Lack of nutrients in cooking water, high energetic
costs, high water consumption and recycling are some drawbacks
of vegetable blanching. Those disadvantages could be
bypassed using microwave blanching. Three blanching
methods (microwave, boiling water and steaming) were compared
in this study in order to determine their effects on some
functional properties of broccoli. In addition, the thermal damage
on broccoli colour was evaluated. The effectiveness of
each blanching process was performed measuring the lost of
peroxidase activity, that results more rapidly in microwaves
and steamtreatments (50 and 60 s respectively) than in boiling
water treatment (120 s). The colour indexes did not allow to
discriminate a significant difference among treatments. The
increase of treatment time caused a vitamin C decrease in
samples blanched by boiling water and steam; this trend was
not observed in microwaved samples. The phenols content did
not significantly vary depending both on type and on time of
treatment.