Response‐Surface Optimization of <i>Nelumbo nucifera</i> Seed Starch Modification Through Crosslinking With Glutaraldehyde and Its Characterization

ABSTRACT Chemical modification of starches has been proved to improve their physical, functional, and biological characteristics for manufacturing environment‐friendly biodegradable materials of industrial and biomedical importance. Response‐surface optimization of native Nelumbo nucifera starch‐glutaraldehyde crosslinking was performed to synthesize a biodegradable material for industrial, environmental, and biomedical applications. A five‐level tri‐factorial central composite design consisting of three process variables Χ 1 : native starch concentration (NSC), Χ 2 : β‐glutaraldehyde concentration (BGAC), and Χ 3 : stirring time (S t ), was constructed using response‐surface methodology. The CLS was subjected to its physical, functional, and biological characterization. The extraction yield of native starch at various levels of the selected variables was 52.98% ± 2.14%, while the yield of cross‐linked starch (CLS) was 48.22% ± 24.4%. However, the optimum yield of CLS calculated from the employed model (56.37%) was observed at NSC: 0.911 g, BGAC: 0.759%, and S t : 11.180 h. The CLS showed oval‐shaped granules with smooth surfaces; improved crystallinity and thermal stability; good tensile strength (62.86 MPa); elongation at break (33.26%); relatively lower water holding (108% ± 9.67%), swelling (104.59% ± 2.86%), and higher oil holding (136% ± 9.45%) capacities; good biodegradability patterns (46.22% ± 6.01%); and considerable antibacterial activity (zone of inhibition: 13.5 mm against Escherichia coli ). Based on these characteristics, CLS would be preferable for manufacturing environment‐friendly packing materials and biomedical equipment.