SURVEY ON THE MICROBIAL AND QUALITY CHARACTERISTICS OF ORANGE JUICE PROCESSED WITH ULTRASONICATION

Background and Aim:Thermal pasteurization is one of the most used methods in the production of orange juice industry, despite that lower the level of microbial population to safety standard, due to the loss of ascorbic acid and the flavonoid compounds, reduces the nutritional value of products.Methods:This study feasibility of replacing ultrasound thermal pasteurization method, with the aim of preserving the functional properties of orange juice was performed. Oranges after dewatering, at a constant temperature of 35 ° C, under different circumstances sonication (intensity ultrasound: 37 and 80 kHz - for 10, 15 and 20 minutes). The qualitative tests (pH, acidity, total soluble solids , the browning and opacity), microbial (determining the total microbial population count of molds and yeasts and coliforms) together with the analysis of color parameters (L *, a *, b * and ΔE) was performed. In the next step the optimal treatment of the first stage (with a frequency of 37 kHz and a sample treated for 15 minutes) with control heat pasteurized (75-70 degrees Celsius temperature and duration of 5 minutes) and fresh orange juice (control) compared to the above factors. respectivelyResults:In the optimal sample ultrasound, the browning and reduced microbial significantly lower the total population of the sample was heated (05/0> p). Colored markers applied on the lack of effect of ultrasound on yellow index (b*), to increase the brightness (L*) and reduce redness (a*), respectively.Conclusion:. The results showed that microbial production of orange juice with an acceptable level of safety and qualitycharacteristics appropriateispossible.

کلیدواژه ها:

Ultrasound ، Orange juice ، non-thermal Pasturization