The report describes the features of physical and mechanical properties and absorption capacity of hydrogels based on highly esterified pectin. Experimental data showed the correlation between these values. Also, an attempt is made to explain the obtained dependencies via the hydrogel morphology and the mechanism of its formation.
The various samples of pectins with degrees of esterification of 40-70% in the work were obtained using pectin with degree of esterification of 81.5%. It was shown that the determining factor for successful formation of hydrogel plates is the degree of esterification of polysaccharide. It was established that hydrogel plates obtained by the method of structuring of calcium salts are formed only on the basis of pectin with the degree of esterification less than 70%.
The thermostability of nisin and Nisaplin® was investigated in the presence and absence of pectin. By mixing with pectin, both nisin and Nisaplin® were able to inhibit microbial growth, even after heating to 433 K. In contrast, without pectin, the nisin was totally inactivated after heat treatment. Nisin and pectin in solution were complexed, as shown by atomic force microscopic analysis. Probably, the complex formation between the polysaccharide and the polypeptide improves the nisin thermostability; however, a detailed mechanism remains to be resolved.