Plant extracts are natural preservatives for encapsulated oils

Friday, November 16, 2007 by: David Gutierrez, staff writer
Tags: food ingredients, food preservatives, artificial preservatives

(NewsTarget) A cocktail of plant extracts from rosemary, broccoli sprouts and citrus may function as a natural preservative for vegetable oils and other foods, according to research conducted by scientists at the Korea Advanced Institute of Science and Technology and published in the Journal of Food Engineering.

Antioxidants are widely used as preservatives, since the oxidation process that breaks down various fats and other chemicals in food can also cause the food's color, taste and texture to deteriorate.

While previous studies have demonstrated rosemary extracts to be an effective antioxidant, the current study also looked at the effectiveness of extracts of broccoli sprouts, citrus and seed oils by measuring the rate at which high oleic sunflower oil broke down when mixed with the various extracts.

The researchers found that the best antioxidant result came from a mixture of broccoli sprout (1 percent), citrus (1 percent) and rosemary extracts (0.05 percent).

"Based on these results, it is evident that natural plant extracts have a combined effect as an antioxidant on microencapsulated high oleic sunflower oil," the researchers wrote.

However, they pointed out that high oleic sunflower oil contains large quantities of oleic acid, which itself tends to prevent lipid oxidation. They hypothesized, however, that the natural plant extracts would prevent the oil from oxidizing even at higher temperatures.

There is a rapidly growing market for antioxidants and preservatives based on natural plant extracts, as opposed to artificially produced antioxidants like butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT). This is due in part to health concerns regarding artificial additives -- evidence suggests that BHA is a carcinogen, and BHT has been banned in Australia, Japan, Romania and Sweden. In the United States, it is prohibited for use in infant formulas.

Even as the market in synthetic antioxidants has declined, the market for natural antioxidants such as vitamins (including C and E) and plant extracts has increased, according to a 2003 report by the growth consulting firm Frost and Sullivan.