Cranberry components: natural antioxidant activity.

Lipid oxidation is one of the major causes of deteriorating quality in foods when they are stored and processed. Incorporating antioxidants into foods can effectively retard lipid oxidation. But consumer concern about the safety and potential toxicity of synthetic antioxidants has led to a search for new natural antioxidants, such as cranberries.

The goal of scientists at the University of Wisconsin was to evaluate the antioxidant activities of cranberry components in muscle foods. The researchers extracted and fractionated cranberry components using aqueous ethanol, methanol and acetone.

The antioxidant activities of cranberry fractions were assessed by their scavenging properties toward the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical as well as their inhibitory effects on lipid oxidation in a washed cod muscle system. The level of thiobarbituric acid reactive substance (TBARS) was determined for evaluating the extent of lipid oxidation in the washed cod muscle.

All cranberry fractions were able to reduce the DPPH radical in a concentration-dependent response. The 51.8% to 93.5% and 15.0% to 33.9% DPPH radicals were quenched by cranberry fractions at levels of 10 mM and 2.5 mM quercetin equivalents, respectively. Adding cranberry fractions at levels of 120 millimoles (mmols) and 60 mmols of quercetin equivalents per kg of wash cod muscle extended the induction time of TBARS formation and reduced the TBARS values by 34.6% to 98.5% and 13.5% to 96.1%, respectively, compared to the control sample.

At a level of 120 mmols of quercetin equivalent per kg of fish, the inhibitory effect of cranberry fractions on lipid oxidation was almost comparable to that of n-propyl gallate at the same concentration. Based on these results, cranberry components are applicable as potential natural antioxidants that could enhance the oxidative stability and shelf life of foods.

Cranberries may also offer health benefits. In 2000, researchers at the University of Western Ontario, London, Ontario, Canada, studied the effect of the daily consumption of cranberry juice and other cranberry products on human breast cancer cell growth in animals. This research found that cranberry components inhibited the development of tumors in mice that had been injected with human breast cancer cells. Further information. Mark Richards, Department of Animal Sciences, University of Wisconsin-Madison, Muscle Biology and Meat Science Laboratory, 1805 Linden Dr. W., Madison, WI 53706; phone: [phone]; fax: [phone]; email: [e-mail].