Physico-chemical Property And Antibacterial Application Of The Gelatin From Swim Bladder Of Sturgeon

As a kind of modern fish processing waste,Sturgeon swim bladder contains a lot of collagen.It has long been favored by China and Southeast Asian countries as a food and medicinal material and tonic.However,with the increasing product of sturgeon,a large amount of sturgeon swim bladder has not been scientifically applied.In this study,sturgeon swim bladder was used as a raw material to establish an efficient extracting technology of gelatin without acid and alkali pretreatment,and to clarify the physico-chemical properties of gelatin.The nanofiber membrane of gelatin/galangal essential oil/β-cyclodextrin（SG/GRO/β-CD-IC）was successfully prepared by electrospinning technology,and its physico-chemical and antibacterial properties were analyzed.The main contents and results are summarized as follows:（1）Under the optimal extraction conditions of 50℃,30 min and 10 mL/g,the yield of gelatin was as high as 94.15%（w/w）,and it showed similar amino acid profile and electrophoresis pattern to type I collagen.Compared to commercial porcine（PG）,bovine（BG）and fish skin gelatin（FG）,it exhibited higher molecular size（9.84 kDa）,emulsion activity（171.76 m²/g）,gel strength（853.23 g）,water-holding capacity（92.37%）,viscoelasticity（tanδ,0.03）and whiteness（ΔE,3.38）.But the transmittance(T_{450 nm}=40.56%,T_{620 nm}=59.07%),emulsion stability（30.09 min）,foam expansion（203.00）and stability（26.92）,gelling（16.88℃）and melting temperature（21.80℃）were lower.While the pH（6.87）and viscosity（28.60 mPa·s）were moderate.In addition,the gelatin could be made into high-quality hydrogels and electrospinning nanofibers.（2）The main components of GRO were analyzed by GC-MS,including Ethyl cinnamate（37.56%）,Methyl cinnamate（19.99%）,n-Pentadecane（14.61%）,Cineole（9.06%）,3-δ-Carene（3.46%）,（-）-camphene hydrate（3.24%）,Isobornyl acetate（2.78%）,18-Crown 6-Ether（2.48%）,L（-）-Borneol（0.67%）.The SG/GRO/β-CD-IC nanofiber membrane was successfully prepared by electrospinning technology,which showed good thickness（0.13 mm）,water solubility（5.06%）,contact angle（89.55°）,water vapor transmission rate（0.49 g·mm/（m²·h·kPa））and controlled release capability（7 d,64.87%）.SEM and FTIR results showed that GRO was included inβ-CD,the GRO composition after inclusion was not significantly changed,and the inclusion compound（GRO/β-CD-IC）could be bound to nanofibers.SG/GRO/β-CD-IC nanofiber membrane could destroy the cell wall of Escherichia coli（O157:H7）,caused cell melting and ulceration,and showed significant antibacterial effect.