| Headspace samples revealed that potent odorants of raw spinach are (Z)-3-hexenal, methanethiol, (Z)-1,5-octadien-3-one, dimethyl trisulphide, octanal, 2-isopropyl- and 2-sec-butyl-3-methoxypyrazine. Boiled spinach contained dimethyl sulphide, methanethiol, dimethyl trisulphide, methional and 2-acetyl-1-pyrroline as the most important odorants. After drying and storage of raw spinach, methylpropanal, 2- and 3-methylbutanal and propanal were identified as the odorants with higher odour activity values. (Z)-1,5-octadien-3-one and methional, in a concentration ratio of about 1 : 100, are responsible for the fishy off-flavour of dry spinach stored at lower temperatures under nitrogen. A hay-like flavour was caused by oxidative degradation of furan fatty acids, yielding 3-methyl-2,4-nonanedione. \\ | Headspace samples revealed that potent odorants of raw spinach are (Z)-3-hexenal, methanethiol, (Z)-1,5-octadien-3-one, dimethyl trisulphide, octanal, 2-isopropyl- and 2-sec-butyl-3-methoxypyrazine. Boiled spinach contained dimethyl sulphide, methanethiol, dimethyl trisulphide, methional and 2-acetyl-1-pyrroline as the most important odorants. After drying and storage of raw spinach, methylpropanal, 2- and 3-methylbutanal and propanal were identified as the odorants with higher odour activity values. (Z)-1,5-octadien-3-one and methional, in a concentration ratio of about 1 : 100, are responsible for the fishy off-flavour of dry spinach stored at lower temperatures under nitrogen. A hay-like flavour was caused by oxidative degradation of furan fatty acids, yielding 3-methyl-2,4-nonanedione. \\ |
| An SDE extract of blanched spinach leaves showed green notes reminiscent of slightly cooked vegetables, notes of tobacco, violet leaves and oolong tea. The classical compounds exhibiting green notes (C6) like hexanal (0.9%), (E)-2-hexenal (37.3%), (E)-2-hexenol (35.6%), (Z)-3-hexenal (0.5%), (Z)-2-hexenal (1.3%), hexanal (2.2%), (E)-3-hexenol (0.4%), and (Z)-3-hexenol (3.0%) dominated. Some aldehydes like the (Z)-hexenals as well as octanal (0.3%), nonanal (0.2%), (E)-2-octenal (0.2%), (E)-2-decenal (0.4%), 2-undecenal (0.3%), (E,Z)-2,6-nonadienal (0.1%) and (E,Z)-decadienal were only present in this extract. A second extract collected after prolonged cooking time exhibited meaty, smoky, phenolic, typical spinach notes. Main components were also green (C6) compounds like (E)-2-hexenal (17.0%) and (E)-2-hexenol (30.6%), but there were more tenacious compounds present like (E)-3-methyl-2-nonen-4-one (//green, stalk, mushroom, sea, fatty, lovage//), (Z)-3-(3-hexenyloxy)-hexanal (//fatty, nutty, herbal, green//) and (E)-3-(2-hexenyloxy)-hexanal (//green, vegetable, green peas, fatty//). Both extracts contained benzaldehyde (0.5% and 1.0% resp.), β-cyclocitral (0.3% and 0.1% resp.), safranal (0.2% and 0.1% resp.), geosmin (0.1% both), β-ionone (0.4%, 0.5%), (E)-6-methyl-6-(5-methyl-2-furyl)-3-hepten-2-one (0.5% and 1.4%; //carrot, woody, orris, fruity, fresh//), epoxy-β-ionone (0.1%, 0.2%), 4-vinylguaiacol (0.4%, 6.7%), and phytol (1.8%, 13.0%). Several alkyl-3-thiophenecarbaldehydes were found as new natural products with interesting organoleptic properties. Some already known known trace compounds with strong flavour impact were 5-ethyl-1-cyclopentene-carbaldehyde, (E,E,E)-2,4,6-nonatrienal, (E,E)-2,4-nonadienal, (E)-2-nonenal, vanillin, 3-methyl-2,4-nonanedione, damascenone, (E,Z)-2,6-nonadienol, indole, and 2-methoxy-3(1-methylpropyl)-pyrazine. \\ | An SDE extract of blanched spinach leaves showed green notes reminiscent of slightly cooked vegetables, notes of tobacco, violet leaves and oolong tea. The classical compounds exhibiting green notes (C6) like hexanal (0.9%), (E)-2-hexenal (37.3%), (E)-2-hexenol (35.6%), (Z)-3-hexenal (0.5%), (Z)-2-hexenal (1.3%), hexanal (2.2%), (E)-3-hexenol (0.4%), and (Z)-3-hexenol (3.0%) dominated. Some aldehydes like the (Z)-hexenals as well as octanal (0.3%), nonanal (0.2%), (E)-2-octenal (0.2%), (E)-2-decenal (0.4%), 2-undecenal (0.3%), (E,Z)-2,6-nonadienal (0.1%) and (E,Z)-decadienal were only present in this extract. A second extract collected after prolonged cooking time exhibited meaty, smoky, phenolic, typical spinach notes. Main components were also green (C6) compounds like (E)-2-hexenal (17.0%) and (E)-2-hexenol (30.6%), but there were more tenacious compounds present like (E)-3-methyl-2-nonen-4-one (//green, stalk, mushroom, sea, fatty, lovage//), (Z)-3-(3-hexenyloxy)-hexanal (//fatty, nutty, herbal, green//) and (E)-3-(2-hexenyloxy)-hexanal (//green, vegetable, green peas, fatty//). Both extracts contained benzaldehyde (0.5% and 1.0% resp.), β-cyclocitral (0.3% and 0.1% resp.), safranal (0.2% and 0.1% resp.), geosmin (0.1% both), β-ionone (0.4%, 0.5%), (E)-6-methyl-6-(5-methyl-2-furyl)-3-hepten-2-one (0.5% and 1.4%; //carrot, woody, orris, fruity, fresh//), epoxy-β-ionone (0.1%, 0.2%), 4-vinylguaiacol (0.4%, 6.7%), and phytol (1.8%, 13.0%). Several alkyl-3-thiophenecarbaldehydes were found as new natural products with interesting organoleptic properties. Some already known known trace compounds with strong flavour impact were 5-ethyl-1-cyclopentene-carbaldehyde, (E,E,E)-2,4,6-nonatrienal, (E,E)-2,4-nonadienal, (E)-2-nonenal, vanillin, 3-methyl-2,4-nonanedione, damascenone, (E,Z)-2,6-nonadienol, indole, and 2-methoxy-3(1-methylpropyl)-pyrazine. \\ |
