Ganoderma lucidum (GL) is a kind of edible fungus with various functions and a precious medicinal material with a long history. Ganoderma lucidum polysaccharide (GLP) is one of the main bioactive substances in GL, with anti-tumor, anti-oxidation, anti-cancer, and other biological activities. GLP is closely related to human health, and the research on GLP is getting deeper. This paper reviewed the extraction and purification methods of GLP, the relationship between structure and activity, and the qualitative and quantitative methods. This review provides solutions for the analysis and application of GLP. At the same time, some new methods for extraction, purification and analysis of GLP, the relationship between advanced structures and activity, and future applications of and research into GLP were emphasized. As a kind of bioactive macromolecule, GLP has unique functional properties. Through the comprehensive summary of the extraction, purification, and analysis of GLP and its future prospects, we hope that this review can provide valuable reference for the further study of GLP.

The development of novel materials with microstructures is now a trend in food science and technology. These microscale materials may be applied across all steps in food manufacturing, from raw materials to the final food products, as well as in the packaging, transport, and storage processes. Microfluidics is an advanced technology for controlling fluids in a microscale channel (1~100 μm), which integrates engineering, physics, chemistry, nanotechnology, etc. This technology allows unit operations to occur in devices that are closer in size to the expected structural elements. Therefore, microfluidics is considered a promising technology to develop micro/nanostructures for delivery purposes to improve the quality and safety of foods. This review concentrates on the recent developments of microfluidic systems and their novel applications in food science and technology, including microfibers/films via microfluidic spinning technology for food packaging, droplet microfluidics for food micro-/nanoemulsifications and encapsulations, etc.

Konjac glucomannan (KGM) hydrogel has favorable gel-forming abilities, but its insufficient swelling capacity and poor control release characteristics limit its application. Therefore, in this study, oxidized hyaluronic acid (OHA) was used to improve the properties of KGM hydrogel. The influence of OHA on the structure and properties of KGM hydrogels was evaluated. The results show that the swelling capacity and rheological properties of the composite hydrogels increased with OHA concentration, which might be attributed to the hydrogen bond between the KGM and OHA, resulting in a compact three-dimensional gel network structure. Furthermore, epigallocatechin gallate (EGCG) was efficiently loaded into the KGM/OHA composite hydrogels and liberated in a sustained pattern. The cumulative EGCG release rate of the KGM/OHA hydrogels was enhanced by the increasing addition of OHA. The results show that the release rate of composite hydrogel can be controlled by the content of OHA. These results suggest that OHA has the potential to improve the properties and control release characteristics of KGM hydrogels.

In this study, nanofiber films were prepared by electrospinning technology with polyvinyl alcohol (PVA) and konjac glucomannan (KGM) as raw materials. Tea polyphenols (TPs) were incorporated in the above matrix, which increased physicochemical (thermal and mechanical characteristics) and antibacterial properties of the nanofiber films. The release behavior of phenolic compounds from PVA/KGM-TPs nanofiber films was determined in different food simulants; antioxidant and antibacterial activity of the films were also evaluated. The results showed that the addition of KGM increased the physical and chemical properties of the films. The tensile strength (TS) and elongation at break (EB) increased from 5.40 ± 0.33 to 10.62 ± 0.34 and from 7.24 ± 0.32 to 18.10 ± 0.91, respectively. PVA/KGM-TPs nanofiber films performed controlled release of TPs, with final release of 49.17% in 3% acetic acid, 43.6% in 10% ethanol, and 59.42% in 95% ethanol. The nanofiber films showed good antioxidation properties, with the free radical scavenging rate increasing from 1.33% to 25.61%, and good antibacterial properties with inhibition zones against E. coli and S. aureus of 24.33 ± 0.47 mm and 34.33 ± 0.94 mm, respectively. In addition, the as-prepared films showed significant preservation performance for raw bananas at 25 °C.

Coating preservation has a remarkable effect on the preservation of aquatic products. This work prepared a composite coating using konjac glucomannan (KGM) as the film-forming matrix and ε-polylysine hydrochloride (ε-PL) and ferulic acid (FA) as the preservative. Three types of treated sea bass (KGM, KGM-ε-PL, and KGM-ε-PL-FA) and untreated sea bass were stored at 4 °C for 20 days to compare freshness changes under different treatment conditions. The results showed that the surface color and texture of sea bass in refrigerated storage changed dramatically and deteriorated as storage time increased. The composite coating treatment was significantly different from the control group. Using Gas-phase ion migration spectrometry (GC-IMS) technology, 32 volatile compounds, such as aldehydes, alcohols, and ketones, were found in fillets during flavor quality analysis. The composite coating can successfully inhibit the formation of odor compounds such as 2-nonenone, isoamyl alcohol monomer, ammonia, and trimethylamine, delaying the deterioration of fish and improving freshness. Among them, KGM-ε-PL-FA composite coating has the most remarkable preservation performance, which significantly inhibits the occurrence of rotten odor, and has a potential application prospect in the field of food preservation.

In order to enforce the mechanical strength and antibacterial ability of biofilm and explore the underlying mechanism, sodium lignosulfonate (SL) and ε-polylysine (ε-PL) were introduced to fabricate the composite film of konjac glucomannan (KGM)/SL/ε-PL in the present study. According to our previous method, 1% (w/v) of KGM was the optimal concentration for the film preparation method, on the basis of which the amount of SL and ε-PL were screened by mechanical properties enforcement of film. The structure, mechanical performance and thermal stability of the film were characterized by SEM, FTIR, TGA and tensile strength tests. The optimized composite film was comprised of KGM 1% (w/v), SL 0.2% (w/v), and ε-PL 0.375% (w/v). The tensile strength (105.97 ± 4.58 MPa, p < 0.05) and elongation at break (95.71 ± 5.02%, p < 0.05) of the KGM/SL/ε-PL composite film was greatly improved compared with that of KGM. Meanwhile, the thermal stability and antibacterial property of film were also enhanced by the presence of SL and ε-PL. In co-culturation mode, the KGM/SL/ε-PL composite film showed good inhibitory effect on Escherichia coli (22.50 ± 0.31 mm, p < 0.05) and Staphylococcus aureus (19.69 ± 0.36 mm, p < 0.05) by determining the inhibition zone diameter. It was revealed that KGM/SL/ε-PL composite film shows enhanced mechanical strength and reliable antibacterial activities and it could be a potential candidate in the field of food packaging.