Antioxidants
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 tests which measure the antioxidant activity in different ways. UAF® is a simplification of expressing the outcome of FRAP test, making it much easier for consumers to choose the antioxidant level which suits them.
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 tests which measure the antioxidant activity in different ways. UAF® is a simplification of expressing the outcome of FRAP test, 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. a number of research laboratories perform FRAP assay which measures the antioxidant activity in an efficient way. The result is presented in a simplified UAF® index system. The scale ranges from 0 – 3000 (ug/100g TE). A higher value indicates stronger antioxidant capacity.
UAF® stands for Unified Antioxidants Factor that evaluates comprehensive Anti-aging strength of Food. It measures foods ability to get rid of free radicals - a kind of waste product produced by human cells. An overall strength of UAF benefits to life activities. Therefore, the higher the UAF level, the stronger its immune and vitality benefits.
UAF strength in honey is occurring from natural active substances. For example, meditree honey contains over 200 nutrients and 140 active enzymes, including 36 rare elements and minerals, over 20 amino acids, over 10 flavonoids and vitamins, as well as SOD anthocyanins, phenols, and polyphenols, along with abundant nectar and prebiotic substances. The combined effects of these substances contribute to comprehensive anti-aging strength or UAF strength of the honey.
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 is the antioxidant test?
FRAP: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+) irons 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.
CRCHBP Special Project 02 [2]:
Development of Standard Operating Procedure (SOP) for the Ferric Reducing Antioxidant Power (FRAP) AssaySupervisor: A/Prof. Fraser Russell (USC and Lead) and A/Prof. Cornelia Locher (UWA)
Autooxidation of substrate molecules such as lipids involve a sequence of chemical reactions, from initiation to propagation and termination. Direct antioxidants interfer with specific sites within this sequence. While these tests provide a reasonable assessment of “real-life” antioxidant activity, they are sometimes limited by their repeatability (Amorati & Valgimigli, 2015). In contrast to direct antioxidant assays, indirect antioxidant assays test free-radical scavenging activity of antioxidants with an introduced radical that is distinct from radicals involved in lipid autooxidation. While these assays are convenient to use and are valuable in providing a preliminary screening of antioxidant activity, the findings may not necessarily translate to activity that is observed in real systems (Amorati & Valgimigli, 2015). Assessment of antioxidant activities of candidate molecules is strengthened when an array of tests is used in combination.
Commonly used assays involve competition of the antioxidant with peroxyl radicals and an oxidizable probe eg. oxygen-radical antioxidant capacity (ORAC) assay, inhibition of lipid peroxidation eg. thiobarbituric acid reactive species (TBARS) assay, measurement of the reduction of a coloured radical such as 2,2-diphenyl-1-picrylhydrazyl by the antioxidant (DPPH assay), and measurement of the interaction of antioxidants with inorganic oxidants such as ferric iron, Fe3+ (Ferric Reducing Antioxidant Power; FRAP) assay. Several of these tests are currently being used in CRC projects to examine the antioxidant activity of Australian honey samples. This project will provide data that will assess the suitability of the FRAP assay for testing Australian honey samples. The FRAP assay examines the capacity of antioxidants to reduce Fe3+ to Fe2+. Activity is detected by the formation of a coloured product when Fe2+ reacts with a substrate molecule. The FRAP assay is an indirect test and is subject to the advantages and limitations noted above. It is proposed that the FRAP assay could allow rapid screening of Australian honey samples for antioxidant activity, and to identify honeys that should be followed up for further investigation.
- Standardization of antioxidant properties of honey by a combination of spectrophotometric/fluorometric assays and chemometrics, Anal. Chimica Acta, 2005, 533, 185-191.
- www.crchoneybeeproducts.com
