| Rose pomace,a by-product in the production of rose essential oil,is generally treated as waste material in practical production.However,there is high utilization value due to its various nutrients.In this study,a rose pomace beverage riching polyphenols was prepared by rose pomace and then detected composition of harmful microorganisms.Further more,ultra-high pressure processing(UHP)technology was used to sterilize rose pomace beverage and it was compared that the shelf life and storage stability of rose pomace beverage treated by UHP and pasteurization.Finally,it was explored that the effect of sterilization and mechanism were through UHP technology were explored.There were some main results in the follows:1.Firstly,the processing technology of rose pomace beverage was determined and then prepared beverage.The sequence of non-sterilized rose pomace beverage was analyzed through 16S/18S/ITS rDNA amplifier sequencing technology.It was shown that the predominant bacteria and fungi were mainly Enterobacteriaceae and Saccharomycetaceae.The UHP process parameters was optimized through response surface methodology by taking the IgS as the index,which the best parameters was under the pressure 525 MPa,25 min,150C and then the IgS was 3.82.It showed that the physicochemical and microbial indexes of the sterilized rose dregs beverage met the national standard for beverage production and commercial aseptic requirements.2.It were compared and analyzed that shelf life and storage stability of rose pomace beverage were treated by UHP and pasteurization.The color of rose pomace beverage was treatment with UHP was better than that of pasteurization after 90 days.Compared with the control group,low temperature storage combined with UHP treatment could maintain the color of rose pomace beverage well.In addition,the variation of stability in the rose pomace beverage treatment with UHP was smaller than that of pasteurization.According to the content of soluble solids,polyphenols decreasing slightly and then the pH value was more stable.It was indicated that UHP could maintain the stability of pH,soluble solids,polyphenols and suspension in the rose pomace beverage.UHP combined with low temperature storage can prolong the shelf life of rose pomace beverageand the shelf life was predicted by ASLT method.After UHP treatment,the shelf life of rose pomace beverage was 135 days at 20? and 494 days at 4?.3.Based on the results of sample sequencing,while using pasteurized comparison.There were explored that the sterilization mechanism of rose pomace beverage treatment with UHP was taking Escherichia coli(bacteria)and Debaryomyces hansenii(fungi)as the research objects.The observation by scanning electron microscopic(SEM)showed that the cell boundaries blurred surface becamerough and wrinkles with hollow and the normal cells were decreased due to cell aggregation.It showed by transmission electron microscope(TEM)that a large number of cytoplasm and organelle out flowed from E.coli and D.hansenii after UHP,which resulted in half-empty or even hollow inside cells and separation of cytoplasmic walls.By combining cell fluorescence labeling with flow cytometry detection,it was known that both UHP and pasteurization could damage the cell membrane of E.coli and D.hansenii and both of their DNA were denatured.More over,UHP changed the secondary structure of microbial intracellular proteins of E.coli and D.hansenii by circular dichroism detection.Above all,UHP can destroy the cell structure,genetic material,intracellular protein and so on,thereby causing the death of the microorganism and achieving the purpose of sterilizing the rose pomace beverage.This study not only provides experimental basis for the application of UHP technology in beverage products,but also provides the possibility for the rose processing enterprises to reuse the rose pomace. |
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