Off-flavor in milk from the cows feeded with swinecress (Coronopus didymus)

The effects of swinecress grass feeding on volatile constituents of cow milk were investigated. Volatiles from milk and swinecress grass were separated by simultaneous distillation-extraction under reduced pressure and analyzed by GC and GC-MS. Off-flavored milk indicated the higher concentrations in aldehydes, terpenes, hydrocarbons and miscellaneous volatiles including 6 sulfur containing compounds, on the contrary, the lower concentrations in fatty acids, ketones and lactones. It was supposed that the alteration of volatile composition was caused by the inhibitory actions of benzyl isothiocyanate on microbial and/or enzymatic activities in the rumen of cows. The isothiocyanate comprised 19% of total amount of volatiles from swinecress grass.