Cold plasma processing of phycoerythrin extracted from cyanobacterium Desmonostoc sp. for inactivation of Bacillus subtilis spores

Cold plasma is a non-thermal technology used in the food industry for microbial inactivation, addressing challenges in spore-forming microorganisms and preventing spoilage. This research investigates the effect of cold processing on the inactivation of Bacillus subtilis spores using treated phycoerythrin (PE) from Desmonostoc sp. with dielectric barrier discharge plasma (DBD) treatment for the first time.

After cyanobacterial culture, the PE was extracted and purified. Then the PE was treated with DBD plasma for thermal stability, contamination with bacterial spores, microbiological analysis, and antioxidant activity at the control condition and treatment times of 1, 3, 4, and 5 min at two temperatures of 0 and 35 °C.

The spectroscopy results showed a significant increase in PE absorption under DBD plasma for 3 min, while the purity and concentration of PE increased at 4 min. The study revealed that 5 min of DBD plasma exposure resulted in the highest thermal stability, antioxidant activity, and spore inactivation, while control conditions yielded the lowest results. DBD plasma exposure for 5 min increased stability and antioxidant activity by 1.003 and 0.89, respectively, while DBD plasma decreased the microbial index by 0.82. In addition, DBD plasma for 3 min at °C led to the inactivation of spores by 1.45 times until the 30th day.

DBD plasma exposure time positively correlates with PE-treated efficiency, making cyanobacterial pigment combination with cold plasma a preferred microbial control technology for decontaminating B. subtilis spores.