Atmospheric-pressure argon plasma (APAP) is a promising non-thermal technology for microbial control and prevention minimally affecting quality of foods. Effect of APAP jet on the growth of bread ...molds, including two Aspergillus sp., Rhizopus stolonifer, and Penicillium roqueforti, isolated from white bread were investigated. The molds were isolated, verified, cultured to fully grown on potato dextrose agar (PDA), and subsequently treated with APAP jet using plasma generating power at 24 W for 5, 10, and 20 min, respectively. The inhibition of mold growth was investigated by comparing fungal dry weights and the effect on fungal cell structure was observed using compound light microscope. The results indicated that the 20-min treatment time is most effective in retarding the growth of the three bread molds. However, this level of generating power did not lead to destruction of the cellular structures for all the four fungi. Plasma generating power and treatment time are significant parameters determining the success of bread mold decontamination and further investigation on real bread matrix is needed.
Premarket, genetically modified (GM) plants are assessed for potential risks of food allergy. The major risk would be transfer of a gene encoding an allergen or protein nearly identical to an ...allergen into a different food source, which can be assessed by specific serum testing. The potential that a newly expressed protein might become an allergen is evaluated based on resistance to digestion in pepsin and abundance in food fractions. If the modified plant is a common allergenic source (e.g. soybean), regulatory guidelines suggest testing for increases in the expression of endogenous allergens. Some regulators request evaluating endogenous allergens for rarely allergenic plants (e.g. maize and rice). Since allergic individuals must avoid foods containing their allergen (e.g. peanut, soybean, maize, or rice), the relevance of the tests is unclear. Furthermore, no acceptance criteria are established and little is known about the natural variation in allergen concentrations in these crops. Our results demonstrate a 15‐fold difference in the major maize allergen, lipid transfer protein between nine varieties, and complex variation in IgE binding to various soybean varieties. We question the value of evaluating endogenous allergens in GM plants unless the intent of the modification was production of a hypoallergenic crop.
Riceberry brown rice (RB) is known as source for valuable nutrients. Recently our group has used plasma treatment on RB to effectively shorten their cooking time and soften their texture. During the ...plasma treatment, rice was also subject to elevated temperature. This sometimes has led to confusion whether the thermal effect dominate. In this study, we have carried on these issues by using Fourier Transform Infrared spectroscopy (FTIR) to follow changes in vibrational characteristics of RB after being plasma treated. The plasma treatment was performed using a low-pressure inductively coupling argon plasma system. This is done in comparison to conventional thermal treatment at 45°, 60°, and 75°C for 120 minutes. The O-H stretching group was found to increase in the plasma treated samples; while decreasing in all the other thermal treated samples. The decrement has varied monotonically with temperature. There is also significantly increasing of C-O-C skeletal mode of α-glycosidic linkage, C-O-H bonding, and C-O-C asymmetric stretching glycosidic bonds in the plasma treated samples; while the decrement was observed in the thermal treated samples. This is understood as a consequence of cross-linking effect; leading to increase in glycosidic bonds along with H2O abstraction during the plasma treatment. It can be concluded that the plasma treatment has caused more inclusive effects which cannot be accounted for by the action of the thermal treatment alone.
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