Comparative Evaluation of Crystallization Behavior of C15:0 and C17:0 Triglycerides Versus Tripalmitin

ABSTRACT Odd‐chain fatty acids (OCFAs), notably pentadecanoic acid (C15:0) and heptadecanoic acid (C17:0), were increasingly recognized for their potential biological and nutritional benefits. However, their crystallization behavior in triglycerides (TAGs) remained less understood compared to even‐chain counterparts. This study investigated the crystallization properties of C15:0 and C17:0 TAGs and compared them with tripalmitin (PPP), a well‐characterized even‐chain TAG. The crystallization behavior, polymorphism, melting characteristics, crystallization kinetics, and crystal morphology of these TAGs were evaluated under varying cooling and heating rates. Similar to PPP, cooling rate was found to influence both crystallization and melting characteristics of odd ones, with faster cooling rates generally leading to lower crystallization temperatures. Anyhow, crystallization rates were primarily influenced by chain length, with longer carbon chains leading to faster crystallization, irrespective of odd or even. Still, odd‐chain TAGs displayed distinct crystal transformation behavior during the melting and polymorph transitions compared to PPP. Specifically, although PPP underwent transitions through multiple polymorphs (α, β′, β), C15‐TAG and C17‐TAG primarily showed α‐to‐β transitions. The results indicated that the introduction of OCFAs led to a decrease in thermal stability. The offset temperature of C17:0 TAG is lower than that of PPP, which were 70.12°C and 68.77°C at a heating rate of 5°C/min, respectively. These findings highlighted the influence of chain length and cooling rate on crystallization dynamics, suggesting that odd‐chain TAGs may offer unique functional properties in food and pharmaceutical applications. Practical applications : Odd‐chain fatty acids (OCFAs) received increasing attention for their biological functions. These new discoveries have provided a fresh perspective on the future development of their applications in food, pharmaceutical, and other systems. The understanding of their basic properties will help us understand their functions in cell membranes or their application systems.