Characteristics of freeze-dried nanoencapsulated fish oil with whey protein concentrate and gum arabic as wall materials

Abstract Fish oil has many health effects, but due to its strong odor and rapid spoilage, its use in food formulations is limited. For these reasons, nanoencapsulation of fish oil can be important. The purpose of this study was to investigate the influence of whey protein concentrate (WPC) and gum arabic as wall materials on the characteristics of nanoencapsulated fish oil powder. Gum arabic and WPC were used in varying amounts for nanoencapsulation of fish oil. An oil-in-water emulsion with 6% fish oil and 20% aqueous solution of wall materials was prepared by sonication (24 kHz for 120 sec). The diameter of the emulsion droplets was measured by particle size analysis and they then were dried in a freeze-drier. The results showed that the type and concentration of wall material influenced the characteristics of the nanocapsules. The smallest emulsion droplet diameter (50 nm) and the highest encapsulation efficiency were found in the sample containing 100% gum arabic; however, the lowest amount of surface oil, pH and highest zeta potential and moisture content also were recorded for this sample. It can be concluded that gum arabic is more suitable for nanoencapsulation and could appropriately contain the volatile compounds within the capsules.

摘要：鱼油具有多种健康功效，但因其气味浓烈且易快速变质，在食品配方中的应用受到限制。基于上述原因，鱼油的纳米包埋技术具备重要研究价值。本研究旨在探究浓缩乳清蛋白（whey protein concentrate, WPC）与阿拉伯胶（gum arabic）作为壁材对纳米包埋鱼油粉末特性的影响。研究中采用不同用量的阿拉伯胶与WPC作为壁材对鱼油进行纳米包埋，通过超声处理（sonication，24 kHz，持续120秒）制备含6%鱼油与20%壁材水溶液的水包油（oil-in-water）乳液，采用粒径分析法测定乳液液滴直径后，通过冷冻干燥机（freeze-drier）进行干燥处理。研究结果表明，壁材的种类与浓度会显著影响纳米胶囊的特性：当采用100%阿拉伯胶作为壁材时，乳液液滴直径最小（50 nm）且包封率（encapsulation efficiency）最高，但该样品的表面油含量、pH值最低，同时zeta电位（zeta potential）与含水率最高。综上可知，阿拉伯胶更适用于鱼油的纳米包埋，能够有效将挥发性成分保留在胶囊内部。