Department of Chemistry, Faculty of Science and Agriculture, University of Fort Hare, P/Bag X1314, Alice 5700, South Africa.
Department of Chemical and Physical Sciences, Faculty of Natural Sciences, Walter Sisulu University, P/Bag X1, Mthatha 5117, South Africa.
Molecules. 2024 Aug 16;29(16):3878. doi: 10.3390/molecules29163878.
Pectin is a natural polymer that is found in the cell walls of higher plants. This study presents a comprehensive analysis of pectin extracted from lemon in two different geographic regions (Peddie and Fort Beaufort) in two consecutive years (2023 and 2024) named PP 2023, PP 2024, FBP 2023, and FBP 2024. The dried lemon peels were ground into a powder, sifted to obtain particles of 500 μm, and then subjected to pectin extraction using a conventional method involving mixing lemon peel powder with distilled water, adjusting the pH level to 2.0 with HCl, heating the mixture at 70 °C for 45 min, filtering the acidic extract, and precipitating pectin with ethanol. The yield of these pectin samples was statistically significant, as FBP 2024 had a maximum yield of 12.2 ± 0.02%, PP 2024 had a maximum yield of 13.0 ± 0.02%, FBP 2023 had a maximum yield of 12.2 ± 0.03%, and PP 2023 had a maximum yield of 13.1 ± 0.03%, The variation in yield could be due to the differences in the growing conditions, such as the climate and soil, which could have affected the pectin content in the lemons. The physicochemical characterization of all samples proved that our pectin samples could be used in the pharmaceutical and food industries, with anhydrouronic acid content which was greater than 65%, as suggested by the FAO. The scanning electron microscope analysis of all extracted pectin was rough and jagged, while the commercial pectin displayed a smooth surface morphology with a consistent size. FTIR confirmed the functional groups which were present in our samples. Thermogravimetric analysis was employed to investigate the thermal behavior of the extracted pectin in comparison with commercial pectin. It was found that the extracted pectin had three-step degradation while the commercial pectin had four-step degradation. Additionally, pectin samples have been shown to have antioxidants, as the IC of PP 2024, PP 2023, FBP 2023, FBP 2024, and Commercial P was 1062.5 ± 20.0, 1201.3 ± 22.0, 1304.6 ± 19.0, 1382.6 ± 29.9, and 1019.4 ± 17.1 mg/L, respectively. These findings indicate that lemon pectin has promising characteristics as a biopolymer for use in biomedical applications.
果胶是一种天然聚合物，存在于高等植物的细胞壁中。本研究对两个不同地理区域（佩迪和博福特堡）连续两年（2023 年和 2024 年）从柠檬中提取的果胶进行了全面分析，分别命名为 PP 2023、PP 2024、FBP 2023 和 FBP 2024。将干柠檬皮粉碎成粉末，过筛获得 500μm 的颗粒，然后用常规方法进行果胶提取，方法是将柠檬皮粉末与蒸馏水混合，用 HCl 将 pH 值调至 2.0，将混合物在 70°C 下加热 45 分钟，过滤酸性提取物，用乙醇沉淀果胶。这些果胶样品的产率具有统计学意义，因为 FBP 2024 的最大产率为 12.2±0.02%，PP 2024 的最大产率为 13.0±0.02%，FBP 2023 的最大产率为 12.2±0.03%，PP 2023 的最大产率为 13.1±0.03%。产率的变化可能是由于生长条件的差异，如气候和土壤，这可能会影响柠檬中的果胶含量。所有样品的理化特性表征表明，我们的果胶样品可用于制药和食品工业，其无水醛酸含量大于 65%，如粮农组织所建议。所有提取的果胶的扫描电子显微镜分析显示其表面粗糙且参差不齐，而商业果胶则显示出光滑的表面形态和一致的尺寸。傅里叶变换红外光谱（FTIR）确认了我们样品中存在的功能基团。热重分析（TGA）用于研究与商业果胶相比提取的果胶的热行为。结果发现，提取的果胶有三步降解，而商业果胶有四步降解。此外，果胶样品具有抗氧化剂的特性，因为 PP 2024、PP 2023、FBP 2023、FBP 2024 和商业 P 的 IC 分别为 1062.5±20.0、1201.3±22.0、1304.6±19.0、1382.6±29.9 和 1019.4±17.1mg/L。这些发现表明，柠檬果胶作为一种生物聚合物，具有在生物医学应用中使用的巨大潜力。
