Submitted to: Innovative Food Science and Emerging Technologies
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/23/2009
Publication Date: 8/25/2009
Citation: Sampedro, F., Geveke, D.J., Fan, X., Zhang, H.Q. 2009. Effect of PEF, HHP and Thermal Treatment on PME Inactivation and Volatile Compounds Concentration of an Orange Juice-Milk Based Beverage. Innovative Food Science and Emerging Technologies. 10:463-469. Interpretive Summary: Beverages made from a mixture of fruit juices and milk are popular functional foods, yet there is a lack of information on the effects of nonthermal pasteurization treatments on the volatile compounds of these mixtures. The effects of thermal, pulsed electric fields (PEF) and high hydrostatic pressure (HHP) processing on pectin methyl esterase (PME) activity and volatile compounds in an orange juice-milk beverage were studied. The nonthermal treatments, either PEF or HHP, inactivated 90% of PME where thermal treatment at 85C was required to achieve the same enzyme inactivation. The loss of volatile compounds for the thermal treatment was significantly greater than for the PEF treatment and was similar to the HHP treatment. The results showed the potential of nonthermal PEF technology in providing fresh-like food with a high standard of quality.
Technical Abstract: The effects of thermal, pulsed electric field (PEF) and high hydrostatic pressure (HHP) processing on pectin methyl esterase (PME) activity and concentrations of volatile compounds in an orange juice-milk beverage were studied. Thermal treatment (85 C for 1 min), PEF treatment (25 kV/cm at 65 C initial temperature) or HHP treatment (650 MPa at 50 C initial temperature) were needed to inactivate 90% of PME revealing the resistance of orange PME to the different preservation methods. PME activity was enhanced after PEF treatment at low temperatures. The volatile compounds were isolated by Solid Phase Micro-extraction (SPME) and the extracts were analyzed by Gas Chromatography and Mass Spectrometry (GC-MS). Twelve aroma compounds were selected for quantification of the change in the volatile compounds concentrations after the different treatments. The average loss in concentration of flavor compounds was between 16.0 and 43.0% after thermal treatment depending on the temperature. After PEF treatment the average loss was between -13.7 and 8.3% at an initial temperature of 25 C depending on electric field, 5.8 to 21.0% at 45 C and 11.6 to 30.5% at 65 C after PEF treatment. After HHP treatment the average loss was -14.2 to 7.5% at an initial temperature of 30 C depending on the pressure levels and 22.9 to 42.3% at 50 C. The results showed the potential of the nonthermal technologies in providing fresh-like food with a high standard of quality.