Combined effect of natural antioxidants and antimicrobial compounds during refrigerated storage of nitrite-free frankfurter-type sausage

The effects of nisin (200 and 400 ppm), epsilon-polylysine (0.1 and 0.2%) and chitosan (0.5 and 1%) in combination with a Mixed Extract (green tea, stinging nettle and olive leaves extracts) on the physicochemical, microbiological characteristics, fatty acid composition and sensory attributes of the nitrite-free frankfurter-type sausages were assessed during 45 days of storage. The results revealed no significant differences on moisture, fat, protein, ash, salt and water activity (aw) among treatments. 1% Chitosan + Mixed Extract sausages displayed the lowest thiobarbituric acid reactive substances (TEARS) and total volatile nitrogen (TVN) values compared to Control after 45 days of refrigerated storage. Combinations of 0.2% epsilon-Polylysine or 1% Chitosan with Mixed Extract were effective to inhibit total viable count (TVC), yeasts and molds growth. 1% Chitosan preserved the luminosity of sausages during refrigerated storage. However, redness values of 1% Chitosan treatment was lower than those obtained from Control sausages and a significant increase was observed between days 30-45. Total amounts of saturated, monounsaturated and polyunsaturated fatty acids (SFA, MUFA, and PUFA) of frankfurter type sausages were not largely influenced by the combination of natural antioxidants and antimicrobial compounds. Combinations of 0.2% epsilon-Polylysine and 1% Chitosan with Mixed Extract were effective to improve the shelf life of nitrite-free frankfurter-type sausages. Therefore, these combinations could be considered as promising nitrite replacer in frankfurter-type sausages.