Rate of pigment degradation in the phloem of dehydrated Red Core Chantenay carrots
Author AffiliationsElliot Weier was Associate Professor of Botany and Associate Botanist in the Experiment Station.
Hilgardia 17(14):485-500. DOI:10.3733/hilg.v17n14p485. September 1947.
Abstract does not appear. First page follows.
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.
Barnes W. C. Effects of some environmental factors on growth and color of carrots. New York (Cornell) Agr. Exp. Sta. Memoir. 1936. 186:1-36.
Bauernfeind J. C., Siemers G. F. Adding ascorbic acid to peaches before freezing. Food Indus. 1945. 17:745-46.
Carolus R. L. The use of rapid chemical plant nutrient tests in fertilizer-deficiency diagnoses and vegetable-crop research. Virginia Truck Exp. Sta. Bul. 1938. 98:1531-56.
Eckey E. W. Composition of fatty matter and process of stabilizing same. 1932. U. S. Patent Office. Patent No. 1,993,152.
Koehn C. J., Sherman W. C. The determination of vitamin A and carotene with the photoelectric colorimeter. Jour. Biol. Chem. 1940. 132:527-38.
Mills R. C., Hart E. B. Studies on the stabilization of carotene in dehydrated feeds and foods. Jour. Dairy Sci. 1945. 28:1-13. DOI: 10.3168/jds.S0022-0302(45)95137-X [CrossRef]
Olcott H. S., Mattill H. A. Antioxidants and the autoxidation of fats. VI. Inhibitols. Amer. Chem. Soc. Jour. 1936a. 58:1627-30.
Olcott H. S., Mattill H. A. Antioxidants and the autoxidation of fats. VII. Preliminary classification of inhibitors. Amer. Chem. Soc. Jour. 1936b. 58:2204-8.
Strain H. H. Unsaturated fat oxidase: specificity, occurrence, and induced oxidations. Amer. Chem. Soc. Jour. 1941. 63:3542 DOI: 10.1021/ja01857a521 [CrossRef]
Sumner R. J. Lipid oxidase studies. III. The relation between carotene oxidation and the enzymic peroxidation of unsaturated fats. Jour. Biol. Chem. 1942. 146:215-18.
Tressler D. K., Du Bois C. No browning of cut fruit when treated by new process. Food Indus. 1944. 16:701 763-65.
Weier T. E. Carotene degradation in dehydrated carrots. I. Cytological changes in carotene and fat droplets under conditions favorable for carotene degradation. Amer. Jour. Bot. 1944a. 31:342-46. DOI: 10.2307/2437199 [CrossRef]
Weier T. E. Carotene degradation in dehydrated carrots. II. Stability of carotene in carrot tissue kept in moist air at 60° C. Amer. Jour. Bot. 1944b. 31:537-44.