ISHS Acta Horticulturae 517: XXV International Horticultural Congress, Part 7: Quality of Horticultural Products
CHARACTERIZATION OF INTERNAL QUALITY OF VEGETABLES BY HEADSPACE GASCHROMATOGRAPHY AND "ELECTRONIC NOSE" |
| Authors: | W.H. Schnitzler, S. Broda, R. Schaller, S. Zellner |
| Keywords: | Daucus carota L., carrot, electronic nose, headspace gaschromatography, internal quality, secundary substances, terpenes |
| Abstract:
The quality of vegetables is predominantly determined by weight, size, appearance, etc. for market criteria. There is little to no selection for nutri-tional or gustatory values. The special aroma of a vegetable is a reflexion of amount and composition of various components. Using the model of carrots, volatile substances mainly of the group of terpenes (Mono- and Sesquiterpenes) were analysed by headspace gaschromatography (HS-GC) and results compared with the spectrum obtained by "electronic nose" detection. Three distinctly different carrot varieties were uniformly cultivated in a field of the research station at the institute for vegetable science in Freising, Germany. The carrots were harvested full ripe, deep frozen and shortly before analysis shredded for 10 g samples each in 20 ml vials. The same material was used for HS-GC and chemosensory analysis by "e-nose" incubated for 45 min at 60°C to obtain a homogenous gas mixture of the volatiles. Both analytical methods are suitable to detect aroma relevant differences of the three carrot varieties and confirm earlier results by steam distillation and human sensory panel. While HS-GC detects quantitatively and qualitatively the single substances, the "e-nose" can only make a cumulative differentiation. But both methods supply comparable results for selection of the best and the least tasting carrot varieties. The "e-nose" is able to produce quicker analytical results but needs for interpretation some online training with standards. | |
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