大,为26.97 g;保水性最好,为97.41%;透光率最低,为1.87%。温度扫描结果表明,增加高酰基结冷胶可以提高乳清分离蛋白的相转变温度,傅里叶红外光谱显示,乳清分离蛋白与高酰基结冷胶存在分子间作用力,扫描电子显微镜表明高酰基结冷胶诱导混合凝胶形成结构紧密的三维网络结构。该研究为拓展乳清分离蛋白和结冷胶的新型凝胶食品,提高传统食品的质量,改善食品的加工工艺提供基础理论数据。     

结冷胶溶液凝胶特性的研究

结冷胶是一种新型食品添加剂。其存在形式为天然式和低酰基式。天然式结冷胶溶液的凝胶特性是粘弹性体,低酰基结冷胶溶液是凝胶体。将两种形式的结冷胶溶液在相同条件下与卡拉胶、琼脂溶液进行了比较,得出两种形式的结冷胶溶液在0.05％时可形成凝胶,大大低于卡拉胶和琼脂的成凝胶浓度。     

基于应力松弛原理的高酰基结冷胶凝胶特性研究

本文采用应力松弛模式研究了一价离子(K+和Na+)和二价离子(Ca2+和Mg2+)对高酰基结冷胶凝胶特性的影响。结果表明:高酰基结冷胶凝胶的应力松弛行为符合Peleg经验模型。离子浓度和离子种类对高酰基结冷胶凝胶应力松弛行为影响显著,平衡弹性模量(EA)随着离子浓度的增加呈马鞍形趋势变化,且其与凝胶硬度呈现较好的正相关(R=0.943~0.983),表明EA可以用来表征高酰基结冷胶凝胶的强度。相对于一价离子(K+、Na+)而言,二价离子(Ca2+、Mg2+)形成的凝胶强度更高,且用量更少。在相同离子浓度下,Na+形成的凝胶比K+形成的凝胶强,Ca2+形成的凝胶则比Mg2+形成的凝胶强。在16000 g下离心10 min,高酰基结冷胶凝胶保水性均在95%以上,与离子浓度基本无关,保水性能优异。高酰基结冷胶应力松弛机制是体系内部物理交联点的移动。     

白鲢鱼糜-大豆蛋白复合物性能改良的研究

本实验就结冷胶对白鲢鱼糜-大豆蛋白复合物的凝胶性能做了一些探讨,并初步确定了改良剂结冷胶、钙离子及柠檬酸钠的添加量。结果表明:在鱼糜-大豆蛋白复合物中加入结冷胶有助于增强其凝胶性能,其凝胶强度显著增强,失水率下降,折叠性能提高。钙离子、柠檬酸钠含量对结冷胶的功效有很大的影响。本研究确定在鱼糜-大豆蛋白-红薯淀粉比例等于85g:5g:10g时,结冷胶的含量为0.2g、CaCl2含量为0.5579g、柠檬酸钠含量0.60g时,其凝胶性能最好。     

少动鞘氨醇单胞菌合成结冷胶研究进展

结冷胶是少动鞘氨醇单胞菌(Sphingomonas paucimobilis)产生的一种细菌胞外多糖,耐热、耐酸性良好,具有优越的凝胶性能,广泛应用于食品、医药和化工等领域。通过代谢调控可使结冷胶改性并提高产量,但目前关于结冷胶在生物合成和代谢调控方面的研究较少。该文结合近年来国内外结冷胶研究现状,总结了少动鞘氨醇单胞菌产结冷胶的生物合成途径及其代谢调控,期望为结冷胶生产菌株改造提供理论依据。     

高酰基结冷胶特性及应用研究进展

目的:介绍新型微生物多糖-高酰基结冷胶的研究进展和前景.方法查阅近年来国内外的相关文献报道,并进行分析、整理和归纳.结果 胶体浓度、外加金属阳离子类型和含量、pH值、糖份都会对凝胶特性和流变性产生影响. 结论 高酰基结冷胶作为一种新型凝胶剂,只有在充分理解掌握其凝胶特性的基础上才能获得理想的效果.     

