Storage stability of minced beef supplemented with chickpea legumin at 4 °C as a potential substitute for nisin

Chickpea legumin has a high molecular weight (300 KDa), consists of 5 subunits (25-45 KDa) and has a relatively high isoelectric point (pH 6.5). It could inhibit the growth of four bacteria strains (Staph. aureus, P. aeruginosa, E. coli and B. subtilis), grown in agar (MIC = 100-150 g/ml) and bring the liquid bacterial growth to their minimum levels after 24 h of incubation using 1 MIC. Transmission electron microscopy micrographs of Staph. aureus (Gram positive) and P. aeruginosa (Gram negative) treated by 150 μg/ml chickpea legumin (1 MIC) showed cellular swelling and cell membrane disintegration explaining the mode of action of this protein. Minced beef samples supplemented with 200 μg/g chickpea legumin extended the storage time to 14-15 days instead of 7-8 days in case of un-supplemented control and 10-11 days in case of nisin, reducing the total viable count by 2.6-2.9 log compared to control against a reduction of 1.6 log in case of nisin.