A new study says that anti-caking agents meant to protect vitamin C from moisture in powdered products may instead hasten degradation of the nutrient.
In an effort to understand how anti-caking agents protect substances such as vitamin C from humidity, the researchers blended different anti-caking agents with powdered sodium ascorbate, a common form of vitamin C, and were exposed to different relative humidities.
Results showed that some of the anti-caking agents caused vitamin C to dissolve at lower humidity levels than normal.
Normally, sodium ascorbate deliquesces, or dissolves, at 86 percent relative humidity and is stable below that level. Some anti-caking agents, however, caused the degradation to begin at lower humidity levels.
"Some of the agents act like little raincoats, covering the particles and protecting them from moisture. Others will absorb the water themselves, keeping it away from the vitamin C particles," said Lisa Mauer, a Purdue University professor of food science.
"I really thought some of those anti-caking agents would help, but they didn't."
The problem, according to the research, is the chemical properties of the anti-caking agents themselves.
The water-repellent agents, which act like raincoats, are mobile, Lipasek said. When they move around, they clump together and leave some of the vitamin C uncovered. When that happens, moisture is able to reach and degrade the exposed vitamin C.
The study has been published in the Journal of Food Science.