Pectic polysaccharides with film-forming ability are often recovered from renewable agrifood by-products through solid-liquid extraction (SLE). Targeting an organic solvent-free approach, in this work, it is hypothesized that pectic polysaccharides of interest for bioplastics development can be recovered by microwave-assisted extraction (MAE) and purified by ultrafiltration. Coffee fruit cascara (CFC) was used as raw material. MAE of CFC-derived pectic polysaccharides was carried out at 120 °C at different times (2 min, 5 min, and 10 min). A 3-times (1 h each) sequential SLE with 2% acetic acid under reflux at atmospheric pressure was also performed. High molecular weight (HMW) extracts obtained by MAE for 2 min (HMW_MAE 2′) and by SLE for 1 h (HMW_SLE1), composed of 60 mol% and 54 mol% uronic acids with 18% and 17% methyl-esterification, and 7% and 8% acetylation, respectively, were selected for bioplastics development. HMW_MAE 2’ originated slightly transparent, dark brown, hydrophilic (. 32° water contact angle), and antioxidant (90% ABTS inhibition after 5 min) bioplastics, similar to HMW_SLE1-derived materials, but 10-fold more stretchable (20% and 2% elongation at break, respectively). Therefore, MAE followed by ultrafiltration showed to be a fast and clean strategy to recover low methyl-esterified CFC pectic polysaccharides with the ability to develop antioxidant and flexible bioplastics.

中文翻译：

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基于微波辅助提取的咖啡果果胶多糖的抗氧化剂和柔性生物塑料

具有成膜能力的果胶多糖通常通过固液萃取（SLE）从可再生农产品副产品中回收。针对无有机溶剂的方法，在这项工作中，假设可以通过微波辅助萃取（MAE）回收生物塑料开发中感兴趣的果胶多糖并通过超滤纯化。以咖啡果皮（CFC）为原料。 CFC 衍生果胶多糖的 MAE 在 120 °C 下不同时间（2 分钟、5 分钟和 10 分钟）进行。还进行了 3 次（每次 1 小时）连续 SLE，使用 2% 乙酸在大气压回流下进行。通过 MAE 2 分钟 (HMW_MAE 2') 和通过 SLE 1 小时 (HMW_SLE1) 获得的高分子量 (HMW) 提取物，由 60 mol% 和 54 mol% 糖醛酸组成，其中 18% 和 17% 甲酯化，以及分别选择 7% 和 8% 乙酰化用于生物塑料的开发。 HMW_MAE 2' 源自微透明、深棕色、亲水性（32° 水接触角）和抗氧化剂（5 分钟后 90% ABTS 抑制）生物塑料，类似于 HMW_SLE1 衍生材料，但可拉伸性高 10 倍（20% 和 20%）断裂伸长率分别为 2%）。因此，MAE 和超滤被证明是一种快速、清洁的策略，可回收低甲基酯化的 CFC 果胶多糖，并具有开发抗氧化剂和柔性生物塑料的能力。