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投稿时间：2020-08-13
投稿时间：2020-08-13
中文摘要: 热变性后的燕麦蛋白（oat protein isolate，OPI）与结冷胶（gellan gum，GG）通过添加不同浓度的葡糖酸-δ-内酯（glucono-delta-lactone，GDL）形成OPI-GG冷诱导凝胶，通过质构分析、扫描电子显微镜、激光共聚焦显微镜以及傅里叶红外光谱，研究不同条件下形成的凝胶微结构以及分子构象的变化，探究不同凝胶微结构与凝胶控释特性的关联性。结果表明，在GG添加量为0.1%、pH 5时，凝胶硬度最大，随着GG浓度升高，凝胶硬度逐渐变弱。通过扫描电镜和激光共聚焦的观察可知OPI-GG凝胶可形成两种网络微结构，在pH 4和pH 5时，OPI与GG之间由于静电引力使其相互作用力增强，形成致密且均匀的单网络微结构；在pH 6和pH 7时，OPI与GG由于静电斥力的作用产生相分离，从而形成双网络结构。具有不同微结构的OPI-GG凝胶可作为基质包埋核黄素，双网络结构的凝胶可有效提高核黄素的包埋率（75%），其在pH 1.2磷酸缓冲溶液（phosphate buffer saline，PBS）中浸泡2 h后核黄素的释放率为33%；致密的单网络结构OPI-GG凝胶包埋率为61%，在pH1.2 PBS中可有效阻止核黄素的释放，其释放率为18%，并在pH 7.4 PBS中使核黄素逐步释放，8 h后释放率为53%。该研究结果表明，在中性条件下制备的OPI-GG双网络结构冷凝胶具有较好的核黄素包埋能力，在酸性条件下制备的OPI-GG单网络冷凝胶具有较好的控释能力，因此，不同微结构的OPI-GG冷凝胶具有作为营养素包埋和递送体系的潜力。
Abstract:Cold-induced oat protein isolate-gellan gum gels were prepared using thermally denatured oat protein isolate（OPI）and gellan gel（GG）by adding various glucono-delta-lactone（GDL）concentrations.The microstructure of the gel formed under different conditions and the changes in molecular conformation were studied through texture analysis，scanning electron microscopy，laser confocal microscopy，and Fourier infrared spectroscopy to explore the influence of different gel microstructures on the gel controlled release properties.The results showed that the highest gel strength was found when adding 0.1% GG and fabricating at pH 5.As the GG concentration raised，the gel strength was gradually weakened.According to the observation of scanning electron microscope and confocal，OPI-GG gel could form two kinds of network microstructures，at pH 4 and pH 5，the interaction between OPI and GG were enhanced due to the electrostatic attraction，and OPI-GG gel formed a dense and uniform single network structure；while at pH 6 and pH 7，a double network structure was found for OPI-GG gel due to the phase separation during gelling process caused by electrostatic repulsion between OPI and GG.OPI-GG gel with different network structure had ability to encapsulate riboflavin，the results indicated that the gel with double network structure could effectively increase the encapsulation efficiency of riboflavin（75%），the release rate of riboflavin in the pH 1.2 phosphate buffer saline（PBS）2 h was 33%；while the gel with dense single network structure formed under the condition of pH5 had encapsulation efficiency of 61%，and the release of riboflavin in pH1.2 PBS was only 18% after 2 h，and allowed gradually release of riboflavin in the pH 7.4 PBS，while the release rate was 53% after 8 h.The results of this study suggested that the cold-induced OPI-GG gels with double network structure fabricated under neutral conditions had better encapsulation efficiency，while the cold-induced OPI-GG gels with uniform dense single network structure prepared under acidic conditions had better controlled release capacity.Therefore，OPI-GG gels with various network microstructure had potential to be used as nutraceutical encapsulation and delivery systems.
keywords: oat protein isolate gellan gum gel microstructure controlled release property double network structure
文章编号：202101002 中图分类号： 文献标志码：
基金项目:天津市自然科学基金项目（18JCYBJC43700）；天津市一二三产业融合发展科技示范工程（18ZXYENC00090）；天津市合成生物技术创新能力提升行动重大科技攻关任务（TSBICIP-KJGG-004-09）
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