title: Separation and characterization of alpha-chain subunits from tilapia (Tilapia zillii) skin gelatin using ultrafiltration.
abstract: Alpha-chain subunits were separated from tilapia skin gelatin using ultrafiltration, and the physicochemical properties of obtained subunits were investigated. As a result, α1-subunit and α2-subunit could be successfully separated by 100 kDa MWCO regenerated cellulose membranes and 150 kDa MWCO polyethersulfone membranes, respectively. Glycine was the most dominant amino acid in both α1-subunit and α2-subunit. However, the tyrosine content was higher in α2-subunit than in α1-subunit, resulting in strong absorption near 280 nm observed in the UV absorption spectrum. Based on the DSC analysis, it was found that the glass transition temperatures of gelatin, α1-subunit and α2-subunit were 136.48 °C, 126.77 °C and 119.43 °C, respectively. Moreover, the reduced viscosity and denaturation temperature of α1-subunit were higher than those of α2-subunit, and the reduced viscosity reached the highest when α-subunits were mixed with α1/α2 ratio of approximately 2, suggesting that α1-subunit plays a more important role in the thermostability of gelatin than α2-subunit.
authors.affiliation: College of Food and Biological Engineering, Jimei University, Xiamen 361021, China.
authors.forename: Shulin
authors.initials: S
authors.lastname: Chen
authors.affiliation: College of Food and Biological Engineering, Jimei University, Xiamen 361021, China.
authors.forename: Lanlan
authors.initials: L
authors.lastname: Tang
authors.affiliation: College of Food and Biological Engineering, Jimei University, Xiamen 361021, China; Fujian Provincial Key Laboratory of Food Microbiology and Enzyme Engineering, Xiamen 361021, China.
authors.forename: Wenjin
authors.initials: W
authors.lastname: Su
authors.affiliation: College of Food and Biological Engineering, Jimei University, Xiamen 361021, China; Fujian Provincial Key Laboratory of Food Microbiology and Enzyme Engineering, Xiamen 361021, China. Electronic address: wwymail@jmu.edu.cn.
authors.forename: Wuyin
authors.initials: W
authors.lastname: Weng
authors.affiliation: Department of Food Science and Technology, Tokyo University of Marine Science and Technology, Tokyo 108-8477, Japan.
authors.forename: Kazufumi
authors.initials: K
authors.lastname: Osako
authors.affiliation: Kokugakuin Tochigi Junior College, 601 Hirai-machi, Tochigi 328-8588, Japan.
authors.forename: Munehiko
authors.initials: M
authors.lastname: Tanaka
mesh_terms: D000818:Animals; D002152:Calorimetry, Differential Scanning; D055598:Chemical Phenomena; D005511:Food Handling; D005780:Gelatin / Q000737:chemistry*; D005998:Glycine / Q000032:analysis; D012867:Skin / Q000737:chemistry*; D017210:Tilapia; D014462:Ultrafiltration; D014783:Viscosity
chemical_list: D005780:Gelatin; D005998:Glycine
keywords: Alpha subunits; Separation; Skin gelatin; Thermal properties; Tilapia skin; Ultrafiltration