Abstract
In order to obtain data on the nutritious characteristics of yacon (Smallanthus Sonchifolius), the present study investigated the free amino acid composition in yacon cultivars from different production districts.
The percentages of water, protein, lipid, carbohydrate and ash in the yacon were 85.9-91.1%, 0.49-0.96%, 0.04-0.13%, 7.9-12.9%, and 0.33-0.56%, respectively. The main component was water. The protein and lipid levels contained in yacon varied among the cultivars from different production districts.
The total free amino acids in the yacon ranged from 147.9 to 341.1 mg/100 g and it differed among the samples from different producing districts. The main free amino acid in yacon were arginine and glutamine in all cultivars. The content of proline significantly varied among the cultivars from different producing districts, ranging from 1.1 to 97.4 mg/100 g.
The free amino acids concentration was lower in the upper portion compared to the root and middle parts ; thus, the free amino acid content varied among the different parts of the yacon.
The total free amino acids, glutamine, and arginine in the freeze-dried yacon powder were 1941.2 mg/100 g, 212.4 mg/100 g, and 994.2 mg/100 g, respectively.
The results from the present study suggest that although the free amino acid content varies among yacon cultivars from different production districts, the main amino acids, glutamine and arginine, were functional amino acids in all cultivars.
