Put in an array what I have selected

If I check 2 fruits from the various options I have, for example banana and apple chek return this

foreach( $checkboxes as $check ) {
    echo $check;  print bananaapple
}

I need that before saving a database it must be like this --->    banana,apple   array?

global $wpdb; 

$wpdb->insert('data',array( 'fruit' => $check ));

If I put it like this it shows me only the last check marked,in this case show apple in db