Chilies contain a variety of health promoting compounds such as vitamins, minerals, phenolics, carotenoids and capsaicinoids. When ingested, capsaicinoids cause a burning sensation, which reduces regular and sufficient integration of chilies in a diet. In this master thesis we investigated the effect of three types of lactic acid fermentations (spontaneous, guided by Lactobacillus plantarum and Lactobacillus fermentum) on bioactive compounds content and pungency reduction of pastes from fresh and stored chili varieties with different degree of pungency. During fermentation we monitored the concentration of lactic acid bacteria and pH value. Then we analysed the samples of chili pastes before (0 hours) and after fermentation (24, 48 and 72 hours) by measuring colour, determining the content of sugars, lactic acid, ascorbic acid, phenolic compounds, carotenoids and capsaicinoids and by an organoleptic test. The highest lactic acid concentration was determined in pastes fermented with L. plantarum, which also proved to be the best type of fermentation for preserving the ascorbic acid content and the colour of the chili pastes. Phenolic compounds and carotenoids were well preserved in most treatments for all fermentation types. The capsaicinoid content was reduced only by fermentation with L. plantarum in 'Monkey face' chili paste. However, in the organoleptic test a pungency reduction was observed in all fermentation types, with the reduction being greatest by L. plantarum. The latter also scored the highest in the organoleptic test in terms of likeability. Considering all the results of this thesis, we have conclude that, of the three types of chili fermentation, the one guided by L. plantarum is the most suitable.
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