Microscopy and calorimetry as complementary techniques to analyze sugar crystallization from amorphous systems.

Area of Science:

• Materials Science
• Physical Chemistry
• Food Science

Background:

• Understanding sugar crystallization kinetics is crucial for food stability and processing.
• Amorphous sugars are prone to crystallization, impacting product texture and shelf-life.
• Microscopic and macroscopic techniques offer different perspectives on crystallization processes.

Purpose of the Study:

• To compare polarized light video microscopy (PLV) and differential scanning calorimetry (DSC) for evaluating sugar crystallization kinetics.
• To investigate the impact of trehalose on lactose crystallization kinetics.
• To explore the complementary nature of PLV and DSC in analyzing amorphous sugar systems.

Main Methods:

• Amorphous lactose and lactose-trehalose mixtures were studied.
• Crystallization kinetics, induction times, and complete crystallization times were measured using PLV and DSC.
• Storage temperatures ranged from 60-95°C.
• Glass transition temperature (T(ag)) was measured by DSC.

Main Results:

• PLV provided real-time, in-situ observation of crystal growth and morphology.
• Both PLV and DSC showed similar temperature dependencies for lactose crystallization rate and completion time.
• Trehalose addition delayed lactose crystallization without altering the glass transition temperature (T(ag)).

Conclusions:

• PLV and DSC are complementary techniques for analyzing sugar crystallization in amorphous systems.
• PLV offers microstructural details not detectable by DSC.
• Validation of PLV results with DSC opens new avenues for microstructural analysis of crystallizing systems.