Changes Of Aroma Components In Processing Of Passionflower Juice

Passion flower,possessed with full aroma,has the good reputation of “King of juice”.It is often processed into juice or concentrated juice and blent with other drinks,because it not only can be easily compounded with other fruits to increase their aroma and mouthfeel but also plays an important role in the international drinks market.In recent years,planting industry of passion flower has developed rapidly,and its processing also has received more and more attention.Aroma is an important element of passion flower juice.Therefore,it will make a great difference for optimizing the processing of passion flower and remain its aroma to study characteristics of its aroma elements and the change of its aroma elements during processing.This paper mainly studies as the following aspects:(1)Make sure the characteristic aromaThis paper use Gas chromatography-olfactometry-mass spectrometer(GC-O-MS)and the human body to sense the volatile components of aroma and its degree.Then,combining the wisdom spectral spectrum library and keeping the common qualitative of indexes,this paper confirms 24 aroma elements of passion flower juice and generally tests out 14 esters,2 ketones,2 aldehydes,3 ene terpendoids,1 alcohol,which contains obvious aroma.(2)Analyze passion flower juice from different production placesAnalyzing aroma compounds of passion flower samples from 6 main production places and using the Principle Component analysis(PCA),this paper find out that the rate of contribution of the first main elements is 42.96%,which reflects the importance of ethyl hexanoate,methyl formate,myrcene and so on;the rate of the second main element is18.65%,which mainly reflects the contribution of ethyl hexanoate,hexyl acetate and so on;the rate of the third main element is 14.58%,which mainly reflects the contribution of benzyl acetate,linalool and so on;the rate of the fourth main element is 14.34%,which mainly reflects the contribution of ethyl butyrate,1-methyl butyrate,butyrate alcohol ester and so on.According to the eigenvector,27 volatile components can be chosen to generallyrepresent almost the overall aroma of passion flower juice.Using the comprehensive evaluation model,this paper get the result that the juice from YuLin,GuangXi province gets the highest evaluation,while the juice from LongYan,FuJian province gets the lowest quality.(3)Build the SPME method of passion flower juice aromaTo build more reliable SPME method for passion flower juice's aroma,this paper use GC-O and PCA to chose 14 characteristic aroma elements as indexes.Selecting the extraction of head,sample amount,sodium chloride addition amount,extraction temperature and analysis time,this paper finds out the optimizing testing conditions of Head space-Solid Phase Micro-extraction-Gas Chromatography-Mass Spectrometer(HS-SPME-GC-MS)method are: the extraction of head is 65 ?m DVB/PDMS.Take 0.5ml juice,without sodium chloride,and then extract it 20 min under the temperature of 40 ?.And the analysis time is 5min.(4)Influences of the key technology during processingThis paper studys the key controlling point during the processing and find that the enzymolysis in processing technology,the sterilization and the concentration have more influence on aroma elements.a.Enzymolysis: Enzymolysis is good to the processing of passion flower juice.The aroma element will increase the enzymolysis,as well as relative nutrition.(1)Sterilization: The heating sterilization(85 ?,15 min)is better than microwave serilization(500 W,1 min,50 ml).The total volatile component decrease,the aroma changes,the total acid decrease while some organic acid increase,the amino acid slightly increase,and the saccharides decompose.(2)Degree of Concentration: 45 °Brix can be chosen as the degree of concentration of the juice.During the concentration process of rotary evaporation,the aroma will lose a lot at the first stage of concentration.As the concentration is processing,the aroma decreases gradually and produces a mount of a-terpilenol,Cyclo propanamide,benzil alcohol,5-hydroxymethyl furfural,leading to the change of favorable aroma as well as undesirable aroma.As the concentration goes on,physicochemical indeses like antioxidant resistance,organic acid,amino acid and sugar are decreasing.(3)Concentration methods: Freeze concentration is better than rotary evaporation concentration.The freeze concentration mainly keep the characteristic aroma,while the rotary evaporation concentration makes the aroma lose a lot.What's more,the indexes like oxidation resistance,organic acid,and the amino acid are higher than rotary evaporation concentration.And there are no big differences between the two methods in total acid and concentration.