Characterization of yam bean (Pachyrhizus spp.) seeds as potential sources of high palmitic acid oil

Abstract

Seeds from 22 accessions of the yam bean species Pachyrhizus ahipa (14 accessions), P. erosus (5), and P. tuberosus (3) were investigated for oil and protein contents, fatty acid composition of the seed oil, and the total tocopherol content and composition. Plants from the accessions were grown under greenhouse conditions during one (P. erosus and P. tuberosus) or two years (P. ahipa). The pattern of the investigated seed quality traits was very similar in the three species. Yam bean seeds were characterized by high oil (from about 20 to 28% in one environment) and protein contents (from about 23 to 34%). Seed oil contained high concentrations of palmitic (from about 25 to 30% of the total fatty acids), oleic (21 to 29%), and linoleic acids (35 to 40%). Levels of linolenic acid were very low, from about 1.0 to 2.5%. Total tocopherol content was relatively low in P. erosus (from 249 to 585 mg kg-1 oil) and P. tuberosus (from 260 to 312 mg kg-1 oil) compared with the levels found in P. ahipa grown under identical conditions (508 to 858 mg kg-1 oil). In all the samples, gamma-tocopherol was predominant, The combination of high oil and protein contents, together with high palmitic acid, low linolenic acid, and high gamma-tocopherol concentration, makes these crops an interesting alternative as sources of high palmitic acid oil for the food industry.