结冷胶LT100流变学特性的研究

研究了结冷胶LT100溶液的凝胶特性及其流变特性,着重研究了结冷胶LT100溶液在不同的浓度、温度、热处理温度、热处理时间、剪切速率、剪切时间、静置时间影响下的流变特性。结果表明:不同浓度的结冷胶LT100形成的凝胶强度有所不同。结冷胶LT100凝胶具有热可逆性、温度滞后性及明显的假塑性。     

结冷胶及其在食品工业中的应用

结冷胶是一种微生物胞外多糖。文中主要介绍了结冷胶的组成、基本特性、制备及其在食品工业中的应用。     

Gellan gum for reducing oil uptake in sev,a legume based product during deep-fat frying

Gellan gum, a high molecular weight anionic linear polysaccharide produced by pure culture fermentation from Sphingomonas paucimobilis ATCC 31461 is used in a variety of food applications that are based on its unique gelling profile. The present work reports on the effective use of gellan gum on the oil uptake of a traditional Indian deep-fat fried product, sev that is based on chickpea flour. The effect of addition of gellan gum at 0.25–0.75% (w/w) (based on chickpea flour) on the dough texture, and that of the sev prepared was also evaluated using TA.XT2i Texture Analyzer. Addition of gellan gum at 0.25% (w/w) markedly reduced the oil content in the sev from 37.02% in the control to 27.91%. The reduction in oil content beyond 0.25% gellan gum addition was not significant (P = 0.05). Furthermore, while addition of gellan gum significantly altered the texture of dough, it did not significantly affect the texture of sev (P = 0.05). Addition of 0.25% gellan gum in combination with sodium alginate (0.25–1.00%), carboxymethylcellulose (0.25–1.00%) or soy protein isolate (2.5–10.0%) did not affect oil uptake significantly (P = 0.05) as compared to that prepared by the addition of 0.25% gellan gum alone.     

结冷胶生物合成及应用

结冷胶是由少动鞘脂单胞菌产生的一种新型微生物多糖,具有用量低、透明度高、耐酸、耐高温、耐酶、兼容性好等优良特性,在食品、制药、化工等行业具有广泛的用途。通过介绍结冷胶理化方面的特性,总结了结冷胶发酵生产工艺,以及提高产量和质量的关键因素,进一步展望了未来结冷胶的发展趋势和应用前景。     

Effect of temperature on the dielectric properties of low acyl gellan gel

Gellan gum is an increasingly popular and a naturally occurring hydrocolloid. It is widely used in the food, chemical, and pharmaceutical industries as a stabilizer, emulsifier, thickener, and gelling agent. The gel is also used as a model material to study microwave heating dynamics of biological materials in the food processing industry. In this study, baseline data on dielectric properties of 1% gellan gel containing 0.17% and 0.3% CaCl₂ were collected at frequencies between 0.2 and 20 GHz and temperatures between 10 and 100 °C. These data are compared with those of distilled water containing similar ionic concentrations. Models describing the behavior of the dielectric constant, loss factor, loss tangent and the penetration depth for 0.2–3.2 GHz were developed. These models can be effectively used in microwave food processing applications of gellan gel, which will save considerable time and effort often used in empirically determining the dielectric spectra.     

高酰基结冷胶凝胶特性的研究

研究了高酰基结冷胶溶液的凝胶特性并对其凝胶机理进行了分析,通过对高酰基结冷胶在不同浓度、温度、pH值和Ca2+盐条件下流变特性和凝胶强度的实验研究,结果表明:胶体浓度、温度、游离的二价阳离子含量以及pH值的差异都会对高酰基结冷胶的粘度和凝胶强度产生影响。对高酰基结冷胶作用力的初步考察结果表明:疏水作用、氢键作用、静电作用在形成凝胶的过程中均起关键作用,疏水作用影响最大。     

Statistical approach to optimization of fermentative production of gellan gum from Sphingomonas paucimobilis ATCC 31461

