Application of chitosan extracted from silkworm pupae by ultrasound-assisted enzymatic method on strawberry preservation

As a naturally derived biomacromolecule, chitosan is widely utilized in food preservation. However, the chitosan derived from silkworm pupae and its application in food preservation are relatively unexplored. To obtain chitosan with enhanced preservation properties, silkworm pupae chitosan was extracted using dual-frequency ultrasound-assisted chemical and enzymatic methods, followed by a comparative analysis of their physicochemical properties, biological activity, and preservation efficacy on strawberries. Compared with the commercial chitosan, the yield, physicochemical properties, and biological activity of silkworm pupae chitosan using the dual-frequency ultrasound-assisted enzymatic method were increased, exhibiting a solubility of 98.1 % and a deacetylation degree of 99.12 %. The silkworm pupae chitosan demonstrated the highest antioxidant activity and effective microbial inhibition at the concentration of 1 % (w/w). When applied as a coating solution for strawberry preservation, this chitosan significantly reduced weight loss, titratable acid degradation, and polyphenol consumption. Furthermore, it decreased the decay rate by 50 % and extended shelf life by two-fold compared to untreated samples. The dual-frequency ultrasound-assisted enzymatic method provides an eco-friendly approach for chitosan extraction, with silkworm pupae-derived chitosan showing excellent potential as a biodegradable food preservative.