|کد مقاله||سال انتشار||مقاله انگلیسی||ترجمه فارسی||تعداد کلمات|
|147220||2017||43 صفحه PDF||سفارش دهید||9970 کلمه|
Publisher : Elsevier - Science Direct (الزویر - ساینس دایرکت)
Journal : International Journal of Food Microbiology, Volume 260, 2 November 2017, Pages 65-74
In this study, the effects of Ultraviolet light-emitting diodes (UV-LEDs) on the inactivation of E. coli K12 (ATCC 25253), an indicator organism of E. coli O157:H7, and polyphneoloxidase (PPO) in cloudy apple juice (CAJ) were investigated. The clear (AJ) and cloudy apple juice were exposed to UV rays for 40Â min by using a UV device composed of four UV-LEDs with peak emissions at 254 and 280Â nm and coupled emissions as follows: 254/365, 254/405, 280/365, 280/405 and 254/280/365/405Â nm. UV-LEDs at 254Â nm achieved 1.6Â Â±Â 0.1 log10 CFU/mL inactivation of E. coli K12 at UV dose of 707.2Â mJ/cm2. The highest inactivation of E. coli K12 (2.0Â Â±Â 0.1Â log10 CFU/mL and 2.0Â Â±Â 0.4Â log10Â CFU/mL) was achieved when the cloudy apple juice was treated with both 280Â nm and 280/365Â nm UV-LEDs. For clear apple juice the highest inactivation 4.4Â log10Â CFU/mL obtained for E. coli K12 was achieved using 4 lamps emitting light at 280Â nm for 40Â min exposure time. For the same treatment time, the experiments using a combination of lamps emitting light at 280 and 365Â nm (2lamp/2lamp) were resulted in 3.9Â Â±Â 0.2Â log10Â CFU/mL reductions. UV-A and UV-C rays in combination showed a better inactivation effect on PPO than UV-C rays used separately. Residual activity of PPO in CAJ was reduced to 32.58% when treated with UV-LED in combination of UV-C (280Â nm) and UV-A (365Â nm) rays. Additionally, the total color change (ÎE) of CAJ subjected to combined UV-LED irradiation at 280/365Â nm was the lowest compared to other studied processing conditions. This study provides key implications for the future application of UV-LEDs to fruit juice pasteurization.