以核磁共振影像分析技術觀察貯存期間兩動物膠膠體之水分子狀態   全文下載

Water Status of Two Gelatin Gels during Storage as Determined by Magnetic Resonance Imaging

本研究建立以核磁共振影像（magnetic resonance imaging, MRI）分析技術探討兩塊不同水活性的動物膠膠體[Aw = 0.968 （H-gel） 及Aw = 0.828 （L-gel）]，於貯存期間，膠體間及膠體內之水分子移動狀態的非破壞性測試技術。膠體中之水分子以MSME脈衝序列測定其氫原子之弛緩時間（relaxation time, T2）。結果顯示，H-gel的平均T2值隨者貯存時間的增加而減小，而L-gel的平均T2值則隨者貯存時間的增加而增大；但貯存15天後，雖然兩膠體的Aw值已達相近，但L-gel的平均T2值遠大於H-gel的平均T2值，且兩膠體內各部位之T2值也不同。此乃由於貯存期間水分子由高Aw的膠體往低Aw的膠體移動，而膠體內的水分子也不斷地再移動。本研究所建立之兩膠體模式系統及MRI分析技術，可以以非破壞性的方式成功地觀察水分子於不同Aw的物質間之移動與分佈情形，同時也可用來評估複雜組成之系統，例如食品，於貯存期間之水分子狀態及結構變化。"

A two-gelatin-gel model system was used to investigate the water status of two gels with different Aw, 0.968 (H-gel) and 0.828 (Lgel), using magnetic resonance imaging (MRI) techniques. A multi slice-multi echo pulse sequence was applied and the transverse relaxation time (T2) of water protons was calculated. During storage the average T2 values of H-gel decreased, while those of L-gel increased. However, at the end of storage (15 days) when the Aw of two gels were the same, the average T2 values of L-gel were larger than those of H-gel, and heterogeneous T2 values were observed in both gels. This was due to water migration between the two gels and redistribution of water in each gel during storage. The two-gelatin-gel model system and nondestructive MRI technique established in this study offer a good method to monitor moisture redistribution between gels with different Aw and to investigate the water status and structural changes in food systems during storage. 本研究建立以核磁共振影像（magnetic resonance imaging, MRI）分析技術探討兩塊不同水活性的動物膠膠體[Aw = 0.968 （H-gel） 及Aw = 0.828 （L-gel）]，於貯存期間，膠體間及膠體內之水分子移動狀態的非破壞性測試技術。膠體中之水分子以MSME脈衝序列測定其氫原子之弛緩時間（relaxation time, T2）。結果顯示，H-gel的平均T2值隨者貯存時間的增加而減小，而L-gel的平均T2值則隨者貯存時間的增加而增大；但貯存15天後，雖然兩膠體的Aw值已達相近，但L-gel的平均T2值遠大於H-gel的平均T2值，且兩膠體內各部位之T2值也不同。此乃由於貯存期間水分子由高Aw的膠體往低Aw的膠體移動，而膠體內的水分子也不斷地再移動。本研究所建立之兩膠體模式系統及MRI分析技術，可以以非破壞性的方式成功地觀察水分子於不同Aw的物質間之移動與分佈情形，同時也可用來評估複雜組成之系統，例如食品，於貯存期間之水分子狀態及結構變化。