Comparing equivalent thermal, high pressure and pulsed electric field processes for mild pasteurization of orange juice Part II: Impact on specific chemical and biochemical quality parameters

The impact of thermal, high pressure (HP) and pulsed electric field (PEF) processing for mild pasteurization of orange juice was compared on a fair basis, using processing conditions leading to an equivalent degree of microbial inactivation. Examining the effect on specific chemical and biochemical quality parameters directly after treatment and during storage at 4 degrees C revealed only significant differences in residual enzyme activities. For pectin methylesterase inactivation, none of the treatments was able to cause a complete inactivation, although heat and HP pasteurization were the most effective in limiting the residual activity. Peroxidase was completely inactivated by heat pasteurization and was much less susceptible to HP and PEF. All other quality parameters investigated, including the sugar profile, the organic acid profile, bitter compounds, vitamin C (ascorbic acid and dehydroascorbic acid), the carotenoid profile, furfural and 5-hydroxymethylfurfural, experienced no significantly different impact from the three pasteurization techniques. Industrial relevance: HP and PEF processing have received important attention during the last years for application as alternatives to traditional thermal pasteurization. For the further implementation of HP and PEF treatment in the food industry, legal approval of such processes is required. Accordingly, an in-depth characterization of products treated by these novel technologies is indispensable. This paper addresses orange juice as a relevant model food product to compare the impact of HP and PEF processing with that of a conventional thermal pasteurization process and to search for significant differences in specific known nutrients, undesired substances and other quality-related aspects of orange juice. (C) 2011 Elsevier Ltd. All rights reserved.