The application of SO2 for the control of both enzymatic and non-enzymatic browning is an established practice in the industrial processing of fruits and vegetables. SO2 functions mainly in a preventive rather than a corrective role. In case of non-enzymatic browning, it complexes with the aldehyde-active group and thereby prevents their reaction with the amines. In enzymatic browning, it appears to have a damaging effect on the enzyme system. Sodium metabisulphite that normally yields 60% of its own weight of SO2 in solution is commonly used for sulphiting vegetables.
- Sodium Metabisulphite
- Prepare three solutions of sulphite to contain 1,000, 500 and 200 ppm SO2.
- Show calculations for your solutions.
- a. Peel and cut potatoes in a suitable size.
- b. Dip the pieces in different sulphite solutions for 1, 3 and 5 minutes.
- Observe the action of sulphite on the potato pieces by comparing it with an untreated sample.
- Note: Peroxidase test and visual examination of the end products after drying in an oven can be employed for evaluation of the efficacy of sulphiting.