Abstract:The effect of different microwave-drying methods on the quality and volatile substances of wild Capsella bursa-pastoris (L.). Different microwave powers (120, 240, 360, 480, 600, and 700 W) were applied to dry the samples of wild Capsella bursa-pastoris (L.) and a combination of head space-solid phase micro-extraction and gas chromatography (HS-SPME-GC-MS) was used to analyze the volatile substances in the dried samples. The results showed that microwave drying extensively decreased the content of characteristic alcohols such as cis-3-hexen-1-ol, trans-2-hexene-1-alcohol, and 2,6-dimethyl cyclohexanol. The types and content of aldehydes slightly decreased, whereas the content of isovaleraldehyde, (E)-2-pentenal, n-octylaldehyde, and phenylacetaldehyde increased. The content of isoamyl nitrite and 2-methyl-ethylvalerate also increased. Acids such as 3-methylbutanoic acid, 2-methylbutanoic acid, and caproic acid were generated, whereas styrene, cyclotetradecane, and other hydrocarbons disappeared during the microwave-drying process. The results showed that good sensory quality of dried Capsella bursa-pastoris (L.) can be obtained with microwave-drying at 480 W, wherein retention rates of chlorophyll and Vc reached 67.14% and 71.20%, respectively. Volatile components comprised a majority of aromatic compounds. Retention rate of volatile substances was 93.68%, where those of alcohols and aldehydes were relatively high, with β-ionone retention rate reaching as high as 84.21%.
