Effects of cold atmospheric plasma on squid proteases and gel properties of protein concentrate from squid (Argentinus ilex) mantle

The effect of cold atmospheric plasma (CAP) on protein concentrate from squid (Argentinus ilex) mantle has been evaluated in terms of gel properties, protease inhibition, texture profile, color attributes, and water holding capacity. Different exposure time (15, 60, 120, 180, 240 and 300 s) at 60 kV have been employed. Our results indicated that protease activity decreases with increasing treatment time. The highest reduction (p < 0.05) in protease activity (64%) was observed after 240 s of CAP treatment. Texture profile analysis, color properties and water holding capacity of the treated squid gel revealed a significant increase. Protein carbonyl and sulfhydryl group contents findings' showed a significant increase in carbonyl content (about three times of the original content), while the total sulfhydryl group decreased (up to about 40%) in the crude extract. Microstructure and SDS-PAGE analysis revealed a high degree of protein aggregation in the squid gel treated with CAP.