Let the Power of Juice Loose

Orange juice and citrus juices are deemed healthy because of their high content of antioxidants. Antioxidants assist to reduce harmful free radicals in our body. New studies show their benefits are greater than previously thought.

A new technique developed by researchers from the University of Granada for measuring antioxidant activity generates values that are ten times higher than those indicated by preexisting analysis methods. The results suggest the tables on the antioxidant capacities of food products that dietitians and health authorities use need to be revised.

In order to study these compounds in the laboratory, techniques that simulate the digestion of food in the digestive tract were used. They analyzed the antioxidant capacities of those substances that can potentially be absorbed in the small intestine. This is the liquid fraction of what we eat.

Currently, the antioxidant activity of the fiber isn’t measured because it’s assumed that it isn’t beneficial. However, this insoluble fraction arrives at the large intestine and the intestinal microbiota can also ferment it and extract even more antioxidant substances.

José Ángel Rufián Henares, professor at the University of Granada and his team developed a technique called “global antioxidant response” (GAR), which includes an in vitro simulation of the gastrointestinal digestion that occurs in our body, while taking into account the antioxidant capacity of the solid fraction.

Upon using the technique on commercial and natural orange, mandarin, lemon and grapefruit juices, it has been proven that their values significantly increase. For instance, in orange juice, the value ranges from 2.3 mmol Trolox/L (units for the antioxidant capacity) registered with a traditional technique to 23 mmol Trolox/L with the new GAR method.

On average, antioxidant activity is ten times greater than previously thought. This is not just in juices, but also in other kinds of food studied with this methodology. This technique and discovery could enable dietitians and health professionals to better determine the antioxidant values of foods.

Source: ScienceDaily, 5 December 2014.