不同魔芋葡甘聚糖降解物抑制肿瘤活性的比较研究

为了进一步明确不同品种魔芋抗肿瘤活性的差异,分别以白魔芋和花魔芋为原料,先对其所含的魔芋葡甘聚糖(KGM)进行辐照酶解处理制备魔芋葡甘聚糖片段(KF),再通过体内外抑瘤试验,分别探究两种降解产物的抗肿瘤活性,并作分析比较。结果表明:两个品种的魔芋葡甘聚糖片段浓度的增加,宫颈癌细胞株的存活率逐渐降低,艾氏腹水瘤(EAC)小鼠的移植性实体瘤和脏器指数均有不同程度的增强;白魔芋葡甘聚糖片段的抑制肿瘤活性比花魔芋葡甘聚糖片段的强。     

Use of Konjac glucomannan as additive to reinforce the gels from low-quality squid surimi

This paper reports a study of the influence of a Konjac glucomannan aqueous dispersion (KAD) as ingredient, at different alkalinity levels, on the thermal stability of low-quality squid surimi (Dosidicus gigas) and the viscoelastic properties of its gel. An increase in elastic (G^′) and viscous (G^″) moduli at T < 50 °C, reflecting protein aggregation, and a strong decrease at T > 50 °C, reflecting structural damage, were observed in thermal gelation profiles of low-quality squid surimi. The contribution of 1% KAD (10%) to enhancement of gelation ability was assessed by evaluating the viscoelastic properties of the gels, with and without KAD, at increasing alkalinity levels. Gels with KAD at high-pH had the best rheological properties. Small amplitude oscillatory shear (SAOS) tests showed a significant decrease in rigidity, an increase in strain amplitude and a decrease in the frequency-dependence of G^′ and G^″. These results were in agreement with instrumental texture analyses, meaning that KAD may be used to overcome the negative effect of the poor protein functionality of low-quality squid surimi and achieve better gels from them.     

The mechanism of sodium hydroxide solution promoting the gelation of Konjac glucomannan (KGM)

The intrinsic viscosity [η] and the theoretical critical concentration c* of Konjac glucomannan (KGM) solution were 18.91 dL/g and 0.053 wt% respectively in distilled water. However, the values of [η] and c* became to 11.55 dL/g and 0.086 wt% in sodium hydroxide solution (0.25 mol/L), moreover, the transition from KGM sol to gel even occurred at 0.5 wt% over 55 °C, furthermore, the morphology structure of KGM was thicker than that in distilled water as observed in SEM. It suggested that the sodium hydroxide solution would restrain the expansion of the molecular chain and promoted the gelation of KGM, which might be due to the obvious effects of deacetylation, self-aggregation, entanglement, local and continuous gel network structure.     

Physicochemical properties of konjac glucomannan extracted from konjac flour by a simple centrifugation process

Konjac flour (KF) contains main polysaccharide, konjac glucomannan (KGM) that is applied in various applications; however, extraction of KGM is complicated. A simple centrifugation process was used to extract KGM from KF and the influence of extraction temperatures on its physicochemical properties was determined. The centrifugation process was effective for the extraction of KGM and the results revealed two effective temperatures (35 °C and 75 °C). The extracted KGM was easy to grind. Ash and protein contents of the extracted KGM were clearly reduced, however the ash and protein contents of the KGM extracted at the high temperature (75 °C) were significantly lower than that extracted at the low temperature (35 °C), and thus proofs the extraction at the high temperature to be more effective. Furthermore, improved purities in both extracted glucomannan samples were attained in comparison to commercial KGM. While the yield percentages of the samples differed, no significant disparity in morphology and particle size was determined. Particles of both extracted KGM were comparable in shape and size. Moreover, the transparency of both extracted KGM solutions was higher than commercial KGM solution. These results suggested that the extraction temperature at 75 °C is effective in extraction KGM from KF.     

魔芋葡苷聚糖的改性及其研究进展

综述了魔芋葡苷聚糖的改性方法,包括共混改性、化学改性及生物改性方法,并介绍了改性后的魔芋葡苷聚糖的应用研究进展。     

魔芋葡甘露聚糖的性质与魔芋精粉品质研究

使用乌氏粘度计测定了从魔芋中分离而得的魔芋葡甘露聚糖的分子物性:分子量、分子旋转半径与分子膨胀系数。使用Haake RV12转筒式粘度计测定了魔芋溶胶的流变性质,研究表明可以使用魔芋葡甘霉聚糖的分子物性和魔芋溶胶的流变参数(稠度指数与流动指数)来评定魔芋精粉的品质。本文从红外光谱分析推测了魔芋葡甘露聚糖加碱胶凝的主要机理是脱乙酰化作用后通过氢键连接形成网状结构。     

魔芋葡甘聚糖/淀粉复合改性研究进展

魔芋葡甘聚糖与淀粉均是资源丰富的高分子多糖,在食品、医药、生物学等领域有着广泛应用;魔芋葡甘聚糖/淀粉复合能够显著地改善彼此性质,从而扩大其应用范围。目前,国内外对二者复合改性研究的系统阐述较少。本文从物理改性、化学改性、生物改性三方面对魔芋葡甘聚糖/淀粉复合改性的方法进行介绍并对其前景进行探讨,以期能够更好地开发利用这些资源,并为其他大分子多糖复合改性提供借鉴。      

