Evaluation of the thermal stability of bioactive compounds in coffee beans and their fractions modified in the roasting process

• Published in: Food chemistry Vol. 387; p. 132888
• Main Authors: Grzelczyk, Joanna, Fiurasek, Petr, Kakkar, Ashok, Budryn, Grażyna
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01-09-2022
• Subjects: Caffeine; Coffea; Coffee; Hot Temperature; Plant Extracts; Pro-health; Properties; Seeds; Stability; Thermal analysis; Pro-health; Stability; Thermal analysis; Coffee; Properties
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2022.132888

•The main thermostable ingredient in coffee is caffeine (hydrated or anhydrous form).•Monoesters of caffeic and quinic acid had the highest antioxidant capacity (48–70%).•To preserve composition, the re-heat treatment of coffee should not exceed 130 °C.•Dark roasted coffee had lower levels of 5-hydroxymethylfurfural and acrylamide.
Coffee is used as flavor or health-promoting additive in thermally processed food. In this study, ground coffee and freeze-dried coffee extracts were evaluated in terms of their thermal stabilities, and for the first time heat resistance of fractions (mono-, dichlorogenic acids and caffeine) with different roasting levels was evaluated. It observed that the degradation of green coffee bean ingredients began at 150 °C, and for the re-heated light and dark roasted, in the range of 171–188 °C. The lyophilized extracts were more stable and their degradation began around 160 °C. However, with the re-treatment (cooking, baking, frying) of the coffee extract fractions, the degradation of the monochlorogenic acids commenced at 114 °C, while for dichlorogenics at 108 °C and caffeine at 146 °C. Monochlorogenic acids in Robusta coffee showed high antioxidant activity (55–70%) and the highest content of fiber (13–17%). Coffee could be used to fortify food.