Determinations of Triacylglycerol and Fatty Acid Esters in Potato Pulp Fermented with Lactic Acid-Producing Fungus

Abstract

The authors established a method for conducting the lactic acid fermentation of potato pulp, an agricultural by-product, by Rhizopus oryzae. Assay of lipid classes in the present study indicated the presence of significant amounts of triacylglycerol and fatty acid esters, an 8:2 mixture of ethyl and methyl esters in fermented potato pulp. Although triacylglycerol was also present as a minor lipid class, no fatty acid ester could be found in raw potato pulp. The principal fatty acids in either lipid were oleic and palmitic acids, the former present only in small amounts in total lipids from raw potato pulp. Triacylglycerol molecular species determined by HPLC in fermented potato pulp was mainly dioleoylpalmitate. γ-Linolenic acid, a major fatty acid in R. oryzae, was found in fatty acid esters, but not in triacylglycerol from fermented potato pulp. Moreover, the fatty acid compositions of triacylglycerol and fatty acid esters in fermented potato pulp differed significantly. The data of the present study should thus be useful for monitoring the extent of lactic acid fermentation. Ester formation would contribute to enhanced palatable of potato pulp. © 2004, Japan Oil Chemists' Society. All rights reserved.