枸杞果皮与果肉细胞壁果胶多糖的构成与酶活抑制差异

Composition of Cell Wall Polysaccharides and Differences in Pectin Activity Between the Peel and Pulp of Goji berry

摘要:

为探明枸杞果皮和果肉细胞壁果胶多糖的组成与活性差异，分别提取枸杞果皮与果肉细胞壁果胶多糖，采用紫外—可见分光光度和傅里叶红外光谱法分析了果皮与果肉细胞壁果胶多糖的基本结构特征，采用阴离子交换色谱和凝胶渗透色谱法检测果皮与果肉细胞壁果胶多糖的单糖组成与分子量分布，并通过酶活抑制实验分析二者对胰脂肪酶和α-淀粉酶的抑制作用。结果显示，枸杞果皮的细胞壁果胶多糖含量均显著高于果肉（P＜0.05）；果皮与果肉细胞壁果胶多糖均主要由阿拉伯糖、半乳糖、半乳糖醛酸、鼠李糖、木糖和葡萄糖组成，且果皮果胶的分子量更高；果肉果胶多糖的胰脂肪酶半抑制浓度（IC50）为4.334 mg/mL，抑制效果较果皮好；而果皮果胶对α-淀粉酶的抑制效果（IC50为6.939 mg/mL）优于果肉细胞壁果胶，且二者均为混合型抑制，表明果皮和果肉果胶多糖均具有潜在的调节机体糖脂代谢的作用。研究结果为枸杞加工皮渣副产物的高值化利用提供了理论依据和开发思路。

Abstract:

To investigate the differences in composition and activity of pectin polysaccharides from the cell walls of Goji berry peel and flesh, the pectin polysaccharides from the both sources were extracted. The basic structural characteristics of the pectin polysaccharides from the cell walls of the peel and flesh were analyzed using UV-Vis spectrophotometry and Fourier-transform infrared spectroscopy; anion exchange chromatography and gel permeation chromatography were used to determine the monosaccharide composition and molecular weight distribution, and the inhibitory effects of pectic polysaccharides from peel and flesh cell wall on pancreatic lipase and α-amylase were measured by enzyme inhibition experiments. The results showed that the content of pectin polysaccharides in the Goji berry peel was significantly higher than that in the flesh (P < 0.05); both peel and flesh pectin polysaccharides were primarily composed of arabinose, galactose, galacturonic acid, rhamnose, xylose, and glucose, with the peel pectin exhibiting a higher molecular weight. The semi inhibitory concentration (IC50) of the flesh pectin against pancreatic lipase was 4.334 mg/mL, showing a better inhibitory effect than that of the peel; the peel pectin demonstrated a superior inhibitory effect on α-amylase (IC50 of 6.939 mg/mL) compared to the flesh cell wall pectin, with both exhibiting mixed-type inhibition, indicating that both peel and flesh pectin polysaccharides have the potential to regulate the body's glycolipid metabolism. The research findings provided theoretical basis and development ideas for the high-value utilization of by-products derived from the processing Goji berry.