I know this is old, but I wanted to add my $0.02 since this comes up on Google when you search for pasteurizing fruit for beer. My wife is gluten intolerant so I've had to play with non-traditional ingredients quite a bit. I've probably now made two dozen beers with raspberries, blackberries, or both raspberries and blackberries.
1) If you want a really fruity flavor, you need to add the fruit in the secondary. I don't want a really fruity flavor. I'm looking for more of a note, not the whole song. The quantity of fruit is as important as when you add the fruit. So I add my fruit at the end of the boil since I'm going for a specific flavor.
2) I have only played with raspberries and blackberries, so I don't know how other fruits react, but what I like to do is:
a) Freeze the fruit,
b) When I start the beer I pull the fruit out of the freezer and set it with my other ingredients,
c) I don't boil more than than 2 gal for a 5gal batch (I just don't have the equipment), so when the boil is done, I turn the stove off, and add some water to bring the temp down to 200*,
d) I add the fruit. If I only add a pound it brings the wort down to about 180*, which is on the high side but has been fine. If I add more than 1lb it brings the temp down more. I watch the temp to make sure I stay above 160*.
e) I keep the temp between 160-180* for 15min.
f) I then cool and pitch as normal.
I play with sorghum since I brew GF (sorghum makes cloudy beers). But, when I use just rice or do a non-GF brew, my beers come out crystal clear (no pectin haze).
For this past winter I made a (non-GF) milk stout with chocolate (powder and nibs) and 1lb of raspberries and 1lb of blackberries. It was fantastic.