Effect of hyperbaric storage at room temperature on pectin methylesterase activity and serum viscosity of strawberry juice

Abstract

Hyperbaric storage at room temperature (HS-RT) has been lately proposed as a promising technology for food preservation. In this paper, the effect of HS-RT on pectin methylesterase (PME) activity and viscosity decay was evaluated in strawberry juice. To do so, two complementary studies were performed: one in crude strawberry PME extract and the other in strawberry juice. The results showed that, at the assayed conditions, the catalytic activity of the PME extract was not affected by pressure up to 200 MPa. Moreover, in strawberry juices, no pressure PME inactivation was observed during storage, at 0.1-200 MPa and 20 °C, for 1, 2, 5, 7, 10, and 15 days. HS-RT enhanced viscosity decay, especially at the beginning of storage, although no increase in PME activity was observed in this phase. Therefore, chemical and/or enzymatic reactions, other than PME de-esterification, could be pressure enhanced and affect pectin characteristics and serum viscosity. Industrial relevance Hyperbaric storage at room temperature (HS-RT) can involve substantial energy savings in food preservation. As food is preserved with no temperature control, the only energy consumption is produced at the beginning of storage, during compression. HS-RT could be applied in different sections of the cold chain in industrialized countries but also in developing countries in which the continuous supply of electric energy is difficult. However, before industrial implementation, much more research is needed to clarify the effect of the storage pressure on mechanisms implied in food quality degradation.