Antioxidant Activities and Taste Qualities of Fresh Onions Produced in Minamishimabara City, Nagasaki, Japan

抄録

In this study, we investigated the antioxidant activities and taste qualities of fresh onions produced in the Minamishimabara city, Nagasaki, Japan. Samples were ‘Super-Up’ (SU), a conventional cultivar, and ‘Kazusa No. 13’ (K13), a new cultivar, and these were compared with ‘Shippowase No. 7’ (S7), a general-use cultivar. The total oxygen radical absorbance capacity of K13 was higher than that of S7. The 1, 1-diphenyl- 2-picrylhydrazyl free radical-scavenging activity and the total quercetin concentration were higher in SU and K13 than in S7. Umami and saltiness values (determined using the Taste Sensing System) and total free amino acid concentrations in SU and K13 were lower than those in S7, with the differences in total free amino acid concentration contributing to the difference in taste responses between the onion cultivars. Total sugar concentration in SU was lower than in S7. These results suggest that the advantages of SU and K13 were in terms of high levels of antioxidant activity and quercetin concentration, rather than in terms of taste or flavor. Thus, onions of cultivars SU and K13 are expected to be new regional brand foods of Nagasaki, targeted at health-conscious consumers.