METHOD FOR OBTAINING FOOD-GRADE FILM MATERIAL BASED ON CHITOSAN Russian patent published in 2021 - IPC C08L5/08 C08J5/18 C08K3/15 C08K3/105 

FIELD: chemical and biochemical technology.

SUBSTANCE: invention relates to chemical and biochemical technology, namely to methods for producing film biodegradable materials for food purposes based on chitosan, which can be used in the food or cosmetic industry for the manufacture of wrapping food film, capsules, as well as in agriculture, medicine, pharmacology. A method for obtaining a food-grade film material based on chitosan consists in dissolving chitosan in 2-4% acetic acid at a ratio of chitosan : acetic acid components of 1:1-1:2, weight percentage, in introducing an antibacterial and antifungal additive in the form of nanosilver in the amount of 1-10 mg/g of chitosan, adding polyhexamethylene guanidine hydrochloride to the mixture in the mass ratio of chitosan:polyhexamethylenguanidine hydrochloride 100:1 - 200:1, intensive stirring for 5 minutes, adding sodium tripolyphosphate as a crosslinking agent and stirring for 15-30 minutes at room temperature until a homogeneous gel is formed, applying the resulting molding mixture to the substrate in an amount of 0.08-0.20 ml/cm² to obtain a film material with a thickness of 50-150 microns, then holding it on the substrate at a temperature of 50°C for 12 hours until the film structure is reached, treating the resulting film material with a neutralizing reagent: 1 M NaOH solution for 2 hours, followed by washing with distilled water to pH≥8 and drying at a temperature of 20°C for 72 hours or at a temperature of 50°C for 24 hours, and as an antibacterial and antifungal additive, a sol of silver nanoparticles with a concentration of 1 mg/ml is used, obtained by reducing silver ions in an aqueous solution of silver nitrate, and glucose or ascorbic acid is used as a reducing agent, while the sol is prepared by mixing silver nitrate solutions with glucose or ascorbic acid in a volume ratio of 1:1.

EFFECT: increased shelf life of food products packed in a film material, by reducing moisture and water absorption and enhancing the antimicrobial properties of film materials.

2 cl, 1 tbl