The health-related properties and potential applications of yacon concentrate NZFOS+

Abstract

Yacon (Smallanthus sonchifolius), a sustainable foodstuff, is perceived as a functional food because it contains biologically active components e.g. fructooligosaccharides (FOS), inulin, and phenolic compounds that may provide physiological benefits beyond basic nutrition to reduce the risk of chronic diseases. There is a growing public interest in why and how to use yacon. Yacon, originally from South America, has been grown in New Zealand since 1980’s. NZ-produced yacon concentrate NZFOS+ contains the purest natural prebiotic FOS. Our study aimed to examine the phytochemical contents of NZFOS+ and its health-related properties. The glycemic index of yacon concentrate was measured by ISO 26642:2010(E) (n=10). Total phenolic and flavonoid contents were measured by spectrometric method. The chlorogenic acid content and phenolic profiling were measured using the liquid chromatography coupled with mass spectrometry (LC-MS). The antioxidant activity of the yacon concentrate and Manuka honey were compared using the cupric reducing antioxidant capacity (CUPRAC), Ferric-ion reducing antioxidant power (FRAP) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assays. The results indicated that compared to Manuka honey, yacon concentrate has a lower glycemic index (40 vs 52); a higher content of total phenolic (5430mg vs 744mg GAE/100g), total flavonoid (329mg vs 22mg QE/100g), and chlorogenic acid (11.88μg vs 0.08μg CA/g); across all assays observed, a significantly higher antioxidant capacity (CUPRAC assay, 892mg vs 52.6mg TE/100g; FRAP assay, 633mg vs 47mg TE/100g; DPPH assay, 383mg vs 22mg TE/100g, respectively). The study proved that yacon concentrate is low in glycemic impact and high in antioxidant capacity, which are associated with the maintenance of health and wellbeing and prevention of chronic diseases. Further investigations are needed for human studies and new applications of yacon concentrate. Yacon concentrate (NZFOS+) has potential markets in the development of new food products and new dietotherapy applications, e.g. in the form of syrup, and functional prebiotic drinks.