Chemical Composition, Aroma Evaluation, and Oxygen Radical Absorbance Capacity of Volatile Oil Extracted from Brassica rapa cv. “Yukina” Used in Japanese Traditional Food

from plants and are an important class of odor-active compounds, owing to their extremely low odor threshold.Depending on concentration, some of these volatiles can be responsible for off-flavors.In strawberry samples analyzed using a pulsed flame photometric detector (PFPD) , VSCs included methyl thiopropionate, ethyl thiobutanoate, methyl thiohexanoate, methyl (methylthio) acetate, ethyl (methylthio) acetate, methyl 2-(methylthio) butyrate, methyl 3-(methylthio) propionate, ethyl 3-(methylthio) propionate, and methyl thiooctanoate 8) .Accordingly, VSCs in B. rapa cv.yukina were also evaluated using a PFPD.In flavor analysis, gas chromatography-olfactometry (GC-O) is the most used method for evaluation of odorants;in particular, GC-O including aroma extract dilution analysis (AEDA) has been used for estimating the contribution of the most odor active compounds.AEDA is a useful method for obtaining desirable results on odor active compounds through sniffing analysis.Volatile compounds can be ranked according to odor potency by sniffing serial dilu-: The chemical composition of the volatile oil extracted from the aerial parts of Brassica rapa cv."yukina" was analyzed using GC-MS, GC-PFPD, and GC-O.A total of 50 compounds were identified.The most prominent constituents were (E)-1,5-heptadiene (40.27%), 3-methyl-3-butenenitrile (25.97%) and 3-phenylpropanenitrile (12.41%).With regard to aroma compounds, 12 compounds were identified by GC-O analysis.The main aroma-active compounds were dimethyl tetrasulfide (sulphury-cabbage, FD = 64), 3-phenylpropanenitrile (nutty, FD = 64), 3-methylindole (pungent, FD = 64), and methional (potato, FD = 32).The antioxidant activity of the aroma-active compounds of the oil was determined using an oxygen radical absorbance capacity (ORAC) assay using fluorescein as the fluorescent probe.The ORAC values were found to be 785 ± 67 trolox equivalents (μmol TE/g) for B. rapa cv."yukina" oil.The results obtained showed that the volatile oil extracted from the aerial parts is a good dietary source of antioxidants.