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 鱼油具备多种健康功效，但因其气味浓烈且易腐败变质，其在食品配方中的应用受到限制。正因如此，鱼油的纳米包埋（nanoencapsulation）技术具备重要研究意义。本研究旨在探究乳清蛋白浓缩物（whey protein concentrate, WPC）与阿拉伯胶作为壁材，对纳米包埋鱼油粉末特性的影响。实验中以不同配比的阿拉伯胶与WPC作为壁材，对鱼油进行纳米包埋。将含6%鱼油与20%壁材水溶液的水包油（oil-in-water）乳液经超声处理（sonication，24 kHz，持续120秒）制备得到。通过粒径分析测定乳液液滴直径，随后采用冷冻干燥机（freeze-drier）对乳液进行干燥处理。结果表明，壁材的种类与浓度会显著影响纳米胶囊的各项特性。在全部使用100%阿拉伯胶的样品中，乳液液滴直径最小（50 nm），包封率（encapsulation efficiency）最高；同时该样品的表面油（surface oil）含量与pH值最低，而Zeta电位（zeta potential）与含水率最高。综上可得出结论：阿拉伯胶更适用于鱼油的纳米包埋，可有效将挥发性组分锁定在胶囊内部。