Transfer kinetics of labeled aroma compounds from liquid media into coffee beans during simulated wet processing conditions

• Published in: Food chemistry 2020-08, Vol.322, p.126779-126779, Article 126779
• Main Authors: Hadj Salem, F., Lebrun, M., Mestres, C., Sieczkowski, N., Boulanger, R., Collignan, A.
• Format: Article
• Language: English
• Subjects: Aroma compounds; Coffee fermentation; Kinetics; Life Sciences; Parchment resistance; Transfer
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2020.126779

•Aromatic compounds could be transferred into coffee beans during fermentation.•The coffee bean parchment acts as a molecular sieve.•Some transferred volatiles underwent degradation reaction in coffee beans.•Interaction between the yeast cell wall and volatiles impact their transfer rate. The transfer kinetics of three labelled compounds (butanal, 2-phenyethanol, isoamyl acetate) was studied from a liquid medium into the coffee beans during simulated wet processing using four media (M) (M1: contained dehulled beans, M2: contained demucilaginated beans, M3: contained depulped beans, M4: contained depulped beans with yeast). Trials were carried out at 25 °C, under agitation and for five time periods (0, 6, 12, 24 and 48 h), and then the labelled volatiles were analyzed by SPME-GC–MS. The three labelled molecules were transferred into the coffee beans with different mass transfer rates; reaching at 12hrs in the M4, 0.2 ± 0.03, 11.2 ± 0.66 and 1.3 ± 0.04 µg/g of coffee respectively for butanal, 2-phenyethanol and isoamyl acetate. The parchment resistance significantly affected the mass transfer of the 2-phenylethanol. Butanal and isoamyl acetate underwent metabolic reactions, which decreased their amount in the coffee beans. Furthermore, an interaction between molecules and the yeast was observed and decreased significantly the butanal’s transfer.