Physicochemical changes in minimal ozone-treated fresh shrimp stored on ice tandem with microbiological efficacy of treatment

Abstract

Physicochemical changes associated with product quality of minimal ozone-treated fresh shrimp were evaluated tandem with microbiological efficacy of treatment during iced storage of up to 10 days. Safely discharged from commercially available  domestic-type ozone facility, a previously defined minimal ozone treatment (100 mg/h at 60 s) has been applied to freshly harvested shrimp prior to iced storage. In particular, the physicochemical properties involved L*, a* and b* colour,  adhesiveness, fracturability and hardness textures, water activity (a_w), water  retention index (WRI), pH, moisture, fat and protein contents as well as lipid  oxidation. Alongside, the microbiological efficacy of treatment has been quantified by way of total viable count reduction ratio (TVC_RR). The result showed that  differences in initial measured iced storage values between processed and control samples were much less compared to the obvious statistical differences (p < 0.05) detected in aw, colour, lipid oxidation, moisture content, pH and WRI during iced storage. The TVC_RR decrease against storage time to estimate only 81.0% of  explained variance most likely resulted due to increase in microbial proliferation  with storage, which should not be considered negatively for the reason that minimal ozone treatment would show antioxidant-like property to decrease both lipid  oxidation and L* colour of treated shrimp and respectively modify and stabilise some chemical and textural properties compared with the control.

Keywords: Ozone processing, ozone facility, Litopenaeus vannamei,  physicochemical properties, microbial effectiveness.