Kahvin paahtoprofiilien vaikutus muodostuviin aromiyhdisteisiin sekä aistinvaraisiin ominaisuuksiin

Tiivistelmä – Referat – Abstract Coffee is a popular beverage, with a growing demand among consumers worldwide. Combining sensory data together with knowledge of impact of roast on aroma compound formation will aid in the development of coffee products in search of the desired coffee. The primary objective of this thesis was to evaluate the effect of different roast profiles, high temperature – short time (HTST), low temperature – long time (LTLT) and medium temperature – medium time (standard) on the sensory characteristics and volatile compounds of coffee blends and coffee of different origins and species. Five coffees (four arabica, one robusta) and two different coffee blends (arabica blend and robusta-arabica blends) were roasted light (L* =21) and dark (L*=17,5), using different roast profiles. Aroma compound analysis was performed with headspace solid-phase microextraction gas chromatography (HS-SPME-GC-MS) and the sensory analysis with quantitatie descriptive analysis (QDA) method and a professional panel. Emphasis was placed on comparing the impacts of roast profiles within specific origins. The study confirmed the identification of 50 compounds. The HTST roast notably enhanced the formation of sweet furfural and 5-methyl-2-furancarboxaldehyde, along with acidic acetic acid, resulting in a sensory profile characterized by fruity, sweet, acidic, and berry-like notes. Conversely, the LTLT roast produced coffee with bitter pyradines and nutty 2,2’-methylenebisfuran, presenting a more roasty, bitter profile with increased cocoa and nutty flavors. The effects were seen across coffee species and varieties. However, LTLT impact did not increase the bitterness of robusta roasts exceptionally, and arabica blends did not display consistent behavioral patterns across different roast profiles. The impact of HTST and LTLT profiles were expected excluding the LTLT impact on robusta roasts. Future roast profile studies should use a flavor dilution (FD) factor to understand how aroma compounds impact flavor independently of their relative quantity.