Preservation effect of curcumin-tyramine cocrystal-mediated photodynamic technology on refrigerated salmon

【Objective】 To evaluate the effects of curcumin–tyramine cocrystal (CTC)-mediated photodynamic treatment on the quality preservation and shelf life of salmon during refrigerated storage. 【Methods】 Salmon samples were subjected to photodynamic treatment using 100 μmol/L CTC as the photosensitizer under 425 nm LED blue light. Changes in appearance, physicochemical properties, microbial growth, and water migration were investigated during storage at 4 ℃.【Results】 Curcumin-tyramine cocrystal-mediated photodynamic treatment(CTC-PDT) significantly inhibited microbial proliferation and retarded the increase in pH, the accumulation of total volatile basic nitrogen (TVB-N), and lipid oxidation during refrigerated storage. After 6 d of refrigerated storage, the total viable count and total volatile basic nitrogen (TVB-N) content in the CTC-PDT group were (3.77±0.15) lg CFU/g and (23.46±0.84) mg/100 g, respectively, both significantly lower than those in the blank control group. The thiobarbituric acid (TBA) value was (0.83±0.02) mg MDA/kg,which was numerically close to that of the blank control group on 3 d. In addition, CTC-PDT also delayed color deterioration, with a ΔE value of 13.94 ± 0.27 on day 9, reduced water loss, better maintained the appearance and textural properties of the samples, including chewiness, and significantly suppressed increases in bitterness and astringency. Compared with the positive control group(1 mg/mL potassium sorbate treatment group), the CTC-PDT group showed overall performance in terms of total viable count, TVB-N content, TBA value, and some texture-related parameters.【Conclusion】 CTC-PDT effectively inhibited microbial growth and delayed quality deterioration, enabling salmon samples to remain acceptable after 6 d of refrigerated storage and thereby extending their refrigerated shelf life. These findings indicate that CTC-PDT has potential as a novel non-thermal preservation method for chilled aquatic products.