Volatile flavour compounds in heated blackberry juices.

Volatile compounds were isolated from the blackberry juices of two wild varieties and one cultivated variety by simultaneous distillations/extractions. All extracts were freed from acids, fractionated, analysed by gas chromatography-mass spectrometry (GC-MS) and gas chromatography-infrared spectrometry (GC-IR) and sensorially assessed at the sniffing-port of the chromatograph. Alcohols, furans and aldehydes are the predominant chemical classes of all kinds of heated juices, the most abundant compound being 2-heptanol in the cultivated variety and furfural in the wild blackberry varieties. The addition of 50% (w/w) sugar during the heating treatment does not modify the odorous profile.