Preparation Of Flavor Sustained-Release Microcapsules By Ultrasonic Spray-Freeze Drying

The composition of food flavor is very complicated,the volatility of each component is large,some components are volatile,and the volatilization of these components not only causes loss of flavor,but also changes the composition of flavor due to the loss of certain components.,thereby distorting the flavor.If these volatile flavor substances are microencapsulated,the loss of volatile flavor compounds can be reduced due to the sealing action of the wall material,which contributes to the complete retention of the flavor substances,thereby improving the stability of storage and use of the flavor substances.Among the flavor components of flavors and fragrances are small molecules of esters and terpenes,which are extremely volatile.The microencapsulation causes the wall material to wrap around the core material,and the volatilization loss can be reduced due to the barrier effect of the wall material.However,whether it is before or after embedding,the detection and evaluation of aroma substances is an indispensable part of the production of flavors and fragrances.Effectively obtaining a more detailed and comprehensive fingerprint of volatile substances is essential for evaluating the quality of aroma sustained-release capsules.The volatile flavor substances in foods are mainly extracted by solid phase microextraction(SPME),Purge and Trap,dynamic headspace(ITEX),static headspace(Headspace)and the like.Different extraction methods have different characteristics,and the substances that can be extracted are different,and the effects are quite different.At present,there is a certain limitation in the single extraction method.Two or more methods are combined to achieve complementarity,and the information of flavor substances in food can be obtained more completely,and the controllable production and flavor evaluation of the flavor microcapsules can be realized..Therefore,the research contents and results of this experiment are as follows:(1)GC-MS was used to detect the extracted materials by different extraction methods.The signal-to-noise ratio was greater than 3 as the qualitative detection limit,and the differences in extraction ability between different extraction methods were compared.The results showed that the solid phase microextraction PDMS/DVB coating had the widest extraction range,and 45 compounds could be extracted from 57 volatile flavors,which had better enrichment effects on alcohols and esters.The dynamic headspace is less affected by the solvent,and the volatile flavor compound with lower retention index(RI value)has better extraction ability,and the enrichment effect of aromatic compound is better.(2)By selecting six normal alkane isotopic internal standards with different RI values as quantitative internal standards,and using SNR of more than 9 as the quantitative limit of quantitative analysis,compare different extraction methods with multi-isotope internal standards to enrich multiple volatile flavor compounds.The difference between quantitative analysis.Among them,SPME PDMS/DVB,DVB/CAR/PDMS coating and ITEX enriched trace volatile compounds have better quantitative effects.Headspace and the sweep and trap trace detection are less effective.Aromatic compounds and hydrocarbon compounds have lower detection limits,while acid compounds have relatively lower detection limits.Compared with other extraction methods,the SPME PDMS/DVB coating has the highest response value except for the deuterated normal decane.For deuterated normal decane,ITEX has the best extraction effect.For the purge and trap,the n-paraffin isotope internal standard with carbon number greater than 13 could not be detected.It can be seen that the compounds with larger retention index of the purge and trap extraction are insufficient.(3)Through the study of the effects of matrix on the enrichment of volatile flavor compounds by different extraction methods,SPME PDMS/DVB,Polyacrylate coating and ITEX extraction method have a small decrease in recovery rate under the influence of matrix.The SPME DVB/CAR/PDMS coating has a small change in the number of volatile flavor compounds extracted under the influence of the matrix.Aromatic compounds are less affected by the matrix.Volatile flavor compounds with more serious matrix interference are acid compounds such as n-heptanoic acid,lauric acid,aldehydes phenylacetaldehyde,vanillin,and(E)-2-octenal.(4)By embedding the embedding ability of different embedding materials on volatile flavor compounds,the embedding ability of ?-cyclodextrin for most volatile flavor substances is higher than that of other embedding materials.Secondly,there are many types of volatile flavor compounds embedded in chitosan.For the ethyl ionone,thymol and4'-methylacetophenone compounds,the embedding effect of chitosan and gelatin is better than that of ?-cyclodextrin.For the alcohol compounds,the embedding effect of the seven embedding walls is poor,especially L-carvyl alcohol,benzyl alcohol,2-phenylethanol,so the alcohol compounds are not suitable for the selection of the seven wall materials.Aroma sustained release capsules.For the volatile flavor release of most volatile flavor compounds,the encapsulated microcapsules have the effect of sustained release of flavor,and the amount of flavor release increases with the increase of incubation time.In general,SPME PDMS/DVB,DVB/CAR/PDMS coatings,and ITEX extraction methods are preferred when measuring volatile flavor compounds.?-cyclodextrin is ideal for embedding volatile flavor compounds.Ultrasonic spray-freeze-drying was used to prepare flavor sustained-release microcapsules,which laid a theoretical foundation for the use of microencapsulated flavors and flavors to enhance the flavor of foods and improve the flavor stability of foods.