| Abstract [eng] |
Nowadays, emergence of antibiotic resistant food-borne pathogens inspired the development of alternative therapies including nutraceuticals with selected natural antimicrobial compounds. One of possible solutions would be the development of hydrogels that are enriched with compounds that have antimicrobial and antioxidant properties such as essential oils and colostrum. These proposed hydrogels should be sensitive to digestive tract pH shifts. Furthermore, exceptional attention has been drawn to use of secondary waste from fruit processing that have high contents of dietary fibers. One of the possible materials is apple pomace. This work aims to evaluate the possibility of hydrogel development from apple pomace along with low calorie sweeteners and selected hydrocolloids, which would be used for immobilization of essential oils and lactic acid bacteria fermented cow colostrum. The HPLC analysis showed that apple pomace is rich in antioxidants such as phloridzin (591,6 g/g), chlorogenic acid (482,1 g/g) and hyperoside (405,9 g/g). The apple pomace exhibited antioxidant activity against DPPH and ABTS radicals with scavenging capacities 63,19 ± 0,35 % and 77,81 ± 0,66 %, respectively. Among investigated clove, thyme and tangerine essential oils, the most significant antimicrobial activity showed thyme essential oil, which minimal inhibitory concentration was 1 %. The SDS-PAGE analysis showed that Lactobacillus uvarium LUHS 245 fermented cow colostrum contains proteins such as lactoferrin, BSA, α-S2 casein, β-casein, κ-casein, β-lactoglobulin and α-lactoglobulin. The best hydrogels texture with apple powder was obtained with gelatin. In addition, the hydrogels texture was improved when sorbitol was added into the composition. The HPLC analysis of “Eunutritech” essential oils components showed that in multi-layered gels structures about 12 times more components remained rather than single layered structures after immobilization. To improve hydrogels structure with apple pomace, the optimal colostrum quantity was 6 % and apple pomace 10 % in gels composition. In vitro phenolic compounds release studies showed that from apple pomace hydrogels with clove and thyme essential oils, the majority of phenolic compound from matrix was released at pH 2 after 120 min. According to the HPLC analysis, procyanidin B1 is the mainly component released from these structures in pH 2 medium. Phenolic compounds from multi-layered gel structure with “Eunutritech” essential oils mixture released in both media (pH 2 and pH 7,5) and after 210 min was reached the highest phenolic compounds concentration in pH 7,5 medium. According to HPLC results, procyanidin B1, catechin and chlorogenic acid were detected 1,2 times more in pH 7,5 medium rather than in pH 2. |
