The antioxidant activity of yacon (polymnia sonchifoliaty) and its application to the pork patties as a natural antioxidant

Abstract

This study was performed to evaluate the extraction method (Yacon ethanol extracts; YEE, Yacon pressed extracts; YPE) and various levels (0.05-1.0%) of Yacon (Polymnia sonchifolia) on antioxidant and antimicrobial activities. In linoleic acid emulsion of YPE, there were higher iron chelation activity and antioxidant activity than those of YEE (p<0.05). A 1,1- diphenyl-2-picryl hydrazyl (DPPH) radical scavenging activity and reducing power of both extracts showed a higher rate at 0.5% level. Ground pork patties, which contain 0.5% YEE and YPE, were manufactured and BHT (0.01%) was used as a reference. Physicochemical properties and microbial counts of ground pork patties, containing a different type of Yacon, were evaluated during the 14 d of storage at 4oC. A pH level, and lightness (Hunter L), as well as the yellowness (Hunter b) values of treatments were not different from those of the control (p>0.05), but increased during storage, at 4°C. Lightness values of ground pork patties, with Yacon extracts, showed the highest. TBARS value of ground pork patties that contains Yacon increased with increased storage at 4°C (p<0.05), and pork patties with YPE or YEE retarded the lipid oxidation, during refrigerated storage, as compared to that of the CTL. Thus, YPE could be used as a potential possibility to inhibit the lipid oxidation of processed meats, during the refrigerated storage.