Antifreeze　peptides　(APP)　obtained　from　pigskin　collagen　hydrolyzates,　with　molecular　mass　distribution　among　150-2000　Da,　rich　in　glycine　(23%),　proline　(15%),　hydroxyproline　(13%)　and　alanine　(8%),　showed　a　high　hypothermia　protection　activity　on　lactic　acid　bacteria　during　freeze-drying　process.　In　this　study,　we　investigated　the　cryoprotective　activity　on　Streptococcus　thermophiles　in　the　presence　of　APP.　The　optimum　condition　for　APP　to　protect　the　cells　was　I　mg/mL　under　pH　9.0.　When　the　S.　thermophiles　were　dried　together　with　1　mg/mL　of　APP,　71%　of　organism　cells　survived.　The　intracellular　proteins,　nucleic　acid　and　the　key　enzyme　activities　were　determined　to　elucidate　the　possible　action　mechanism,　and　the　results　showed　that　the　intracellular　proteins　and　nucleic　acid　were　more　stable　in　the　APP-treated　group　than　those　in　the　groups　treated　by　sugars　and　skim　milk　as　cryoprotectants.　Moreover,　the　activities　of　lactate　dehydrogenase　and　beta-galactosidase　were　both　higher　in　the　APP-treated　group　than　those　in　control　groups.　Under　the　investigation　of　SEM,　cells　of　APP-treated　group　were　significantly　full　and　integral,　while　cells　in　control　group　were　shrinking.　FTIR　studies　implied　that　APP　had　interactions　with　the　cell　membrane　phospholipids　during　freeze　drying.　(C)　2015　Elsevier　Ltd.　All　rights　reserved.