The effects of thermal, pulsed electric field (PEF) and high hydrostatic pressure (HHP) processing on pectin methyl esterase (PME) activity and volatile compounds concentration in an orange juice-milk beverage were studied. Thermal treatment (85 °C, 1 min), PEF treatment (25 kV/cm, 65 °C) or HHP treatment (650 MPa, 50 °C) were needed to inactivate 90% of PME. Twelve volatile compounds were extracted by solid-phase microextraction (SPME) and selected for quantification by GC-MS following the application of the different treatments. The average loss in concentration of volatile compounds was between 16.0 and 43.0% after thermal treatment. After PEF treatment the average loss was between - 13.7 and 8.3% at 25 °C, 5.8 and 21.0% at 45 °C and 11.6 and 30.5% at 65 °C. After HHP treatment the average loss was between - 14.2 and 7.5% at 30 °C and 22.9 and 42.3% at 50 °C. The results showed the potential of the nonthermal technologies in providing food with a higher standard of quality compared to thermal processing. Industrial relevance: The use of nonthermal technologies as an alternative to heat processing in the pasteurisation of beverages has acquired relevance in the last years. In this manuscript, we have shown that PEF treatment could achieve a high degree of PME inactivation in an orange juice based beverage, while better preserving the natural aroma than HHP and thermal treatments. PEF processing has an enormous potential to pasteurise fruit juice and preserve its natural quality characteristics.
Bibliographical noteFunding Information:
This research was supported by the Food Safety Intervention Technologies Unit at the Eastern Regional Research Centre, Agricultural Research Service, United States Department of Agriculture. The author is grateful to the Spanish Ministry of Education and Science for providing a pre-doctoral grant to the first author. The technical assistance of Glenn Boyd, Kim Sokorai, Zareena Azhuvalappil and Dr. Dike Ukuku is gratefully acknowledged.
- Orange juice
- Pectin methyl esterase
- Volatile compounds