THE STUDY OF NATURAL POLYSACCHARIDES: ORGANOLEPTIC, PHYSICAL, CHEMICAL, MICROBIOLOGICAL PROPERTIES, AND THERMODYNAMIC CHARACTERISTICS OF AQUEOUS SOLUTIONS

Natural polysaccharides is a promising raw material for biodegradable polymers production. To properly select sources of their origin would require conformity with safety standards in force for the similar products. This work conducts a study with a view to examine the extent to which the organoleptic, physical and chemical properties of the polysaccharides in question, as well as their safety indicators conform with the provisions of GOST 16280-2002, CAS 11114-20-8 and CAS 9004-65-3. It is determined that the samples selected, namely, agar-agar produced by Panreac (Germany) and Helicon (USA), carrageenan produced by Boc Sciences (USA) and Newgreen Pharmchem Co. (China) and hydroxypropylmethyl cellulose produced by Acros (Belgium) and Ashland Aqualon Functional Ingredients (USA), meet safety requirements for this type of raw material. Simultaneously, we employ high-sensitivity differential scanning calorimetry method to analyze thermodynamic characteristics of natural polysaccharides’ aqueous solutions. It is shown that gels based on agar-agar have high melting temperature and can withstand temperature rise; after, their microscopic structure is not affected by thermal history, and the gel system remains stable. Thermodynamically, aqueous solution of kappa-carrageenan forms more stable gel than iota-carrageenan; strength and melting point of kappa-carrageenan gels can be adjusted by changing the concentration of potassium chloride in the solution. Aqueous solutions of hydroxypropylmethylcellulose are thermodynamically stable. The experimental data obtained confirm the feasibility of natural polysaccharides application in the production of biodegradable polymers.