Unterschiede

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--- brassica_oleracea_capitata_group [2015/09/21 06:39] – angelegt andreas
+++ brassica_oleracea_capitata_group [2020/06/10 22:12] (aktuell) – andreas
@@ Zeile 4: / Zeile 4: @@
 B. oleracea L. var. capitata L. f. rubra (L.) Thell - red cabbage, **Rotkohl** \\
 B. oleracea L. var. sabauda L. - Savoy cabbage, **Wirsing**
 "Dimethyl trisulfide was identified as a major aroma component in cooked Brassicaceous vegetables. A mechanism for dimethyl trisulfide formation from precursors known to be present in cabbage is proposed. No evidence was found to indicate that new sulfur compounds develop as cooking time increases. It is proposed that the strong unpleasant aroma which is characteristic of overcooked Brassicaceous vegetables is due to the gradual loss of pleasant volatile components and resultant “unmasking” of the unpleasant sulfur components." \\
 [Identification of dimethyl trisulfide as a major aroma component of cooked brassicaceous vegetables., Maruyama, F.T., Journal of Food Science, 35(5), 1970, 540-543]
-"In cabbage, glucosinolates such as sinigrin are hydrolyzed by plant myrosinase to allyl isothiocyanate (AITC), allyl cyanide, and, in the presence of an epithiospecifier protein, 1-cyano-2,3-epithiopropane (CEP). Isothiocyanates have been implicated in the cancer-protective effects of Brassica vegetables. The effect of processing on the hydrolysis of glucosinolates was investigated in cabbage. Cabbage was steamed or microwaved for six time durations over 7 min. Glucosinolate concentrations were slightly reduced after microwave cooking (
+Alkenyl glucosinolates like sinigrin are enzymatically degraded forming nitriles or isothiocyanates, but in the presence of epithiospecifier protein (ESP), epithionitriles are released. Not allyl isothiocyanate (AITC), but 1-cyano-2,3-epithiopropane (CEP) was the primary volatile in all dichlormethane extracts of white cabbage (six cultivars). \\
-P < 0.001) but were not influenced after steaming (P < 0.05). Myrosinase activity was effectively lost after 2 min of microwave cooking and after 7 min of steaming. Hydrolysis of residual glucosinolates following cooking yielded predominantly CEP at short cooking durations and AITC at longer durations until myrosinase activity
+[Kyung, K. H., et al. "1‐Cyano‐2,3‐epithiopropane as the primary sinigrin hydrolysis product of fresh cabbage." Journal of food science 60.1 (1995): 157-159]
+[[https://fbns.ncsu.edu/USDAARS/Acrobatpubs/P221-253/p251.pdf]]
+"In cabbage, glucosinolates such as sinigrin are hydrolyzed by plant myrosinase to allyl isothiocyanate (AITC), allyl cyanide, and, in the presence of an epithiospecifier protein, 1-cyano-2,3-epithiopropane (CEP). Isothiocyanates have been implicated in the cancer-protective effects of Brassica vegetables. The effect of processing on the hydrolysis of glucosinolates was investigated in cabbage. Cabbage was steamed or microwaved for six time durations over 7 min. Glucosinolate concentrations were slightly reduced after microwave cooking (P < 0.001) but were not influenced after steaming (P < 0.05). Myrosinase activity was effectively lost after 2 min of microwave cooking and after 7 min of steaming. Hydrolysis of residual glucosinolates following cooking yielded predominantly CEP at short cooking durations and AITC at longer durations until myrosinase activity
 was lost. Lightly cooked cabbage produced the highest yield of AITC on hydrolysis in vitro, suggesting that cooking Brassica vegetables for a relatively short duration may be desirable from a health perspective." \\
 [Changes in glucosinolate concentrations, myrosinase activity, and production of metabolites of glucosinolates in cabbage (Brassica oleracea var. capitata) cooked for different durations., Rungapamestry, V., Duncan, A.J., Fuller, Z., Ratcliffe, B., Journal of agricultural and food chemistry, 54(20), 2006, 7628-7634]
+{{:allylitc.jpg|allyl isothiocyanate}} allyl isothiocyanate
+"From the sensory test results, freshly shredded cabbage and low pH (pH 3.3 and 4.6) samples had significantly less off odor, lower total aroma intensity and higher fresh aroma than high pH (pH 6.4 and 7.4) samples. In the SIFT-MS results, the desirable cabbage odor, allyl isothiocyanate, formation was higher in lower pH samples, than higher pH samples. Off odors (dimethyl sulfide, dimethyl disulfide, dimethyl trisulfide and methyl mercaptan) were formed in lower concentrations in low pH samples than high pH samples. Low pH samples formed less undesirable and more desirable volatile compounds overall. Higher concentrations of all volatile compounds
+were formed at 25 °C than 4 °C except from allyl isothiocyanate. Allyl isothiocyanate concentration was higher at 25 °C only on day 0, after that, there was a rapid decrease during the storage and it was higher in 4 °C samples. The degradation of the compound at 4 °C was slower when compared to 25 °C; therefore, characteristic fresh cabbage aroma was maintained better at lower temperature. High temperature is not suitable for cabbage
+storage, since undesirable aroma compound formation is high, loss of desirable aroma occurs rapidly, and microbial growth occurs at very early stage of storage." \\
+[Akpolat, H., & Barringer, S. A. (2015). The effect of pH and temperature on cabbage volatiles during storage. Journal of food science, 80(8), S1878-S1884]