Thermal behavior of different cocoa powder varieties and their physicochemical, phytochemical and microbiological characteristics

• Published in: Journal of thermal analysis and calorimetry Vol. 143; no. 6; pp. 4217 - 4228
• Main Authors: Dippong, Thomas, Mihali, Cristina, Vosgan, Zorica, Daniel, Andrada, Dumuta, Anca
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01.03.2021; Springer; Springer Nature B.V
• Subjects: Amino acids; Analysis; Analytical Chemistry; Caffeine; Chemistry; Chemistry and Materials Science; Cocoa; Decomposition; Differential thermal analysis; High performance liquid chromatography; Inorganic Chemistry; Lipids; Mass spectrometry; Measurement Science and Instrumentation; Microbiology; Phase transitions; Phenolphthalein; Physical Chemistry; Phytochemicals; Polymer Sciences; Polyphenols; Polysaccharides; Thermal transformations; Thermodynamic properties; Water loss; Polyphenols; Cocoa powder; Microbiological analysis; HPLC; TG–DTA-MS
• ISSN: 1388-6150; 1588-2926
• DOI: 10.1007/s10973-021-10559-y

Four cocoa powder varieties processed in different European countries (Germany, Poland, Romania and Bulgaria) were subjected to physicochemical, phytochemical and microbiological analysis. The cocoa powders were extensively characterized by recording their pH and titratable acidity, respectively, the polyphenols and also the methylxantine derivatives content (theobromine and caffeine). The cocoa powders pH ranged between 5.37 and 8.23, while the titratable acidity was 3.2–4.3 miliequivalent (100 g) −1 of cocoa powder. Their total polyphenols content ranged between 0.986 ÷ 2.003 g GAE/(100 g) −1 . The methylxanthine derivatives (theobromine and caffeine) were analyzed by the HPLC method and ranges of 0.992–1.174% for theobromine and 0.096–0.369% for caffeine were obtained. Thermal analysis (TG–DTA) combined with mass spectrometry (MS) elucidated the decomposition processes and the volatile substances (CO, CO 2 , H 2 O, NO, theobromine, caffeine). The thermal analysis revealed transformations in the cocoa powders composition: drying and water loss; decomposition of pectic polysaccharides; lipids, amino acids and proteins, crystalline phase transformations and carbonizations. The microbiological analysis tested the degree of preservation of the cocoa powders across time, specifically immediately after unwrapping and after 14 days.