Glass transition and caking of spray‐dried lactose
Glass transition and caking of spray‐dried lactose
复制标题
喷雾干燥乳糖的玻璃化转变和结块
DOI：
10.1046/j.1365-2621.1996.00352.x
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发表时间：
1996
影响因子：
3.3
通讯作者：
Jim B. Hargreaves
中科院分区：
文献类型：
--
作者：
R. Lloyd;X. D. Chen;Jim B. Hargreaves
简单的测试方法来确定喷雾干燥的无定形乳糖的粘流和结块的起始温度。在特定温度下孵育3小时后，将粘性流动的程度测量为圆柱形铝压实装置内乳糖塞密度的增加。结块的特征在于所形成的乳糖塞的硬度增加。粘流的起始温度随水活度的增加而降低，A w，对应于玻璃化转变的起始温度，Tgl。使用差示扫描量热法（DSC）和核磁共振（NMR）自旋弛豫来确定玻璃化转变温度。结果表明，粉末温度高于T gl的升高促进粘性流动，并增加了无定形食品粉末结块的可能性。
Simple test methods to determine the onset temperatures of viscous flow and caking of spray-dried amorphous lactose are described. The extent of viscous flow was measured as an increase in the density of lactose plugs within a cylindrical aluminium compaction apparatus after incubation for 3 h at a specified temperature. Caking was characterized by an increase in the hardness of the lactose plugs formed. The onset temperature of viscous flow decreased with increasing water activity, A w , and corresponded to the onset temperature of glass transition, T gl . Glass transition temperatures were determined using both differential scanning calorimetry (DSC) and nuclear magnetic resonance (NMR) spin relaxation. The results suggest that elevation of the powder temperature above T gl promotes viscous flow and increases the potential for caking of amorphous food powders.