Analysis of volatile compounds in cell-cultured coffee

Abstract

Increasing challenges in traditionally land-grown coffee production have driven the exploration of alternative solutions for coffee cultivation. Cell-cultured coffee can be identified as an emerging alternative for traditional land-grown coffee. Quality and consumer acceptance of coffee is highly influenced by coffee aroma. The aroma of coffee arises from a complex mixture of volatile compounds formed in coffee beans. Earlier studies have given insights on volatile compounds in roasted cell cultured coffee. There is still limited information available on the effect of storage conditions and epigenetic modifications on volatile profile of unroasted cell-cultured coffee and how comparable it is with volatile composition of unroasted land-grown coffee. To evaluate the sensory potential and technological feasibility to use it as a successful alternative, it is important to understand aroma forming precursors and volatile compounds of unroasted cell-cultured coffee. In this study, volatile compounds of unroasted cell-cultured coffee and land-grown green Coffea arabica beans were analyzed using headspace-solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS). The study focused on analysis of volatile compounds in cell-cultured coffee stored under different conditions, including refrigerated, frozen and freeze-dried, and analysis of volatile profiles of epigenetically modified cell-cultured coffee compared to land-grown green coffee. Differences in volatile compound profiles were observed indicating the influence of storage condition and epigenetic modification on volatile composition of unroasted cell-cultured coffee. Refrigerated samples showed more similar volatile profile to fresh samples but with relatively lower abundance of majority of volatile compounds. Freeze-dried samples showed comparatively higher preservation of volatile compounds but some volatile compounds were lost in frozen and freeze-dried samples. As the epigenetic modification, demethylation was applied on cell-cultured coffee. Modified cell-cultured coffee samples showed differences in volatile compound composition compared to control cell-cultured coffee samples. 1-Hexanol, 1-tetradecene, heptadecane, tridecanal, hexadecanal and octanoic acid which were present in modified cell-cultured coffee samples were absent in control cell-cultured coffee sample. Both land-grown green coffee samples and unroasted modified cell-cultured coffee samples contained hexanal, benzaldehyde, benzeneacetaldehyde, 1-pentanol, 1-hexanol and 2-penten-1-ol as common compounds but PCA indicated differences in their overall volatile composition. Except for 1-hexanol, all other common compounds were also present in control cell-cultured coffee samples.