| Sweet orange oil is a great popular source of natural aroma in food and daily chemistry industry.It also has antibacterial and antioxidant properties and has great potential in the application of nutrition and health.However,the water solubility of sweet orange oil is poor and its stability is greatly affected by light,heat and oxygen.Therefore,in order to improve the stability of sweet orange oil,this paper was studied on the sweet orange oil and its two embedding forms of nano-emulsion and nanomicroencapsulation.Through the single factor analysis to screen suitable natural emulsifier and the response surface methodology to optimize the preparation process,which were to prepare nanoemulsion to enhance the stability of sweet orange oil.And with reducing particle size of capsule,studying on the effect of particle size and water activity on the stability of encapsulated sweet orange oil as well as further investigation on the flavor release mechanism of tableting candy and the comprehensive quality of sensory evaluation,so as to provide scientific basis for the preparation of sweet orange oil nano-emulsion and nano-capsule with high stability and optimal sustained release.The main results are as follows:1.Compared with Q-naturale and tween 80,tea saponin was the best natural emulsifier which could stabilize sweet orange oil-in-water nano-emulsion.And the optimal preparation process obtained by response surface methodology included sweet orange oil content of 4.05 wt% and ester gum content of 2.17 wt%.Under these conditions and using high-pressure microfluidization with 22000 psi for twice,the MDD,PDI,turbidity,turbidity loss rate and D-limonene oxidation rate of sweet orange oil nano-emulsion were(130.8±1.4)nm,0.178±0.010,0.322±0.001,(0.0072±0.0023)A/day and(0.69±0.00)%,respectively.The MDD of the optimal sweet orange oil nanoemulsion was less than 140 nm,and PDI was less than 0.3 when stored at 4 ? for 60 days.It showed good dynamic stability.2.The particle size and water activity had significant effects on the physical properties,D-limonene release characteristics and oxidation stability of sweet orange oil nano-microcapsules(LP-1.173 ?m,MP-0.684 ?m,SP-0.313 ?m and NP-0.173 ?m).With the decrease of particle size,the NP surface oil content was the lowest,the encapsulation efficiency was the highest and the D-limonene release rate and oxidation rate were significantly reduced.With the increase of water activity from 0.25 to 0.75,the D-limonene release rate in LP,SP and NP increased significantly first and then increased slowly,while the D-limonene release rate in MP first increased significantly and then decreased significantly.And 0.33 was a key water activity value,in which MP release rate reached the highest,and NP release rate was the lowest,while the release rate of LP and SP were higher without significant difference.With the increase of water activity from 0.25 to 0.75,the oxidation rate first increased and then decreased,and reached the highest at 0.33 aw,where NP oxidation rate was the lowest,MP oxidation rate was the highest and the oxidation rates of SP and LP were relatively high without significant difference.The release characteristics and oxidation stability of D-limonene were closely related to the surface particle morphology of the nano-microcapsules.The more complete the particle surface morphology,the higher the stability.Therefore,the storage stability of NP was the highest and MP was the lowest.3.During the first 30 min of equilibrium,the release of D-limonene in tableting candy followed a general trend in water and acid systems: C-MP > C-LP > C-SP > CNP.During the first 10 min of equilibrium,the release mechanism of D-limonene followed the Peppas-Sahlin model.And the smaller the particle size of the sweet orange oil nano-microcapsules,the release of D-limonene followed the diffusion release mechanism.And the larger the particle size,the release of D-limonene was susceptible to the system solution and followed the erosion release mechanism in the acid system.And the comprehensive sensory quality of tabletting candy prepared by the sweet orange oil microcapsule with larger particle size was better. |
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