In　order　to　exploit　their　industrial　applications,　sericin　peptides　(3K-SP)　were　obtained　by　membrane　separation　and　their　physiochemical　properties　and　cryoprotective　function　were　investigated.　Results　showed　that　3K-SP　were　mostly　distributed　less　than　3000　Da,　and　rich　in　the　amino　acids　Ser,　Asp,　Gly,　Thr　and　Glu,　which　have　been　associated　with　the　cryoprotective　activity　of　ice-structuring　proteins.　Addition　of　3K-SP　to　a　frozen　solution　led　to　the　reductions　in　melting　temperature　and　melting　time　compared　to　control　solution.　In　addition,　3K-SP　inhibited　ice　recrystallization,　since　it　could　maintain　small　ice　crystal　sizes　within　a　frozen　solution.　Furthermore,　3K-SP　demonstrated　high　cryogenic　protection　activity　of　Lactobacillus　delbrueckii　Subsp.　Bulgaricus　during　freezing,　and　provided　optimal　protection　of　cells　at　conditions　in　which　its　concentration　was　1.0　mg/mL　and　the　pH　of　the　solution　was　7.0.　In　these　conditions,　the　percentage　of　surviving　cells　was　as　high　as　84.78　+/-　3.07%.　Flow　cytometric　and　scanning　electron　microscopy　analyses　showed　that　treatment　with　3K-SP　increased　the　percentage　of　viable　cells　from　52.9%　to　80.1%,　and　suggest　that　3K-SP　may　mediate　its　protective　effects　through　interaction　with　cell　membranes,　whereby　it　surrounds　cells　in　a　glassy　matrix　that　helps　maintain　their　membrane　integrity.　(C)　2016　Elsevier　Ltd.　All　rights　reserved.