Rapid ¹³C Solid-State Quantitative NMR Method for Multiple Physical and Chemical Analyses of Cocoa-Based Products:...

Chocolates and other cocoa products represent a multibillion-dollar industry that has faced significant price increases, largely due to a surge in cocoa plant diseases linked to climate change. One potential solution for mitigating cocoa prices involves the use of cocoa butter equivalents, substitutes, or replacers. Consequently, a rapid method for simultaneously determining multiple properties of cocoa derivatives can serve as a valuable tool for research and development of new products, quality control, and regulatory agencies to ensure compliance with cocoa product standards. In this context, a rapid quantitative ¹³C solid-state NMR (¹³C qSS-NMR) approach has been developed to assess various physical and chemical properties of cocoa products in a single measurement. In this study, ¹³C qSS-NMR spectra were obtained by directly exciting the ¹³C transitions using 90° or low-flip-angle pulses, along with high-power decoupling and 3 kHz magic-angle sample spinning (MAS). The areas and chemical shifts of the signals at approximately 34.5 and 30 ppm, assigned to the solid and liquid phases of triacylglycerides (TAGs), were utilized to determine the solid fat content (SFC) and the polymorphic forms of TAGs. Additionally, the sucrose content in chocolates was estimated by the ratio of the sucrose signals between 103 and 82 ppm and the TAGs signals. The SFC values were consistent with those obtained by standard methods. The ¹³C SS-NMR approach also holds promise for measuring other cocoa product properties, such as isothermal crystallization, and it can be applied to assess similar properties in other fat-based food products.