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The role of sulphur dioxide and nitrate on detinning of canned grapefruit juice
Author(s) -
SAGUY I.,
MANNHEIM C. H.,
PASSY N.
Publication year - 1973
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.1365-2621.1973.tb01700.x
Subject(s) - corrosion , dissolution , nitrate , chemistry , tin , grapefruit juice , sulfur , inorganic chemistry , metallurgy , materials science , organic chemistry , medicine , pharmacokinetics
Summary In this work, the effect of the corrosion accelerating substances sulphur dioxide and nitrate, which may be present in foods as residues was investigated. The amount of dissolved tin and iron were taken as the corrosion criteria. Sulphur dioxide was found to act as a corrosion accelerator, in an acid medium of grapefruit juice, with even 1 ppm of SO 2 having a highly significant effect on corrosion. Using statistical analysis, a mechanism describing the corrosion as a function of time was found. The process was divided into two main stages, namely, a first fast stage lasting for about 7 days described by the polynomial: γ= A 0 + A 1 X ‐ A 2 X 2 + A 3 X 3 and a second stage described by the linear equation γ= a + bX . Nitrate also acted as a corrosion accelerator. The threshold value of nitrate for tin dissolution in cans with a 3 mm headspace was 6 ppm while with a 30 mm headspace it was 2 ppm. For iron dissolution the threshold was 6 ppm at both headspace levels. The corrosion mechanism for nitrate and iron was similar to the one mentioned above. A linear relationship between dissolved tin and iron in the presence of nitrates was found.