胃蛋白酶酶法改性藻蓝蛋白及其稳定性研究

Research on the preparation and stability of phycocyanin with enzymatic modification by pepsin

中文关键词:  藻蓝蛋白  酶法改性  胃蛋白酶  稳定性

英文关键词:phycocyanin  enzymatic modification  pepsin  stability

中文摘要:

      目的 探究胃蛋白酶酶法改性藻蓝蛋白在不同温度和pH条件下的呈色和结构稳定性。方法 通过比较藻蓝蛋白在胃蛋白酶改性前后的分子量变化和色度色差, 确定最佳的改性条件; 利用紫外-可见吸收光谱和圆二色谱分析改性对藻蓝蛋白结构的影响; 并通过液相色谱-质谱技术分析改性藻蓝蛋白的肽段序列; 最终以色度和色差、色素保留率、紫外-可见吸收光谱和圆二色谱等指标, 评价改性藻蓝蛋白在不同温度和pH下的呈色和结构稳定性。结果 藻蓝蛋白的最佳改性条件为酶解pH 2.0、灭酶方式煮沸6 min、酶解时间2 h。此条件下改性藻蓝蛋白与未改性藻蓝蛋白相比, 紫外-可见吸收光谱显示藻蓝蛋白分子结构发生变化, 圆二色谱结果说明酸性和酶解条件会导致藻蓝蛋白从典型的α-螺旋结构向无序结构转变。通过液相色谱-质谱联用技术, 本研究鉴定到7条含有藻蓝胆素的肽段序列, 这些肽段与藻蓝胆素的稳定结合对维持改性藻蓝蛋白的呈色稳定性起关键作用。稳定性评价结果表明, 改性藻蓝蛋白在高温和酸性环境显示出优异的呈色和结构稳定性。70℃以下的温度范围内, 色素保留率大于(91.25±0.08)%, 关键色度b*和二级结构占比无显著变化; 在pH 2.0附近时改性藻蓝蛋白呈色和结构最稳定。结论 本研究所得改性藻蓝蛋白较未改性藻蓝蛋白在高温和酸性环境的呈色和结构稳定性显著提升, 为藻蓝蛋白在食品加工过程中应用于不同食品基质、应对不同加工处理条件提供理论基础和技术支持。

英文摘要:

      Objective To explore the color and structural stability of phycocyanin modified by pepsin under different temperature and pH conditions. Methods By comparing the changes in molecular weight and color difference of phycocyanin before and after pepsin modification, the optimal modification conditions were determined; the impact of modification on the structure of phycocyanin was analyzed using ultra violet-visible absorption spectroscopy and circular dichroism spectroscopy; and the peptide sequences of the modified phycocyanin were analyzed using liquid chromatography-mass spectrometry (LC-MS); finally, the color and structural stability of the modified phycocyanin under different temperature and pH conditions were evaluated using indicators such as color difference, pigment retention rate, ultra violet-visible absorption spectroscopy, and circular dichroism. Results The optimal conditions for phycocyanin modification were found to be a digestion pH of 2.0, inactivation of pepsin by boiling for 6 minutes, and a digestion time of 2 hours. Under these conditions, compared to the unmodified phycocyanin, the ultra violet-visible absorption spectroscopy showed changes in the molecular structure of phycocyanin, and the circular dichroism results indicated that acidic and enzymatic conditions led to a transition of phycocyanin from a typical α-helix structure to a disordered structure. Through LC-MS, 7 peptide sequences containing phycocyanobilin were identified, which were crucial for the stable combination with phycocyanobilin and maintaining the color stability of the modified phycocyanin. Results showed that the modified phycocyanin exhibited excellent color and structural stability at high temperatures and in acidic environments. The pigment retention rate was greater than (91.25±0.08)% in the temperature range below 70°C, with no significant change in critical color value of b* and secondary structure proportion; the modified phycocyanin exhibited the greatest stability in terms of color and structure at approximately pH 2.0. Conclusion The modified phycocyanin obtained in this research has significantly improved color and structural stability at high temperatures and in acidic environments compared to the unmodified phycocyanin, providing a theoretical basis and technical support for the application of phycocyanin in different food matrices and under various processing conditions in the food processing industry.