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Chemistry of sulphur dioxide in vegetable dehydration
Author(s) -
WEDZICHA B. L.
Publication year - 1987
Publication title -
international journal of food science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.831
H-Index - 96
eISSN - 1365-2621
pISSN - 0950-5423
DOI - 10.1111/j.1365-2621.1987.tb00509.x
Subject(s) - chemistry , sulfur dioxide , dehydration , preservative , browning , autoxidation , inorganic chemistry , sulfur , nucleophile , food additive , environmental chemistry , organic chemistry , food science , catalysis , biochemistry
Summary The state of sulphur dioxide in partially dehydrated or dehydrated foods is complex and depends on pH, ionic strength, water activity and concentration, and on the effects of anions and cations on the solubilities of sulphite and disulphite salts. The chemical basis of the preservative action is explained in terms of the nucleophilicity of the sulphite ion and the possible consequences of the changing state of the additive during dehydration are evaluated. The significance of autoxidation of the sulphite ion to its fate in food, and role as an antioxidant, or prooxidant, is critically discussed. The most widely studied reaction of sulphur dioxide in food is its inhibition of non‐enzymic browning; the current state of knowledge concerning the mechanism of this action is explained. The loss of sulphur dioxide during vegetable dehydration obeys first‐order kinetics. This observation is considered in terms of known first‐order reactions in foods and processes which are limited by rate of diffusion. There are still insufficient data to suggest ways in which the composition of the food could be altered to reduce its requirement for sulphur dioxide during dehydration.