Preparation And Characterization Of Orange Oil Nanoemulsions And Nano-Encapsulation

The application of nanoemulsions and nanocapsules in the food industry is very promising.In this study,orange oil nanoemulsions and nano-capsules were used as research objects.Low-cost,small-molecule emulsifiers were used in place of high-cost embedding materials(such as acacia gum),and the best wall materials for compounding and embedding essential oils' flavors were screened.In the preparation process,the production technology of high-pressure microfluidic nanoemulsions is optimized.The characteristics of the nanoemulsions are studied by comparing different emulsifiers,and the influence of the composition of the continuous phase and the ratio of the phase viscosities on the formation of the nanoemulsions is studied,and the interface composition is analyzed.In order to elucidate the instability mechanism of the prepared nanoemulsions,and study the shelf life of emulsions prepared with different emulsifiers at different storage temperatures.1.Study the properties of nanoemulsions by changing the conditions for preparing nanoemulsions.The results show that many passes can be successfully produced under high pressure homogenization with a smaller average droplet diameter(MDD)of the nanoemulsion,the MDD of the nanoemulsion can be as low as 108 nm.The temperature,emulsifier type,and concentration affect the MDD of the nanoemulsion within a certain range.The influence of these factors with the homogenous pressure and number of passes on the MDD is complicated,and it is observed that there are interactions between the factors.The study also found that phase viscosity has a great influence on the homogenization efficiency,so the optimal phase viscosity ratio(?d/?c)for emulsifying ratio is also of great significance for the production of nanoemulsion.This study provides a theoretical basis for revealing the factors of nanoemulsion formation,thus providing guidance for the preparation of nanoemulsions and practical food applications.2.The optical properties and physical stability of nanoemulsions under different shelf life and temperature were studied.The interface composition was found to affect turbidity in terms of temperature and droplet size.More specifically,the effect of interface composition on turbidity was related to size.The relationship between MDD and turbidity of the nanoemulsion was established,providing valuable information for the optical properties of the nanoemulsion.(1)At 5?,the turbidity at the interface of Whe protein isolate(WPI)is higher than the turbidity of MDD at modified starch(MS).The WPI emulsion aggregated in a large turbidity range(64.9-192 NTU)but the MDD range was small(120-131 nm).The factors that affect turbidity are determined as droplet size and interface composition.More specifically,the influence of interface composition on turbidity is related to size(2)From the 21-day shelf life experiment at 25?,the main destabilizing mechanism of the nanoemulsion prepared with modified starch as emulsifier was coalescence.The MDD and turbidity of nanoemulsions prepared with sodium lauryl sulfate(sodium dodecyl sulfate,SDS)as an emulsifier during storage.Over time,both MDD and turbidity were stable,indicating that no Ostwald ripening occurred(3)At 45? for 5 days,there is a significant increase in turbidity and particle size with increasing storage time,which can be attributed to the droplet coalescence discussed above and/or Ostwald Curing process.At storage temperatures of 45?,storage for 5 to 21 days,turbidity and MDD increased significantly over longer storage periods.Emulsifiers may undergo some chemical degradation(hydrolysis),which causes the emulsion to lose its ability to form micelles and stabilize the emulsion3.Different microcapsules are prepared by controlling the particle size of the emulsion,comparing the oxidation condition of the limonene prepared under different conditions and the total oil amount of the microcapsules to determine which of the microcapsules under the treatment conditions has the best.As a result,the effect of the particle size of the emulsion on the properties of the microcapsules can also be seen.The highest degree of oxidation was found in the sample with high shear rate(HS),the lowest oxidation degree was found in sample(M)treated with high pressure microfluidization,and the smaller the initial emulsion particle size,the better the protective effect on the core material.The total oil loss of the emulsion prepared under high pressure is larger,and the emulsion without pressure treatment is lower than the total oil amount of the emulsion under low pressure.Therefore,the higher the pressure when preparing the emulsion,the lower the oxidation level of limonene,and the total oil content of the microcapsules with the total oil content prepared under the medium pressure is the highest.