Antioxidants continue to gain momentum as a major trend in today’s food markets. Consumers are becoming more aware of the connection between antioxidants in foods and the prevention of chronic diseases such as cancer and diabetes.

Many products in the market contain the phrases “rich in antioxidants” or “antioxidants added” on the label, but what are antioxidants and how do they work? First, let us define oxidation.

Simply put, oxidation is the effect that oxygen and other substances have on fats and oils as well as on animal cells and tissues. In the food industry, fats and oils are used as functional ingredients, and their oxidation affects the taste and shelflife of food products. Healthy oils -- such as mono- and polyunsaturated fats -- are more prone to the oxidation process than saturated and trans fats. In food manufacturing, natural and synthetic antioxidants are used to delay the oxidation process and extend the shelflife of products.

Oxidation also affects plant and animal tissues. For example, human and animal cell membranes contain phospholipids, which play an important role in the functionality of the cells. Certain radicals will result in the oxidation of the phospholipids resulting in the damage to the cells. This process may eventually result in the onset of the various chronic diseases. Antioxidants naturally present in the foods consumers eat will slow or eliminate the action of these radicals. As a result, there is a great deal of emphasis on and interest in these antioxidants with respect to the prevention of chronic diseases.

In recent years, the focus of antioxidant research has been on the natural antioxidants found in fruits, vegetables, seeds, grains, spices and other plant parts. Many fruits and vegetables have been investigated for their antioxidant ability. Many of the actual substances responsible for the antioxidant activity within these vegetables and fruits have been identified. These include resveratrol in grapes, rutin in asparagus, lycopene in tomatoes, vitamin C in citrus, vitamin E and many others. Many fruits and vegetables with bright colors are known to contain higher antioxidants. Processing these into ingredients fulfills two current needs for the food industry: the demand for antioxidant-rich ingredients and the need for new natural colors. Recent research in France investigated carrots in various colors such as white, yellow and pink, both for their natural color and antioxidant strength.

How do we know the strength of antioxidant activity in different foods? There are many different methods for determining the natural antioxidant activity of foods. One of the most popular and practical is the determination of Oxygen Radical Absorbance Capacity (ORAC) value, and the quest for which food has the highest ORAC value continues.

Quite often, the highest quantities of these antioxidants are present in the outer layers of foods, such as the skin of fruits and the bran of seeds. The skins of tomatoes, apples, peaches, pears, grapes, plums and other fruits often contain more antioxidants than the whole fruit. Traditional processing practices in the food industry discarded these by-products as animal feed or disposed them in landfills. Recently, however, the health benefits of these by-products have gained attention. Researchers in many parts of the world are investigating by-products such as fruit peelings, pulp, seeds and skins for their antioxidant capacity and the production of ingredients from these by-products. Investigations at the Guelph Food Technology Centre have resulted in the process for production of grape skin flour which is high in the antioxidant resveratrol. The grape skin flour can be incorporated into breads, pasta and other food products to enhance the antioxidant activity of such products.

Commercial production processes for stable antioxidant-rich ingredients has to be carefully considered. Normally, ingredients for the food processing industry come in the form of powders. The production of powders from these products requires dehydration, which is normally done with heat. Elevated heat reduces and sometimes completely eliminates the antioxidant activity. Various new gentle processing technologies have emerged recently to accommodate this need. Preserving the antioxidant activity of ingredients will be meaningless if the antioxidants cannot reach the consumer. It is therefore important that the processing of food products themselves is not so severe as to destroy these antioxidants. However, it is also very important that the food processing is adequate to safeguard the consumer from the danger of food pathogens. It is a careful balancing exercise.

Other Resources
* Antioxidants and Flavor Masking
* Cumin's Applications
* Antioxidant Intake - Formulating for Heart Health
* Harm from Antioxidants?
* Purple Corn's Antioxidants
* Natural Antioxidants in Beef Patties

From the August 30, 2010, Prepared Foods E-dition