Kinetic studies of microwave assisted extraction of functional compounds from cinnamon in the preparation of a coffee flavoring technique

Abstract Kinetic studies were investigated to evaluate the success of Natural Deep Eutectic Solvent-Citric Acid Sucrose (NADES-CAS) 1% as a green solvent in extracting functional compounds from cinnamon using Microwave-Assisted Extraction (MAE) to prepare liquid extracts for coffee bean flavoring techniques. It is a novel technique to enhance coffee quality with the aromatic and functional compounds of cinnamon. This research aims to investigate the kinetics of extracting Total Phenolic Content (TPC) and Proanthocyanidin (PA), as well as the immersion effect of their extract on green coffee beans (GCB). The Peleg model and a mechanistic model were compared for their performance in describing the profiles of TPC and PA 30 min during MAE at 80, 90, and 100 °C. The Peleg model suggests that MAE temperature affects extraction performance by increasing the maximum capacity ( $${C}_{e}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>C</mml:mi> <mml:mi>e</mml:mi> </mml:msub> </mml:math> ) for TPC extraction (4.730–6.547 mg/mL) and for PA (3.605–4.046 mg/mL). The mechanistic model illustrates the temperature's impact on the increase in distribution coefficient (H) for TPC (0.0238–0.0358 mg/mL) and for PA extraction (0.0175–0.0201 mg/mL). Both models perform well in predicting the extraction. The activation energies required to increase the $${C}_{e}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>C</mml:mi> <mml:mi>e</mml:mi> </mml:msub> </mml:math> -value extraction were 17.743 kJ/mol and 6.349 kJ/mol, while those for improving the H-value were 22.241 kJ/mol and 7.610 kJ/mol for TPC and PA, respectively. The bean's immersion in cinnamon extract successfully infuses TPC, PA content, and aromatic compounds into the GCB, as confirmed by spectroscopy and GC–MS analysis. It's essential as a reference for developing a coffee flavoring technique to enhance coffee bean quality.