Gellan gum, a high-molecular-weight anionic linear polysaccharide produced by pure-culture fermentation from Sphingomonas paucimobilis ATCC 31461, has elicited industrial interest in recent years as a high-viscosity biogum, a suspending agent, a gelling agent, and an agar substitute in microbial media. In this paper we report on the optimization of gellan gum production using a statistical approach. In the first step, the one factor-at-a-time method was used to investigate the effect of medium constituents such as carbon and nitrogen sources; subsequently, the intuitive analysis based on statistical calculations carried out using the L16 -orthogonal array method. The design for the L16 -orthogonal array was developed and analyzed using MINITAB 13.30 software. All the fermentation runs were carried out at 30+/-2 degrees C on a rotary orbital shaker at 180 rpm for 48 h. In the second step, the effects of amino acids and gellan precursors such as uridine-5'-diphospate (UDP) and adenosine-5'-diphospate (ADP) on the fermentative production of gellan gum were studied. Media containing 4% soluble starch, 0.025% yeast extract, 1.0 mM ADP and 0.05% tryptophan gave a maximum yield of 43.6 g l(-1) starch-free gellan gum, which was significantly higher than reported values in the literature.     

Determination of gellan gum by capillary electrophoresis and CE–MS

Intact gellan gum (0.1% m/v) was detectable by capillary electrophoresis (CE) with UV detection. Characteristic tetrasaccharide fragments, prepared with a newly characterised gellan-degrading enzyme, provided a clearer signal that was detectable in complex food products containing other polysaccharides. Food products spiked with gellan gum could be analysed reproducibly with high accuracy and specificity by CE–ESI–MS, which is recommended as the technique of choice. Gellan gum declared as a fruit flavour drink ingredient could not be identified by CE–ESI–MS. When added to the product at the start of sample preparation, before enzyme treatment, the gum was readily detectable, demonstrating that the method was compatible with this sample type. Possible explanations for the negative results are that gellan gum was used as a trace component, with other texturing agents; that its declaration was precautionary only; or that the product contained a chemically modified form. Further work will establish whether modified gellan gums can be similarly analysed.     

微生物多糖结冷胶的发酵过程优化

利用玉米浆和尿素作为廉价氮源进行结冷胶的发酵生产,通过对发酵过程中的初糖浓度、通气量和搅拌转速进行优化,获得具有生产成本优势的新工艺。结果表明:结冷胶发酵的最佳初糖浓度和通气量分别为40g/L和1 vvm;最佳的搅拌转速控制策略为延滞期(0～12 h)400 r/min,对数期(12～32 h)800 r/min,稳定期(32～40 h)400 r/min。在上述条件下,结冷胶产量、黏均分子量和发酵液表观黏度分别为16.7 g/L、625.8 kDa和7495 cP。     

Influence of pH and added gums on the properties of konjac flour gels

The gel strength and texture of konjac gel and mixed gels of konjac and various gums were measured after gelation at various concentrations of alkali. A selection of different alkaline reagents was used. Regardless of alkali concentration, increasing konjac levels caused a decrease in pH but an increase in hardness and strength of konjac/gellan gum mixed gels. The highest gel strength and hardness were given by mixed konjac/gellan gum gels using sodium carbonate as the gelling medium. Under similar gelling conditions, the addition of gellan gum resulted in the greatest gel hardness. Of the gums examined, a possible synergistic effect on konjac/gellan gum mixed gel texture was observed.     

Caffeine-loaded whey protein hydrogels reinforced with gellan and enriched with calcium chloride

Gellan gum and CaCl₂ were exploited to modulate the textural and techno-functional properties of heat-set whey protein hydrogels. Enrichment with CaCl₂ increased the amount of released caffeine from the protein hydrogel in conjunction with decreasing cohesiveness index and microstructural features modification. Gellan bundles as visualised by microscopic images conferred a remarkable reinforcing influence to gel samples; enrichment with gellan at 0.5 mg mL⁻¹ increased the gel hardness value approximately 6.4 fold. Based on Fourier transform infrared (FTIR) spectroscopy it was suggested that gellan and CaCl₂ enrichments decreased the β-sheet content of the protein gel matrix in favour of random coil structures. FTIR spectroscopy also proposed cation-π interactions between Ca²⁺ ions and electron-rich amide bonds of whey proteins, as well as interactions between carboxyl groups of gellan and the ε-amino group of lysine in β-lactoglobulin.