"Vox Humana" > wrote in message >.. .

>
> Do you think that the whipped cream will be as stabile as the egg white
> foam?

It will not be, but the purpose of adding whipping cream in such
refrigerated desserts is to modify the texture of the mass....It will
bring body just as any added fatty material will do to the food
texture; and so will improve the eating quality.
The egg whites perform a different function and it is important in
chiffon pie for the structural reason.
The type of pumpkin pie that the poster is using is probably the
refrigerated type as the baked type of the same pie does not need it(
or can benefit from its addition).
Roy