Stability of Nanocomposite Edible Films Based on Polysaccharides and Vitamin C from Agroindustrial Residue

The agroindustrial residue from the production of acerola pulp is rich in residual vitamin C. Thus, aiming its extraction and stabilization, this work proposed the nanoparticle (NP) encapsulation via ionic gelation with subsequent preparation of nanocomposites (NC) film based on galactomannan matrix. NP were characterized and their stabilities were evaluated under different storage conditions (incidence of light, temperature and oxidizing atmosphere). The results by Dynamic Light Scattering (DLS) and Scanning Electron Microscopy (SEM) indicated homogeneous morphology, spherical shape and size of ~220 nm. Regarding the stability, the UV-visible spectrophotometric analysis showed a much lower degradation rate for encapsulated vitamin C, resulting in more than 30% of preservation compared with the non-encapsulated systems at the end of 15th day of storage. In agreement, the NC films also resulted in preservation of vitamin C mainly for the test in high temperature, which maintained about 80% of the initial concentration, whereas in the non-encapsulated condition this value fell to 45%. The morphological analysis of these films by SEM indicated good distribution of the NP in the galactomannan matrix. Thus, the results indicate the feasibility of using the encapsulation method to stabilize vitamin C extracted from the agroindustrial residue of acerola.

从针叶樱桃果肉生产过程中产生的农业工业副产物富含残留维生素C。为实现其中维生素C的提取与稳定化，本研究提出通过离子凝胶法进行纳米颗粒（NP）包封，并以此为基础制备基于半乳甘露聚糖基质的纳米复合（NC）薄膜。对所制备的纳米颗粒进行了表征，并在不同储存条件（光照、温度与氧化气氛）下评估了其稳定性。动态光散射（Dynamic Light Scattering, DLS）与扫描电子显微镜（Scanning Electron Microscopy, SEM）的表征结果显示，该纳米颗粒形貌均一、呈球形，粒径约为220 nm。在稳定性测试中，紫外-可见分光光度分析（UV-visible spectrophotometric analysis）结果显示，包封后的维生素C降解速率显著更低；储存15天后，包封体系的维生素C保留率较未包封体系高出30%以上。与之一致的是，纳米复合（NC）薄膜同样可有效保留维生素C，尤其在高温测试条件下，其维生素C保留量约为初始浓度的80%；而未包封体系的该保留率仅降至45%。通过扫描电子显微镜（SEM）对该纳米复合薄膜的形貌分析显示，纳米颗粒（NP）在半乳甘露聚糖基质中分布均匀。综上，本研究结果证实，采用该包封法稳定化提取自针叶樱桃农业工业副产物的维生素C具有可行性。