> I have a few general questions for anyone.  I know cooking food kills enzymes,
> but what about freezing foods?  Like having an occassional frozen banana or
> frozen grapes for dessert.  If freezing simply diminishes the enzyme content,
> is it significant, or does it vary per food/time frozen/temp?

I have no sspecific answer about enzymes in bananas, but generally, enzyme activity is
decreased by freezing and thawing, but the effects of freezing and thawing
depend on the enzyme.

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Pearce RE, et al., Effects of freezing, thawing, and storing human liver
microsomes on cytochrome P450 activity, Arch Biochem Biophys. 1996 Jul 15;
331(2): 145-169.

Microsomes from five human livers were
prepared from fresh (unfrozen) tissue and from tissue that was stored frozen
at -80 degrees C for 1, 2, 4, or 6 months. The apparent concentration of
cytochromes P450 and b5 and the activity of NADPH-cytochrome c
reductase decreased 20-40% as a result of freezing the liver, regardless of
whether the liver was stored for 1 or 6 months.
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El-Badawi AA, Hamm R, Influence of temperature and rate of freezing of bovine
muscle on the subcellular distribution of some mitochondrial enzyme, Z Lebensm
Unters Forsch. 1976 Nov 24; 162(3): 217-226.

Samples of bovine muscle were frozen at -5 degrees, -10 degrees, -20
degrees, -40 degrees, -60 degrees, -80 degrees, and -196 degrees C at
slow (about 1 degrees/10 min) and high freezing rate (maximum 1
degrres/0.05 min) and subsequently thawed at room temerature. The
changes in the extractable activity ("total activity") of the enzymes
aconitase (AC), fumarase (FU) succine dehydrogenase (SDH), glutamic
oxaloacetic transaminase (GOT), the mitochondrial isozyme of the COT
(GOTM) and glutamate pyruvate transaminase (GPT) by freezing and
thawing were studied. Neither the temperature nor the rate of freezing
influenced the total activity of these enzymes.