Promising sulfite alternatives.

Promising sulfite alternatives

As antioxidants, sulfites help control wilting and discoloringof fresh produce. Last year, however, the Food and Drug Administration banned their use on produce because of concern about their ability to trigger life-threatening reactions in some asthmatics (SN: 8/17/85, p.100). Right now, the best stand-ins are ascorbic acid (vitamin C) and erythorbic acid, says Gerald M. Sapers, a food technologist with the Agriculture Department's Eastern Regional Research Center in Philadelphia. However, he says, these substitutes are easily oxidized by reactions with both food and air. The result: They disappear quickly, leaving treated foods vulnerable.

In an 18-month study, however, Sapers and his co-workershave turned up two related classes of compounds--ascorbic acid-2-phosphate and ascorbic acid-6-fatty acid esters--that avoid these pitfalls and remain effective at room temperature for at least one or two days.

The phosphate version works much like a controlled-releaseantioxidant, Sapers says. It doesn't begin action--and therefore doesn't become oxidized--until acted upon by an enzyme (acid phosphatase) in produce. The fatty-esters version is just oxidized much more slowly, making it available for a longer time. Both compounds work even longer when combined with cinnamic acid or an inorganic polyphosphate (made in Korea any not yet commercially available in the United States). To date, all have been successfully tested as a dip for fresh apples and a browning inhibitor for apple juice.