Santos Jenifer, Calero Nuria, Trujillo-Cayado Luis Alfonso, Martín-Piñero María José, Muñoz José
Departamento de Ingeniería Química, Escuela Politécnica Superior, Universidad de Sevilla c/Virgen de África 7, E41011 Sevilla, Spain.
Departamento de Ingeniería Química, Facultad de Química, Universidad de Sevilla c/P. García González 1, E41012 Sevilla, Spain.
Materials (Basel). 2020 Aug 7;13(16):3486. doi: 10.3390/ma13163486.
Emulsions can be used as delivery systems for bioactive ingredients for their incorporation in food products. Essential oils are natural compounds found in plants that present antioxidant and antimicrobial activity. Therefore, the main goal of this work was to develop emulsions, containing mandarin essential oil stabilized by two food-grade surfactants and guar gum, and to evaluate their physical stability. The initial droplet size of emulsions developed by microfluidization was optimized, obtaining diameters below one micron regardless of the processing conditions. However, the emulsion processed at 25,000 psi and one pass exhibited the lowest mean droplet sizes and polidispersity, and therefore, a higher stability. Different ratios of Tween 80 and Span 80 were assessed as stabilizers. Results obtained indicated that the ratio of surfactants had a significant effect on the mean droplet sizes, physical stability, and rheological properties. Thus, we found that the optimum ratio of surfactants was 75/25 (Tween80/Span80) on account of the lowest droplet mean diameters, lack of coalescence, and a low creaming rate. The rheological characterization of the stable emulsions showed a shear thinning flow behavior, and G″ (loss modulus) values higher than G' (storage modulus) values, in all the frequency range. The rheological behavior may be governed by the guar gum, which was confirmed by field emission scanning electron microscopy (FESEM). This research can be considered as the starting point for future applications of mandarin essential oil in emulsions, which can be incorporated in products as food preservatives.
乳液可作为生物活性成分的递送系统，用于将其添加到食品中。香精油是植物中发现的天然化合物，具有抗氧化和抗菌活性。因此，本研究的主要目标是开发由两种食品级表面活性剂和瓜尔胶稳定的含柑橘属植物精油乳液，并评估其物理稳定性。通过微流化技术制备的乳液的初始液滴尺寸得到了优化，无论加工条件如何，均能获得直径小于1微米的乳液。然而，在25000 psi压力下处理一次的乳液具有最低的平均液滴尺寸和多分散性，因此具有更高的稳定性。评估了不同比例的吐温80和司盘80作为稳定剂。结果表明，表面活性剂的比例对平均液滴尺寸、物理稳定性和流变学性质有显著影响。因此，我们发现表面活性剂的最佳比例为75/25（吐温80/司盘80），这是由于其具有最低的液滴平均直径、无聚并现象以及较低的乳析率。稳定乳液的流变学特性表明，在所有频率范围内，其呈现出剪切变稀的流动行为，且损耗模量（G″）值高于储能模量（G'）值。流变行为可能受瓜尔胶的控制，场发射扫描电子显微镜（FESEM）证实了这一点。本研究可被视为柑橘属植物精油在乳液中未来应用的起点，其可作为食品防腐剂添加到产品中。
