This code system http://hl7.org/fhir/ingredient-function defines the following codes:

CodeDisplay
Antioxidant Antioxidant
AlkalizingAgent Alkalizing Agent
<status value="draft"/><experimental value="false"/><date value="2021-01-05T10:01:24+11:00"/><publisher value="HL7 (FHIR Project)"/><contact><telecom><system value="url"/><value value="http://hl7.org/fhir"/></telecom><telecom><system value="email"/><value value="fhir@lists.hl7.org"/></telecom></contact><description value="A classification of the ingredient identifying its precise purpose(s) in the drug product (beyond e.g. active/inactive)."/><caseSensitive value="true"/><valueSet value="http://hl7.org/fhir/ValueSet/ingredient-function"/><content value="complete"/><concept><code value="Antioxidant"/><display value="Antioxidant"/></concept><concept><code value="AlkalizingAgent"/><display value="Alkalizing Agent"/></concept></CodeSystem>