Methylglyoxal (MGO) is an organic compound that occurs naturally in various biological systems. It is found in many foods and beverages, but its presence in Manuka honey in notable concentrations has drawn considerable attention. This compound contributes to the distinct characteristics of Manuka honey.
The Science of MGO
Methylglyoxal is a dicarbonyl compound, meaning it contains two carbonyl groups. This chemical structure contributes to its reactivity within biological environments. MGO forms naturally in living organisms primarily through the breakdown of dihydroxyacetone phosphate (DHAP), an intermediate molecule in metabolic pathways such as glycolysis. This conversion typically involves enzymes like methylglyoxal synthase, which facilitates the transformation of DHAP into MGO and inorganic phosphate.
The formation of MGO is not limited to enzymatic processes; it can also occur non-enzymatically. Its reactive nature means it can readily interact with various biomolecules, making its regulation important in cellular systems. While MGO is a natural byproduct of metabolism, its accumulation is influenced by factors like increased sugar concentrations in cells.
MGO’s Special Role in Manuka Honey
Manuka honey stands apart due to its notably higher levels of methylglyoxal compared to other types of honey. This elevated MGO content originates from dihydroxyacetone (DHA), a precursor compound found in the nectar of the Manuka (Leptospermum scoparium) plant. The concentration of DHA in Manuka nectar can be substantial, setting the stage for MGO formation.
The transformation of DHA into MGO occurs primarily during the honey’s ripening and storage processes. When bees collect nectar rich in DHA, enzymatic activity within their digestive systems begins the conversion process as the nectar is processed into honey. This non-enzymatic conversion continues gradually after the honey has been harvested, with MGO levels increasing as DHA levels decrease over time.
The MGO in Manuka honey is responsible for its non-peroxide activity (NPA). Unlike the hydrogen peroxide activity found in many honeys, MGO’s activity remains stable. Various factors can influence the final MGO concentration in Manuka honey, including:
The specific Manuka floral source
Geographical and environmental conditions
Seasonal variations
Harvesting time
Beekeeping and storage practices
Decoding MGO Ratings
Consumers often encounter MGO ratings on Manuka honey product labels. This rating specifies the concentration of MGO in milligrams per kilogram (mg/kg) of honey. For instance, a label stating “MGO 550+” signifies that there are at least 550 milligrams of MGO present in every kilogram of that honey.
These ratings provide insight into the MGO levels within a given batch of honey. Higher MGO numbers on the label correspond to a greater concentration of methylglyoxal in the product. To ensure accuracy, Manuka honey undergoes testing by independent third-party laboratories to measure MGO levels.