Innovative silk protein peptide-modified soy protein isolate-xanthan gum films for food packaging

A novel packaging material (SXS) composed of silk protein peptide (SPP), xanthan gum (XG), and soy protein isolate (SPI) was developed. The incorporation of SPP significantly enhanced the antioxidant activity of the SXS cling film. The aromatic amino acids in SPP and SPI absorbed ultraviolet light, improving the film's UV resistance. Molecular docking verified the interactions among SPI, XG and SPP, indicating multipoint binding that supports the proposed network-strengthening mechanism. The optimum amount of SPP is 6%, providing the best overall balance between UV barrier properties, mechanical strength, and water contact angle. For food preservation, SXS6% reduced the weight loss rate from 6.42% to 4.34%, increased vitamin C (V_c) retention for grape (61% to 79%) and for yellow peaches (51% to 84%). By reducing water evaporation, delaying respiration, and preserving nutrients, the SXS6% film effectively extended the shelf life of fruits, demonstrating its potential for use in food preservation applications.