An overview of classifications, properties of food polysaccharides and their links to applications in improving food textures

Application of nonthermal processing technologies in extracting and modifying polysaccharides: A critical review

Polysaccharides are natural polymer compounds widely distributed in plants, animals, and microorganisms, most of which have a broad spectrum of biological activities to promote human health. They could also be used as texture modifiers in food industry due to their excellent rheological and mechanical properties. Many researchers have shown that nonthermal processing technologies have numerous advantages, such as high extraction efficiency, short extraction time, and environmental friendliness, in the extraction of polysaccharides compared with the traditional extraction methods. Moreover, nonthermal technologies could effectively change the physicochemical properties and structural characteristics of polysaccharides to improve their biological activities or processing properties. Therefore, a comprehensive summary about the extraction and modification of polysaccharides by nonthermal technologies, including ultrasound, high hydrostatic pressure, pulsed electric fields, and cold plasma, was provided in this review. In particular, the underlying mechanisms, processing operations, and current application status of these technologies were discussed. In addition, the applications of combining nonthermal techniques with other technological methods in polysaccharide extraction and modification were briefly introduced.

Recent progress in green and biopolymer based photocatalysts for the abatement of aquatic pollutants

Enormous research studies on the abatement of anthropogenic aquatic pollutants including organic dyes, pesticides, cosmetics, antibiotics and inorganic species by using varieties of semiconductor photocatalysts have been reported in recent decades. Besides, many of these photocatalysts suffer in real applications owing to their high production cost and low stability. In many cases, the photocatalysts themselves are being considered as secondary pollutants. To eliminate these drawbacks, the green synthesized photocatalysts and the use of biopolymers as photocatalyst supports are considered in recent years. In this context, recent developments in green synthesized metals, metal oxides, other metal compounds, and carbon based photocatalysts in water purification are critically reviewed. Furthermore, the pivotal role of biopolymers including chitin, chitosan, cellulose, natural gum, hydroxyapatite, alginate in photocatalytic removal of aquatic pollutants is comprehensively reviewed. The presence of functional groups, electron trapping ability, biocompatibility, natural occurrence, and low production cost are the major reasons for using biopolymers in photocatalysis. Finally, the summary and conclusion are presented along with existing challenges in this research area.

In-situ fermentation with gellan gum adding to produce bacterial cellulose from traditional Chinese medicinal herb residues hydrolysate

In this study, bacterial cellulose was synthesized by Taonella mepensis from traditional Chinese medicinal herb residues hydrolysate. To overcome the inhibitory effect of fermentation environment, in-situ fermentation with gellan gum adding was carried out for the first time. After 10 days' static fermentation, both high-acyl gellan gum and low-acyl gellan gum adding showed certain beneficial effects for bacterial cellulose production that the highest bacterial cellulose yield (0.866 and 0.798 g/L, respectively) was 59% and 47% higher than that (0.543 g/L) without gellan gum adding. Besides, gellan gum based bacterial cellulose showed some better texture characteristics. Gellan gum was loaded in the nano network of bacterial cellulose, and gellan gum adding had some influence on the crystal structure and thermal degradation behaviors of bacterial cellulose but affected little on its functional groups. Overall, this in-situ fermentation technology is attractive for bacterial cellulose production from low-cost but inhibitory substrates.

Physicochemical characterization and emulsifying properties evaluation of RG-I enriched pectic polysaccharides from Cerasus humilis

Rhamnogalacturonan I (RG-I) enriched pectic polysaccharides were extracted from Cerasus humilis fruits (RPCF, RG-I: 74.46 %). Structural characterization including FTIR, XRD, NMR, HPAEC and SEM demonstrated that RPCF was a high-methoxy acetylated pectin macromolecule with abundant arabinose and galactose side chains (DM: 53.41 %, MW: 1098 kDa, (Ara + Gal)/Rha: 5.37 %). RPCF afforded additional lipid oxidation stability for emulsions, and exhibited significantly better emulsification performance than citrus pectin. In addition, RPCF formed a weak gel network that stabilized the emulsions (G' > G″). Interestingly, RPCF had behaviors that are divergent from those of commercial high-methoxy pectin because it demonstrated potential in forming sugar-free gels systems. Overall, Cerasus humilis is a new source of pectin rich in RG-I. RPCF can be used as a novel emulsifier with gelling and antioxidant effects, providing its alternative application as a natural emulsifier and rheological modifier in a wide range of products, including those with oil-in-water and low sugar.

Microwave treatment to modify textural properties of high protein gel applicable as dysphagia food

The study aimed to formulate a high protein base as a dysphagia food and investigate the possibility of textural modification by applying microwave treatments. The formulated mixture contained 41.7% pea protein (dry basis), which exhibited shear thinning behavior. The application of microwave processing at 300, 500, and 700 W for 60, 120, and 180 s showed that at a higher level of energy induction by microwave, the hardness of the sample gradually increased from a fluid gel to a soft solid and more rigid levels. Processing at 300 and 500 W in the tested range showed that textural properties (hardness, adhesiveness, cohesiveness, springiness, gumminess, and chewiness) of the sample could be modulated within the recommended criteria for dysphagia food, providing the possibility of individualization of food texture for dysphagia disorder. Two main causes of these textural changes could be water evaporation and protein denaturation, in which, regarding the ratio of water evaporation to the size of textural changes, protein denaturation was thought to have the main impact on the phenomena.

