The effects of nisin (200 and 400 ppm), ε-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 (TBARS) and total volatile nitrogen (TVN) values compared to Control after
45 days of refrigerated storage. Combinations of 0.2% ε-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% ε-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.