Methoxy polyethylene glycol amine-modified curcumin derivative: Synthesis, photophysical properties, and photodynamic inactivation preservation on peeled Pacific white shrimp (Litopenaeus vannamei)

To improve the water solubility and photodynamic inactivation (PDI) activity of curcumin (Cur), a novel methoxy polyethylene glycol amine (mPEG-NH 2 )-modified Cur derivative, mPEG-NH-Cur, was synthesized and characterized. The results showed that mPEG-NH-Cur had extremely high water solubility with a saturated solubility of 6.71 mg/mL, which was 15-fold that of Cur. Theoretical calculations revealed that the introduction of PEG markedly enhanced hydrogen bonding, electrostatic interactions, and van der Waals interactions between mPEG-NH-Cur and H 2 O while simultaneously reducing the energy gap to its excited state. These effects contributed to its enhanced stability and resistance to aggregation in aqueous solutions, thereby significantly improving its capacity for singlet oxygen ( 1 O 2 ) generation (achieving 100 % degradation of 1,3-diphenylisobenzofuran within 30 s). In the PDI preservation experiments, the peeled Pacific white shrimp ( Litopenaeus vannamei ) treated with mPEG-NH-Cur showed the greatest sensory acceptability after eight days of storage at 4 °C compared to the control group. Moreover, the inhibitory effects of mPEG-NH-Cur-mediated PDI treatment on the total volatile basic nitrogen content, pH, thiobarbituric acid value, and total viable count were significantly higher than those of the control group. Ultimately, the use of mPEG-NH-Cur increased the refrigerated shelf life of the peeled L . vannamei by 8 days. Further, the weak interaction analysis demonstrated that PEG effectively suppressed molecular aggregation through enhanced hydrogen bonding and steric hindrance over an extended duration (40,000 ps), thereby improving aqueous solubility and dispersion stability. Overall, the findings of this study provide novel insights into the potential application of Cur derivatives in PDI preservation.