Biomedical Engineering Reference
In-Depth Information
However, WHO and European legislations need more studies before their usage in
food products. The spraying of antimicrobials on the product can prevent the micro-
bial growth and can provide improved shelf life.
1.10
Minimal Processing Techniques
The thermal treatments, non-thermal treatments, low temperature storage, applying
new packaging techniques, and treated with natural antimicrobials alone or in
combination are commonly used for minimally processed foods.
1.10.1
Thermal Methods
Thermal methods are can inactivate the lethal organisms and enzymes. It can form
aromatic and fl avor compounds. However, heating can also destroy the sensitive
components like vitamins and health functional compounds (Bansal et al.
2014
).
Thus, optimum heat treatments can make the food microbiologically safe and nutri-
ent enriched. High temperature short time (HTST) can be used to achieve the target.
1.10.2
Coupling with Non-thermal Methods
Non-thermal processing techniques are emerging in the food industry. These tech-
niques are extended their potential to food preservation with limiting losses of the
nutritional and sensory characteristics. These are high hydrostatic pressure, pulsed
electric fi elds, high intensity pulsed light, pulsed white light, high power ultrasound,
oscillating magnetic fi elds, irradiation, and microwave processing. All these tech-
niques have provided a reliable alternative for processing of liquid foods, such as
beverages, juices, soups, purees along with solid whole fruits, vegetables and pack-
aged foods. Numerous reports have been published on the high hydrostatic pressure
and pulsed electric fi elds for inactivating the lethal micro-organisms and enzymes.
Apart from their microbial inactivation, these are used to extract bioactive com-
pounds, such as polyphenols, fl avonoids, hydroxycinnamic acids and. These are
termed as non-thermal methods and temperature of processing remained within
30-55 °C. The low temperature safeguards the heat labile components, such as vita-
min C, and pigments (e.g. carotenoids).
Pulsed electric fi elds
The concept of treating foods with pulsed electric fi elds was
introduced in 1960. Initially the technique was confi ned to kill microorganisms with
optimized parameters such as electric fi eld, pulse shape, pulse width and treatment time.
