No abstract

Table III. General Base Requirement in the Nonenzymatic Formation of Acetoin Catalyzed by Thiamine at pH 8.4 and 35°C. for 24 Hours [Pyruvic acid (0.1 M), acetaldehyde (1.0M), thiamine (O.lAf

The fleshy roots of the sweet potato are shown to contain appreciable amounts of yellow pigments other than beta-carotene. The carotene/total-pigment ratio varies among different varieties and within varieties. In the varieties tested, the carotene/total-pigment ratio increased with increase in intensity of yellow color. Triumph, a very light-colored variety, contained a small amount of carotene shortly after harvest, but this soon disappeared in storage.

Increase, harvest, storage, Variety Harvested Storage 100 g. 100 g.

Carotene supplies approximately three fifths of the vitamin A values in the normal diet. Dark green, leafy vegetables are especially rich in carotene, but may lose it rapidly unless properly handled after harvest. Temperature and humidity are primary factors in the preservation of these crops. Kale, collards, turnip greens, and rape were subjected to slow, moderate, and rapid wilting at 32°, 50°, and 70°F. Conditions favorable to wilting resulted in a more rapid loss of carotene, but unfavorable temperatures hastened its destruction much more rapidly than did wilting. Vitamin a is not found in plants, but carotene-provitamin A-occurs regularly in many fruits and vegetables. The structure of ß-carotene, the principal carotene of most plants, is such that on hydrolysis in the animal body two molecules of vitamin A may be formed from each molecule of ßcarotene.