提取pH值对猪皮明胶凝胶性能和特征性多肽鉴定的影响

Effect of Extraction pH on Gelling Properties and Characteristic Peptide Identification of Pigskin Gelatin

为探究提取pH值对猪皮明胶凝胶特性和特征性多肽鉴定的影响,在不同pH值条件下提取猪皮明胶,通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳、质构仪和流变仪分别对其分子质量分布和凝胶特性进行研究,同时利用高效液相色谱-串联质谱(high performance liquid chromatography-tandem mass spectrometry,HPLC-MS/MS)技术研究其特征性多肽。结果发现,随着提取pH值降低,猪皮明胶的相对分子质量先增大后减小,凝胶强度逐渐降低,胶融温度和凝胶温度均呈现先升高后降低的趋势,提取pH值为1时猪皮明胶的凝胶特性最差。HPLC-MS/MS检测发现提取pH值显著影响了明胶的溯源效果,从提取pH值为1、3、5、7的猪皮明胶中分别鉴定出62、71、79、76条特征性多肽,其中存在于所有猪皮明胶的共有特征性多肽有37条。与课题组前期的研究比较,发现不同条件下提取的猪皮明胶有17条共有特征性多肽,这些稳定存在的共有特征性多肽可作为猪皮明胶溯源的重要依据,以提高猪明胶鉴定的准确性。

In order to study the effect of extraction pH on gelling properties and characteristic peptide identification of pigskin gelatin,the molecular mass distribution and gelling properties of pigskin gelatin extracted under different pH conditions were studied by dodecyl sodium sulfate-polyacrylamide gel electrophoresis(SDS-PAGE),a texture analyzer and a rheometer.Moreover,the characteristic peptides were identified by high performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS).The results showed that with a decrease in pH,the relative molecular mass of pigskin gelatin initially increased and then decreased,the gel intensity gradually declined,and the gel melting temperature and gelling temperature initial increased and then decreased.Gelatin extracted at pH 1 had the worst gelling properties.HPLC-MS/MS analysis showed that pH significantly affected the traceability of gelatin.In this study,62,71,79 and 76 characteristic peptides were detected from pigskin gelatins extracted at pH 1,3,5 and 7,respectively.Among them,37 characteristic peptides were common to all pigskin gelatins.Compared with our previous research,17 characteristic peptides were found to be common to pigskin gelatins extracted under different conditions.These stable common characteristic peptides could be used as an important basis for pigskin gelatin traceability with high accuracy.