Decoding Internal Defects in Taurine through DSC Thermodynamic Signatures: A Roadmap for Defect Minimization via Crystallization Process Parameters

Taurine is widely utilized in the food, pharmaceutical, and feed industries; however, the defects formed during the industrial crystallization of taurine result in internal moisture retention, which affects product quality and stability. While qualitative characterization methods are available, a standardized quantitative approach remains lacking. This study introduces a differential scanning calorimetry (DSC)-based method for quantifying total moisture content in taurine crystals. Gradient crystallization experiments (80–15 °C, cooling rate: 20–60 K/h, stirring speed: 150–450 rpm) were conducted, integrating thermal analysis with microscopy. Results indicate that larger crystals (≤20 mesh) exhibit significantly higher defect levels than smaller ones (30–40 mesh), with internal defect content approximately 15.6 times greater, as determined by DSC enthalpy measurements (7.4701 vs 0.4778 W/g). Furthermore, crystal agglomeration mitigates defect formation; for crystals of the same size (20–30 mesh), agglomerated forms such as trimers contain 50% fewer defects than single crystals (1.619 vs 3.2395 W/g). Higher crystallization temperatures promote molecular disorder, increasing defects, while a critical cooling rate maximizes defect formation. Stirring enhances mass transfer, reducing defects and shifting this critical cooling rate. This study provides theoretical insights into optimizing taurine crystallization and establishes the first quantitative method for evaluating taurine crystal defects.