COMPARISON OF THE COMPOSITION OF PROCESSED AND FRESH VEGETABLES AS CONSUMED

A range of products has been studied although this paper only includes results for peas. For each crop, a single variety was grown, harvested at appropriate maturities and separated into samples for treatment as "fresh" and "processed". Fresh samples were treated to imitate typical market and domestic storage and cooking; processed samples were frozen or canned and stored to simulate normal commercial and domestic storage before reheating. Samples were analysed at each stage.

The major effects of increasing maturity in peas were shown to be reductions in moisture and in vitamin C. Similar trends occurred on storage in the pod and in addition a large increase in protein content was observed. Cooking in tap water resulted in leaching of potassium and vitamin C and uptake of calcium and sodium. The extent of these changes was dependent upon the amount of cooking liquid and mode of heating ie. microwave or conventional.

Canning, freezing and reheating resulted in similar changes to those observed in cooking but composition generally remained stable on storage.

The relative rates and extent of changes in vitamin C were such that the processed product, ready to eat, was similar to the fresh material which would be commonly available in the home.

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