title: Effects of microwaves on the reduction of Aspergillus flavus and Aspergillus parasiticus on brown rice (Oryza sativa L.) and barley (Hordeum vulgare L.).
abstract: Aspergillus flavus and Aspergillus parasiticus are primary pathogen moulds on brown rice and barley. This study investigated the effects of microwave irradiation (MWI) (2450 MHz, 700 W, 10-50 s) on inactivation of A. flavus and A. parasiticus on brown rice and barley and the quality of these samples. The counts of both strains were significantly (p < 0.05) reduced by the stepwise increase in MWI treatment time. The log reductions of A. flavus on brown rice and barley were 0.05 and 0.04 after 10 s; 1.06 and 1.05 after 20 s; 1.59 and 1.52 after 30 s; and 3.04 and 2.78 after 40 s. The log reductions of A. parasiticus on brown rice and barley were 0.06 and 0.10 after 10 s; 1.20 and 1.00 after 20 s; 2.04 and 1.61 after 30 s; and 2.89 and 2.90 after 40 s. Moreover, neither strain survived after 50 s of MWI. The Hunter colour 'L' gradually increased with increasing MWI treatment time. However, there were no significant differences in the 'L' of brown rice after 10-40 s of MWI treatment and of barley after 10-30 s of MWI treatment. The Hunter colour 'a' and 'b' gradually increased with increasing microwave time. No significant change was observed in the moisture content of either cereal treated with 10-20 s of MWI. The differences in the sensory quality (colour, appearance, flavour, texture and overall acceptability) after 0-30 s of MWI were not significant. However, values for colour, appearance, texture and overall acceptability were significantly reduced when treated with 40-50 s of MWI. Therefore, with 20 s of MWI at 2450 MHz, 700 W could be effective for > 90% reduction of mould without causing deleterious changes to the colour, moisture content and sensory qualities of these cereals.
authors.affiliation: a Department of Food Science and Technology, Advanced Food Safety Research Group, BrainKorea21 Plus , Chung-Ang University , Ansung , Kyunggido , South Korea.
authors.forename: Seung-Hun
authors.initials: SH
authors.lastname: Lee
authors.affiliation: a Department of Food Science and Technology, Advanced Food Safety Research Group, BrainKorea21 Plus , Chung-Ang University , Ansung , Kyunggido , South Korea.
authors.forename: Shin Young
authors.initials: SY
authors.lastname: Park
authors.affiliation: a Department of Food Science and Technology, Advanced Food Safety Research Group, BrainKorea21 Plus , Chung-Ang University , Ansung , Kyunggido , South Korea.
authors.forename: Kye-Hwan
authors.initials: KH
authors.lastname: Byun
authors.affiliation: a Department of Food Science and Technology, Advanced Food Safety Research Group, BrainKorea21 Plus , Chung-Ang University , Ansung , Kyunggido , South Korea.
authors.forename: Hyang Sook
authors.initials: HS
authors.lastname: Chun
authors.affiliation: a Department of Food Science and Technology, Advanced Food Safety Research Group, BrainKorea21 Plus , Chung-Ang University , Ansung , Kyunggido , South Korea.
authors.forename: Sang-Do
authors.initials: SD
authors.lastname: Ha
mesh_terms: D001230:Aspergillus / Q000302:isolation & purification*; D005506:Food Contamination / Q000032:analysis* / Q000517:prevention & control*; D001467:Hordeum / Q000382:microbiology*; D008872:Microwaves; D012275:Oryza / Q000382:microbiology*; D010084:Oxidation-Reduction
keywords: Aspergillus flavus; Aspergillus parasiticus; barley; brown rice; microwave irradiation