Technical Talk: May 2007
November 6, 2007
By Dr. John Michaelides
Grains – Antioxidant Rich, Wholesome, healthful baked goods
This column is written by Dr. John Michaelides of the Guelph Food Technology Centre, 519-821-1246, www.gftc.ca
Question: What are antioxidants, and how do they provide health benefits?
Answer: Chemical compounds present in plants are generally called phytochemicals. There are literally many thousands of these compounds naturally occurring in the leaves, fruits, and seeds of various plants. They can help plants grow, fight diseases caused by different pathogenic micro-organisms or perform other functions we are not aware of yet.
We often refer to the term phytochemicals as those chemical compounds from plants that somehow provide health benefits to our diets.
Antioxidants are various phytochemicals that are grouped together, according to their function in providing health benefits to humans. Their role is to prevent the oxidation of different compounds in the human body, preventing the formation of harmful radicals that lead to various chronic diseases, such as cancer, cardiovascular disease, diabetes, Alzheimer’s, and others. These compounds are found in many fruits, vegetables and grains. They are numerous, and categorized into groups according to their chemical composition, phenolic compounds, flavanoids, carotenoids and terpenes.
Various antioxidants in grains have been known for a long time. However, in the past, they did not provide much benefit to the consumer, since antioxidants do not survive the refining process. Almost all of these compounds are present in high levels in the outer parts of the kernel, and are removed during milling of the flour as bran and germ. Specifically, the bran contains many phenolic compounds, flavonoids, ferulic acid and carotenoids, while germ contains high amounts of tocopherols (vitamin E).
Recently, as we became more health-conscious, more products are being made with whole grain flour. While this is largely because of growing demand for high-fibre products, the fibre itself is tightly bound with phytochemicals in grains, such as phenolics, flavonoids and carotenoids, which are responsible for many health benefits. This is very significant for their survival through the harsh environment of the stomach and the small intestine. Once they reach the colon, further digestion will release these compounds, so they can provide site-specific health benefits for prevention of colorectal and breast cancer, coronary heart disease, diabetes, and many other chronic diseases.
A Canadian company, Vinifera for Life (based in Ontario’s Niagara region), developed, with the assistance of the Guelph Food Technology Centre, a grape-skin flour which can be used in baked goods at levels of five to 10 per cent of the total formula of flour. This is made by carefully drying the residual skins of Cabernet and Chardonnay grapes, after the separation of the juice for wine making. The flour contains, among other nutrients, vitamins and minerals, a powerful antioxidant, Resveratrol, which may provide protection against CVD and cancer.
There are many methods used for the determination of the antioxidant activity of different grains, fruits and vegetables. Some are more specific or more effective than others. One of the methods that has been quite popular recently, and is becoming well recognized, is the ORAC (Oxygen Radical Absorbance Capacity) value, which measures the total antioxidant activity of the sample, giving an overall value without identifying the individual source.
Adding antioxidants in baked goods can be achieved by various methods. Incorporating whole grains or other antioxidant-rich parts of grains such as bran and germ, or fruits, will boost their content in the finished product. Choosing this method of incorporating wholesome ingredients containing antioxidants is good, because these are in their natural state, but there are drawbacks. There is a limit to the amounts of antioxidants that you can deliver in the final product. Alternatively, extracted antioxidants from many sources are available from many ingredient suppliers. They can be incorporated into foods at higher levels.
Whatever the method of incorporation or the source, we have to make sure that the finished product delivers the functional antioxidant to consumers, because many of these compounds can be damaged or altered by the various processing methods used for the production of foods.
For more information, or fee for service help with product or process development needs please contact the GFTC at 519-821-1246, by fax at 519- 836-1281, by e-mail at firstname.lastname@example.org.
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