Evaluation of refrigerated storage in nitrogen-enriched atmospheres on the microbial quality, content of bioactive compounds and antioxidant activity of sauerkrauts.

The aim of this work was to investigate the influence of storage at 4 ºC in conventional or nitrogen (N2)-enriched atmospheres for 3 months on the microbial status of sauerkraut obtained by natural fermentation or by Leuconostoc mesenteroides inoculation. The content of vitamin C, glucosinolate derivatives and the antioxidant activity of stored sauerkrauts were also evaluated. Aerobic/anaerobic mesophilic bacteria and lactic acid bacteria populations decreased sharply during N2 storage, whilst they increased during conventional storage. Ascorbigen and vitamin C levels decreased gradually during storage and no significant differences were found between both storage types. The concentration of nitriles and isothiocyanates decreased during storage and, in general, lower content of these compounds were found in N2-stored sauerkrauts. The antioxidant capacity of fermented cabbages was retained after storage at both conditions, and L. mesenteroides sauerkrauts presented significantly higher antioxidant activity at the end of the storage period when N2 atmosphere were used. Thus, the use of N2-atmosphere during refrigerated storage is a promising and cost-effective approach to improve the microbial quality of sauerkraut, and consequently, to extend its shelf-life. Sauerkrauts stored in these conditions had large antioxidant activity and retained high phytochemical concentrations.

This work was supported by the Spanish Commission of Science and Technology (CICYT), project number AGL2007-63462. Elena Peñas is indebted to a José Castillejo mobility grant nº JC2009-00100 funded by the Ministry of Science and Innovation and to a JAE-doc grant ref. 2008-092 funded by CSIC and ESF.

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