Application Of Ultrasonic Spray-Freeze Drying Technique In Preparation Of Seasoning Powder For Soup

Most of the natural seafood seasoning powder is prepared by spray drying technology.After the seafood powder obtained by spray drying technology is rehydrated,it has obvious hazel flavor,and the sticky wall problem in the drying tower may directly affect the quality of the product.Freeze-drying technology directly solves the problem of storage of thermally unstable components,and easily produces porous structure particles,so that the dried particles have higher quality,but the freeze-drying technology has a long processing cycle,large energy consumption,and process requirements.The disadvantages of high cost,high production cost,and high equipment cost limit the use of freeze-drying technology.Therefore,ultrasonic spray-freeze drying is the subject of this study.First,ultrasonic spray-freeze drying equipment is set up and the process parameters are optimized.The three drying processes of ultrasonic spray-freeze drying,vacuum freeze drying and spray drying are compared.Microstructure,volatile flavoring substances,and taste flavors are described,and natural seafood flavoring powders are prepared using ultrasonic spray-freeze drying technology,further provide a theoretical basis for the preparation of better flavored seafood soup powder.The main research contents and results of this article are as follows:(1)By setting up an ultrasonic spray-freeze drying device,the injection flow rate,ultrasonic power,material concentration,annealing temperature,and annealing time were optimized.As a result,the device can obtain a powder product with a smooth surface,the powder is produced in a small degree of agglomeration,the installation and disassembly of the device is simple,the use is convenient,the control is easy,the real-time monitoring is easy,the spray rate is fast,and the injection parameters can be determined by optimizing the device parameters.When the flow rate was 3 mL/min,the ultrasonic power was 3 W,and the solids content was 5%,the obtained powder had the best morphology and particle size,and ultrasonic spray-freeze-dried powders have an average particle size of approximately 23.109 ?m.(2)Ultrasonic spray-freeze drying,vacuum freeze-drying and spray drying were compared by the physical properties and microstructure of the powders.The results showed that ultrasonic spray-freeze drying had low water content of 4.79%,and a small bulk density of 0.102 g/mL,good solubility,small particle size,and very good particle sphericity.The powders prepared by ultrasonic spray-freeze drying are spherical particles,and the freeze-dried powder particles are needle-shaped,flat-shaped,irregular and various in shape;most of the powder particles prepared by spray-drying show flat balls shape.(3)Through the optimization of SPME extraction methods,determined in the incubation time is 40 min,incubation temperature is 50 °C,extraction time is 50 min for the best flavor extraction conditions.Sensory evaluation,electronic nose,and GC-MS were used to compare ultrasonic spray-freeze drying,vacuum freeze-drying,and spray-dried powder flavors,and data were analyzed by principal components.The results showed that a total of 40 volatile flavors were detected in samples treated by ultrasonic spray-freeze drying,including 7 alcohols,7 aldehydes,1 ketone,4 esters,8 heterocycles,and 13 paraffins.Species.Compared with the other two drying methods,the samples processed by USFD can recover the flavor of the flavoured broth better than the other two types of volatile compounds.The electronic nose results are consistent with the GC-MS results.PCA can better differentiate the flavors processed by three different drying methods.(4)The taste of the three substances was compared by LC-MS.The total free amino acid content of samples treated by USFD was 10.407 mg/g,and the total free nucleotide content was 0.619 mg/g.The significance of the free amino acid nucleotides in the three drying modes was analyzed.The content of free nucleotides in SD was significantly different from that of USFD and FD samples,which further indicated that there may be some changes in the free nucleotides of the samples treated by spray drying.(5)Key technology research and development of natural seafood seasonings using ultrasonic spray-freeze drying process.Through sensory evaluation,the optimal Maillard reaction conditions were determined as xylose addition 15%,reaction temperature 120 °C,and reaction time 50 min.Analysis of volatile flavors in samples not treated with USFD and those processed with USFD by electronic nose and GC-MS,and the data was analysis by PCA.As a result,recoveries of volatile flavor conten was 69.2%t by USFD.However,the samples processed by USFD also produced new volatile flavor substances,indicating that the USFD-treated samples had a certain influence on the overall flavor characteristics of the powder.But the effect was less than that of samples treated by vacuum freeze drying and spray drying.It has laid a theoretical foundation for the preparation of variegated alfalfa natural seafood sauce.In general,the powders prepared by ultrasonic spray-freeze drying have spherical granular shape,small particle size,low water content,small bulk density,good solubility,and good powder shape.Ultrasonic spray-freeze dried samples compared to vacuum freeze-dried and spray-dried samples were able to reduce the overall flavor of the sample in terms of the type and content of volatile compounds,to provide a theoretical basis for further preparation of a better flavor of seafood soup powder.