Journal of Food Science and Agricultural Technology

Application of advanced oxidation processes (ozone/UV) to reduce Escherichia coli contamination in flour slurry from rice noodles production

Amornrat Jewsuwan, Aluck Thipayarat — Thu, 30 Jun 2022 00:00:00 +0700

This paper aimed to demonstrate another potential use of AOPs for reclaiming flour slurry
from rice noodle making process by destroying spoilage microorganisms and preventing
further microbial growth using Escherichia coli as a model microorganism. A prototype
AOPs system, consisting of UV sterilizer (45 W), ozone generator (2 L/min) and combined
ozone/UV, was fabricated and tested on water and flour slurry (53 g/L) systems using the
initial E. coli concentration at approximately, 7 log CFU/ml. The E. coli cell counts showed
that UV disinfection was very effective in water, enabling the reduction of cell density from 7
to 0 log CFU/ml within 15 min at all mass circulation flow rates (0.4, 0.6, and 0.8 kg/s). For
flour slurry, the blockage of UV radiation by flour suspension substantially compromised the
effectiveness of UV sterilization and E. coli destruction. Although, the ozone treatment by
itself showed slower E. coli inactivation kinetics on both transparent and turbid flour slurry,
it produced powerful disinfecting effect when it installed prior to the UV sterilizer. The
synergic combination of UV and ozone treatments in inactivating E. coli was demonstrated
on the flour slurry experiment and able to eliminate E. coli viability within 8-10 min. Faster
mass circulation rate facilitated higher E. coli elimination due to higher UV exposure of E. coli
and better mixing/dissolution of ozone gas in flour slurry.

Bioactive compounds in fruits are affected by light quality

Satoru Kondo — Thu, 01 Jan 2015 00:00:00 +0700

The effects of blue and red light irradiation at night on anthocyanin synthesis and abscisic
acid (ABA) metabolism were investigated in grape berries. Endogenous ABA were highest
in red light-emitting diode (LED)-treated skin. In contrast, anthocyanin concentrations
were highest in blue LED-treated skin, followed by red LED treatment. However, the
expressions of VlMYBA1-2 and UDP-glucose-flavonoid 3-O-glucosyltransferase(VvUFGT)
did not necessarily coincide with anthocyanin concentrations. The results suggest that blue
LED irradiation at night may be effective in increasing anthocyanin in grape berries. The
effect of UV-C irradiation on jasmonate, polyamines (putrescine) and antioxidant activities
was investigated in apple plants. The EC50 values of O2
- -scavenging activity in the UV-C
treated leaves were lower than those in the untreated control. The endogenous jasmonic
acid and putrescine concentrations in the UV-C treated plants were higher than those in the
untreated control. These facts suggest that the increase of jasmonates and polyamines may
be associated with UV-C stimulation, and UV-C irradiation may be effective for increasing
antioxidant activity in apple plants.

Novel postharvest technologies for prolonging fruit shelf life in Japan

Daisuke Hamanaka — Thu, 01 Jan 2015 00:00:00 +0700

In order to prolong the shelf life of highly perishable fruits and vegetables, new technologies
should be introduced during storage and transportation. Temperature control is surely
important for keeping freshness and quality higher. In addition, both humidity and microbial
controls are also playing important role for avoiding the wilting, discoloration, microbial
growth, etc. The nano-sized mist is generated by Lenard effect with high speed impact of
water droplet to metal mesh. The peak diameter of mist is approximately 80 nm, which is
roughly several times smaller than that of the normal mist for humidity control of fresh
produces generated by ultrasonication. The nano-sized mist has the advantage for preventing
over-wetting which results in the collapse of cardboard even with high relative humidity
environment, whereas no considerable effects on the physiological responses of fresh
produces were found.Infrared/Ultaviolet treatment was applied to the decontamination
process of microbes infecting the surface of fresh produces. A 1-1.5 logs reduction of surface
microbe of fruits was obtained by infrared or ultraviolet treatment individually. In addition,
another 1-2 logs reduction were enhanced by their combination without negative effects on
surface color, hardness, and respiration.

Cassava, cyanide and hypothyroidism

Brian J. B. Wood — Thu, 01 Jan 2015 00:00:00 +0700

Cassava (manioc) is an important crop as a basic, starchy energy food for both humans and farm animals throughout the tropics and sub-tropics and it is also exported to temperate regions, but does not seem to receive attention equivalent to that accorded to the other crops in this group. Its status as a good subsistence crop owes something to its self-protection by way of cyanogenic glycosides hydrolysed to release cyanide ions when tissue is damaged and the glycosides are thus placed into contact with an enzyme that hydrolyses them and is also present in the plant tissue. Cyanide toxicity and the toxin’s links, proven and possible, with goitre and hypothyroidism are described and their practical significance is discussed. The potential for responses to be changed by deficiencies in nutrients such as Vitamin B12, iodine and certain amino acids, as well as consumers’ overall nutrient status, is discussed. Suggestions are offered for future research to clarify significant issues presented from these considerations.