Solubility of Polyvinyl Alcohol in Ethanol

Solubility studies of the food additive E 1203 (polyvinyl alcohol-PVA) were carried out to update the solubility data reported in Commission Regulation (EU) N° 231/2012.The support of the Joint Research Centre (JRC), one of the Directorates General of the European Commission, was requested by EFSA to investigate the currently reported solubility of PVA.Methods based on saturation experiments were developed based the indications of the Joint FAO/WHO Expert Committee on Food Additives (JECFA) and the test guidelines from the Organisation for Economic Co-operation and Development (OECD).A more sensitive colorimetric quantification was developed as confirmation method for PVA.The adequacy of methods was verified by testing four other food additives listed in Regulation (EU) 231/2012.The solubility of the commercial food grade PVA with certification regarding the degree of hydrolysis (86.5 to 89 %) and viscosity (4.8 to 5.8 mPa.s) was measured in ethanol (≥99.8 %).The solubility of food grade PVA was found to be approximately 10 6 parts solvent (ethanol) for 1 part solute (PVA) a value which, according to JECFA, is considered "practically insoluble or insoluble".An analytical grade PVA of similar degree of hydrolysis (87 to 89 %) and viscosity (5.2 to 6.2 mPa.s) was tested and also led to a solubility value of 10 6 parts solvent to solubilise 1 part solute.The influence of the purity of the ethanol on the solubility of PVA was also evaluated by carrying out experiments using ethanol 96 %, with results showing a slight increase in the solubility (> 300,000 parts solvent for 1 part solute) due to its higher aqueous content.The solubility experiments, regardless of the type of PVA or ethanol, provided solubility values of 10 6 parts solvent for 1 part solute corresponding to the "practically insoluble or insoluble" interval according to the JECFA guidelines.