Abstract:
Ultraviolet (UV) radiation is one such non-thermal processing alternative
that has been shown to be effective against many types of foodborne pathogens. But
there is a limitation of practical application of UV to disinfect liquid food products
due to low penetration depth. Ohmic heating (OH), another promising technology,
has been widely applied in food processes. This generates heat immediately in the
food product, creating a rapid and uniform heating that reduces thermal abuse, as
opposed to conventional thermal processing methods. Often times, ohmic heating
cause heat-sensitive nutrients within food to be deteriorated by excessive current
flow. These advanced technologies could contribute to shorten processing times,
energy savings, and highly balanced safe food; however, they alone still cannot
guarantee food safety without damaging the food’s quality. Therefore, a new
concept to combine ultraviolet and ohmic heating has been extensively evaluated.
This combination technology would optimize each of the individual technology’s
strengths and reduce each of their individual weaknesses. The present study
envisages development of a UV radiation assisted with ohmic heating system for
pineapple juice and evaluation of the developed system in retaining the quality
characteristics and microbial safety. In this study, a dual cylindrical ohmic and
ultraviolet treatment combination continuous flow chambers was designed and
fabricated to pasteurize the pineapple juice. UV treatment 800, 1200 and 1600
mJ/cm 2 . Ohmic treatment until the sample temperature reached 50°C, 55°C and
60°C; and ohmic heating combined with UV treatment as the temperature rose to
50 °C, 55 °C, and 60 °C along with 800, 1200 and 1600 mJ/cm 2 dosages. Combined
ohmic heating at 50 °C and UV treatment of 1200 mJ/cm 2 were found to be superior
based on biochemical, microbiological and organoleptical characteristics. Storage
study of best sample revealed that could give a shelf life of 25 days under a
refrigeration temperature at 4 °C retaining its biochemical characteristics while
keeping the microbial level safe.
