ABSTRACT The objectives of this study were to characterize physicochemical properties of two collagens, tilapia skin (TS) and hybrid catfish skin (HS). Angiotensin-converting enzyme (ACE) inhibitory peptides from extracted TS and HS collagen using pepsin were also determined. HS collagen had a higher amount of imino acid than TS collagen, while TS contained higher amounts of tyrosine (Tyr) and lysine (Lys). Fourier-transform infrared spectra of both collagens showed predominant helix structure. The HS collagen hydrolysate prepared by pepsin was fractionated using sequential ultrafiltration membranes, and the fraction with molecular weight (MW) <5 kDa showed the highest ACE inhibitory activity (p < .05). After cation exchange and two steps size exclusion chromatography, peptides showed ACE inhibitory activity of 72.06%. This study revealed that ACE inhibitory peptides derived from HS collagen could be developed as a functional food with potential antihypertensive properties.

中文翻译：

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淡水鱼皮胶原的理化性质和血管紧张素I转化酶抑制肽

摘要 本研究的目的是表征两种胶原蛋白、罗非鱼皮 (TS) 和杂交鲶鱼皮 (HS) 的理化特性。还测定了使用胃蛋白酶从提取的 TS 和 HS 胶原中提取的血管紧张素转换酶 (ACE) 抑制肽。HS 胶原蛋白的亚氨基酸含量高于 TS 胶原蛋白，而 TS 胶原蛋白的酪氨酸 (Tyr) 和赖氨酸 (Lys) 含量更高。两种胶原的傅里叶变换红外光谱均显示出主要的螺旋结构。用连续超滤膜对胃蛋白酶制备的 HS 胶原水解物进行分级，分子量 (MW) <5 kDa 的级分显示​​出最高的 ACE 抑制活性 (p < .05)。经过阳离子交换和两步尺寸排阻色谱后，肽显示出 72.06% 的 ACE 抑制活性。