Multifunctional phloroglucinol-loaded pea starch coating for refrigerated salmon

The bulk incorporation of phloroglucinol (2%, 4%, 6% and 8%, w/v), a naturally occurring seaweed benzenetriol, into pea starch coatings was investigated to extend the shelf life of salmon cuts. Phloroglucinol increased the in vitro antioxidant activity of the starch matrix, bringing IC50 down by up to 90% with 8% (w/v) phloroglucinol. All coating solutions exhibited shear-thinning and gelling behaviors. However, 8% phloroglucinol coatings showed significantly lower viscoelastic moduli than the other coatings. Phloroglucinol resulted in a significant, and generally dose-dependent, delay of flesh proteolysis. This was demonstrated by the slower rise of pH, trimethylamine, and flesh softening during storage (4 °C for up to 17 days). Moreover, phloroglucinol inhibited or retarded (in a dose-dependent manner) the microbial growth and the formation of oxidation markers, including sulfur-derived, and ethyl and methyl-esters volatiles (SPME-GC-MS). However, at the highest phloroglucinol concentration (8%), the abundance of these compounds was slightly higher than at lower concentrations.