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Combination of controlled enzymatic hydrolysis and ultrafiltration as the technique for bioactive peptide production intended for the food industry
No full textHypertension is the main risk factor for cardiovascular disease and one of the most common diseases worldwide. Long-term use of antihypertension drugs causes potentially adverse effects. The ACE-inhibitory peptides from natural sources are a safer therapeutic alternative without side effects. This work investigates obtaining bioactive peptides from whey proteins by combining controlled enzymatic hydrolysis and ultrafiltration. Hydrolysis of whey protein with three enzymes showed a significant increase in antioxidant and ACE-inhibitory capacity compared to the non-hydrolyzed sample. The hydrolysate obtained by proteinase k, trypsin, and thermolysin shows 60, 33, and 24 times higher ACE-inhibitory activity than the non-hydrolyzed sample. Hydrolysis with trypsin increases the amount of peptides with molecular weight lower than 3 kDa from 0.2 to 31, thermolysin to 52 and proteinase k to 62 %. Since large differences in the bioactivities of the peptide fractions of the hydrolysate were shown, ultrafiltration as a step after hydrolysis proved to be a good option for increasing the overall bioactivity of the sample after hydrolysis. Thermolysin showed the highest need for single-stage ultrafiltration after hydrolysis, while proteinase k showed no need for ultrafiltration. Hydrolysis of whey proteins by proteinase k creates the largest amount of peptides with a molecular weight below 3 kDa, and the highest antioxidant and ACE-inhibitory activity which can be used as pharmaceuticals or additives to functional food specially created for people with hypertension. The confectionery filling enriched with bioactive peptides didn't change the sensory properties but significantly increased antioxidant and ACE-inhibitory activity and stayed stable during storage
Comparison of Corrosion Resistance of Cu and Cu72Zn28 Metals in Apricot Fermentation Liquid
No full textThe production of fruit brandies is based on distilling fermented fruit juices. Distillation equipment is usually made of copper. In traditional manufacturing, it consists of a boiler (batch) distiller, a boiler (pot), a steam pipe, and a condenser, all of which are made of pure copper. This study determined the corrosion parameters for copper (Cu) and Cu72Zn28 (in wt%) alloy in fermented apricot juice at room temperature. The fermentation process examined in this research utilized natural strains of yeast and bacteria, supplemented by active dry yeast Saccharomyces cerevisiae strains. This research used the following methods: open circuit potential (OCP), linear polarization resistance (LPR), and Tafel extrapolation to identify corrosion parameters. Cu had a 3.8-times-lower value of corrosion current density than brass, and both were within the range of 1–10 μA·cm−2, with an excellent agreement between LRP and Tafel. This study proved that Cu is an adequate material for the distillation of fruit brandies from a corrosion perspective. Despite this, there are occasional reports of corrosion damage from the field. Significant corrosion impacts can arise, as evidenced by laboratory tests discussed in this paper. In the absence of a highly corrosive environment, this study indicates that, to some extent, microbiologically influenced corrosion (MIC) can influence the degradation of the equipment material
Viscoelastic properties of whole grain buckwheat flour dough substituted with wheat flour hydrolysates
No full textThis study aimed to assess the effect of substituting whole
grain buckwheat flour (WGBF) with wheat flour hydrolysate (WFH) with
reduced content of allergenic epitopes (< 20 ppm). The amount of added
hydrolysate was varied, with the final substitutions being 1% and 5%. Whole
grain buckwheat flour is considered gluten-free and beneficial for human diet
due to high protein and fiber content. It is rich in minerals and nutrients
which are considered bioactive. The lack of gluten proteins in WGBF
hinders the formation of a stable protein network, resulting in decreased
viscoelastic properties of dough. Therefore, the addition of WFH and the
effects on the dough properties were investigated
Innovative approaches to corrosion control: insights from electrochemical methods and polymer coatings
No full textCorrosion, the deterioration of materials due to chemical or electrochemical reactions with their environment, remains a significant challenge across industries. Driven by the thermodynamic tendency of metals to revert to their lower-energy oxide states, corrosion incurs substantial economic costs and impacts infrastructure, safety, and operational efficiency. While corrosion cannot be entirely prevented, its rate can be effectively managed using various techniques. Electrochemical methods have emerged as indispensable tools for investigating corrosion mechanisms and assessing material susceptibility.
This study provides a comprehensive overview of widely employed electrochemical techniques, including linear polarization resistance, electrochemical impedance spectroscopy and potentiodynamic polarization. These methods enable rapid and accurate evaluations of corrosion rates and mechanisms for different metals and alloys, offering insights that are critical for both laboratory research and field monitoring.
