The influence of pH and temperature on stability of artificial saliva based on porcine gastric mucin

Natural saliva performs many important functions in the human body. Maintaining its production at a constant level is a very important aspect of the proper functioning of the oral cavity. However, due to certain factors, a reduction of salivary secretion is observed. In such situations, saliva substitutes are used, which should have similar properties to natural saliva. Such properties are fulfilled by our saliva preparations based on porcine gastric mucin. Its oligosaccharide chains affect the physicochemical and rheological properties of saliva substitutes. In the work, the influence of two factors: temperature (4°C, 21°) and pH (2, 7) on physicochemical (pH, electrolytic conductivity, surface tension, contact angle) and rheological (viscosity, viscoelasticity) properties of saliva preparations were tested in the study. Saliva substitutes were prepared based on pure deionized water or phosphate buffer solution (PBS) with the addition of porcine gastric mucin. Measurements were made after 1, 3, 5, 7 days after the preparation of the solutions. The obtained results showed that under the influence of the temperature and pH, the stability of the mucin-based preparation is disturbed, especially in the case of water-based solutions. This is associated with a change in the spatial conformation of the mucin structure. Therefore, solutions based on mucin may lose their specific functional properties. This is due to improve hydration and lubrication between the surfaces of the mouth, or the lack of adequate protection against bacteria.