Hexametaphosphate, a Common Food Additive, Aggregated the Hen Egg White Lysozyme

Polyphosphate polymers are chains of phosphate monomers chemically bonded together via phosphoanhydride bonds. They are found in all prokaryotic and eukaryotic organisms and are among the earliest, most anionic, and most mysterious molecules known. They are everywhere, from small cellular components to additives in our food. There is a strong association between hyperphosphatemia and mortality. That is why it is crucial to assess how polyphosphates, as food additives, affect the quality of edible proteins. This study investigated the effect of inexpensive and widely used food additives (hexametaphosphate labeled as E452) on bakery items, meat products, fish, and soft drinks. Using various spectroscopic and microscopic techniques, we examined how hexametaphosphate affected the aggregation propensity, structure, and stability of a commonly used food protein: hen egg white lysozyme (HEWL). The solubility of HEWL is affected in a bimodal fashion by the concentration of hexametaphosphate. The bimodal concentration-dependent effect was also observed in the tertiary and secondary structural changes. Hexametaphosphate-induced HEWL aggregates were amorphous, as evidenced by ThT fluorescence, far-UV CD, and TEM imaging. This study showed that the food additive (hexametaphosphate) may denature and aggregate proteins and may lead to undesirable health issues.