The potential application of a novel biodegradable film activated with co-encapsulated epsilon-poly-l-lysine and Spirulina platensis extract for fish fillets preservation

In this study, novel biodegradable films were fabricated by adding W2/O/W1 emulsion (containing coencap-sulated Spirulina platensis extract (SE, 800 mu g/mL) and epsilon-poly-L-lysine (EPL, 200 mu g/mL)) into soybean polysaccharide (SBP)-bovine skin gelatin (GL). Emulsions with zeta-potential of -40.33 to -50.93 mV and droplet size of 6.32-9.69 mu m were achieved. The incorporation of microemulsion into the structure of the film was justified by ATR-FTIR and SEM. The water solubility, water vapor permeability, tensile strength and elongation at break of the films loaded with microemulsions were improved. Films containing coencapsulated SE-EPL presented high antioxidant and antibacterial activities. Coating grass carp fillets with the film significantly decreased the K-value and ATP-related compounds (especially hypoxanthine, Hx), limited the formation of 8 biogenic amines (tryptamine, phenylethylamine, putrescine, cadaverine, histamine, tyramine, spermidine, and spermine), protected the sensorial quality, and increased their shelf life by approximately 4 days, proposing its potential application in preserving aquatic products.