Dipartimento di Chimica, Università degli Studi "Aldo Moro" di Bari, Via Orabona, 70126 Bari, Italy.
Chemistry Interdisciplinary Project (ChIP) Research Center, School of Pharmacy, University of Camerino, Via Ma-donna delle Carceri 9/B, 62032 Camerino, Italy.
Int J Mol Sci. 2023 Jul 14;24(14):11462. doi: 10.3390/ijms241411462.
Water-resistant and environmentally friendly sodium-alginate-based films have been investigated to develop functional materials to extend the food's shelf-life. A water-stable alginate-based film was prepared, employing both the internal and external gelation approach in the presence of CaCl. To apply this film to food packaging and thus preserve food quality, the aim of this work is to perform a chemical and physical characterization of the proposed materials, evidencing the main features and stability under different work conditions. Water contact angle measurements showed a value of 65°, suggesting an important reduced hydrophilic character of the obtained alginate films due to the novel CaCl-induced compacted polymer network. The film's stability was thus checked through swelling measurements in water after varying pH, temperature, and ionic strength. The film was stable at high temperatures and not pH-responsive. Only highly concentrated salt-based solutions negatively affected the proposed packaging, causing a large swelling. Furthermore, a water-based polyphenolic extract from grape ( L.) pomace waste was embedded inside the films in different amounts in order to confer additional properties. The extract's polyphenolic content (evaluated from HPLC/MS-MS measurements) endowed the films' UV-light screening and enhanced antioxidant properties. These important findings suggest the additional potential role of these films in protecting food from light deterioration. The stability of these hybrid films was also checked by observation, as the polyphenols' presence did not largely alter the alginate network that occurred yet was water-resistant under the described work conditions.
研究了耐水和环保的基于海藻酸钠的薄膜，以开发功能性材料来延长食品的保质期。在 CaCl 的存在下，采用内部和外部凝胶化方法制备了水稳定的海藻酸钠基薄膜。为了将这种薄膜应用于食品包装并保持食品质量，本工作的目的是对所提出的材料进行化学和物理特性分析，证明其在不同工作条件下的主要特征和稳定性。水接触角测量表明接触角为 65°，这表明由于新型 CaCl 诱导的聚合物网络紧密化，所得海藻酸钠薄膜的亲水性显著降低。通过在不同 pH 值、温度和离子强度下在水中进行溶胀测量来检查薄膜的稳定性。该薄膜在高温下稳定且对 pH 无响应。只有高浓度的盐基溶液会对所提出的包装产生负面影响，导致大量溶胀。此外，为了赋予额外的性能，将来自葡萄（ L.）果皮废物的水基多酚提取物以不同的量嵌入到薄膜中。提取物的多酚含量（通过 HPLC/MS-MS 测量评估）赋予了薄膜的紫外线屏蔽和增强的抗氧化性能。这些重要发现表明这些薄膜在保护食品免受光降解方面具有额外的潜在作用。通过观察也检查了这些混合薄膜的稳定性，因为多酚的存在并没有在很大程度上改变发生的海藻酸钠网络，但在所述工作条件下仍然耐水。
