QOPNA, Departamento de Química, Universidade de Aveiro, 3810-193 Aveiro, Portugal.
QOPNA, Departamento de Química, Universidade de Aveiro, 3810-193 Aveiro, Portugal.
Carbohydr Polym. 2014 Nov 26;113:490-9. doi: 10.1016/j.carbpol.2014.07.032. Epub 2014 Jul 22.
Chitosan has been studied as a renewable polymer to form edible films allowing the incorporation of functional compounds. The aim of this work was to evaluate the effects in the chitosan films properties of the incorporation of grape pomace extracts: 0.15% of hot water extract (mainly polysaccharides), 0.15 and 0.3% of chloroform extract (wax), and 0.3 and 0.75% of n-hexane extract (oil). The evaluation of the surface morphology revealed that the films with the aqueous extract had the most homogeneous and smoother topography. The incorporation of higher proportion of wax and oil led to changes in mechanical properties of the films, namely lower resistance and stiffness. The chitosan-based films with 0.75% oil demonstrated a 75% decrease of solubility in water, due to their hydrophobicity, as confirmed by the contact angle and surface free energy measurements. The hydrophobic films showed higher antioxidant capacity in organic medium (ABTS and DPPH assays) whereas the most hydrophilic films showed an improvement in FRAP and reducing power assays. Therefore, all the chitosan-based films prepared by incorporation of these grape pomace extracts are promising for food shelf life extension.
壳聚糖作为一种可再生聚合物，已被研究用于形成可食用薄膜，以加入功能性化合物。本工作旨在评估葡萄渣提取物对壳聚糖膜性能的影响：0.15%的热水提取物（主要是多糖）、0.15%和 0.3%的氯仿提取物（蜡）以及 0.3%和 0.75%的正己烷提取物（油）。表面形貌评估表明，含有水提取物的薄膜具有最均匀和更光滑的形貌。蜡和油比例的增加导致薄膜机械性能的变化，即阻力和刚性降低。基于壳聚糖的含 0.75%油的薄膜由于其疏水性，在水中的溶解度降低了 75%，这一点通过接触角和表面自由能测量得到证实。疏水性薄膜在有机介质（ABTS 和 DPPH 测定）中显示出更高的抗氧化能力，而最亲水的薄膜在 FRAP 和还原力测定中显示出改善。因此，通过加入这些葡萄渣提取物制备的所有壳聚糖基薄膜都有望延长食品的货架期。
