Chitosan is a multifunctional biopolymer that is widely used in the food and medical fields because of its good antibacterial, antioxidant, and enzyme inhibiting activity and its degradability. The biological activity of chitosan as a new food preservation material has gradually become a hot research topic. This paper reviews recent research on the bioactive mechanism of chitosan and introduces strategies for modifying and applying chitosan for food preservation and different preservation techniques to explore the potential application value of active chitosan-based food packaging. Finally, issues and perspectives on the role of chitosan in enhancing the freshness of food products are presented to provide a theoretical basis and scientific reference for subsequent research.

Iron deficiency anemia has been a widespread disease. As an effective and stable iron supplement, the physiochemical properties of the polysaccharide iron complex have been widely studied. In this study, we characterized a novel polysaccharide-iron(III) complex extracted in an edible fungal species Auricularia auricular (AAPS-iron(III)). The highest iron content (28.40%) in the AAPS-iron(III) complex was obtained under the optimized preparation conditions including an AAPS to FeCl_3∙6H₂O ratio of 2:3 (w/w), a pH value of 8.0 in solution, a reaction temperature of 50°C, and a reaction time of 3 h. The physical and chemical properties of the AAPS-iron(III) complex were characterized by qualitative and quantitative analyses using scanning electron microscope, particle size distribution, thermogravimetric analyzer, Fourier transform infrared spectroscopy, circular dichroism, and ¹H nuclear magnetic resonance. Result showed that, although the iron was bound to the polysaccharide, it was released under artificial gastrointestinal conditions. The AAPS-iron(III) complex exhibited high stability (under 50-256°C) and water solubility. The AAPS-iron(III) complex also showed high antioxidant activity in vitro, demonstrating an additional health benefit over other typical nonantioxidant iron nutritional supplements. Furthermore, the AAPS-iron(III) complex showed high efficiency on the treatment of the iron deficiency anemia in the model rats. Therefore, the AAPS-iron(III) complex can be used as a nutritional fortifier to supply iron in industrial processing and to assist the treatment of iron deficiency anemia.

Edible mushrooms are esteemed worldwide for their significant contributions to food, medicine, and economy. Post-harvest edible mushrooms are vulnerable to mechanical damage, microbial infection, and discoloration due to inadequate preservation techniques. This review aims to systematically examine the current state of postharvest preservation techniques for edible mushrooms. Firstly, this review presents an overview of the physiological changes that occur in edible mushrooms after harvesting, encompassing water loss, weight loss, morphological and color alterations, nutrient and flavor depletion, and microbial susceptibility. Subsequently, this review outlines common postharvest preservation techniques for edible mushrooms, including low-temperature storage, air-conditioned storage, radiation, plasma treatment, and coatings, with brief descriptions of their application cases. Lastly, the future direction of development for postharvest preservation technologies for edible mushrooms is envisioned. This review seeks to serve as a reference for the edible mushroom industry and to stimulate further development and application of postharvest preservation technologies for edible mushrooms.