The chemical substance in corn that causes allergic reactions, the allergen, is called profilin. Profilin is a protein that breaks down and is completely destroyed at temperatures over 55°C. In order to produce PLA bioplastic resin, the initial raw material, corn, goes through the following high heat processes:
1. Starch is extracted from the corn. Corn, depending on its source, contains about 5-9% protein and 60-65% starch. In order to extract the starch, corn gets cleaned and then goes through steeping (wet milling) where it gets soaked in water above 50°C) for over 40 hrs to break the starch and protein bonds. Then the starch is separated from gluten by centrifugation. At this point it might still contain about 1% protein. In order to remove the last traces of protein, it goes through multiple wash cycles.
2. The resulting starch is converted to D-glucose (dextrose) and then to lactic acid.
3. The lactic acid is then “polymerized” to produce PLA resin at over 200°C.
Given the long timeframes of applied heat, plus the final polymerization stage where the temperature far exceeds the level at which corn proteins can remain intact, the resulting PLA resin is free from any trace of initial substances, particularly, the immunologically reactive allergen, profilin.