ABSTRACT In the present investigation, bigeye tuna (Thunnus obesus) skin waste was utilized for the extraction of gelatin. Physico-chemical, rheological, and surface-active properties of the obtained gelatin were assessed. Proximate compositional analysis of tuna skin gelatin recorded high protein content of 88.6% and low levels of fat and ash contents. The isoelectric point (IEP) of tuna skin gelatin was around 6.24. Amino acid profiling recorded a glycine [31.7%] higher proportion, followed by imino acids (hydroxyproline + proline) [18.4%], and alanine [12.2%]. The electrophoretic pattern of purified gelatin exhibited three major bands (β, α1, and α2) with wider molecular weight distribution in the range of 200–120 kDa. The Fourier Transform Infrared (FT-IR) spectra of gelatin also confirmed the bands corresponding to α helix, β sheet, and random coil structures. The rheological studies of tuna skin gelatin revealed Newtonian and shear thickening properties. The method of extraction and assessment of its characteristic properties could be useful in the field of formulation of functional foods, nutraceutical, and biomedical applications.

中文翻译：

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从大眼金枪鱼 (Thunnus obesus) 皮肤废料中提取的明胶的流变学、物理化学和表面活性特性

摘要 在本研究中，大眼金枪鱼 (Thunnus obesus) 皮肤废料被用于提取明胶。评估了所得明胶的物理化学、流变学和表面活性特性。金枪鱼皮明胶的近似成分分析记录了 88.6% 的高蛋白质含量和低水平的脂肪和灰分含量。金枪鱼皮明胶的等电点 (IEP) 约为 6.24。氨基酸分析记录到甘氨酸 [31.7%] 的比例较高，其次是亚氨基酸（羟脯氨酸 + 脯氨酸）[18.4%] 和丙氨酸 [12.2%]。纯化明胶的电泳图谱显示出三个主要条带（β、α1 和 α2），其分子量分布在 200-120 kDa 范围内。明胶的傅里叶变换红外 (FT-IR) 光谱也证实了对应于 α 螺旋、β 折叠、和随机线圈结构。金枪鱼皮明胶的流变学研究揭示了牛顿和剪切增稠特性。提取和评估其特性的方法可用于功能性食品的配方、营养食品和生物医学应用领域。