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In this study, ɛ-polylysine (ɛ-PL) or ɛ-polylysine nanoparticle (ɛ-PLN) combined with plants extracts (including green tea, olive leaves and stinging nettle extracts) were used as nitrite replacers in frankfurter-type sausages. The sausage samples were wrapped in polyethylene bags (in vacuum conditions) and their physicochemical, microbiological and sensory properties were evaluated during 45 days of refrigerated storage. The results showed that the incorporation of ɛ-polylysine had no significant effects on proximate composition of sausages. However, ɛ-PL and ɛ-PLN sausages had significantly (P < 0.05) lower lightness, redness and higher yellowness compared to control samples. At the end of storage, sausages formulated with ɛ-PLN had significantly (P < 0.05) higher contents of phenolic compounds and lowest TBARS values. Microbiological counts also indicated that ɛ-PLN displayed significantly higher inhibitory effects. Higher sensory indices were obtained in ɛ-PLN sausages. Based on the obtained results, ɛ-PLN was effective to improve frankfurter-type sausages shelf life. Therefore, these ingredients could be useful for frankfurter-type sausages production as nitrite replacers., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

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 (a w ) 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., (Copyright © 2018 Elsevier Ltd. All rights reserved.)