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.

以针叶樱桃浆生产过程产生的农业工业副产物富含残留维生素C为背景，本研究为实现其中维生素C的提取与稳定，提出采用离子凝胶法制备纳米颗粒（NP），并以此为基础制备半乳甘露聚糖基质的纳米复合（NC）薄膜。本研究对所制备的纳米颗粒进行了表征，并评估了其在不同储存条件（光照、温度及氧化气氛）下的稳定性。动态光散射（DLS）与扫描电子显微镜（SEM）表征结果显示，该纳米颗粒形貌均一、呈球形，粒径约为220 nm。稳定性测试方面，紫外-可见分光光度分析结果表明，包埋后的维生素C降解速率显著更低，在储存15天后，包埋体系的维生素C保留率较未包埋体系高出30%以上。与之相符的是，纳米复合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保留率约为初始浓度的80%，而未包埋体系的保留率仅降至45%。通过扫描电子显微镜（SEM）对薄膜的形貌分析结果显示，纳米颗粒在半乳甘露聚糖基质中分布均匀。综上，本研究结果证实了采用该包埋方法稳定从针叶樱桃农业工业副产物中提取的维生素C的可行性。