Study On The Effect Of Processing Technologies On The Quality Of Concentrated Apricot Juice

Using Saimati apricot as test materials, total sugar,taking total acid, reducing sugars, flavonoids, polyphenols,vitamin c, browning index, volatile components as test targets, we amis to find the researched the influences of key processes such as clarification, microwave sterilization, and freeze concentration on the quality of apricot juice, so as to provide researching foundation manufacturing technology and technical parameters of non-thermal processed apricot juice. Results of the study are as follows:(1) Taking transmittance as test targets, chooseing pectinase method as the best clarification method from the following 4 methods:Sodium alginate-sodium carbonate method, gelatin method, chitosan method, and pectinase method. Through Single factor experiments and orthogonal experiments,we draw a conclusion that order of the factors which effect the clarification result is temperature>pH>pectinase usage. And the best technology parameters are:pectin usage 1.0%o, pH3.5, treating for 3h at 40℃.(2) Compared the effect of microwave sterilization and thermal sterilization on quality of apricot juice, the results showed that after treated by the two sterilization methods above at 70℃, the loss rate of total phenols were 72% and 82% separately, loss rate of flavonoids were 75% and 88% separately, Vc content loss rates were 78% and 85% separately, polyphenol oxidase (PPO) inactivation were 82% and 65% separately, peroxidase (POD) inactivation were 96.7% and 51.8% separately, superoxide dismutase (SOD) inactivation were 86.4% and 51.03% separately, total number of colonies were 1/9 and 1/5 of CK. Compared to thermal sterilization, loss of total phenols and flavonoids of microwave sterilizated apricot juice were at a less extent, and the color and browning index changed a little, and total sugar, total acid, and Vc lost a little, the enzymes was effectivly passivated.(3) Using SPME-GC-MS identified 45 species of volatile compounds from apricot juice,49 species of volatile compounds from microwave sterilized apricot juice,38 species of volatile compounds from vacuum thermal concentrated apricot juice, and 46 species of volatile compounds from freeze concentrated apricot juice. Microwave sterilization and freeze concentration effect little on volatile components, vacuum thermal concentration made greater effect on volatile components. components that did not effectively detected were as follow:Polymaleic acid, Lanceol.cls, 1-butyn-3-one.1-(6,6-dimethyl-1,2-epoxycyclohexy), cinnamic acid Methylester,1-(3-methoxy-2,4,6-trimethyl) ketene, 1,3,3-trimethyl-2-(2-cyclopropyl)-cyclohexene,7-methyoxy-2,2,4,8-tetramethytricyclo[5.5.3.10(4,11)]undecane, Isolonglfolene-7,8-dehydro-8-hydroxy,3,5-di-tert-butyl-4-hydroxybenzaldehyde, palmitic acid, Methyloctadec-9-en-12-ynoate, Ethyltran-9-Hydroxyoctadecenoate,6,17-dihydroxy-16-methylandrosta, Androst-5,7-dien-01-17-one, volatile compounds that newly added were:9-hexyl-Heptadecane,3,7-dimethyl-6-octadienoic acid,Butylated, Hydroxytoluene,1-Methoxy-4-(1-propenyl)-Benzene,2-N-propyl-4-methyl-methylbenzene, Tetracyclo[16.1.0.0(2,9).0(10,17)]nonadeca-2(9),10(17)-diene,19,19-dimethyl,4,8,9-Trihydroxy-6-methyl-3,4-dihydro-2H-enthracen-1-one. All that above revealed that freeze concentration could effectively protect volatile compounds.(4) Compared the influences of vacuum thermal concentration and freeze concentration on quality of apricot juice, the results indicated that the browning degree of 56°Brix apricot juice increased by 60% and 2.6% separately, the loss of total phenols were 35.6% and 20% separately, flavonoids loss rate were 20.4% and 14.5% separately, Vc loss rates were 85% and 40% separately, loss of pectin contents were 2.84% and 2.43% separately, total colonies were 1/2 and 1/3 of blank. Compared to vacuum thermal concentration, loss of total phenols and flavonoids of freeze concentrated apricot juice were at a less extent, and the color and browning index changed a little, and total sugar, total acid, and Vc lost a little, the total clonies was less.(5) Storage temperature made significant influences on the quality of concentrated apricot juice. Color, browning index, total phenols, flavonoids, total number of colonies of apricot juice stored at 4℃and 20℃after 120 days changed less, stored at 4℃was better, while targets all above of the juice stored at 40℃for 10 days changed greatly, and total phenols, flavonoids such antioxidants seriously lost.