The Ratio of Carotene to Carotenoid Pigments in Sweet-potato Varieties

Abstract

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.

Quality of Sweetpotato Flour During Processing and Storage

“…More importantly, β-carotene, being a precursor of vitamin A, bestows a high nutritive value. The use of depth of the orange color due to carotenoids within a variety as a criterion to select improved strains was mentioned as early as 1946 (43). More recently, researchers have tried to find a correlation between the carotenoid content in fresh roots and the color of sweetpotato flour.…”

“…The carotene/total carotenoid pigment ratio varies among different varieties and within varieties. The greater the concentration of total pigments, the higher the carotene/total pigment ratio (43).…”

“…The significance of carotenoids is that some are converted into vitamin A. Beta-carotene has the highest (100%) provitamin A activity, followed by α and γ-carotenes (50% activity). Even as long ago as the 1940s, the importance of sweetpotato as a source of carotene was stressed (43).…”

Influence of Storage Temperature on Carotene, Total Carotenoids and Ascorbic Acid Content of Sweetpotatoes

“…The vitamin constituents occur in very small amounts and are accompanied by large quantities of foreign material; they are relatively unstable and their distribution in the root is far from uniform. Some roots may contain four times as much carotene as others of the samesvariety and three times as much in the proximal-end as in the distal-end of the same root (5). Among 30 individual roots of the Porto Rico variety the highest vitamin C content was 2.6 that of the lowest (7).…”

Analysis of genes developmentally regulated during storage root formation of sweet potato

“…SRF9 is thought to encode an enzyme involved in carotenoid biosynthesis. Because the sweet potato storage root accumulates carotenoids (Ezell and Wilcox, 1946), it is natural that the expression of this gene increases during storage root formation.…”