Physico-chemical and microbiological changes during the cabbage hybrid bravo heads fermentation: Salt, temperature...

The influence of temperatures (18, 22 and 26 °C), salt (60, 70 and 80 g/kg) and starter culture (0, 0.025 and 0.050 g/kg) on physico-chemical and microbiological changes during fermentation in cabbage heads were investigated. The experiment was set up in industrial conditions, samples were taken after 0, 5, 12, 27 and 62 days in order to determine the changes in color, texture, biogenic amines content, microbiological parameters, pH, a_w, total sugar content, total acidity and salt content. Analysis of variance and Principal component analysis were applied to get a better overview of differences between samples and the similarities between different fermentation conditions. Significant color changes and softening of cabbage tissue did not occurred during the entire fermentation process. Cadaverine was not detected in samples containing starter culture, also the results were in range for maximum allowed putrescine and cadaverine doses for all cabbage samples. Total number of molds increased, contrary to number of yeasts on the last examined day in comparison with raw cabbage sample. Enterobacteriaceae were not detected after 5^th fermentation day, while sharp increase of lactic acid bacteria number occurred until 12^th day, and on the 12^th fermentation day was in range of 7.82 to 9.84 log cfu/g. The fermentation process led to decrease in pH, a_w and total sugar content, meanwhile total acidity 0.54%-0.89% and salt content 2.08%-3.19% in the cabbage heads increased, in comparison with raw sample where results for total acidity and salt content were 0.13% and 0.05%, respectively. Additionally, according Principal component analysis, temperature of fermentation had the greatest influence on the fermentation process, followed by the application of starter culture and then concentration of added salt.