Antimicrobial and antioxidant properties of chitosan-furcellaran-gelatin hydrolysate coatings enhanced with bioactive peptides

The aim of the study was to investigate the antioxidant and antimicrobial properties of novel, edible biopolymer coatings consisting of chitosan, furcellaran, carp skin gelatin hydrolysate and 8 different bioactive peptides: Lfcin-β, MBP-1, PLGG, LL37, Cys-LL37, melittin, RW4 and nisin. In vitro analyses consisted of evaluating FRAP and ABTS radical scavenging properties as well as effectiveness against various food pathogens. Consequently, the coatings were used to investigate their antimicrobial effect during cold storage of smoked pork ham dipped into the coating solutions with and without the presence of CaCl2. Finally, the 2 most effective coatings were applied onto fresh cold stored pork loins with different doses of the investigated peptides (1.25–10 μg/mL). The biopolymer matrix had high radical scavenging properties (76.94%) and FRAP value (5.41 μmol of Trolox/mL), however, the antioxidant power was reduced when peptides were included. The coatings with peptides inhibited the growth of all tested food pathogens aside from Aspergillus flavus. They successfully inhibited the growth of total viable counts (TVC) with reductions even above 3.5 log cfu/g. The inclusion of CaCl2 provided contradictory results for different groups and it was impossible to confirm its effectiveness. Coatings with RW4 and LL37 were selected as the most promising and proved effective in inhibiting the TVC of fresh pork loin, even at doses of 1.25–2.5 μg/mL. The newly developed coatings exhibit high antioxidant and antimicrobial power and could be used to effectively extend the shelf-life of perishable meat products.