Desulfitation

Desulfitation 

the removal from uncooked preserved fruit and vegetables of the sulfurous acid used in sulfitation. The desulfitation is performed in such a way that the semifinished and finished products retain their original natural qualities (color, odor, food value, and taste).

There are two methods of desulfitation: one is thermal, and the other is chemical. The thermal method is based on the fact that the heating of products treated with sulfurous acid leads to rapid decomposition of the acid, with the liberation of sulfur dioxide. The desulfitation of fruit and berries before processing is accomplished by washing and heating for a short period (5–10 min) in pure hot water at 95°-100°C (blanching); purees are heated by steam in open kettles.

Desulfitation under a low-temperature vacuum does not always permit the attainment of permissible standards for sulfur dioxide, although it gives good preservation of the natural qualities of the raw material. The vacuum method is used for grape juice, since under known conditions the semi-finished product retains its aroma and freshness, which are essential for the production of high-quality wines.

The desulfitation method in which the sulfurous acid is converted (by means of any reagent) into a substance that is harmless to the body is called chemical desulfitation. The method is not widely used in the USSR.

REFERENCES

Markh, A. T., and R. V. Krzhevova. Khimiko-tekhnicheskii kontrol’ konservnogo proizvodstva, 5th ed. Moscow, 1962.
Rabiner, N. Ia., and D. N. Molchanov. “Tekhnologicheskie linii sul’fitatsii i desul’fitatsii plodovogo syr’ia.” In Referaty nauchnykh rabot Vsesoiuznogo nauchno-issledovatel’ skogo in-ta konservnoi i ovoshchesushil’noi promyshlennosti, issue 3. Moscow, 1955.
Spravochnik po proizvodstvu konservov, vols. 1–2. Moscow, 1965–66.

V. N. GRIAZNOVA