Atmospheric pin-to-plate cold plasma modification of amaranth starch & its application as a stabilizer in low-fat mayonnaise

This study investigates the changes in physicochemical, functional, rheological, and structural characteristics of the amaranth seed starch upon atmospheric cold plasma exposure with the generation/input voltages of 170, 200, and 230 V for 5-15 min and its potential as a fat replacer in a model emulsion system (mayonnaise). The surface modification by cold plasma is expected to enhance the native amaranth starch characteristics. Plasma treatment reduced the amylose content to a minimum of 9.00 % (230 V-15 min) resulting in a rise in relative crystallinity (74 %) and % syneresis (48.42 %). The hydratability remarkably elevated to a maximum rise of similar to 158 %, similar to 37 %, and similar to 41 % in solubility, absorption index, and swelling power respectively. Increased hydration, reduced the turbidity from 5.10 % (untreated) to a minimum of 3.42 % (230 V-15 min) of the pastes due to the cracked granular surface seen in electron micrographs. The rheological attributes improved up to 200 V15 min with the peak viscosity of 5690 cP as the starch molecules tend to crosslink/aggregate which was confirmed by the increase in the C-O-C stretching band area in FTIR spectra. On 30 % fat substitution with the plasma-treated amaranth starch (200 V-15 min), the mayonnaise viscosity increased significantly (p < 0.05) from similar to 7.60 Pa.s (control) to similar to 15.82 Pa.s (200 V-15 min) resulting in better emulsion stability (similar to 82 %) and lightness. This proves the potential of cold plasma technology to modify under-utilized starches for sustainable food applications.