利用低场核磁共振技术研究山楂酒发酵过程中水分的变化规律

Moisture variation in hawthorn wine fermentation process by low-field nuclear magnetic resonance

运用低场核磁共振（LF-NMR）技术研究山楂酒发酵过程中水分的变化规律，选用弛豫时间编辑（CPMG）脉冲序列测定样品在不同发酵时间的横向弛豫时间T2，并通过T2反演数据的拟合结果得出自由水和结合水的变化趋势。结果表明，在发酵0～12d时，样品中半结合水百分含量逐渐降低为0，自由水百分含量增加2．47％，结合水百分含量不变；发酵12d后，自由水百分含量开始缓慢降低，结合水百分含量逐渐增加；发酵结束后，结合水百分含量增加了17．59％，半结合水降低为0，自由水百分含量增加了2．31％。

Moisture variation in hawthorn wine during fermentation process was studied with low-field nuclear magnetic resonance. Transverse relax- ation time T2 of samples at different fermentation stages was determined with Carr-Purcell-Meiboom-Gill pulse sequence. Furthermore, the changing trends office water and bound water were concluded by fitting T2 inversion data. The results showed that the percentage content of semi-bound water in the samples gradually reduced to 0, free water percentage content increased 2.47%, and hound water percentage content remained constant in 0-12 d. After 12 d, percentage content of free water decreased slowly, percentage content of bound water increased gradually. After fermentation, the per- centage comcnt of bound water increased 17.59%, semi-bound water reduced to 0, and free water increased by 2.31%.