Lipophilic components from cranberry juice powder inhibit lipid oxidation.

Deteriorating quality caused by lipid oxidation is a major problem in the food industry. Adding antioxidants to products can inhibit lipid oxidation processes. Natural antioxidants are preferred over synthetic antioxidants by consumers who are more open to natural solutions to product problems. Cranberries are natural sources of phenolic compounds that can potentially inhibit lipid oxidation processes in muscle foods.

Scientists at the University of Wisconsin wanted to determine the ability of lipophilic components from spray-dried cranberry juice to inhibit lipid oxidation in mechanically separated turkey (MST), using chloroform as an extractant. They sought to fractionate the extract and determine the components that most effectively inhibit lipid oxidation.

They found that lipophilic components from cranberry powder, especially flavonols, are effective in inhibiting lipid oxidation in MST. Flavonols are a class of antioxidants found in plant-based foods and beverages, such as cocoa, wine and tea, that have been increasingly linked to heart benefits.

Researchers fractionated chloroform extract in reverse phase silica gel using a methanol-water gradient. The fractions obtained were analyzed using reversed-phased HPLC to determine the predominant classes of cranberry phenolics within each fraction. The investigators then attempted to identify the components in the fraction that were more effective in inhibiting lipid oxidation.

The fractions were tested for their antioxidant potency in MST when the product was stored at -4 C. The extent of lipid oxidation was determined by measuring thiobarbituric acid reactive substances (TBARS) and peroxide value.

Adding 0.01%, 0.05%, 0.1% and 0.2% of the chloroform extract to the turkey inhibited lipid oxidation by 8, 14, 27 and 33 days respectively, compared to turkey that did not contain the extract. The 0.1% w/w fraction inhibited the formation of TBARS for up to 40 days compared to the turkey alone, which was completely oxidized in 13 days. The researchers believe that the efficacy of this fraction is attributable to the presence of flavonols. They base their reasoning on mass spectrometry data and absorbance values.

Further information. Mark Richards, Department of Animal Sciences, University of Wisconsin-Madison, Meat and Muscle Biology Laboratory, 1805 Linden Dr. W., Madison, WI 53706; phone: [phone]; fax: [phone]; email: [e-mail].