β-环糊精稳定南极磷虾油Pickering乳液的制备及其稳定性的研究

Preparation of Antarctic krill Pickering emulsion stabilized by β-cyclodextrin and its stability

摘要:

为了确定β-环糊精稳定南极磷虾油Pickering乳液的制备工艺并研究其稳定性，实验通过研究不同乳化方法 (超声、高速剪切和高压微射流)、不同油相体积分数 (30%、40%、50%、60%和70%)及不同β-环糊精添加量 (1%、2%、3%、4%和5%，质量分数)对乳液特征指标 (浊度、离心稳定性、粒径和ζ-电位)的影响，初步确定了β-环糊精稳定南极磷虾油Pickering乳液的制备工艺，而后通过乳液的形貌及显微变化、乳液的特征指标评价乳液的热杀菌稳定性、冻融稳定性和贮藏稳定性。结果表明，油相体积为60%、β-环糊精添加量为3%、采用高速剪切乳化的方法可以得到南极磷虾油Pickering乳液，乳液的浊度、离心稳定性、粒径和ζ-电位分别为1.83、85.12%、110.50 nm和−28.39 mV。热杀菌对乳液的形貌及显微结构、乳液的特征指数没有显著影响。冻融显著影响了乳液的特性，冻融后乳液出现了严重的沉淀、乳析等现象，乳液不再呈现均一、稳定的状态。乳液在25 ℃，密闭条件下贮藏16 d内，虽然乳液的形貌结构、显微结构及乳液的特征指标发生了变化，但乳液仍保持了基本特性。总之，β-环糊精作为稳定剂可以用来制备南极磷虾油Pickering乳液，该乳液具有良好的热杀菌和贮藏稳定性 (16 d内)，但不具备冻融稳定性。

关键词:南极磷虾油;β-环糊精;Pickering乳液;形貌变化;显微变化;特征指标;稳定性

Abstract:

Pickering emulsion is a new type of emulsion system that uses solid particles to achieve the stability. Compared with traditional emulsions, Pickering emulsion has not only the basic characteristics of classic emulsions, but also better stability, higher safety and a wider range of applications. As a result, Pickering emulsion has received widespread attention. However, most researchers used inorganic particles or organic polymers to prepare Pickering emulsions. These particles have shortcomings such as low biocompatibility and poor degradability, which limit their use in the food industry. Therefore, seeking food-grade natural stabilizers has become a development trend. β-cyclodextrin is a cyclic oligosaccharide composed of seven glucose molecules. It has a unique structure of hydrophobic internal and hydrophilic external, and has good emulsifying properties. In the water-oil system, β-cyclodextrin can embed the oil phase in the inner cavity and adsorb the water phase on the outer wall, forming an interfacial film at the oil-water interface in the form of clathrate particles, thereby forming a stable emulsion system. In order to make the Antarctic krill oil Pickering emulsion stabilized by β-cyclodextrin and study its stability, the effects of different emulsification methods (ultrasonic, high-speed shearing, high pressure microfluidics), different oil phase volume fractions (30%, 40%, 50%, 60%, 70%), and different β-cyclodextrin mass fraction (1%, 2%, 3%, 4%, 5%) on the emulsion system (turbidity, centrifugal stability, particle size, ζ-potential) were studied and the preparation process of β-cyclodextrin stabilized Antarctic krill oil Pikering emulsion was determined. Then, the thermal sterilization stability, freeze-thaw stability and storage stability of the emulsion were investigated through the appearance, microscopic changes of the emulsion and the characteristic indexes. The results showed that a stable Antarctic krill oil Pickering emulsion was prepared with 60% oil volume fraction, 3% β-cyclodextrin mass fraction and high-speed shear emulsification. The turbidity, centrifugal stability, particle size and ζ-potential of the emulsion were 1.83, 85.12%, 110.5 nm and -28.39 mV, respectively. Thermal sterilization had no significant effect on the appearance and microstructure of the emulsion, and the characteristic index of the emulsion. Freezing and thawing process had a significant impact on the emulsion. After the freezing and thawing, serious precipitation and emulsification took place in the emulsion, and the emulsion was no longer in a uniform and stable state. After the emulsion was stored for 16 days, although the appearance structure, microstructure and characteristic indexes of the emulsion had changed, the emulsion still showed a uniform and stable state. In short, β-cyclodextrin as a stabilizer could be used to prepare Antarctic krill oil Pickering emulsion, which could have good thermal sterilization and storage stability (within 16 days), but no freeze-thaw stability.

Key words:Antarctic krill oil;β-cyclodextrin;Pickering emulsion;morphology change;microscopic change;characteristic index;stability