Composite coatings based on konjac glucomannan and sodium alginate modified with allicin and in situ SiO x for ginger rhizomes preservation

Physicochemical Evaluation of Coated Ginger during Long-Term Storage: Impact of Chitosan and Beeswax Bilayer Coatings at Different Temperatures

Fresh ginger can spoil quickly owing to a variety of factors, including inappropriate postharvest handling, microbial and enzymatic activities, and chemical reactions during storage. This study evaluated the physicochemical properties of ginger coated with chitosan and beeswax during storage for 6 months at different temperatures (18°C and 25°C). Fresh ginger was treated with chitosan coating (1.5 and 3.5%), followed by beeswax coating (3 and 6%). The coated ginger was wrapped in a plastic net and stored at ambient (25°C) and low temperatures (18°C) for six months. The results confirmed that coating treatment slowed down the changes in physicochemical properties (moisture, phenolic content, and so on) of ginger during storage. Ginger stored at 25°C showed shorter shelf lives than those stored at 18°C. Coating ginger with 3% chitosan followed by 6% beeswax exhibited the best results in maintaining the moisture and phenolic content, reducing weight loss, and increasing total soluble solid (TSS) and cell compartment size for six months of storage. This study provides a promising approach to delaying the spoilage of fresh ginger by applying coating treatments useful for developing handling protocols for fresh ginger during storage and distribution.

Furoic acid-mediated konjac glucomannan/flaxseed gum based green biodegradable antibacterial film for Shine-Muscat grape preservation

Considering the growing threats to the environment and human health, such as plastic pollution and food spoilage, the development of naturally antibacterial food packaging materials with biodegradable capabilities has recently attracted considerable attention. This work applies the concept of green environmental protection to packaging technology, and a new type of green edible antibacterial packaging film was developed. The basic idea is to incorporate furoic acid (FA), which possesses excellent antibacterial activity, into the flaxseed gum and konjac glucomannan matrix (FK) as a filler to obtain a series of FK-FA bioactive films. This incorporation simultaneously improves the hydrophobicity and UV-barrier ability by 12.28 % and 42.87 %, respectively. Meanwhile, the diameters of the antibacterial zone of the FK-FA0.4% films (composite FK films containing 0.4 % FA) against E. coli and S. aureus increased to 38.98 mm and 36.29 mm from 24.00 mm of pure FK film, respectively. As a consequence, the grape sample sealed with FK-FA0.4% film remained edible on the 18th day of storage, while those packaged with commercial PE film and pure FK were seriously rotted and lost edible value on the 12th day, further confirming the enhanced preservation capacity. Finally, the as-prepared films were established to be biodegradable and were almost completely degraded within 25 days under simulated environmental conditions. Overall, these promising results show the potential of FK-FA films for replacing plastic packaging materials as eco-friendly edible films with prolonged shelf life for active packaging.

Characterizations of konjac glucomannan/curdlan edible coatings and the preservation effect on cherry tomatoes

In this study, konjac glucomannan (KGM) and curdlan were used to fabricate composite coating (KC). The coating solutions were investigated using a rheological method, and the coatings were characterized by water solubility tests, water vapor permeability (WVP), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The preservation effect of KC coating on cherry tomatoes stored at room temperature was determined. Results indicated that the curdlan addition can adjust the hydrophilicity/hydrophobicity of KGM coatings. Curdlan addition enhanced intermolecular entanglement and film-forming property. Increasing curdlan content in KC coatings significantly decreased the moisture content, dissolution and swelling ratio, and WVP. The KGM-curdlan composites behaved as high-performance coatings with good compatibility and uniformity. The K₃C₂ coating showed the best uniformity, water barrier, and thermal stability. The application of K₃C₂ coating significantly reduced the weight loss, decay loss, and delayed the decreases of firmness, soluble solids, total acid, and VC contents of cherry tomatoes. The KGM/curdlan edible coatings have promising potential for prolonging the shelf life of cherry tomatoes and applications in fruits preservation in the future.

A comprehensive review of food gels: formation mechanisms, functions, applications, and challenges

Gels refer to the soft and flexible macromolecular polymeric materials retaining a large amount of water or biofluids in their three-dimensional network structure. Gels have attracted increasing interest in the food discipline, especially proteins and polysaccharides, due to their good biocompatibility, biodegradability, nutritional properties, and edibility. With the advancement of living standards, people's demand for nutritious, safe, reliable, and functionally diverse food and even personalized food has increased. As a result, gels exhibiting unique advantages in food application will be of great significance. However, a comprehensive review of functional hydrogels as food gels is still lacking. Here, we comprehensively review the gel-forming mechanisms of food gels and systematically classify them. Moreover, the potential of hydrogels as functional foods in different types of food areas is summarized, with a special focus on their applications in food packaging, satiating gels, nutrient delivery systems, food coloring adsorption, and food safety monitoring. Additionally, the key scientific issues for future food gel research, with specific reference to future novel food designs, mechanisms between food components and matrices, food gel-human interactions, and food gel safety, are discussed. Finally, the future directions of hydrogels for food science and technology are summarized.