Microencapsulation of nisin in alginate-cellulose nanocrystal (CNC) microbeads for prolonged efficacy against Listeria monocytogenes (original) (raw)

The present study was undertaken to develop edible nisin-microencapsulated beads in order to inhibit growth of Listeria monocytogenes in readyto-eat (RTE) ham. Different concentrations of nisin (16, 31, and 63 lg/ml) were microencapsulated into alginate-cellulose nanocrystal beads. Microencapsulation kept the available nisin (63 lg/ml) content 20 times greater compared with free nisin (63 lg/ml) during 28 days of storage at 4°C. Results showed that 63 lg/ml microencapsulated nisin exhibited 31.26 lg/ ml available nisin content after 28 days of storage at 4°C, whereas there was no available nisin content left for free nisin. Cooked ham slices were then coated by the microencapsulated nisin beads, inoculated with L. monocytogenes [*3 log colony-forming units (CFU)/g], and stored at 4°C under vacuum packaging for 28 days. The beads containing 16, 31, and 63 lg/ ml nisin significantly (P B 0.05) reduced the L. monocytogenes counts by 2.65, 1.50, and 3.04 log CFU/g after 28 days of storage compared with free nisin. Furthermore, microencapsulated nisin beads did not change the physicochemical properties (pH and color) of RTE ham during storage.