Effect of cooking and industrial processing on Polyacetylenes from Parsnips.
9 Jun 2010
J. Valverde
Some late work carried out in Teagasc Ashtown Food Reseach Centre and National University of Galway on the effect of cooking on polyacetylene content in Parsnips has been recently published in the Journal of Agriculture and Food Chemistry (JAFC). The study was funded by the Department of Agriculture, Fisheries and Food under a FIRM measure.
The article studies in detail the effect of blanching (95 ± 3 °C) followed by sous vide (SV) processing (90 °C for 10 min) on levels of two polyacetylenes in parsnip disks (falcarinol and falcarindiol).
Levels of polyacetylenes were determined immediately after processing and during chill storage and compared with the effect of water immersion (WI) processing (70 °C for 2 min.).
Blanching had the greatest influence on the retention of polyacetylenes in sous vide processed parsnip disks resulting in significant decreases of 24.5 and 24% of falcarinol and falcarindiol (2) respectively (p < 0.05). Subsequent SV processing did not result in additional significant losses in polyacetylenes compared to blanched samples. Subsequent anaerobic storage of SV processed samples resulted in a significant decrease in falcarinol levels (p < 0.05) although no change in falcarindiol levels was observed (p > 0.05). Falcarinol levels in WI processed samples were significantly higher than in SV samples (p ≤ 0.05).
Falcarindiol was particularly susceptible to aerobic storage following WI processing with losses of up to 70% occurring after 5 days storage. Falcarinol type polyacetylene undergoes degradation such as oxidation, dehydrogenation when thermally treated forming oxidized form of Falcarinol type molecules, in this case falcarindione, dehydrofalcarinol, dehydrofalcarinone.
Thermal processing had a significant effect on instrumental color of parsnip samples compared to minimally process in both SV and WI processed samples resulting in parsnip disks becoming darker, yellower and browner following processing and storage.
For further details on this study please check:
Rawson, A.; Koidis, A.; Rai, D. K.; Tuohy, M.; Brunton, N., Influence of Sous Vide and Water Immersion Processing on Polyacetylene Content and Instrumental Color of Parsnip (Pastinaca sativa) Disks. Journal of Agricultural and Food Chemistry.