Furthermore, the application of electroactive polymers, particularly polypyrrole (PPy) and polyaniline (PANI), in corrosion protection is reviewed. These polymers exhibit remarkable potential for forming protective coatings, which inhibit corrosion through mechanisms such as barrier formation, passivation, and self-healing properties. The integration of these electroactive materials with electrochemical monitoring techniques offers a promising pathway for enhancing the durability and sustainability of materials exposed to corrosive environments
Probiotic Cell-free Supernatants vs. Viable Cells: Antimicrobial Activity Against Klebsiella Pneumoniae in Wound Care
No full textThe rise of Gram negative pathogens poses a serious threat to public health due to their high resistance to existing antibiotics and lack of novel therapeutic options. Klebsiella pneumonia is one of the pathogens frequently isolated from chronic wounds, where it contributes to delayed healing, increased inflammation, and consequently, enhanced risk of complications. Its ability to withstand conventional treatments highlights the urgent need for alternative antimicrobial strategies, especially as multidrug resistant (MDR) strains become increasingly prevalent. This challenge is further amplified in the context of diabetic foot ulcers (DFUs), a serious complication of the metabolic disease diabetes mellitus. In these wounds, sustained hyperglycemia creates an ideal environment for bacterial colonization and immune dysfunction, making infection control particularly difficult. The dual burden of impaired healing and MDR infections calls for innovative approaches that target both microbial and metabolic dysregulation. Probiotics are emerging as promising candidates due to their antimicrobial and immunomodulatory properties. In this study, four probiotic strains, Lactobacillus rhamnosus, Lactobacillus acidophilus, Lactobacillus plantarum, and Lactobacillus gasseri, were evaluated for their ability to inhibit a resistant strain of K. pneumoniae. Cultures were grown under anaerobic conditions, and both cell free supernatants and viable cells were prepared and tested in simulated wound fluid under microaerophilic conditions. To replicate diabetic wound environments, experiments were conducted under both hyperglycemic and normoglycemic conditions (20 mM and 5 mM, respectively) over 24 hours. Among the supernatants, L. plantarum demonstrated the most potent antimicrobial effect in both environments while L. gasseri was the least effective showing that glucose levels had little impact on the efficacy of cell free supernatants. On the other hand, the antimicrobial activity of live probiotic cells was clearly influenced by glucose concentration. Under hyperglycemic conditions, L. rhamnosus and L. plantarum reduced K. pneumoniae growth by approximately fourfold and fivefold, respectively, whereas their efficacy was diminished under normoglycemic conditions. These findings suggest that select probiotic strains, particularly L. rhamnosus and L. plantarum, may serve as effective antimicrobial agents against K. pneumoniae, especially in the hyperglycemic environment characteristic of diabetic wounds. This highlights their potential role in the development of targeted, adjunctive therapies for managing DFUs complicated by resistant Gram negative infections
Effect of conifer cones extracts on biomass and polysaccharide production using Fomes fomentarius TMF2 mycelium
No full textMedicinal fungi have a long tradition of usage in Asia. They
have been recognized as sources of immunomodulators, prebiotics,
antimicrobials, antioxidants, anticarcinogenic, and antidiabetic substances.
