Effect of antimicrobial substances on "raw food" durability

Submitted diploma thesis deals with an effect of antimicrobial substances on raw food durability. Nowadays, the raw food has become very required style of nutrition, which is being practised by more and more people. The issue is that this kind of alimentation, especially vegetable raw food is not prepared in heat treatment which is higher than 42–45 °C. The main aim of the thesis is to study antioxidant and antibacterial properties of the herbal and spice extracts and their following implementation into raw desserts to prolong their durability. At the beginning of the theoretical part, there is an analysis of the issue of raw food and the description of micro-organisms, which are mostly occurred on plant materials. Afterwards, selected herbs and spices, and mechanisms of their antimicrobial effects, and also the methods used to test the products are characterised. The experimental part focuses on characterization of ethanol extracts from 13 selected kinds of spices and herbs. The determination of biologically active substance was accomplished, specifically, polyphenols, flavonoids, anthocyanins and their antioxidant properties. Moreover, these extracts were tested to antimicrobial effect towards gram-positive species of germs Micrococcus luteus, gram-negative species of germs Escherichia coli and yeast Candida glabrata. The molecular part of the thesis contains the DNA isolation from the tested raw material, which was enriched of combination of the selected herbs and spices. Change of expiry date of selected samples of raw desserts was monitored. The presence of chosen micro-organisms was confirmed by the PCR method