Study On Raw Material Classification,Storage And Transportation Quality Guarantee Technology Of Not From Concentrate Apple Juice

Not from concentrate(NFC)apple juice processing is not high-temperature concentrated and fruit juice reduced,it has good natural flavor and rich nutrients,and is favored by consumers at home and abroad.In view of the lack of raw fruit grading standards in the production of NFC apple juice,the quality of semifinished freshly squeezed juice is prone to deteriorate during the frozen storage period,and the impact of transportation vibration on the quality of the finished juice during storage and transportation is unknown,and in this study,Aksu Fuji apples were used as test materials,through the soluble solid content(SSC)sorting technology,low-voltage electrostatic field assisted freezing technology and simulated refrigerated transport technology,the SSC grading standards for raw fruits were established;the suitable storage period of fruits with different SSC grades was clarified;the suitable low-voltage electrostatic field parameters and storage period of freshly squeezed juice were determined;the suitable packaging form and shelf life of NFC juice storage and transportation were explored,which provides a strong technical support for the quality maintenance of NFC apple juice and the sustainable development of its processing industry.The main findings are as follows:1.In the process of establishing SSC grading standards for raw fruits suitable for juice production,according to the frequency distribution of SSC,the optimum classification range for processing raw fruit was determined to be 11.0%-16.9%,and the quality of harvested fruits was divided into 3 grades(11.0%-12.9%,13.0%-14.9%and 15.0%-16.9%).The characteristics of the three SSC grade fruits quality(flavor,color,suspension stability,browning degree and total phenol)under the(-1±1)storage conditions(0-150 d)were compared and analyzed,fruits with suitable SSC grade of 11.0%-12.9%and the storage period of less than 90 days was better,which were determined to be suitable for juice-processing.The freshly squeezed NFC apple juice were prepared by the fruit in a better storage period,which were had a moderate solid acid ratio,rich taste,sweet and sour flavor,bright yellow color,high suspension stability and better quality.2.The electrostatic field assisted freezing technology suitable for field strength can extend the storage shelf life of freshly squeezed apple juice,and the three-field strength assisted freezing rates were compared,the low field strength(120 V/cm)was finally selected as the better freezing technology.Freshly squeezed apple juice under low field strength(120 V/cm)electrostatic field-assisted freezing conditions,the freezing rate was detected as 1.43 cm/h,which was 19.23%higher than the blank freezing rate;the number of natural flora in the frozen storage period of 60 days was less than the maximum safety limit value,which were compared with CK frozen freshly squeezed juice could effectively reduce the number of microorganisms in the frozen storage period;the changes of low field strength assisted freezing freshly squeezed apple juice quality(pH,flavor,color,suspension stability,turbidity and browning degree)was relatively stable,which was stored under the-20? cold storage conditions(0-60 d),and 45 days before as the more suitable storage shelf life for thawing and subsequent juice processing was selected,which was 15 days longer than the frozen storage quality of the blank frozen juice.3.NFC apple juice(refrigerated at 4?)during storage and transportation(0-30 d)was easily caused by transportation vibration to a certain degree of turbidity,but the flavor,color and browning degree of the juice were not affected.Flavor acidification,lightening of color,delamination and precipitation phenomenon,higher quality deterioration in bottled and vibrated NFC apple juice,was found to be more serious than bagged juice,which was in the storage and transportation period,and the suitable storage and transportation time was found to be 10 days;during the storage and transportation of bagged juice,the quality was remained relatively stable,and the shelf life of the bottled vibrating sample was suitable for 5 days longer storage and transportation;the suitable storage and transportation time of bottled and bagged NFC apple juice was found to be 20 days.Finally,the bag was selected as the packaging form of NFC apple juice refrigerated transportation,which could extend the effective shelf life after transportation and maintain good quality.