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Recipe of a food supplement based on bioactive substances isolated from Prunus spinosa
Červinková, Zuzana ; Hudečková, Helena (referee) ; Kovalčík, Adriána (advisor)
Blackthorn fruits (Prunus spinosa) are small blue-purple drupes containing a range of bioactive substances that give them diverse biological effects. They are traditionally used not only in folk medicine, as they are attributed with many preventive and therapeutic effects. The presented master´s thesis deals with the preparation and characterization of an ethanol extract and dietary supplements based on bioactive substances isolated from the fruits of blackthorn. The ethanol extract was prepared by maceration fresh Prunus spinosa fruits in 40% alcohol. The extract was analyzed for the polyphenols (2111.39±11.32 mg GAE/l), flavonoids (903.89±5.08 mg CAE/l) and anthocyanins (165.24±0.38 mg CGE/l) content, antioxidant (11.99±0.40 mmol TE/l) and antimicrobial activity, phenolic compounds profile and sugars profile. The ethanolic extract exhibited antibacterial effect against the gram-positive bacterium Micrococcus luteus and gram-negative bacterium Escherichia coli but was not effective against the yeast Candida glabrata. After gentle concentration on a vacuum evaporator, the extract was used to prepare a dietary supplement. Two types of dietary supplements were prepared, namely gelatine candies with blackthorn fruit extract and gelatine capsules filled with lyophilized fruit powder. The nutritional profile of these products, content of bioactive substances (i.e. total polyphenols, flavonoids, and anthocyanins), phenolic compound profile and antioxidant activity were characterized. Additionally, the release of polyphenols was monitored during a simulated in vitro digestion. The gelatine candies with different extract concentrations (5, 10, 15 and 20 %) were subjected to sensory evaluation, where the aim was to optimize the addition of the extract to the gelatine matrix. According to the preferences of the evaluators, the sample with 15 % extract was rated as the best in terms of overall taste. In the ranking test, this sample was ranked second, behind the sample with 5 % extract, which, on the other hand, received a worse sensory profile rating. The thesis also included monitoring the effect of freezing, lyophilization, and drying on the bioactive compounds content (i.e. total polyphenols, flavonoids, anthocyanins) and antioxidant activity of Prunus spinosa fruits. The highest contents of total polyphenols (57.49±0.33 mg GAE/g DW), flavonoids (45.75±0.12 mg CAE/g DW) and anthocyanins (6.41±0.19 mg CGE/g DW) were quantified in lyophilized fruits, but the highest antioxidant activity (281.72±0.70 mol TE/g DW) was observed in frozen fruits. A statistically significant moderately strong positive correlation (0.641) of antioxidant activity and total flavonoids was observed for the analyzed samples. The results of the thesis showed a great potential for the use of blackthorn berries in the nutraceutical industry, where they can contribute as active additives to increasing both the bioactive and nutritional quality of dietary supplements.
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