Celem badań było określenie aktywności przeciwdrobnoustrojowej wyciągów otrzymanych z Urtica dioica L. za pomocą nadkrytycznego CO2. Badaniami objęto następujące drobnoustroje: Bacillus subtilis, Saccharomyces cerevisiae, Aspergillus niger, Botrytis cinerea i Geotrichum candidum. Na Bacillus subtilis najsilniej działał wyciąg otrzymany z 500 g wysuszonych liści o wielkości cząstek 0,125 mm i wilgotności 8,32% w warunkach: p = 210 barów, T = 50°C, czas ekstrakcji 6 h. Dla Saccharomyces cerevisiae największe strefy zahamowania wzrostu wokół krążków otrzymano w przypadku wyciągu z liści (wilgotność 8,32%, wielkość cząstek 0,630 - 0,125 mm) otrzymanego w warunkach: p = 350 barów, T = 60°C, czas ekstrakcji 6 h. Wyciąg otrzymany przy p = 210 barów, T = 40°C w czasie 6 h wykazywał wysoką aktywność wobec Botrytis cinerea i Geotrichum candidum, natomiast na Aspergillus niger najsilniej działał wyciąg otrzymany przy p = 210 barów, T = 60°C i czasie ekstrakcji 6 h.
Z punktu widzenia zdrowia ludzkiego pałeczki z rodzaju Campylobacter spp., obok takich patogenów jak Salmonella sp., Escherichia coli, Listeria monocytogenes, należą do najbardziej niebezpiecznych bakterii odzwierzęcych rozprzestrzeniających się głównie drogą pokarmową. Pomimo ich wrażliwości na większość antybiotyków, coraz więcej izoluje się szczepów opornych na powszechnie stosowane terapeutyki. Wzrasta również liczba szczepów niewrażliwych na antyseptyki i dezynfektanty. Dlatego też naukowcy poświęcają wiele uwagi opracowaniu nowych strategii walki z tymi patogenami. Jedną z takich metod może być wykorzystanie substancji przeciwbakteryjnych produkowanych przez rośliny. Celem artykułu jest przegląd aktualnego stanu wiedzy na temat bakterii z rodzaju Campylobacter spp. i ich wrażliwości na substancje bioaktywne zawarte w ekstraktach roślinnych.
The article reviews the literature pertaining to functional proprieties of yeast cell wall components used as dietary supplements. The chemical construction of the yeast cell wall was discussed in connection with the ability of toxin binding, like mycotoxins, as well as heavy metals. Toxin removal with yeast utilization is mainly based on the physical adsorption of harmful chemicals to β-glucans, mannoproteins or glucomannans of the yeast cell wall. Special attention was also paid to the usage of yeast cell wall components as anti-infectious agents on account of antimicrobial activity of glucans and mannoproteins. A possible mechanism of such activity was presented.
Milk proteins possess a wide range of nutritional and biological properties. They are used as a source of energy, amino acids, vitamins, and minerals which are needed for the growth and development of organisms. Milk proteins contain physiologically active peptides encrypted in the protein sequences. Peptides with biological activity are produced during gastrointestinal digestion or food processing and could play an important role in metabolic regulation and modulation. This suggests the potential use of biopeptides as nutraceuticals and ingredients of functional foods to promote health and reduce the risk of diseases. Milk-derived bioactive peptides were shown to have antihypertensive, antihrombotic, antimicrobial, antioxidative, opioid, mineral-binding properties and anticancer activities. In vitro and in vivo studies are currently being carried out to identify milk bioactive peptides as well as to study their bioavailability and molecular mechanisms of action. Milk as a traditional food product can serve as the example of a functional food and be relevant for health-promoting as well as health-preventing factors.
The aim of the study was to determine the content of bioactive ingredients in American cranberry extracts (Vaccinium macrocarpon), the antimicrobial activity of these extracts, and the efficiency of the selected extract in minced pork meat together with its sensory evaluation. Three extracts were made: aqueous (w-FACE), ethanol (e-FACE) and aqueous-ethanol (we-FACE). The content of bioactive components was tested by HPLC. Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) were determined against ten Gram-negative bacteria strains and six Gram-positive bacterial strains by the serial macrodilution method. Minced pork meat with or without the addition of 2.5% w-FACE was inoculated with four pathogenic strains (Escherichia coli, Salmonella Enteritidis, Listeria monocytogenes and Staphylococcus aureus) and stored at 4°C for 6 days. At 0, 2, 4 and 6 days, the number of bacteria was determined by the plate method. Sensory evaluation of meat samples with and without in-FACE included general appearance and smell. All extracts contained organic acids (p-coumarin, benzoic, chlorogenic and coffee) and flavone (quercetin, miristin, epicatechin and isorhamnetin). E-FACE also contains ursolic acid. The MIC/MBC values of the extracts were in the range of 1.56-6.25 (3.13-25.0) mg/ml against Gram-positive bacteria and 6.25-12.5 (6.25-25.0) mg/ml against Gram-negative bacteria. Statistically significant (p ≤ 0.05) inhibition of the growth of all pathogens in minced pork meat containing in-FACE was found. The 2.5% w-FACE had no significant effect (p ≤ 0.05) on the initial sensory characteristics of minced pork meat and after 4 and 6 days of storage was significantly higher than that of FACE-free meat. The results of the study suggest the possibility of using an aqueous extract of cranberry fruit as a natural preservative of minced pork meat.
Biologically active peptides are of particular interest to food science and nutrition because they may act as potential physiological modulators of metabolism. Hidden or inactive in the amino-acid sequence of food proteins, they can be released or activated in vivo during gastrointestinal digestion, or in vitro during enzymatic hydrolysis and food processing. Egg proteins are an important source of these bioactive peptides. In recent years, major egg protein components, ovoalbumin, conalbumin, ovomucin and phosvitin, have also been shown to contain bioactive sequences. Peptides showing antiadhesive, anticancer as well as immunomodulatory activities were found in ovomucin sequence. Immunoregulative peptides were also found in peptic and chymotryptic hydrolysates of ovoalbumin. Ovocinin and ovocinin(2-7) - angiotensin-converting enzyme inhibitory peptides, whose pharmacological activity was observed in micromolar concentrations - were liberated during in vitro proteolysis of ovoalbumin. Furthermore, many egg protein hydrolysates showed antimicrobial and antioxidant activity after proteolysis with different enzymes, and several active peptides were isolated and identified.