Analysis of Internal Moisture Change of Camphor Seeds during Drying by Low-Field NMR作者：Yan XUAN Yilong XIANG Jing YANG Buhong GAO Ying TANG Feng LIN来源：《农业生物技术（英文版）》2019年第04期
Abstract In this study， lowfield nuclear magnetic resonance （LFNMR） was used to collect the transverse relaxation signals of camphor seeds that had been dried at different temperatures and for different durations. The transverse relaxation time of the hydrogen nucleus was obtained by SIRT （Simultaneous Iterative Reconstruction Technique） inversion， and the correlation between the moisture content on dry basis and the amplitude of NMR signal of camphor seeds sampled at different drying stages was analyzed. The results showed that water existed in three main forms strongly bound water， weakly bound water and free water in camphor seeds. During the drying process， the peak position of strongly bound water remained unchanged， but the peak positions of weakly bound water and free water fluctuated. Drying rate increased with drying temperature increasing. In addition， there was a very significant linear relationship between the total NMR signal amplitude and moisture content on dry basis， and the correlation coefficient reached 0.984 4.
Key words Nuclear Magnetic Resonance （NMR）; Camphor seed; Water distribution; Relaxation time spectrum; Correlation
Camphor tree （Cinnamomum capmhora） is an evergreen broadleaved tree species belonging to the family Lauraceae. It has a dense crown， and thus is extensively used as ornamental， landscape， shade and shelter tree， and it is also widely grown in the south of the Yangtze River in China[1-4]. The strong aroma and volatile oils released by camphor trees have the functions of expelling insects and resisting corrosion. The roots， stems and fruits of camphor contain the active ingredient camphor oil[5-6]， while its leaves contain several volatile organic compounds such as camphene， αpinene， βpinene， cineole， linalool and safrole[7]. Camphor fruit has certain pharmacological effects such as relieving pain， alleviating diarrhea， lowering blood lipid and cholesterol levels. Camphor seed contains more than 55% fat and oil， and decanoic acid and lauric acid are the main fatty acids[8-9]. In recent years， owing to urbanization and afforestation， camphor trees have been cultivated in many areas， so there is an urgent need to determine the optimal conditions for drying and storage of camphor seeds.
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