Polysaccharides-based bio-nanostructures and their potential food applications

Polysaccharides are omnipresent biomolecules that hold great potential as promising biomaterials for a myriad of applications in various biotechnological and industrial sectors. The presence of diverse functional groups renders them tailorable functionalities for preparing a multitude of novel bio-nanostructures. Further, they are biocompatible and biodegradable, hence, considered as environmentally friendly biopolymers. Application of nanotechnology in food science has shown many advantages in improving food quality and enhancing its shelf life. Recently, considerable efforts have been made to develop polysaccharide-based nanostructures for possible food applications. Therefore, it is of immense importance to explore literature on polysaccharide-based nanostructures delineating their food application potentialities. Herein, we reviewed the developments in polysaccharide-based bio-nanostructures and highlighted their potential applications in food preservation and bioactive "smart" food packaging. We categorized these bio-nanostructures into polysaccharide-based nanoparticles, nanocapsules, nanocomposites, dendrimeric nanostructures, and metallo-polysaccharide hybrids. This review demonstrates that the polysaccharides are emerging biopolymers, gaining much attention as robust biomaterials with excellent tuneable properties.

The complete chloroplast genome of Litsea molis Hemsl. (Lauraceae): genome structure and phylogenetic analysis

Litsea molis Hemsl. is a precious wild aromatic oil tree species and important medicinal plant. In this study, we sequenced and characterized the chloroplast genome of L. molis for the first time. Its complete chloroplast genome is 152,311 bp in length, containing a large single copy region of 93,258 bp and a small single copy region of 18,917 bp separated by a pair of inverted repeat regions of 20,068 bp. The chloroplast genome contains 130 unique genes, including 85 protein-coding genes, 37 tRNA and 8 rRNA genes. Phylogenetic analysis based on chloroplast genome sequences of 36 plants from the family Lauraceae showed that L. molis is more closely related to species of Lindera genus than other genera in Lauraceae.

Nano-technological approaches for plant and marine-based polysaccharides for nano-encapsulations and their applications in food industry

Novel food preservation methods, along with preservatives have been employed to prevent food products from spoilage. There is an increasing demand to substitute synthetic preservatives with natural bioactive compounds since they are safe and environmentally friendly. Bioactive compounds with functional and therapeutic properties are found in foods and have also beneficial physiological and immunological health effects. However, there are some issues associated with bioactive compounds, such as low stability, solubility, and permeability. Encapsulation techniques, especially nano-encapsulation, are a promising technique to overcome these restrictions. A range of the plants' constituents can be converted into bio-nanomaterials. Major plant constituents are polysaccharides which have good biocompatibility properties and therapeutic activities, such as antioxidant, antiviral, anti-inflammatory, anti-allergic, and anti-tumor. Among plant and marine-based polysaccharides, cellulose, starch, alginates, chitosan, and carrageenans have been used as carrier materials to preserve core material. Moreover, many studies indicated that favorable sources such as plant and marine based polysaccharides are emerging. This chapter will cover plant and marine-based polysaccharides for nano-encapsulation and their application in the food industry.

Applications of asymmetrical flow field-flow fractionation for separation and characterization of polysaccharides: A review

Polysaccharides are the most abundant natural biopolymers on the earth and are widely used in food, medicine, materials, cosmetics, and other fields. The physicochemical properties of polysaccharides such as particle size and molecular weight often affect their practical applications. In recent years, asymmetrical flow field-flow fractionation (AF4) has been widely used in the separation and characterization of polysaccharides because it has no stationary phases or packing materials, which reduces the risk of shear degradation of polysaccharides. In this review, the principle of AF4 was introduced briefly. The operation conditions of AF4 for the analysis of polysaccharides were discussed. The applications of AF4 for the separation and characterization of polysaccharides from different sources (plants, animals, and microorganisms) over the last decade were critically reviewed.

New insights into food hydrogels with reinforced mechanical properties: A review on innovative strategies

Enhancement on the mechanical properties of hydrogels leads to a wider range of their applications in various fields. Therefore, there has been a great interest recently for developing new strategies to reinforce hydrogels. Moreover, food gels must be edible in terms of both raw materials and production. This paper reviews innovative techniques such as particle/fiber-reinforced hydrogel, double network, dual crosslinking, freeze-thaw cycles, physical conditioning and soaking methods to improve the mechanical properties of hydrogels. Additionally, their fundamental mechanisms, advantages and disadvantages have been discussed. Important biopolymers that have been employed for these strategies and also their potentials in food applications have been summarized. The general mechanism of these strategies is based on increasing the degree of crosslinking between interacting polymers in hydrogels. These links can be formed by adding fillers (oil droplets or fibers in filled gels) or cross-linkers (regarding double network and soaking method) and also by condensation or alignment of the biopolymers (freeze-thaw cycle and physical conditioning) in the gel network. The properties of particle/fiber-reinforced hydrogels extremely depend on the filler, gel matrix and the interaction between them. In freeze-thaw cycles and physical conditioning methods, it is possible to form new links in the gel network without adding any cross-linkers or fillers. It is expected that the utilization of gels will get broader and more varied in food industries by using these strategies.

Cryostructuring of Polymeric Systems. 55. Retrospective View on the More than 40 Years of Studies Performed in the A.N.Nesmeyanov Institute of Organoelement Compounds with Respect of the Cryostructuring Processes in Polymeric Systems

The processes of cryostructuring in polymeric systems, the techniques of the preparation of diverse cryogels and cryostructurates, the physico-chemical mechanisms of their formation, and the applied potential of these advanced polymer materials are all of high scientific and practical interest in many countries. This review article describes and discusses the results of more than 40 years of studies in this field performed by the researchers from the A.N.Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences-one of the key centers, where such investigations are carried out. The review includes brief historical information, the description of the main effects and trends characteristic of the cryostructuring processes, the data on the morphological specifics inherent in the polymeric cryogels and cryostructurates, and examples of their implementation for solving certain applied tasks.