The effects on orange juice batch pasteurization in an improved pilot-scale microwave (MW) oven was evaluated by monitoring pectin methyl-esterase (PME) activity, color, carotenoid compunds and vitamin C content Trials were performed on stirred orange juice heated at different temperatures (60, 70, 75, and 85 degrees C) during batch process. MW pilot plant allowed real-time temperature control of samples using proportional integrative derivative (PID) techniques based on the infrared thermography temperature read-out. The inactivation of heat sensitive fraction of PME, that verifies orange juice pasteurization, showed a z-value of 22.1 degrees C. Carotenoid content, responsible for sensorial and nutritional quality in fresh juices, decreased by about 13% after MW pasteurization at 70 degrees C for 1 min. Total of 7 carotenoid compounds were quantified during MW heating: zeazanthin and beta-carotene content decreased by about 26%, while no differences (P < 0.05) were found for beta-cryptoxanthin in the same trial. A slight decrease in vitamin C content was monitored after MW heating. Results showed that MW heating with a fine temperature control could result in promising stabilization treatments.
Digital Object Identifier (DOI): | http://dx.doi.org/10.1111/j.1750-3841.2009.01412.x |
Codice identificativo ISI: | WOS:000273839400038 |
Codice identificativo Scopus: | s2.0-74249094095 |
Handle: | http://hdl.handle.net/11695/3926 |
Abstract: | The effects on orange juice batch pasteurization in an improved pilot-scale microwave (MW) oven was evaluated by monitoring pectin methyl-esterase (PME) activity, color, carotenoid compunds and vitamin C content Trials were performed on stirred orange juice heated at different temperatures (60, 70, 75, and 85 degrees C) during batch process. MW pilot plant allowed real-time temperature control of samples using proportional integrative derivative (PID) techniques based on the infrared thermography temperature read-out. The inactivation of heat sensitive fraction of PME, that verifies orange juice pasteurization, showed a z-value of 22.1 degrees C. Carotenoid content, responsible for sensorial and nutritional quality in fresh juices, decreased by about 13% after MW pasteurization at 70 degrees C for 1 min. Total of 7 carotenoid compounds were quantified during MW heating: zeazanthin and beta-carotene content decreased by about 26%, while no differences (P < 0.05) were found for beta-cryptoxanthin in the same trial. A slight decrease in vitamin C content was monitored after MW heating. Results showed that MW heating with a fine temperature control could result in promising stabilization treatments. |
Titolo: | Effect on Orange Juice of Batch Pasteurization in an Improved Pilot-Scale Microwave Oven |
Autori: | |
Appare nelle tipologie: | 1.1 Articolo in rivista |