膳食纤维——魔芋葡甘聚糖膜的制备及应用

膳食纤维具有独特的性质及保健功能 ,可制成各种类型的食品及相关产品。本文介绍了一类新型的膳食纤维食品———可食性魔芋葡甘聚糖膜的制备及应用     

魔芋葡甘聚糖与大豆分离蛋白复合凝胶作用研究

以魔芋葡甘聚糖(KG)与大豆分离蛋白(SPI)作为基材,系统研究两者间的复合凝胶作用保持SPI为2.0％,复合凝胶随KG浓度从0.8％增至2.5％,凝胶强度不断上升;凝胶失水率直线下降;凝胶松弛度也逐渐下降;而粘着性则在KG浓度为1.5％时达最大值。在SPI为0—3.0％范围内,随SPI的增加,复合凝胶粘着性和失水率皆逐渐上升;在6.0％范围内,凝胶松弛度变化较小,此后迅速上升;而凝胶强度则随SPI增加光增强,当SPI为2.0％时达最大值,此后逐渐下降。KG的添加,对复合凝胶颜色无明显影响,凝胶保持浅黄色;而随SPI的添加,凝胶则逐渐由乳白色转为浅黄色、黄色,当SPI>3.0％后,凝胶褐色逐渐加深。根据氯化钠和脲对复合凝胶强度的影响,推断复合凝胶中以氢键作用为主。     

魔芋葡甘聚糖与琼脂共混溶胶的剪切流变特性研究

利用流变仪研究了不同质量浓度、溶胀时间和温度条件下魔芋葡甘聚糖/琼脂(KGM/Agar)共混体系的剪切流变特性。结果表明:KGM/Agar共混体系随着质量浓度增大,黏稠系数k增大;随着加热时间延长,黏稠系数k增大;而温度在30~60℃范围内,黏稠系数k随着温度升高先增大再减小然后再增大,呈现波浪式。从黏稠系数和流动指数结果表明,其混合胶的最佳工艺为:KGM/Agar共混胶的质量浓度1.2%,溶胀温度40℃,溶胀时间120 min。魔芋葡甘聚糖/琼脂(KGM/Agar)共混体系流变特性服从幂律方程,通过进一步对黏稠系数k和流动指数n随浓度、时间和温度的变化趋势进行拟合,其关系曲线分别用指数函数和多项式曲线拟合,以期为KGM/Agar的应用和质量评价提供指导。      

魔芋葡甘露聚糖的化学结构与流变性质

本文着重研究了从四川白魔芋(Amorphophallus albus)和花魔芋(Amorphophallus rivieri)分离而得的白魔芋葡甘露聚糖(aKGM)和花魔芋葡甘露聚糖(rKGM)的化学结构与流变性质,还研究了aKGM与其它多糖黄原胶(XanthanGum 简称XG)的协同作用以及aKGM与蛋白质的相互作用。由X-射线衍射法证明aKGM与rKGM均属无定形结构,因而具有非常强的吸水膨胀性能:由凝胶过滤与光散射法证明aKGM的分子量大于rKGM,两者的分子量都较均一;由HPLC法测得aKGM与rKGM中葡萄糖(G)与甘露糖(M)的摩尔比分别为1:1.70与1:1.60。魔芋葡甘露聚糖(Konjac Glucomannan 简称KGM)水溶液为典型的假塑性流体,aKGM水溶液的稠度大于rKGM。研究结果表明,KGM-XGKGM-SP与I(SPI为分离大豆蛋白)是两种新型的胶凝剂,这对于拓宽魔芋的应用范围有极其重要的价值。.     

魔芋胶溶液浓度对其流变学特性的影响研究

目的 研究魔芋胶溶液浓度对其流变学特性的影响.方法 配制质量分数为0.1％～1.0％的魔芋胶溶液,通过稳态流动、应变扫描、频率扫描以及粘弹性-温度扫描、粘度-温度扫描研究粘度特性随剪切速率及温度的变化情况,粘弹性随应变、频率及温度的变化及考察模量相交点、松驰时间等与结构特性相关的各因素.结果 在0.1％～1.0％浓度范...     

一种新型可食性包装材料-胶原蛋白-葡甘聚糖(C-KGM)共混膜

利用溶液共混法制备了胶原蛋白-葡甘聚糖(C-KGM)其混膜。通过FT-IR、X-RD、扫描电镜对共混膜进 行了结构表征,同时测定了共混膜的透光率、力学性能、吸水率、透水汽性和热稳定性。结果表明:葡甘聚糖、胶原蛋白之间存在着强烈的相互作用和良好的相容性,(C-KGM)膜的力学性能和热稳定性明显优于2种单 一聚合物,作为一种潜在的可食性包装膜将具有良好的应用前景。     