The Western scientific community has expressed interest in this topic in
recent years. It has been proven that many of those beneficial properties are
owed to polysaccharides. The primary source of polysaccharides is the
fruiting body of the mushroom. However, submerged-cultivated mycelia
produce exopolysaccharides (EPS). They are secreted into the liquid medium
and easily isolated by ethanolic precipitation. Moreover, intracellular
polysaccharides (IPS) can be isolated from mycelia. Plant extracts could
stimulate polysaccharide production. Therefore, the present study aimed to
investigate the effect of three different conifer cone extracts, i.e., thuja
(Thuja orientalis), spruce (Picea excelsa), and cypress (Cupressus
sempervirens), on the biomass and polysaccharide production by the
mycelium of the medicinal fungus Fomes fomentarius TMF2 during
submerged fermentation
Eco-friendly hydrogel systems for pH-responsive caffeine delivery
No full textKontrolisano oslobađanje lekova ima mnoge prednosti u odnosu na konvencionalne oblike
lekova kod raznih terapija, zato što omogućava da se nivo koncentracije leka tokom vremena održava
konstantnim. Na ovaj način se smanjuje učestalost doziranja leka i minimizuju neželjeni efekti. pHosetljivi hidrogelovi, posebno oni na bazi poli(metakrilne kiseline) (PMAA), imaju veliku primenu
kao sistemi za dostavu lekova. Metoda sinteze sistema za dostavu lekova predstavlja važan faktor koji
utiče na efikasnu inkapsulaciju leka i očuvanje njegove bioaktivnosti. U ovom istraživanju je ispitana
mogućnost inkapsulacije slabo rastvornog model leka – kofeina, u PMAA hidrogelove tokom njihove
sinteze, a zatim i mogućnost kontrolisanog oslobađanja kofeina iz tako pripremljenih PMAAk hidrogelova. Priprema PMAAk hidrogelova izvedena je primenom inovativne, ekološki prihvatljive metode
slobodno-radikalskom polimerizacijom u vodenom rastvoru u ambijentalnim uslovima. Ovakav način
sinteze je postignut primenom inicijatorskog sistema na bazi vodonik-peroksida i vitamina C. Pripremljeno je četiri PMAAk hidrogela sa različitim koncentracijama umreživača. Bubrenje PMAAk
hidrogelova i kinetika oslobađanja kofeina ispitani su u dve sredine različite pH vrednosti – pH 1 i
pH 6,8, koje su simulirale pH sredine u ljudskom želucu i crevima, redom. PMAAk hidrogelovi su
imali osam puta veće vrednosti ravnotežnog stepena bubrenja u sredini sa pH 6,8. Kao posledica
takvog načina bubrenja, tri puta veća količina kofeina je oslobođena u sredini sa pH 6,8 u odnosu na
sredinu sa pH 1. Takođe, povećanje koncentracije umreživača dovodi do smanjenja stepena bubrenja
hidrogelova i nižeg stepena oslobađanja model leka. Dobijeni rezultati pokazuju da PMAAk hidrogelovi, dobijeni ekološki prihvatljivom metodom, imaju veliki potencijal za efikasno kontrolisano
oslobađanje slabo rastvorljivih lekova.The controlled release of drugs provides a significant advantage in therapeutic applications by
ensuring a stable drug concentration over time. This approach reduces dosage frequency and helps
minimize side effects. pH-sensitive hydrogels, particularly those based on poly(methacrylic acid)
(PMAA), are widely utilized in drug delivery systems. The synthesis method plays a crucial role in
drug encapsulation and preserving its bioactivity. This study explores the incorporation of a poorly water-soluble model drug - caffeine, into PMAAk hydrogels during synthesis and evaluates its controlled release. A novel, environmentally friendly approach is employed for hydrogel preparation,
using a free radical polymerization process in an aqueous solution under ambient conditions. The
initiation system, based on hydrogen peroxide and vitamin C, enables the formation of PMAAk hydrogels. Four PMAAk hydrogels with different crosslinker concentrations are prepared. The swelling
behavior and caffeine release profiles are analyzed at two pH values, pH 1 and pH 6.8, which simulate the human stomach and intestines, respectively. The PMAAk hydrogels exhibit an eightfold increase in equilibrium swelling degree at the pH 6.8, which lead to a threefold higher caffeine release
compared to the environment with pH 1. Additionally, increasing the crosslinker concentration results in reduced swelling degree and lower level of drug release. These findings highlight the potential
of PMAAk hydrogels as an effective system for the controlled delivery of poorly water-soluble drugs
Optimized production of oligosaccharides using arabinogalactan-rich fraction isolated from blackcurrant pomace as raw material
No full textIntroduction: Growing awareness of gut microbiome importance is leading
to an increased interest in novel compounds able to selectively stimulate
growth of intestinal microorganisms conferring a health benefit. Beside
established prebiotics, such as galacto-oligosaccharides (GOS, derived from
lactose), and fructo-oligosaccharides (FOS, from inulin-rich sources or
derived from sucrose), other oligosaccharides classes (e.g., xylooligosaccharides (XOS), pectic-oligosaccharides (POS)) produced from
various plant-based substrates, including agro-industrial residues, are being
intensively investigated as potential prebiotics. At the same time, harnessing
bioactive potential of food waste has stood out as promising way for
achieving sustainable development goals and circularity. Particularly rich
sources of different valuable compounds are berry-fruit pomaces obtained
during juice production as by-products, making about 20-30% of the fresh
fruit weight [1]. Blackcurrant is polyphenol- and polysaccharide-rich berryfruit which annual production reaches 764 499 tons globally and most of the
fruit is being processed to juices leaving large amounts of its pomace unused
[2]. Here, we examined possibility of using blackcurrant pomace as a raw
material for the production of prebiotic oligosaccharides. ..
