蛋白基体系美拉德反应在荔枝皮原花青素作用下的抑制研究

Inhibitory Effect of Litchi Pericarp Procyanidins on Maillard Reactions in Protein-based Systems

摘要:

本试验分别研究了在乳清蛋白-葡萄糖和牛血清白蛋白-葡萄糖模拟生理体系中，荔枝果皮原花青素（Litchi pericarp procyanidins，LPPC）对美拉德反应和晚期糖基化终末产物（advanced glycation end products，AGEs）的抑制作用，以荧光性AGEs的强度为表征依据。结果表明，在乳清蛋白-葡萄糖模拟体系中孵育35 d时，LPPC对AGEs的抑制效果最强，达60.21±1.34%。LPPC浓度为1 mg/mL时，相对抑制率最大可达85.33±9.02%（显著高于维生素C（Vc），p<0.05）。在牛血清白蛋白-葡萄糖体系中，孵育35 d后LPPC对AGEs的相对抑制率最高达70.01±1.32%，且与LPPC浓度呈现正相关。当LPPC浓度为0.5 mg/mL时，抑制率最大为95.46±10.12%（显著高于氨基胍（AG），p<0.05）。不同pH值下蛋白质的稳定性研究表明，乳清蛋白在与LPPC长期孵育后，其热稳定性明显降低，再次提示了LPPC对美拉德反应的抑制作用。LPPC可作为一种天然的食品基质的AGEs抑制剂深度开发。

Abstract:

The inhibitory effect of litchi pericarp procyanidins (LPPC) on the Maillard reaction and advanced glycation end product (AGE) formation was studied in whey protein (WPI)-glucose (Glu) and bovine serum albumin (BSA)-Glu simulations systems, and characterization was based on the fluorescence intensity of AGEs. The results indicated that the maximum inhibitory rate of LPPC on AGE formation in the WPI-Glu system after incubation for 35 d was 60.21±1.34%. Furthermore, at a concentration of 1 mg/mL, the inhibitory rate of LPPC reached a maximum of 85.33±9.02%, significantly higher than that of vitamin C (Vc, p<0.05). In the BSA-Glu system, the maximum inhibitory rate of LPPC on AGE formation after incubation for 35 days reached 70.01±1.32%, and showed a positive correlation with LPPC concentration. At an LPPC concentration of 0.5 mg/mL, the inhibition of AGE formation reached 95.46±10.12%, which was significantly higher than that of aminoguanidine (AG, p<0.05). Studies of protein stability at different pH values suggested that the thermal stability of WPI was significantly decreased after 35 d of incubation with LPPC, further implying the inhibitory effect of LPPC on the Maillard reaction. Overall, LPPC could serve as a food resource with natural AGE inhibition.