| Speciosa S.Nakai is mainly produced in in Xuancheng City Anhui Province,which is famous for its high nutrition.And it belongs to the high acid fruits with oleanolic acid,malic acid,citric acid,other organic acids,saponins and flavonoids,while it is firstly batch announced the use of food by the Ministry of Health,which is used as medicine as well as food.Currently,food processing research on Speciosa S.Nakai is focused on fruit,canned food,wine and fruit juice,etc.,but their food development is still in its infancy,what is more,reports on the Speciosa S.Nakai juice and instant powder is relatively rare.The Speciosa S.Nakai is not a easy long-term storage fruit,thus in this study we took it as raw material,on the one hand,it could be processed into a semi-finished product,which was processed into clear or cloudy juice according to market demand,on the other hand,it was processed into instant powder.In this study,we studied the effect of microwave on enzyme inactivation,the key processing technology of clear or cloudy juice and instant powder,in order to provide the technical basis for exploration of Speciosa S.Nakai food.The main results of the test are as follows:1.Detection basic ingredients of Speciosa S.Nakai,the result is 3.85% of total sugar,total acid is 3.22%,Vc is72.85mg/100 g,total flavonoids is 0.17%,0.183% of oleanolic acid,ursolic acid is 0.092%.2.In experimental study on pre-treatment of Speciosa S.Nakai,we studied the effect of microwave,hot water,steam and mixed on enzyme inactivation,and compared the change of polyphenol oxidase activity,moisture content,Vc content of speciosa S.Nakai before and after treatment.The results showed microwave power of520 W and 45 s were the best treated methods to inactivate enzymes,and the relative activity of polyphenol oxidase was 6.5%,relative content of Vc was 59.3%,the efficiency of nutrients retention level were better than blanching,steam treatment,and could save a lot of water.3.In experimental study on drying process of Speciosa S.Nakai,we found the best slice thickness was 5mm.And we compared the effect of hot air drying,freeze drying and microwave drying on quality of Speciosa S.Nakai.The results showed the maximum drying rate of hot air drying was 2~10h;microwave drying rate faster in the first stage,then reached 10% of the moisture content in the final stage,which was very easy to appear the phenomenon of coke and became difficult to control.At the same time,the results of microwave inactivation and color protection showed 520 W for 45 s following 280 W for 5min,water content reduced to 17.6%,subsequent 65 ℃for 4h,water content reduced to 4.1% and color value was 9.63,which were the best effect and quality of drying.4.In experimental study on direct pressing and the extraction technology of drying fruit slices of Speciosa S.Nakai,the squeezing rate after hot water was only57.6%,titration acid content was 1.68%,oleanolic acid content was not detected.Extracting rate of titration acid and oleanolic acid by the extraction technology under the same state of dried fruit was significantly higher than that by direct pressing with2.07% and 0.011% respectively.The best technology of the dried fruit slices was the water extraction ratio 4 times,the extraction temperature 60 ℃ and the extraction time 2 h.5.In experimental study on deployment test of Speciosa S.Nakai juice,all raw materials adding amount on juice quality effect was as follows: Speciosa S.Nakai juice,sucrose,concentrated pear juice and honey,what is more,Speciosa S.Nakai juice was the very significant factors,the concentrated pear juice,sucrose and honey were the significant factors,and the optimum technology were 20% Speciosa S.Nakai juice,4% sucrose,3% concentrated pear juice and 2% honey.6.In experimental study on juice clarification,0.2um ceramic membrane filtration was chose.The results showed,under conditions of 0.2MPa operating pressure and 30 ℃ operation temperature,the filtration efficiency was best with13.2L/(m2·h),the transmittance of the filtered juice rate was 96.1%,and the product was no turbidity without precipitation after being stored for 90 days.7.In experimental study on cloudy juice stability,adding 0.05% sodium alginate,0.05% yellow,0.05% gum and 0.05% CMC-Na was best to make juice with good fluidity and good taste.Using the homogeneous effect as the index to determine the best homogeneous pressure,results showed above 45 MPa the juice was good,thus we chose 60 MPa as the uniform pressure.8.In experimental study on sterilization process,using examining colony and the total number of Escherichia coli group number as the index,we found 80℃ for10 minutes and 135 ℃ for 4s could meet the requirements.And in the sensory evaluation study,ultra-high temperature instantaneous sterilization was better than that of ordinary heat sterilization.9.In experimental study on spray drying powder,the method of directly crushing process,microwave heat treatment and 100 mesh filter was chose,then determined the optimization technology of spray drying process.We chose sensory evaluation and the content of oleanolic acid as the index to study the effect on drying agent dosage,feed flow rate,air temperature and inlet temperature of spray drying process of spray drying process.Results showed pretreatment optimal conditions were colloid mill treatment for 3min,25 MPa pressure for homogeneous and spray drying process parameters were adding 0.15% trichloro sucrose and 30% maltodextrin,feed speed 20mL/min,inlet air temperature 170℃,feeding temperature of 40℃,which was the best with the mean sensory scores of 86.67% oleanolic acid content of0.083%,moisture content of 3.561%.then the product was made to 15 g / bag,whose fruit powder dissolved quickly with no caking and a unique flavor. |
