基于正交试验法优选菊苣中总多糖的提取工艺研究

优选菊苣中总多糖的提取工艺。采用正交试验法,以提取液中总多糖的含量为评价指标进行试验。最佳提取工艺为：加入20倍量的水,提取2次,每次2h,温浸温度为60℃。该工艺合理,菊苣中总多糖提取率较高。     

7种常见食用菌中多糖的提取和测定

采用热水提取、乙醇沉淀的方法从7种食用菌中提取出了水溶性多糖,采用蒽酮-硫酸法在波长620nm处进行了糖含量的测定,求得其校准曲线的回归方程为y=0.0094x+0.0057,相关系数r为0.9998。平均回收率为98.3%—102.7%,RSD为2.1%—3.2%。结果显示粗多糖的提取率为4.44%—16.75%,多糖含量为3.48%—6.91%。     

Effect of sodium hydroxide pre-treatment on the optical and structural properties of lyocell

Lyocell is a type of regenerated cellulose. Fibres spun from cellulose solution in N-methylmorpholine-N-oxide hydrate consist of crystalline cellulose II and amorphous cellulose. Lyocell fabrics were treated with aqueous sodium hydroxide solution (NaOH) to study the influence of alkali on optical and structural properties. It was observed that sodium hydroxide treatment causes the density, orientation and crystallinity of lyocell fibre to decrease with increasing sodium hydroxide concentration, a corresponding decrease in tensile strength is also observed. The greatest change in fibre properties occurs between 3.0 and 5.0 mol dm⁻³ NaOH. This is attributed to the onset of formation of Na-cellulose II at 3.0 mol dm⁻³ NaOH; a fully formed Na-cellulose II structure is expected above 6.8 mol dm⁻³ NaOH. Formation of Na-cellulose II causes plasticization of the lyocell fibres as both inter- and intra-molecular hydrogen bonds are broken by these higher sodium hydroxide concentrations.     

Peculiar behavior of polysaccharide/borax hydrogel tablets: a dynamomechanical characterization

The peculiar unidirectional elongation observed during swelling of tablets prepared with scleroglucan (Sclg) and borax was compared with that of other synthetic and natural polymers capable of physical/chemical interactions with borate ions. A dynamomechanical characterization of “squared” Sclg/borax tablets was carried out to study the differences detectable on the two sides of the matrix corresponding to the two directions, respectively, the parallel and perpendicular one with respect to the applied compression force. Different compression forces were used and, in some cases, a second compression was applied on the tablets along a direction perpendicular to the first one. Birefringence experiments were carried out on the swelled tablets along the two directions. Obtained results allow correlating the anisotropic swelling behavior with the detected dynamomechanical and optical properties of the Sclg/borax system. Among the various tested polymers, only guar gum and, to a lesser extent, locust bean gum, showed an anisotropic elongation during swelling.     

Antimicrobial Properties and Application of Polysaccharides and Their Derivatives

With the quick emergence of antibiotic resistance and multi-drug resistant microbes, more and more attention has been paid to the development of new antimicrobial agents that have potential to take the challenge. Polysaccharides, as one of the major classes of biopolymers,were explored for their antimicrobial properties and applications, owing to their easy accessibility, biocompatibility and easy modification.Polysaccharides and their derivatives have variable demonstrations and applications as antimicrobial agents and antimicrobial biomaterials. A variety of polysaccharides, such as chitosan, dextran, hyaluronic acid, cellulose, other plant/animal-derived polysaccharides and their derivatives have been explored for antimicrobial applications. We expect that this review can summarize the important progress of this field and inspire new concepts, which will contribute to the development of novel antimicrobial agents in combating antibiotic resistance and drug-resistant antimicrobial infections.     

Comprehensive review in moisture retention mechanism of polysaccharides from algae,plants, bacteria and fungus

Polysaccharides have attracted much attention due to their significant bio-activities. This review aims to summarize the main polysaccharides sources of related polysaccharides from algae, plants, fungus, and bacteria, and give insights into the structure–activity relationship between the moisture retention and structural characteristics of polysaccharides. The molecular weight, functional groups, polysaccharide modifications and apparent structure of polysaccharides are closely related to the moisturizing properties of polysaccharides in terms of moisturizing conformation. Based on recent moisturizing pieces of evidence, we propose a new framework focusing on the moisturizing intrinsic and extrinsic mechanisms. Polysaccharides molecular weight has different effects on moisturizing property. The extrinsic moisturization is mainly via the formation of hydrogen bonds between polysaccharides, the intrinsic moisturizing is mainly by regulating the production of some tight junction proteins. Accordingly, this review could further open the door for the production and application of polysaccharides as novel moisturizing agents in the cosmetic field.     

Kinetics and mechanism of permanganate oxidation of pectin polysaccharide in acid perchlorate media

The kinetics of oxidation of pectin polysaccharide as a natural polymer by permanganate ion in aqueous perchloric acid at a constant ionic strength of 2.0 mol dm⁻³ has been investigated spectrophotometrically. The reaction time curves showed two distinct stages, the initial stage was relatively slow, followed by an increase in the rate of oxidation at longer times. The results of the initial rates reveal first-order kinetics in permanganate ion and fractional-order with respect to pectin concentration. Kinetic evidence for the formation of an intermediate complex between the polysaccharide and the oxidant is presented. The results obtained at various hydrogen ion concentrations showed that the reaction is acid catalyzed. The added salts lead to the prediction that Mn⁴⁺ and/or Mn³⁺ play an important role in the autoaccleration period kinetics. A tentative reaction mechanism consistent with the kinetic results is discussed.     

枸杞干红酒对小鼠抗疲劳、抗氧化作用的影响

将枸杞干红酒、枸杞干红三倍浓缩液以及枸杞多糖分别灌胃小鼠，进行游泳疲劳实验，结果显示枸杞干红酒能明显降低运动时血清尿素氮水平，减少肝糖原的消耗量，并且它能使血清SOD的活性明显提高，说明枸杞干红酒具有明显的抗疲劳作用和抗衰老作用。     

Non-thermal atmospheric plasma: Opportunities for the synthesis of valuable oligosaccharides from biomass

In this short review, we highlight the potential of breakthrough of non-thermal atmospheric plasma for the synthesis of valuable oligosaccharides with controlled degree of polymerization. We considered two cases (i) the selective polymerization of mono- and disaccharides and (2) the selective depolymerization of polysaccharides. Context, advantages but also limitations of this technology are discussed.     

Development and characterization of biodegradables packaging obtained from biopolymers mixture

The aim of this work is the development and the characterization of biodegradables films obtained from a mixture of soluble starch and sodium alginate. The influence of sodium alginate ratio on the behavior of these films is also studied in order to use them as new formulations to produce food packaging. The obtained films are generally homogeneous, thin, smooth and having a good coherence with no visual defects. The results of the FITR, SEM and XRD tests have shown the existence of a good compatibility, between alginate and starch due to both kind of strong interactions like hydrogen bonds and ionic interactions. Water sorption isotherm, water vapor permeability, and mechanical tests were strongly influenced by the addition of sodium alginate in the different formulations. This influence is caused by the plasticization effect of sodium alginate.