In vitro антиоксидативна активност хидразида никотинских киселина: експериментална и теоретска студија
No full textThe formation of reactive oxygen species (ROS) in the human body can lead to cell damage. Despite the body’s natural defences, including the enzyme superoxide dismutase, novel antioxidant small molecules are needed. In this work, in vitro antioxidant activity of seven nicotinic acid amides (NcAs) derived from nicotinic acid and mono-thiocarbohydrazones was investigated using DPPH, ABTS, CUPRAC and TAC assays. The compounds exhibited IC50 values between 0.202 to 1.297 mM in the DPPH assay, which improved to 0.114–0.638 mM upon the addition of water in the system. In the ABTS assay, IC50 values ranged from 0.107 to 0.365 mM. CUPRAC and FRAP assays indicated reducing antioxidant power of 1.973–4.650 and 1.564–3.472 mM L-1, respectively. Moderate antioxidant activity was also observed in the phosphomolybdenum assay for total antioxidant capacity. The density functional theory calculations revealed that the S–H bond of thioenol 1 tautomer, with a low bond dissociation enthalpy (BDE) of around 270 kJ mol-1, is the favourable site for hydrogen atom transfer (HAT) to reactive free radicals. Additionally, all compounds exhibited high stability constants with Fe2+ and Fe3+ (Ks ≈ 108), forming complexes with ML stoichiometry.Формирање реактивних кисеоничних врста у организму може да оштети ћелије.
Поред природних одбрамбених механизама као што је ензим супероксид-дизмутаза,
потребни су и нови мали молекули као антиоксиданси. У овом раду испитивана је антиоксидативна активност више амида никотинске киселине, синтетисаних у реакцији са
mono-тиокарбо-хидразонима, помоћу DPPH, ABTS, CUPRAC и TAC метода. IC50 вредности
су биле између 0,202 и 1,297 mM за DPPH (0,114–0,638 mM уз додатак воде) и 0,107–
–0,365 mМ за ABTS. Дистрибуција електронског спина је показала да је S–H веза тиоенолног облика испитиваних никотинамида погодно место за транфер атома водоника на
реактивне слободне радикале. Сва једињења су показала високе константе стабилности
комплекса типа ML са Fе2+ и Fе3+
Ispitivanje kvaliteta desno-desnih pletenina izrađenih od organske vune
No full textThis study investigates the quality of organic wool double weft knitted fabrics
with different knit structures. Fabrics were produced in three knit structures - 1×1 rib, half
Milano rib, and Milano rib - using 20×2 tex organic wool yarn. Quality evaluation was
based on volume electrical resistivity, compression, and strength properties. Compression
properties were evaluated through compressibility and compressive resilience, while
strength properties were assessed using bursting strength and ball traverse elongation. The
results indicated that the 1×1 rib structure exhibited the highest compressibility and ball
traverse elongation. The Milano rib structure demonstrated the highest compressive
resilience and bursting strength, whereas the half Milano rib fabric showed the lowest
volume resistivity. Based on the application of the ranking method, the Milano rib fabric
exhibited the best quality, while the half Milano rib structure ranked the worst quality.U ovom radu je ispitivan kvalitet desno-desnih pletenina različitog
prepletaja izrađenih od organske vune. Pletenine su proizvedene u tri različita prepletaja - 1x1 prepletaj, polumilanski prepletaj i milanski prepletaj - koristeći pređu od organske
vune finoće 20×2 tex. Procena kvaliteta pletenina vršena je na osnovu njihove specifične zapreminske električne otpornosti, kompresionih i prekidnih svojstava. Kompresiona
svojstava su ocenjena na osnovu kompresibilnosti i elastičnog oporavka, a prekidna
svojstava na bazi sile probijanja i hoda kugle pri probijanju. Rezultati su pokazali da
pletenina u 1x1 prepletaju ispoljava najveću kompresibilnost i hod kugle pri probijanju.
Pletenina u milanskom prepletaju pokazuje najveći elastični oporavak i silu probijanja,
dok pletenina u polumilanskom prepletaju ispoljava najmanju specifičnu zapreminsku
električnu otpornost. Na osnovu metode rangiranja, pletenina u milanskom prepletaju
pokazala je najbolji kvalitet, dok je pletenina u polumilanskom prepletaju pokazala
najlošiji kvalitet