46
OCT 2017
FOOD FOCUSTHAILAND
SMART
PRODUCTION
Asopposed topasteurisationandsterilisation,non-thermal treatments
can be applied to inactivate micro-organisms and enzymes without
affecting the freshness and palatability of food matrix. These include
irradiation, antimicrobials, ultrasounds, electricalmethods suchaspulse
electric fields, high-intensity light pulses, and oscillatingmagnetic fields,
andhighhydrostaticpressure.The latter, inparticular,hasbeenperformed
ona variety of convenient foodproducts suchas guacamole in theU.S.,
slicedham1 inSpain (shelf lifeextended from3weeks to8weeks), and
oranges and grapefruit juices2 (shelf life extended from 5-8 days to 3
weeks under refrigerated storage).
Operationof aTypical HPPUnit
HighPressureProcessing (HPP) isa technique topreserve foodby
applyinghighpressures, typically100-900MPa,onasample through
apressure transmittingmedium (usuallywater) inorder to inactivate
vegetative cells. The temperature of the sample increases by 3
o
C
per 100MPa rise. The sample can be either solid or liquid, with or
without packaging. The pressure is applied isostatically i.e. equally
applied in all direction, allowing a packaged solid food to retain its
originalshape,provided that the food isvacuumsealed.Theoperating
temperatures range frombelow0
o
C toabove100
o
C, therefore, this
method is feasible at room temperature. The compression time can
be froma few seconds to over 20minutes.
HighPressureProcessing (HPP)
forFoodPreservation
Over the last fewyears,due togovernmentpromotional campaigns in “health-and-wellness” foodandbeverages, consumers
have developed better health awareness and hence demands in high-quality food and beverages. The effects of internet
penetration togetherwitheasy-toaccessknowledge resourcesandsocialmediaserviceshave ledconsumers toseekonline
advices for healthy eating. Consequently, this has encouraged the food industrial sector to produce preserved food with
minimisedchemical treatment,maintainedhighnutrients, and longer shelf life.Traditionally, high-temperaturemethodsused
for foodpreservation require size reductionand causeunavoidable losses of essential nutrients andoriginal characteristics
such as colours, textures, and flavours.
