Modulation of physicochemical and spectroscopic properties of l-serine and l-proline by propionate based food preservatives

• Preservatives lowered sweetness of l-serine and enhanced bitterness of l-proline.
• Hydration number of solutes decreased in the presence of preservatives.
• Calorimetric results indicate dehydration of amino acids and preservatives.
• Solute protons become shielded owing to dehydration by preservatives.

To have an insight into the effect of preservatives on various ingredients of processed items, it is important to study their thermodynamic, transport and spectroscopic properties in aqueous solutions to elucidate various solute-co-solute interactions. The densities, viscosities and enthalpies of dilution of l-serine and l-proline have been determined in water and in aqueous solutions of sodium propionate and calcium propionate at different temperatures. The derived parameters elucidate the changes in taste quality and hydration number of l-serine and l-proline in the presence of the studied preservatives. Predominance of dehydration effect has been observed from calorimetry and changes in chemical shifts from nuclear magnetic resonance spectroscopy also support the above results.