Food Discoloration, Darkening of Food Purees and Concurrent Changes in Composition of Head-Space Gas

Abstract

It is not the intent of the authors to encourage careless handling and cold storage practices for apples and pears in the Pacific Northwest. They do feel, however, that the popular conception of the possible hazard presented by a few ripe apples in commercial fruit cold storages has been distorted beyond its true eco-

Endogenous Polyphenoloxidase Activity Associated with the “Black Ring” Defect in Canned Beet (Beta vulgaris L.) Root Slices

“…Potential causes of the "black ring" defect include a boron deficiency during beet root development (Halbrooks, 1981), the presence of oxygen in the can headspace (Vilece et al, 1955), microbial activity (Cameron et al, 1936), nonenzymic browning (Parkin and Im, 1990) or the action of oxidative enzymes (Stevenson, 1925;Boscan et al, 1962: Lee andSmith, 1979).…”

Chemical and Physical Changes in Beet (Beta vulgaris L.) Root Tissue During Simulated Processing–Relevance to the “Black Ring” Defect in Canned Beets

“…A black discoloration in thermally processed beet root products may be due to a boron deficiency and the attendant blackheart injury in raw beet roots (Halbrooks, 1981), microbial activity in the presence of iron during preliminary processing (Cameron et al, 1936), oxygen in the container headspace (Vilece et al, 1955) or the potentiation of endogenous oxidase activities (Stevenson, 1925;Boscan et al, 1962;Lee and Smith, 1979). Another possible cause is non-enzymic (Maillard) browning reactions, favored by the high temperatures encountered during retorting.…”