That seems a bit odd to me. You already have a hash, so why not work with that directly instead of putting its contents into independent variables.

However, this code:

foreach my ($blastresult, $value) {$_ = $$self{_$_};}
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is not doing what you think it does. It is just looping over the two values.

my $blastresult = "foo";
my $value       = "bar";
foreach my ($blastresult, $value) {print;}
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prints "foobar". What you want would be more along the lines of

use strict;
use warnings;

my $foo;
my $bar;
my %hash = ("_foo" => "FOO", "_bar" => "BAR");

foreach my $varname (keys %hash)
{
    eval "\$" . substr($varname,1) . " = '" . $hash{$varname} . "';";
}

print "$foo\n$bar";
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