However, the level of acoustic intensity can also affect the type
of influence on the mass transport. The levels of acoustic intensity
used by Cárcel et al. (2007a) (11.5 W/cm2) in the osmotic dehydration
of apples increased the two main mass transport processes
that took place in these treatments: moisture loss and solute gain,
but the higher levels used by Cárcel et al. (2007c) in meat brining
(>51 W/cm2) not only affected the kinetics of transport but, in the case of moisture, the transport direction. The samples treated ultrasonically at the higher acoustic intensities tested (75.8 W/cm2) did not undergo a dehydration process like the conventionally brined meat, but had a higher moisture content than fresh meat.
Moreover, the NaCl content of the ultrasonically brined samples
after 45 min of treatment was 115% higher than conventionally
brined samples. That means that the conventional brining process
produced a water loss and a NaCl gain while, at these intensity levels,
the application of ultrasound, induced the gain of both water
and NaCl. The influence of ultrasound on apple treatments can be
explained by ultrasonic effects such as the ‘‘sponge effect’’ or the
creation of microchannels, which can affect the internal mass
transport resistance, and the generation of microstirring or cavitation,
which affect the external resistance by reducing the boundary
layer of diffusion. In the case of meat brining, the highest applied
acoustic intensity generates a more intense cavitation in brine.
The asymmetric implosion of cavitation bubbles near the meat surface
produces the formation of microjets that hit the solid (Mason
and Lorimer, 2002) and could produce the microinjection of brine
into the meat samples. This fact could not only explain the increase
in NaCl content but also the increase in sample water content.
However, the level of acoustic intensity can also affect the typeof influence on the mass transport. The levels of acoustic intensityused by Cárcel et al. (2007a) (11.5 W/cm2) in the osmotic dehydrationof apples increased the two main mass transport processesthat took place in these treatments: moisture loss and solute gain,but the higher levels used by Cárcel et al. (2007c) in meat brining(>51 W/cm2) not only affected the kinetics of transport but, in the case of moisture, the transport direction. The samples treated ultrasonically at the higher acoustic intensities tested (75.8 W/cm2) did not undergo a dehydration process like the conventionally brined meat, but had a higher moisture content than fresh meat.Moreover, the NaCl content of the ultrasonically brined samplesafter 45 min of treatment was 115% higher than conventionallybrined samples. That means that the conventional brining processproduced a water loss and a NaCl gain while, at these intensity levels,the application of ultrasound, induced the gain of both waterand NaCl. The influence of ultrasound on apple treatments can beexplained by ultrasonic effects such as the ‘‘sponge effect’’ or thecreation of microchannels, which can affect the internal masstransport resistance, and the generation of microstirring or cavitation,which affect the external resistance by reducing the boundarylayer of diffusion. In the case of meat brining, the highest appliedacoustic intensity generates a more intense cavitation in brine.
The asymmetric implosion of cavitation bubbles near the meat surface
produces the formation of microjets that hit the solid (Mason
and Lorimer, 2002) and could produce the microinjection of brine
into the meat samples. This fact could not only explain the increase
in NaCl content but also the increase in sample water content.
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