Upcycling onion peels for enhanced gas barrier and antioxidant bioplastics based on starch from potato processing slurries

IF 7.1 2区环境科学与生态学 Q1 ENGINEERING, ENVIRONMENTAL

Waste management Pub Date : 2025-07-12 DOI:10.1016/j.wasman.2025.115005

Mariana Vallejo , Beatriz Esteves , Pedro Carvalho , Manuel A. Coimbra , Martinho Oliveira , Paula Ferreira , Idalina Gonçalves

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引用次数: 0

Abstract

The upcycling of food waste into high-value materials presents a key opportunity for sustainable waste management. While onion peel (OP) extracts have been investigated as additives for bioplastics, this study explores the direct incorporation of whole powdered OP (5–20 wt%) into starch-based films, eliminating extraction steps and fully valorizing this agro-industrial by-product. Using starch recovered from potato processing slurries as the polymeric matrix, the influence of OP on film structure, mechanical performance, water resistance, gas permeability, and antioxidant activity was evaluated. Chemical analysis of OP revealed a composition of 47% alcohol insoluble compounds (mainly pectin and cellulose), 12% alcohol soluble matter (primarily glucose-based carbohydrates), 6% lipids, 2% proteins, 5% gallic acid equivalents, and 27% ashes. The direct incorporation of powdered OP resulted in natural pigmentation, producing transparent films with an orangish hue. This approach enhances the aesthetic properties of films while eliminating the need for artificial dyes, contributing to a more sustainable product design. The developed bioplastics exhibited enhanced mechanical properties and improved water resistance, making them attractive for sustainable packaging applications. At OP concentrations above 10 wt%, Young’s modulus increased from 1214 MPa to 1496 MPa, while tensile strength and elongation at break decreased from 31.4 MPa to 24.6 MPa and from 4.5% to 2.1%, respectively. Water contact angles increased from 75° up to 87°, and water vapor permeability was reduced by up to 60%, improving moisture resistance. Importantly, OP incorporation did not compromise oxygen (O₂), carbon dioxide (CO₂), or nitrogen (N₂) barrier properties and imparted significant antioxidant activity, with 20 wt% OP-based films inhibiting 93% of the 2.2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic) acid radical cation (ABTS^.+) after 6 h. This study presents an innovative waste-to-resource strategy that eliminates processing waste, aligns with circular economy principles, and demonstrates the first use of whole OP as a multifunctional additive in starch-based bioplastics. By replacing conventional extraction-based approaches, this method enhances material sustainability while promoting a scalable, zero-waste approach to packaging development.

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以马铃薯加工浆料中的淀粉为基础，对洋葱皮进行升级回收，用于增强气体屏障和抗氧化生物塑料

将食物垃圾升级为高价值材料为可持续废物管理提供了一个关键机会。虽然洋葱皮（OP）提取物已被研究作为生物塑料的添加剂，但本研究探索将整个粉末状的OP （5-20 wt%）直接掺入淀粉基薄膜中，从而消除提取步骤并充分利用这种农工业副产品。以马铃薯加工浆料中回收的淀粉为聚合物基体，考察了OP对薄膜结构、力学性能、耐水性、透气性和抗氧化性能的影响。对OP的化学分析显示，其组成成分为47%的醇不溶性化合物（主要是果胶和纤维素），12%的醇溶性物质（主要是葡萄糖基碳水化合物），6%的脂类，2%的蛋白质，5%的没食子酸当量和27%的灰烬。粉末OP的直接掺入导致自然色素沉着，产生带有橙色色调的透明薄膜。这种方法增强了薄膜的美学特性，同时消除了对人造染料的需求，有助于更可持续的产品设计。开发的生物塑料表现出增强的机械性能和改善的耐水性，使它们对可持续包装应用具有吸引力。当OP浓度高于10 wt%时，杨氏模量从1214 MPa增加到1496 MPa，抗拉强度和断裂伸长率分别从31.4 MPa和4.5%下降到24.6 MPa和2.1%。水接触角从75°增加到87°，水蒸气透气性降低了60%，提高了防潮性。重要的是，OP的加入不会影响氧气（O2）、二氧化碳（CO2）或氮气（N2）的阻隔性能，并具有显著的抗氧化活性，20%的OP基薄膜在6小时后抑制了93%的2.2 ' -氮化氮-（3-乙基苯并噻唑-6-磺酸）酸自由基阳离子（ABTS.+）。该研究提出了一种创新的废物转化资源策略，消除了加工废物，符合循环经济原则。并首次在淀粉基生物塑料中使用全OP作为多功能添加剂。通过取代传统的基于提取的方法，这种方法增强了材料的可持续性，同时促进了可扩展的、零浪费的包装开发方法。

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来源期刊

Waste management 环境科学-工程：环境

CiteScore

15.60

自引率

6.20%

发文量

492

审稿时长

39 days

期刊介绍： Waste Management is devoted to the presentation and discussion of information on solid wastes,it covers the entire lifecycle of solid. wastes. Scope: Addresses solid wastes in both industrialized and economically developing countries Covers various types of solid wastes, including: Municipal (e.g., residential, institutional, commercial, light industrial) Agricultural Special (e.g., C and D, healthcare, household hazardous wastes, sewage sludge)