Antioxidants are compounds that help protect body cells against free radical damage that leads to oxidation and subsequent cell damage that potentially accelerates the ageing process and aids diseases. Free radicals are generated by our body as a result of normal metabolic processes or are derived from external sources such as alcohol, smoke, pesticides and air pollutants. If free radicals overwhelm our body oxidative stress occurs and this may trigger a number of diseases including heart and liver problems in addition to a number of cancers.

Unified Antioxidants Factor UAF® 
UAF® is a system that allows the antioxidant levels in different honeys to be directly compared to make it easier for buyers of Australian honey bee products to make informed purchasing decisions.

UAF® is a simple rating system of the measurement of antioxidant activity in a honey. Antioxidant activity varies greatly between honeys, meaning not all honeys are the same when it comes to antioxidant properties. At present all food antioxidant activity is measured using two tests which measure the antioxidant activity in different ways. UAF® is a simplification of expressing the outcome of these two tests, making it much easier for consumers to choose the antioxidant level which suits them.
UAF® represents the level of antioxidants in honey through the measurement of the capacity of the honey to absorb free radicals. An accredited independent food  science laboratory performs two different assays, FRAP and ORAC, which measure the antioxidant activity in different ways. The results are presented in a simplified UAF® index system. The scale ranges from 0 – 1000 (ug TE/100g), with 1000 being the highest antioxidant activity. The UAF® in Acacia honey ranges up to 80 whilst that of Manuka honey can be 300 and Jarrah honey around 600. [1],The majority of Australian honeys are rated at UAF® 50 to 800, ​​more than 50 is considerable of high in antioxidants.
What are the antioxidant tests?

Oxygen Radical Absorbance Capacity (ORAC) is a method used to estimate the antioxidant capacities of biological samples (e.g. honey). In a test tube, the sample is combined with certain molecules that generate free radical activity and molecules that are susceptible to oxidation. The antioxidant capacity is estimated by measuring how well the sample protected the susceptible molecules from oxidation (by stabilising the free radicals) over a certain amount of time.
Ferric Reducing Ability of Plasma (FRAP) is another method used to estimate antioxidant capacity of biological samples (e.g. honey). The method utilises the reduction of ferric (Fe3+) to ferrous (Fe2+) ions at low pH. When ferric ions are added to a sample, the reduction by the antioxidant causes a coloured molecule (with ferrous ions) to form. The antioxidant capacity can be measured by comparing luminance at a specific wavelength of the sample with a mixture with ferrous ions of a known concentration.

[1] Standardization of antioxidant properties of honey by a combination of spectrophotometric/fluorometric assays and chemometrics, Anal. Chimica Acta, 2005, 533, 185-191.