Rate of pigment degradation in the phloem of dehydrated Red Core Chantenay carrots

Abstract

Abstract does not appear. First page follows. Introduction The deterioration of dehydrated carrots in storage involves complex reactions. Although detailed information about these changes is not available at present, the following general facts are known: (1) the pigments present disappear; (2) haylike and other off-odors develop; (3) changes in the oil droplets within the cells result in a positive test for aldehydes with Schiff’s reagent; (4) the carrots darken (apparently because the amino acids combine with sugars), and the substance responsible for this change in color is water-soluble; (5) blanching inactivates enzymes and also modifies other changes that occur in storage; (6) sulphite preserves color, especially by preventing the darkening reaction and by acting somewhat as an antioxidant; (7) other changes unquestionably occur. In preliminary studies on carrots during processing and storage, the overall changes in pigment concentration were expected to serve as a marker for at least some of the oxidations taking place in the lipid phase. This assumption was based on the following facts: (1) concentration of pigment may change greatly in storage; (2) carotene is a pro-oxidant (Olcott and Mattill, 1936a)3 and its breakdown in oil solution results from the previous oxidation of the oil (Strain, 1941); and (Sumner, 1942); (3) carotene in blanched and in dried carrots is dissolved in oil droplets (Weier, 1944a). This paper reports experiments to test the stability of the pigment complex in carrots after various treatments. These treatments include blanching, leaching, and soaking in buffers, in solutions of high and low pH, in organic and mineral acids, and in antioxidants. Pigment concentration has been measured on the Evelyn colorimeter. Thus far, no attempt has been made to isolate individual pigments or to follow the details of their breakdown.