The objective of scientists at the University of Maine was to evaluate the effectiveness of sodium acid sulfate
(SAS) dip treatments, compared to other anti-graying treatments and a control, to see how effective SAS would be in reducing after-cooking darkening in boiled Katahdin potatoes.
Their efforts revealed that malic acid, citric acid and a combination of sodium acid sulfate, citric acid and sodium erythorbate are better acidulants for inhibiting color change as well as the growth of spoilage bacteria, yeast and mold than is sodium acid pyrophosphate, the industry standard.
In tests, Burbank and Norkotah potato slices were dipped into 3% sodium acid sulfate, citric acid, sodium erythorbate, malic acid, sodium acid pyrophosphate, or a combination of sodium acid, sulfate citric acid and sodium erythorbate.
Sodium acid sulfate, citric acid and malic acid inhibited some browning, while sodium erythorbate and the combination of sodium acid sulfate, citric acid and sodium erythorbate prevented browning.