DEVELOPMENT OF VOLATILE AROMA COMPOUNDS IN ARCTIC BRAMBLE, Rubus arcticus L.

The formation of volatile aroma compounds of a wild strain cultivated arctic bramble, Rubus arcticus L. was studied during the ripening of the berries in the field. The amount of 2,5‐dimethyl‐4‐methoxy‐2,3‐dihydro‐3‐furanone, which is the most important aroma compound for the berry, increased from 0.2 up to over 20% of the volatiles. The total content of the most appreciable groups, alcohols, acids and esters, varied between 35–66%. The amount of the acids studied, acetic, 3‐methyl‐2‐butenoic, 2‐methylpropanoic, 3‐methylbutanoic and 3‐methyl‐3‐butenoic, increased up to ca 5% during the ripening. The relative amounts of 2‐heptanol, benzylalcohol, cis‐3‐hexen‐1‐ol, 2‐phenyl‐ethanol, 1‐butanol and 1‐hexanol decreased from unripe to over‐ripe samples, whereas tram‐3‐penten‐1‐ol, 3‐methyl‐2‐buten‐1‐ol, linalool, ethanol, α‐terpineol and geraniol increased up to the ripe stage and began to decrease after that. The esters, ethyl acetate, methyl pyruvate, 2‐methyl‐2‐butenyl acetate, benzyl acetate and cis‐3‐hexenyl acetate followed mainly the same pattern as the alcohols mentioned last. The three carbonyl compounds measured were acetone, 2‐heptanone and 2‐methyl‐2‐butenal, of which the last mentioned showed extremely rapid increase until the berries were ripe. The content of acetoin increased drastically during the ripening of the fruit.