Aggregation and conformational change of mushroom (Agaricus bisporus) polyphenol oxidase subjected to atmospheric cold plasma treatment.

Atmospheric cold plasma (ACP) is a novel nonthermal technology with potential applications in maintaining and improving food quality. The effect of ACP on the activity and structure of mushroom (Agaricus bisporus) polyphenol oxidase (PPO) was evaluated. Results demonstrated that the dielectric barrier discharge (DBD) based plasma technology could inactivate PPO (up to 69%) at 50 kV with the increased concentrations of H2O2 and NOx. An obvious enhancement of surface hydrophobicity was observed, whereas a gradual reduction of total sulfhydryl content was recorded with the increasing exposure time. Data from circular dichroism, atomic force microscopy, particle size distribution and fluorescence spectra displayed the rearrangement of secondary structure and disruption of the tertiary structure. Red shifts of fluorescence spectra showed positive correlations with the inactivation rate of PPO. Therefore, ACP treatment could be served as an alternative approach to inactivate undesirable enzymes to minimize the loss of food nutrition and quality.

Effects of a cold plasma-assisted shrimp processing chain on biochemical and sensory quality alterations in Pacific white shrimps (Penaeus vannamei).

In this paper, remodeling the shrimp processing chain and the effects of the transformation on the biochemical and sensory qualities of fresh Pacific white shrimp (Penaeus vannamei) under refrigeration storage were investigated. In the proposed model, a dielectric barrier discharge atmospheric cold plasma pretreatment step using a 60 kV source for 60, 90, 120, and 150 s was introduced after the first and second wash followed by refrigeration storage at 4 ± 1 °C for 12 days. Chemical, biochemical, and sensory attributes of the shrimp were monitored and compared with those of shrimp processed through the traditional method without atmospheric cold plasma pretreatment (control). Incorporating minimal dielectric barrier discharge atmospheric cold plasma pretreatment step had more desirable quality outcomes characterized by low malondialdehyde concentration, low volatile nitrogen products content, and comparable proximate composition. Texture, pH, and color were remarkably retained at 120 and 150 s of atmospheric cold plasma pretreatment and protein degradation was negligible up to 90 s than at 120 and 150 s of pretreatment. We conclude that remodeling the shrimp processing chain through incorporating minimal dielectric barrier discharge atmospheric cold plasma pretreatment with key considerations on operation parameters can maximize the beneficial biochemical and sensory quality outcomes while minimizing the negative impacts associated with traditional shrimp processing.