Characteristics of Both Embraced and Penetrated Fatty Acids of Starch

Abstract

The embraced fatty acids in various commercial starches, such as those of sweet potato, potato, tapioca, wheat, corn and rice, were investigated.
In spite of the fact that the compositions of fatty acids are not uniform, there exists a general tendency that, the higher the fatty acid content of starch, the larger the proportion of linoleic acid, while the lower the fatty acid content of starch, the larger the proportion of palmitic acid. It was also confirmed that the ratio of palmitic acid to total fatty acids was higher in the starch granules, while low in the whole tissues, irrespective of plant source.
The respective samples of starch were defatted and then treated with hot methanol solution containing six kinds of fatty acids, found ordinarily in the starch granules as the embraced fatty acids. This made the fatty acids penetrate into the defatted granules. Little difference in total quantity and composition of the fatty acids penetrated was shown among the respective starch samples. However, a large difference in penetration rate among the fatty acids used here was found, that is, palmitic acid penetrated in the richest amount and increase of unsaturated bond in C-18 acid was accompanied by de-crease of penetration rate.