Changes in Lipid Composition of Sweet Potatoes as Affected by Controlled Storage

Abstract

SUMMARY— The fatty acid composition of the lipids extracted from Georgia Red and Centennial varieties of sweet potatoes was studied to determine changes during storage at 15.5, 10, and 4.5°C. The two varieties did not differ initially in the relative proportions of fatty acids. However, changes in fatty acid composition were noted during storage and appeared to be mere pronounced at low storage temperatures. The most consistent changes noted were an increase in tetra‐cosaenoic acid and a decrease in short chain saturated acids. The Centennial variety contained higher levels of total lipids, which were generally reflected in higher levels of the three fractions, (1) non‐phospholipids, (2) cephalin and (3) lecithin. The increase in total lipids and the individual lipid fractions with storage is indicative of two processes that may have occurred in the stored roots. The lipids may have become more extractable as the respiring potato underwent compositional changes, or lipids were being synthesized from non‐lipid components. Although changes observed in the relative proportions of fatty acids during storage at different temperatures were not always consistent, the possibility is suggested that changes in fatty acid composition may be related to changes in quality of the potato during storage.

Lipids of Cured Centennial Sweet Potatoes

“…Further comparison of the make-up of Centennial lipids as found by Boggess et al (1967;1970) and this study is not possible because of the differences in methodology.…”

“…THE LIPID content of cured Centennial sweet potatoes from this study was found to be 2.7% (dry weight). Boggess et al (1967;1970) found 1.6% lipids for Centennials. This discrepancy could easily be due to differences in curing and storage or methodology.…”

“…However, very little is known about the nature of lipids present in sweet potatoes. Boggess et al (1967;1970) studied lipid changes in a number of varieties of sweet potatoes including Centennials during curing and storage by separating lipids into "nonphospholipids," "cephalin" and "lecithin." These workers found the lipid content to be 0.44% (fresh weight) for cured Centennials stored for 180 days at 15.5"C.…”

Lipid Changes During Processing and Storage of Sweet Potato Flakes

“…Total lipids of pureed raw, Centenntial sweet potatoes, were found to be 2.45% on a dry weight basis. Walter et al (1971) reported 2.7% and Boggess et al (1967Boggess et al ( , 1970 1.6% total lipids. In the work reported here, neutral lipids were found to be the most abundant at 48.1%, followed by glycolipids, 31.2% and phospholipids, 20.7%.…”

“…Little is known about the lipids of sweet potatoes ahd their changes upon storage. Boggess et al (1967) studied the lipid changes of sweet potatoes after curing and storage for 5 months. They separated lipids into three classes: a nonphosphorus fraction, a lecithin fraction, and a cephalin fraction and found changes in both total and fraction lipids.…”