1 Nippon Shokuhin Kagaku Kogaku Kaishi Vol. /,, No.2, -,/-,3 (,**/) 325 Patricia Yuca Hamaguchi Film-forming Mechanism of Biodegradable Films Prepared from Fish Myofibrillar Proteins Yusuke Shiku, Patricia Yuca Hamaguchi, Weng WuYin and Munehiko Tanaka Department of Food Science and Technology, Tokyo University of Marine Science and Technology,./1 Konan, Minato, Tokyo +*22.11 In our previous study, semi-transparent and flexible biodegradable films were successfully prepared from myofibrillar proteins of blue marlin meat. The objective of this study was to elucidate the mechanism of film formation. E#ect of ph on the amount of surface hydrophobicity and surface SH group in the film-forming solution, solubility of film proteins in various protein denaturant solutions, SDS-PAGE, and addition e#ect of protein denaturants in the film-forming solutions were investigated. At first, the necessity of unfolding of protein molecules was revealed for the formation of self-standing films. Secondly, the important chemical bondings involved in the protein-protein interactions were confirmed to be hydrophobic interaction for acidic condition, hydrogen bondings for neutral condition, and hydrophobic interaction and disulfide bondings for alkaline condition. (Received Feb. +*,,**/ ; Accepted May +,,,**/) / *** / -* +, CMC -. +*22.11./1 corresponding author mune@s.kaiyodai.ac.jp / 0 1 0 ph / ph,- 1+, ph.0 ph 1 ph ph + Makaira mazara 0 /,* mm EDTA *.+ M Tris-HCl ph 1.0
326 /, 2,**/ 2 2 Laboratory Blender, Model -2B0, Waring Prod. Co. 3,**g, -*.,,/, + /* + M HCl + M NaOH ph, +, Hybrid Mixer HM-/** - + 2 ANS ; ANS 2 *.*+ ph,+,. ml *.*. ANS *.. ml. +* +/ RF-+/** -0/ nm,.1* nm ph ph 1 +. SH SH, DTNB ; 3 *.*/ ph,+, / ml +* mm ph 1.* *.*+ M DTNB *.*-- ml. 0* + 1**g, +* UV-+0*.+, nm + g SH +.-0 +*. M + cm + /. g /.* cm/.* cm Environmental Chamber H++*K--*DM ;,/*./ /*/,. 0 SDS-PAGE ph,+,, SDS 2 M,* mm Tris-HClpH 2.2,, SDS-PAGE Laemmli +* 1./ NPU-1./L, ATTO *.+ R-,/*-* +* - -* +* 1,* 1* +,/ ++,, +, 1* + 2 Perez-Mateos +-. ph 1 *.0 M NaCl S+ *.0 M NaCl+ M S, *.0 M NaCl2 M S- *.0 M NaCl2 M *./ M, S.,/* mg / ml -*,. Advantec No. /C, Bradford +.. S+S. 3 ph ph, 1 +,, *.**/+.* M *.*++.* M *.*+ *./ M TS EAB 0,/*./ /*/ 1, TS EAB RE---*/ ;,* mm,./ mm *./ mms + TS MPa N m, EAB +* +* Excel SPSS Statistical Software, USA Duncan s multiple-range test +/ p*.*/ + SH ph,+,
3 : 327 SH Fig. + ph 1 ph SH ph 1 ph ph.0, SDS- PAGE SDS-PAGE ph SDS- PAGE Fig., ph SDS-PAGE ph, - +0 -. S+S. Table + S+ ph, -,,.. ph 1+, -.-1 S, S, S+ S,-S+ S,-S+ Fig. + E#ect of ph on the amounts of surface hydrophobic group () and surface SH group () of myofibrillar protein film-forming solutions Fig., SDS-PAGE patterns of myofibrillar protein based films M+ : High molecular weight standard (,3,*/ kda). M, : Low molecular weight standard (,300 kda). Table + ph Protein solubility () of myofibrillar protein based films in protein denaturant solutions* +,, Protein denaturant solutions S+ /, /- S., - 1 2 3 +* ++ +,,,4.-4+ a,,4.-4, a -.4..41 b -14/.4, b -042-4- b -040-4+ b -.4/-41 b -.4-.43 b,24/.4- a,14-.4, a /04.-4/ b /34,/4, b.04..43 c.142.43 c.,4*/4* c -24./42 d /141/4+ a 0*4//4- a 0-40/4* b 014,/43 b 0/4/04+ b 004+04. b 0-4+/4, b /24-04. a /34304+ a 0,4//4- a 0.4.04, b 1*4+041 b 0/43/40 a 0243/4/ ab 1,4+041 b 0/4104. a * + S+ : *40M NaCl, S, : *40M NaCl+4/M urea, S- : *40M NaCl24*M urea, S. : *40M NaCl24*M urea*4/m,-mercaptoethanol4 *, Meansstandard deviation4 Any two means in the same column followed by the same letter are not significantly di#erent (p*4*/)4
328 /, 2,**/ 2 4 Table, E#ect of additives on the mechanical properties of myofibrillar protein based films Additives Urea Guanidine hydrochloride,-mercaptoethanol Concentration (M) * *4*+ *4+ *4/ +4* *4*+ *4+ *4/ *4**/ *4*+ *4+ +4* TS (MPa) ph, ph 1 ph +, +.4, 043 +.4- +-4* /41 +-4- +/4/ 043-42 -4+ 241 341 34, +*4. 04, 243 241 /40 242 EAB () ph, ph 1 ph +,,-42 +040 -+4,,24* -*4,,/4. 141 +043,.42,14*,+41,,4* +142,.42,/40,.4-,34+ +34- +.4- : Unable to measure4 : Unformed4 S- /1.101., S- S, S--S, S. /3.31,.+ S.-S- / Table, ph +, +.* M, *.+ M TS, EAB ph, *./ M *.+ M ph 1 *.+ M, *.*+ M, ph +, *.+ M ph, +.* M ph 1 *.**/ M TS ph 1 ph 0 Fig. + ph +1 unfolding Kim +2 ph SH ph ph 1 Fig. + +3 unfolding SH,* S+S. Table + S. +**-S.
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