Proline is the dominant free amino acid in honey, added by bees during nectar ripening, and its concentration serves as an indicator of honey maturity and freedom from adulteration with sugar syrups.
In trade practice
Accredited laboratories measure proline content using photometric or HPLC methods and report the result in milligrams per kilogram on the certificate of analysis. A low proline value can indicate premature harvesting, dilution with sugar syrups or artificial feeding of bees, making it a standard parameter in authenticity panels. Buyers sourcing honey for retail or organic channels increasingly include a minimum proline threshold in their specifications. The test is often run alongside HMF, diastase activity and sugar profile as part of a comprehensive authenticity screen.
In a specification
A honey specification may state a minimum proline content, expressed in milligrams per kilogram, as a contractual authenticity criterion alongside the physicochemical parameters required by the EU Honey Directive.