unwanted symbol spreadsheet-excel (0.3.5.1) gem

Hi,

      I am using the ruby version 1.8.while i export the excel sheet i
found different symbol (company’s) instead of company's,i am using
the
gem spreadsheet-excel (0.3.5.1).I tried and found one solution

format4 =
workbook.add_format(:color=>"black",:bold=>1,:underline=>0,:align=>'left',:size=>10,:border=>5,:font_charset=>0x01),
but these :font_charset is not removing the symbol(’)
FONT_ENCODINGS =
    {
      0x00 => :iso_latin1,
      0x01 => :default,
      0x02 => :symbol,
      0x4d => :apple_roman,
      0x80 => :shift_jis,
      0x81 => :korean_hangul,
      0x82 => :korean_johab,
      0x86 => :chinese_simplified,
      0x88 => :chinese_traditional,
      0xa1 => :greek,
      0xa2 => :turkish,
      0xa3 => :vietnamese,
      0xb1 => :hebrew,
      0xb2 => :arabic,
      0xba => :baltic,
      0xcc => :cyrillic,
      0xde => :thai,
      0xee => :iso_latin2,
      0xff => :oem_latin1,
    }
i tried all these but not working ,please reply me

Thanks
selvaraj