Glucosinolates and myrosinase activity in red cabbage (Brassica oleracea L. var. Capitata f. rubra DC.) after various microwave treatments.
Level 5 - mechanism / opinion, no new human data
Bench/food chemistry experiment without human subjects
PubMed 15563214 · doi:10.1021/jf0493268
What was done
Researchers measured total and individual glucosinolate (GS) concentrations and residual myrosinase enzyme activity in red cabbage (*Brassica oleracea* L. var. *Capitata* f. *rubra* DC.) subjected to various microwave cooking treatments differing in power and duration (including 180 W for 24 min, 540 W for 8 min, and 900 W for 4.8 min), comparing results against untreated raw cabbage.
What was found
Total glucosinolate levels remained high across all microwave conditions and frequently exceeded levels measured in untreated raw cabbage, correlating with total energy input (attributed to improved chemical extractability following heat treatment). Substantial myrosinase enzyme activity was retained after treatment at 180 W for 24 min and 540 W for 8 min, but was completely abolished after 4.8 min at 900 W (259.2 kJ energy input). Exact numerical glucosinolate concentrations or retention percentages were not reported in the abstract.
Why it matters
Selecting intermediate or low-power microwave settings allows retention of both glucosinolates and active myrosinase in red cabbage, which is necessary for the conversion of glucosinolates into bioactive isothiocyanates.
Limits
The abstract reports no sample replicate numbers, baseline glucosinolate concentrations, or quantitative myrosinase activity values. As an in vitro food chemistry investigation, it did not evaluate actual bioavailability, isothiocyanate formation in vivo, or human health outcomes.
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