魔芋葡甘聚糖与大豆分离蛋白共混形成凝胶过程中的相互作用力研究

为研究魔芋葡甘聚糖(KGM)与大豆分离蛋白(SPI)在水和碱性促凝剂存在条件下的相互作用力,采用红外光谱、扫描电子显微镜和化学方法等手段进行分析。结果表明:在KGM-SPI共混凝胶形成过程中氢键为主要的分子作用力,其次为较弱的静电作用。碱性凝固剂的加入可使凝胶的韧弹性更好,氢键作用更强。此外,交互作用的强弱还与KGM和SPI的含量及配比密切相关。魔芋葡甘聚糖与大豆分离蛋白分子间可依靠多点氢键作用形成热不可逆性凝胶。     

魔芋低聚糖的研究进展

魔芋低聚糖是魔芋葡甘露聚糖的降解产物。综述了魔芋低聚糖的结构组成、生理功能、制备方法及其衍生物等方面的研究进展。     

Thermodynamic incompatibility between denatured whey protein and konjac glucomannan

The current study investigated the effect of a neutral polysaccharide, konjac glucomannan, on the heat-induced gelation of whey protein isolate (WPI) at pH 7. Oscillatory rheology (1 rad/s; 0.5% strain), differential scanning calorimetry and confocal laser scanning microscopy were used to investigate the effect of addition of konjac in the range 0-0.5% w/w, on the thermal gelation properties of WPI. The minimum gelling concentration for WPI samples was 11% w/w; the concentration was therefore held constant at this value. Gelation of WPI was induced by heating the samples from 20 to 80 °C, holding at 80 °C for 30 min, cooling to 20 °C, and holding at 20 °C for a further 30 min. On incorporation of increasing concentrations of konjac the gelation time decreased, while the storage modulus (G′) of the mixed gel systems increased to ∼1450 Pa for 11% w/w WPI containing 0.5% w/w konjac gels, compared to 15 Pa for 11% w/w WPI gels (no konjac). This increase in gel strength was attributed to segregative interactions between denatured whey proteins and konjac glucomannan.     

An investigation into the application of konjac glucomannan as a flavor encapsulant

The application of konjac glucomannan (KGM) in flavor encapsulation in the spray-dry method was investigated in this paper using sweet orange oil as the model. KGM provided the highest encapsulation yield when the apparent viscosity of the KGM solution was reduced to 200 mPa S by cellulase hydrolysis. In the presence of emulsifier Tween 80, the hydrolyzed KGM offered comparable encapsulation yield with Arabic gum and starch sodium octenyl succinate (SSOS), but provided significantly higher encapsulation yield than maltodextrin. Besides, the combination of KGM with Arabic gum, SSOS, and maltodextrin, were also studied. The combination could significantly (P < 0.05) increase the encapsulation yield in the KGM content up to 80% compared with pure KGM; when the KGM content was reduced to 20%, the combination with maltodextrin resulted in a significant (P < 0.05) decrease in encapsulation yield, possibly due to the poor emulsifying capability of both KGM and maltodextrin. The effect of encapsulation on flavor composition was investigated by using the fingerprint technique and the vectorial angle method was adopted to assess the similarity between the chromatographs. The comparison showed that KGM had similar flavor retention with SSOS and Arabic gum, but provided a significant (P < 0.05) higher retention than maltodextrin. The encapsulated flavors exhibited few pores and smooth surface under TEM with the size ranging from 5 to 15 μm. It was concluded that KGM provided comparable flavor retention capability as the most widely used Arabic gum and SSOS and had great potential as a flavor encapsulant.     

魔芋葡甘聚糖-壳聚糖-大豆分离蛋白可食膜的成膜条件研究

利用魔芋葡甘聚糖、壳聚糖和大豆分离蛋白的成膜性及相容性,研制出魔芋葡甘聚糖-壳聚糖-大豆分离蛋白三元复合可食膜。研究了成膜材料配比、成膜液pH和甘油用量对该复合膜的透湿性、吸油性、机械性能和透光率的影响。结果表明。制备该复合膜的适宜条件为：魔芋葡甘聚糖、壳聚糖和大豆分离蛋白的比例为1：1：1,成膜液的适宜pH值为3-4。甘油用量为6～8％。     

微波辅助H2O2降解魔芋葡甘聚糖的研究

研究了在微波辐射下H2O2对魔芋葡甘聚糖的降解作用，考察了微波功率、pH、H2O2浓度、反应时间等对降解的影响。研究结果表明，微波能有效促进H2O2对魔芋葡甘聚糖的降解，降解的最适条件为：微波功率540W，pH3．6，H2O2浓度为1．8％，降解时间3min。     

魔芋葡甘聚糖超微粉碎过程中的自由基效应研究

研究魔芋葡甘聚糖超微粉碎过程中的机械力化学效应之—-自由基效应.利用超弱发光和电子白旋共振技术研究超微粉碎过程中自由基的产生及其变化情况.结果表明,魔芋葡甘聚糖在超微粉碎过程中产生大量自由基;在一定范围内随粉碎时间的延长,自由基浓度不断上升;但产生的自由基并不稳定,在粉碎后呈减速淬灭趋势.本研究结果为魔芋葡甘聚糖的机械力化学改性提供了理论依据.