본 연구에서는 열처리가 야콘의 항산화 활성에 미치는 영향을 살펴보기 위하여 열처리 온도(100 및 121℃)와 시간 (15, 30 및 60분)에 따른 항산화 성분 및 항산화 활성 변화를 조사하였다. 열처리 후 야콘의 갈변도, 유리형 및 결합형 폴리페놀 함량, 유리형 및 결합형 플라보노이드 함량, DPPH radical 소거 활성 및 ABTS radical 소거 활성을 측정하였 다. 열처리 후 야콘의 갈변도, 유리형 폴리페놀 및 플라보노이드 함량과 항산화 활성은 열처리 온도와 시간에 따라 유의적(p<0.05)으로 증가하였고, 결합형 폴리페놀 및 플라보노이드 함량은 감소하였다. 야콘의 유리형 폴리페놀 및 플라보노이드 함량은 121℃, 60분 열처리 시 생야콘에 비해 각각 1.2배 및 1.1배로 유의적(p<0.05)으로 증가하였다. 또한, 야콘의 DPPH radical 소거 활성 및 ABTS Radical 소거 활성도 121℃, 60분 열처리 시 생야콘에 비해 각각 1.7배 및 2.0배로 유의적(p<0.05)으로 증가였다. 야콘의 갈변도, 폴리페놀 및 플라보노이드 함량과 DPPH radical 및 ABTS radical 소거 활성 간의 상관관계를 분석한 결과, 높은 상관관계(p<0.01)가 있는 것으로 나타났다. 본 연구결과, 열처리 방법을 통해 야콘의 항산화 성분과 항산화 활성을 강화시킬 수 있으며, 이를 활용한 기능성 식품 소재 개발이 가능할 것으로 생각된다.

This study was carried to investigate the antidiabetic effect of ethanol extract of Smallanthus sonchifolius(S.S) in Streptozotocin(STZ)- induced diabetic rats. Diabetes was induced by intravenous injection of STZ at a dose of 43mg/kg dissolved in citrate buffer. The ethanol extract of S,S in leaves and root were orally administrated once a day for 7 days at a dose of 1,000mg/kg. The contents of serum glucose, triglyceride(TG), total cholesterol were significantly decreased in S.S treated group compared to the those of STZ-control group. The content of hepatic glycogen and activity of glucokinase(GK) were significantly increased,and activity of glucose-6-phoshatase(G-6-Pase) was significantly decreased in S.S treated group compared to the those of STZ-control group, but activity of glucose-6-phosphate dehydrogenase(G-6-PDH) was not significantly increased, These results indicated that ethanol extract of S.S would have antidiabetic effect in STZ-induced diabetic rats.

In this study, the effects of yacon (Smallanthus sonchifolius) leaf on the quality characteristics of cookies were examined. In order to investigate its effects, four different amounts (0%: Control, Y-0.5, Y-1.0, Y-1.5) of yacon leaf powder were added to the cookie dough. Among the physicochemical and sensory characteristics, the density and pH of the dough, spread factor, color value, firmness, consumer acceptability, and Pearson's correlation coefficients were measured. Although there was no significant difference in pH of the doughs among the groups, density significantly decreased with increasing amount of yacon leaf powder (p<0.05). While the L, a, b values, and hardness decreased significantly, DPPH free radical scavenging activity increased significantly as the content of yacon leaf powder increased (p<0.05). Overall acceptability, appearance, taste, and texture between the control and Y-0.5 groups showed no significant differences. This study suggests the possibility of yacon leaf as an ingredient that increases the functionality of cookies.

This study was conducted with the aim of evaluating the antibiotic effects of leaves, stems, and roots in yacon (Smallanthus sonchifolius). Antibacterial activity of leaf extract by disk diffusion method with Bacillus subtilis and Escherichia coli respectively showed 13.3 and 13.75mm diameters of clear zone. There was no significant difference between the stems and leaves. The minimum inhibitory concentration of leaves’ heating and agitation extraction showed a restrain of strain at 1mg/ml, but the stems and root extract did not appear. Yacon is a functional antibacterial material, and methanol extraction is more effective than water. This research was to investigate the growth stage of collection has the most effective antibacterial effects. It has collected yacon's leaves from June to October, which is an appropriate time for collection right before reaping. Yacon leaf has antibacterial effects on Bacillus subtilis, Escherichia coli, Enterococcus faecium, and Salmonella enteritifis. There were no significant differences by the growth stage of collection. Leaves collected in July are high in phenol which helps in sulfating activity works well considering the high scavenging capability of DPPH. Leaves collected in September are high in total flavonoid.

The purpose of this research was to find the most appropriate process for making yacon leaf tea. We applied both green tea and black tea brewing and fermenting methods for producing yacon leaf tea. This research included consumer test and descriptive analysis of professional trained panel on yacon tea tastes and flavors. Both consumer test and descriptive evaluation preferred yacon tea produced by black tea brewing and fermenting methods because it tasted less bitter and had a sweet, delicate taste. According to orthogonal transformation resulting from varimax rotation, first principal component was positively affected by black tea brewing and fermenting methods, while it was negatively affected by green tea brewing and fermenting methods. As a result, the study concluded black tea brewing and fermenting methods were appropriate for producing yacon leaf tea.