Jin Xiaolin, Han Yue, Sun Qingshen
Engineering Research Center of Agricultural Microbiology Technology, Ministry of Education & Heilongjiang Provincial Key Laboratory of Plant Genetic Engineering and Biological Fermentation Engineering for Cold Region & Key Laboratory of Microbiology, College of Heilongjiang Province & School of Life Sciences, Heilongjiang University, Harbin, China.
J Food Sci. 2025 Apr;90(4):e70216. doi: 10.1111/1750-3841.70216.
The aim of this study was to extract watermelon rind (WR) pectin (WRP) and watermelon rind polyphenols (WRE) and evaluate the effect of pectin/sodium alginate composite films (WRPSA) with or without WRE on strawberry preservation. WRP was extracted using citric acid, whereas WRE was obtained through ethyl acetate extraction. The extracted WRP was characterized for composition and structural properties, multi-angle laser light scattering (MALLS), Fourier Transform Infrared Spectroscopy (FTIR), differential scanning calorimetry (DSC), x-ray diffraction (XRD), ζ-potential analysis, and rheological measurements. The pectin/SA film (WRPSA) and pectin/SA composite film containing WRE (WRPESA) were prepared. Both films were analyzed for physical properties and structurally characterized. Strawberries were wrapped with either WRPSA, WRPESA, or no treatment (exposed) and stored under lightproof conditions at 4°C for 12 days. The results showed that WRP was a low-ester pectin (degree of methylation [DM] = 38.7%) with a molecular weight of 683 kDa. WRP had typical polysaccharide characteristic peaks and good thermal stability that could be used as a film-forming substrate. WRPESA showed better mechanical strength and antioxidant capacity than that of WRPSA, indicating that WRE showed synergistic effects on the improvement of composite films. Additionally, WRPESA effectively reduced strawberry softening, color deterioration, and weight loss, in addition to the delay in the dynamic changes in sugar content and pH and accumulation of malondialdehyde (MDA). WRPESA also helped maintain the total phenolic content of the strawberries. These findings suggest that watermelon byproducts could be valorized for sustainable food packaging, reducing both agricultural waste and reliance on synthetic materials. Practical Application: This article confirmed the feasibility of a sequential extraction process for watermelon rind pectin and polyphenols, which can later be applied to industrial production lines to increase the utilization rate of watermelon rind. The practical application value of this research lies in the development of biodegradable packaging materials. By extracting pectin and polyphenols from watermelon rind, the resulting films can effectively extend the shelf life of strawberries and reduce food waste. Furthermore, this study promotes the utilization of agricultural waste, enhances the nutritional value of food, and provides new opportunities for local economic development. Additionally, it offers a scientific basis for advancing sustainable packaging technology and food preservation innovations, which is significant for environmental protection and healthy consumption.
本研究的目的是提取西瓜皮果胶（WRP）和西瓜皮多酚（WRE），并评估含或不含WRE的果胶/海藻酸钠复合膜（WRPSA）对草莓保鲜的影响。WRP采用柠檬酸提取，而WRE通过乙酸乙酯萃取获得。对提取的WRP进行了组成和结构性质表征，包括多角度激光光散射（MALLS）、傅里叶变换红外光谱（FTIR）、差示扫描量热法（DSC）、X射线衍射（XRD）、ζ电位分析和流变学测量。制备了果胶/海藻酸钠膜（WRPSA）和含WRE的果胶/海藻酸钠复合膜（WRPESA）。对这两种膜进行了物理性能分析和结构表征。用WRPSA、WRPESA或不进行处理（暴露）包裹草莓，并在4℃的避光条件下储存12天。结果表明，WRP是一种低酯果胶（甲基化程度[DM]=38.7%），分子量为683 kDa。WRP具有典型的多糖特征峰和良好的热稳定性，可作为成膜基质。WRPESA比WRPSA表现出更好的机械强度和抗氧化能力，表明WRE对复合膜的改善具有协同作用。此外，WRPESA有效减少了草莓的软化、颜色劣化和重量损失，还延缓了糖含量、pH值的动态变化以及丙二醛（MDA）的积累。WRPESA还有助于维持草莓的总酚含量。这些发现表明，西瓜副产品可用于可持续食品包装，减少农业废弃物并降低对合成材料的依赖。实际应用：本文证实了西瓜皮果胶和多酚顺序提取工艺的可行性，该工艺随后可应用于工业生产线，以提高西瓜皮的利用率。本研究的实际应用价值在于开发可生物降解的包装材料。通过从西瓜皮中提取果胶和多酚，所得薄膜可有效延长草莓的货架期并减少食物浪费。此外，本研究促进了农业废弃物的利用，提高了食品的营养价值，并为地方经济发展提供了新机遇。此外，它为推进可持续包装技术和食品保鲜创新提供了科学依据，对环境保护和健康消费具有重要意义。
