Li Zelin, Zhou Bin, Zheng Tingting, Zhao Chunyan, Gao Yan, Wu Wenjun, Fan Yingrun, Wang Xuefeng, Qiu Minghua, Fan Jiangping
College of Food Science and Technology, Yunnan Agricultural University, Kunming 650201, China.
State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China.
Foods. 2023 Jan 16;12(2):423. doi: 10.3390/foods12020423.
As primary coffee by-products, Arabica coffee husks are largely discarded during coffee-drying, posing a serious environmental threat. However, coffee husks could be used as potential material for extracting pectin polysaccharides, with high bioactivities and excellent processing properties. Thus, the present study aimed to extract the pectin polysaccharide from Arabica coffee husk(s) (CHP). The CHP yield was calculated after vacuum freeze-drying, and its average molecular weight (Mw) was detected by gel permeation chromatography (GPC). The structural characteristics of CHP were determined by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), proton nuclear magnetic resonance (H NMR), and scanning electron microscopy (SEM). Additionally, the rheological and antioxidant properties of CHP and the inhibition capacities of advanced glycation end products (AGEs) with different concentrations were evaluated. The interaction mechanisms between galacturonic acid (GalA) and the AGE receptor were analyzed using molecular docking. The results demonstrated that the CHP yield was 19.13 ± 0.85%, and its Mw was 1.04 × 10 Da. The results of the structural characteristics results revealed that CHP was an amorphous and low-methoxyl pectic polysaccharide linked with an α-(1→6) glycosidic bond, and mainly composed of rhamnose (Rha, 2.55%), galacturonic acid (GalA, 45.01%), β-N-acetyl glucosamine (GlcNAc, 5.17%), glucose (Glc, 32.29%), galactose (Gal, 6.80%), xylose (Xyl, 0.76%), and arabinose (Ara, 7.42%). The surface microstructure of CHP was rough with cracks, and its aqueous belonged to non-Newtonian fluid with a higher elastic modulus (G'). Furthermore, the results of the antioxidant properties indicated that CHP possessed vigorous antioxidant activities in a dose manner, and the inhibition capacities of AGEs reached their highest of 66.0 ± 0.35% at 1.5 mg/mL of CHP. The molecular docking prediction demonstrated that GalA had a good affinity toward AGE receptors by -6.20 kcal/mol of binding energy. Overall, the study results provide a theoretical basis for broadening the application of CHP in the food industry.
作为主要的咖啡副产品，阿拉比卡咖啡果壳在咖啡干燥过程中大多被丢弃，对环境构成严重威胁。然而，咖啡果壳可用作提取果胶多糖的潜在原料，果胶多糖具有高生物活性和优良的加工性能。因此，本研究旨在从阿拉比卡咖啡果壳中提取果胶多糖（CHP）。真空冷冻干燥后计算CHP的得率，并用凝胶渗透色谱法（GPC）检测其平均分子量（Mw）。通过傅里叶变换红外光谱（FT-IR）、X射线衍射（XRD）、质子核磁共振（H NMR）和扫描电子显微镜（SEM）测定CHP的结构特征。此外，还评估了CHP的流变学和抗氧化性能以及不同浓度的晚期糖基化终产物（AGEs）的抑制能力。利用分子对接分析了半乳糖醛酸（GalA）与AGE受体之间的相互作用机制。结果表明，CHP得率为19.13±0.85%，Mw为1.04×10 Da。结构特征结果表明，CHP是一种与α-(1→6)糖苷键相连的无定形低甲氧基果胶多糖，主要由鼠李糖（Rha，2.55%）、半乳糖醛酸（GalA，45.01%）、β-N-乙酰氨基葡萄糖（GlcNAc，5.17%）、葡萄糖（Glc，32.29%）、半乳糖（Gal，6.80%）、木糖（Xyl，0.76%）和阿拉伯糖（Ara，7.42%）组成。CHP的表面微观结构粗糙且有裂纹，其水溶液属于具有较高弹性模量（G'）的非牛顿流体。此外，抗氧化性能结果表明，CHP具有显著的剂量依赖性抗氧化活性，在CHP浓度为1.5 mg/mL时，对AGEs的抑制能力达到最高，为66.0±0.35%。分子对接预测表明，GalA与AGE受体具有良好的亲和力，结合能为-6.20 kcal/mol。总体而言，研究结果为拓宽CHP在食品工业中的应用提供了理论依据。
