Simple array_walk_recursive:

// var example
$myArray = Array(
  Array('keyA1' => '    textA1 ', 'keyA2' => '  textA2     '),
  Array('keyB1' => '    textB1 ', 'sub' => 
        Array('keyB1_sub1' => '      textB1_sub1   '),
          Array('keyB1_sub2' => '      textB1_sub2   ')
      ),
  Array('keyC1' => '    textC1 ', 'keyC2' => '  textC2     '),
  Array('keyD1' => '    textD1 ', 'keyD2' => '  textD2     '),
  Array('keyE1' => '    textE1 ', 'keyE2' => '  textE2     ')
);

// function for "trim" (or your function, use same structure)
function trimming($data) {
  if (gettype($data) == 'array')
    return array_map("trimming", $data);
  else
    return trim($data);
}

// get array
$myArray = array_map("trimming", $myArray);

// show array trimmed
var_dump($myArray);

/*
RESULT

array (size=5)
  0 => 
    array (size=2)
      'keyA1' => string 'textA1' (length=6)
      'keyA2' => string 'textA2' (length=6)
  1 => 
    array (size=3)
      'keyB1' => string 'textB1' (length=6)
      'sub' => 
        array (size=1)
          'keyB1_sub1' => string 'textB1_sub1' (length=11)
      0 => 
        array (size=1)
          'keyB1_sub2' => string 'textB1_sub2' (length=11)
  2 => 
    array (size=2)
      'keyC1' => string 'textC1' (length=6)
      'keyC2' => string 'textC2' (length=6)
  3 => 
    array (size=2)
      'keyD1' => string 'textD1' (length=6)
      'keyD2' => string 'textD2' (length=6)
  4 => 
    array (size=2)
      'keyE1' => string 'textE1' (length=6)
      'keyE2' => string 'textE2' (length=6)

*/