三种方法提取龟甲胶原蛋白的理化特性比较

Comparison of the Physical and Chemical Properties of Collagens Extracted from Tortoise Shell using Three Methods

摘要:

该文检测了中华草龟腹甲和背甲的基本成分和矿物质组成，并利用酸法、酶法和热水辅助酶法从中提取胶原蛋白（分别为ASC、PSC和H-PSG），然后通过紫外光谱、红外光谱、SDS-PAGE电泳、氨基酸分析和扫描电镜等方法对胶原蛋白的理化特性进行表征。结果表明，龟甲中含有大量蛋白质（22.06%~22.50%）、钙（16 004.25~16 592.50 mg/100 g）、磷（6 014.25~6 188.25 mg/100 g）。三种方法提取胶原蛋白的得率依次为0.45%~0.51%（ASC），4.38%~4.75%（H-PSG）和1.47%~1.56%（PSC）。6种胶原蛋白的最大紫外吸收峰均出现在220~226 nm，红外图谱和SDS电泳图谱显示ASC和PSC均为Ⅰ型胶原蛋白，拥有较高的纯度保留了较为完整的三螺旋结构，但H-PSG 已变性为明胶并部分水解为胶原蛋白肽。6种胶原蛋白氨基酸组成基本一致，拥有丰富的甘氨酸（18.19%~24.10%）和脯氨酸（12.52%~15.05%）。从微观结构上看，ASC拥有更好的三维网状结构。综上所述，中华草龟腹甲和背甲胶原蛋白在组成与性质方面没有显著差异，不同的提取方法对龟甲胶原蛋白得率、组成和结构方面有一定的影响。

Abstract:

The basic and mineral compositions of the ventral and dorsal shells of tortoise (Chinemys reevesii) were analyzed, and collagens (ASC, PSC, and H-PSG) were extracted from shell samples using acid, enzymatic, and hot-water assisted enzymatic methods. Subsequently, the physical and chemical properties of the extracted collagens were characterized through ultraviolet spectrometry, infrared spectrometry, SDS-PAGE, amino acid analysis, and scanning electron microscopy. The results indicated that tortoise shells had high protein (22.06%~22.50%), calcium (16 004.25~16 592.50 mg/100 g), and phosphorus (6 014.25~6 188.25 mg/100 g) contents. ASC, H-PSG, and PSC yields were 0.45%~0.51%, 4.38%~4.75%, and 1.47%~1.56%, respectively. The maximum absorption peaks of ASC, H-PSG, and PSC extracted from ventral and dorsal shell samples appeared at 220~226 nm. The infrared spectra and SDS-PAGE patterns showed that ASC and PSC were both type Ⅰ collagen with high purity and a relatively intact triple-helix structure, but H-PSG had degenerated into gelatin and had been partially hydrolyzed to collagen peptide. ASC, H-PSG, and PSC extracted from the ventral and dorsal shell samples had essentially the same amino acid composition, with abundant glycine (18.19%~24.10%) and proline (12.52%~15.05%). In terms of microstructure, ASC exhibited a superior three-dimensional network structure compared to H-PSG and PSC. In conclusion, the collagens extracted from the ventral and dorsal shells of tortoise using the same methods showed no significant difference in composition or properties; however, different extraction methods affected the yield, composition, and structure of collagens extracted from tortoise shells.