Editorial for a Special Issue on the Latest Research on Polysaccharides: Structure and Applications

1. Introduction

Polysaccharides, the most abundant macromolecular polymers essential for organismal development, play crucial roles in fields such as food science, biology, and pharmacy due to their biocompatibility, biodegradability, and tunable functionality [1]. Their diverse origins and structural complexity also make them ideal candidates for modification to achieve innovative properties [2]. Over the past decades, extensive research has been conducted to broaden our knowledge of polysaccharides, specifically our understanding of their structures, applications, and interrelationships, meaning they continue to attract scientific interest [3]. Therefore, this Special Issue in Polysaccharides highlights recent progress regarding these perspectives, concentrating on applications in food, biomedicine, and biomaterials, with an emphasis on green synthesis and interdisciplinary innovation.

2. Overview of the Published Articles

Natural polysaccharides such as starch and glycogen serve as major energy storage components in plants and animals [4,5]. Advances in their exploration and characterization have provided a fundamental basis for extending their potential applications. In one study, native mango seed starches from different cultivars were analyzed for their molecular structure and physicochemical properties, supporting their value-added use in food formulation over waste disposal (Contribution 1). Sweet potato starch was evaluated in salad dressing-type emulsions, showing stability and sensory attributes comparable to those of a commercial brand (Contribution 2). Meanwhile, a biophysical technique was developed to elucidate the interaction between oyster glycogen and rabbit muscle glycogen phosphorylase, deepening our understanding of glycogen metabolism in disease management [5]. Beyond native polysaccharides, changes in their features under processing have also gained attention. A molecular-level analysis of hydrogen bonding between water and starch during cooking revealed its role in affecting the organoleptic characteristics of potatoes (Contribution 3).

Chitin is the most abundant natural biopolymer after cellulose, and its deacetylated derivative, chitosan, exhibits promising therapeutic properties [6,7]. Since chitosan’s functionality depends on its structure, various strategies have been adopted to achieve specific objectives [8,9]. Physical modifications, including ultrasonication as well as a combination of thermal shock and grinding, have been employed to synthesize nanochitosan, with the ultrasonicated form revealing antifungal activity against Colletotrichum chrysophillum and Colletotrichum musae (Contribution 4 and [9]). Electrospinning, following parameter optimization, enabled the fabrication of chitosan-based nanofibrous scaffolds that were non-cytotoxic and supported cell adhesion and proliferation (Contribution 5). Additionally, hydrophobicity-enhancing approaches involving chitosan for gene and drug delivery in cancer therapy have been extensively reviewed, covering safety, cellular internalization, and targeting [7].

Nanofabrication, highlighted as a prominent topic in this Special Issue, has been applied not only to chitosan but also to arabinoxylan and Auricularia auricula polysaccharides. Electrospinning produced arabinoxylan nanofibers via physical entanglement, providing insight into fabricating biomaterials from single-component polymers (Contribution 6). Green synthesis of Auricularia auricula polysaccharide-mediated gold nanoparticles (AuNPs) yielded particles with excellent physical stability and effective radical scavenging activity (Contribution 7).

To address functional enhancement, a chemical linkage route was also employed. Carboxymethyl cellulose was successfully copolymerized with poly(N-vinylimidazole), enabling targeted delivery of metronidazole (Contribution 8). Sacran aldehyde, serving as a cross-linker, produced gelatin hydrogels with high mechanical stability and practical utility in biomedicine (Contribution 9). In addition, a starch-based siRNA delivery system was established by quaternizing potato starch at varying substitution degrees, exhibiting great cellular uptake and gene silencing capabilities (Contribution 10).

The 13 articles included in this Special Issue collectively describe diverse advances in the exploration, modification, and application of natural polysaccharides, emphasizing the progress made in their molecular-level characterization, innovative nanofabrication, and targeted delivery.

3. Conclusions and Outlook

This Special Issue presents the current status and emerging trends in the structure and applications of polysaccharides, illustrating that native and modified forms of starch, glycogen, and chitosan show versatile functions across food and biomedical fields. Modifications including ultrasonication, electrospinning, and chemical linkage have enhanced their mechanical strength, antifungal activity, and targeted delivery performance. Continued efforts to deepen our understanding of their physicochemical characteristics and strengthen interdisciplinary collaboration will further promote their sustainable and biocompatible applications.