INHIBITION OF BROWNING BY SULFUR AMINO-ACIDS .3. APPLES AND POTATOES

Sodium sulfite, widely used to inhibit enzymatic and nonenzymatic browning in fruits and vegetables, has been reported to be an irritant to some consumers. In an effort to develop sulfite alternatives. Russet Burbank potatoes, Washington Golden Delicious apples, and Washington Red Delicious apples were subjected to enzymatic browning in air and evacuated plastic pouches in the absence and presence of the following potential browning inhibitors: L-cysteine, N-acetyl-L-cysteine, reduced glutathione, sodium bisulfite, sodium sulfhydrate, and sodium hydrosulfite. Studies on the effects of concentration of inhibitors, storage conditions, and pH revealed that N-acetyl-L-cysteine and reduced glutathione were nearly as effective as sodium sulfite in preventing browning of both apples and potatoes. In contrast, a previously proposed mixed solution of salicylic and ascorbic acids and potassium sorbate was effective only for short periods. N-Acetyl-L-cysteine and reduced glutathione are promising alternatives to sulfite in preventing browning in fruits and vegetables. © 1990, American Chemical Society. All rights reserved.