Utjecaj dodatka laktoferina i lizozima izoliranih iz mlijeka magarice na svojstva jogurta

Food industry has mostly focused on natural preservatives due to the undesirable effects of chemical additives on the human health. Among milk proteins, lactoferrin and lysozyme are the best-known for their antimicrobial. In this study, lactoferrin and lysozyme were extracted from donkey milk and applied on the yoghurt surface by spraying. The obtained yoghurt samples enriched with antimicrobial proteins were compared with the control sample produced without the addition of any preservatives as well as the samples treated with natamycin, a commercial preservative used in dairy products. Thereby physicochemical, microbiological and textural properties of the samples were investigated during the 30 days of storage. Yoghurt samples treated with antimicrobial agents had lower microbial load than control samples, which indicated that the donkey milk lactoferrin and lysozyme inhibit microbial activity in yoghurts. However, the addition of the mentioned preservatives did not change the gross composition and the textural properties of the yoghurt samples. Most importantly, the incorporation of lactoferrin or lysozyme did not adversely affect the sensory properties of yoghurt samples, but achieved higher appreciation points than the control sample on the 30th day of storage. In brief, lactoferrin and lysozyme extracted from donkey milk could be used to control the undesirable microbial growth, hence extending the shelf life of yoghurt.Zbog neželjenih učinaka kemijskih konzervansa na zdravlje ljudi, prehrambena se industrija uglavnom usredotočila na primjenu prirodnih konzervansa. Laktoferin i lizozim ubrajaju se u mliječne proteine najjačeg antimikrobnog djelovanja. U ovom su istraživanju ti proteini izolirani iz mlijeka magarice te prskanjem naneseni na površinu jogurta. Tako dobiveni uzorci jogurta obogaćeni proteinima s antimikrobnim djelovanjem uspoređivani su s kontrolnim uzorkom proizvedenim bez dodatka ikakvih konzervansa, kao s i uzorcima tretiranim natamicinom kao komercijalnim konzervansom, a koji se često koristi u mliječnim proizvodima. Svim uzorcima su ispitivana fizikalno-kemijska, mikrobiološka i teksturalna svojstva tijekom 30 dana skladištenja. Prema dobivenim rezutatima, uzorci jogurta tretirani antimikrobnim sredstvima imali su manje mikroorganizama od kontrolnog uzorka, što ukazuje da laktoferin i lizozim izolirani iz mlijeka magarice djeluju inhibitorno na mikrobnu aktivnost u uzorcima jogurta. S druge strane, dodatak spomenutih konzervansa nije promijenio sastav ni teksturalna svojstva ispitivanih uzoraka jogurta. Međutim, najvažniji rezultati odnose se na senzorska svojstva jogurta koja su ostala nepromijenjena odnosno dodatak laktoferina ili lizozima nije negativno utjecao na njih. Naprotiv, jogurti s dodatkom laktoferina ili lizozima su nakon 30 dana skladištenja bolje ocijenjeni od kontrolnog uzorka. Uzimajući sve rezulatte u obzir, laktoferin i lizozim izolirani iz mlijeka magarice mogli bi se koristiti za kontrolu rasta neželjenih mikroorganizama te za produljenje roka trajanja jogurta

Surface Plasmon Resonance Based on Molecularly Imprinted Polymeric Film for l-Phenylalanine Detection

In this study, we designed a simple, rapid, sensitive and selective surface plasmon resonance (SPR) sensor for detection of L-phenylalaine by utilizing molecular imprinting technology. l-phenylalanine imprinted and non-imprinted poly(2-hydroxyethyl methacrylate-methacryloyl-l-phenylalanine) polymeric films were synthesized onto SPR chip surfaces using ultraviolet polymerization. l-phenyalanine imprinted and non-imprinted SPR sensors were characterized by using contact angle, atomic force microscopy and ellipsometry. After characterization studies, kinetic studies were carried out in the concentration range of 5.0–400.0 μM. The limit of detection and quantification were obtained as 0.0085 and 0.0285 μM, respectively. The response time for the test including equilibration, adsorption and desorption was approximately 9 min. The selectivity studies of the l-phenylalanine imprinted SPR sensor was performed in the presence of d-phenylalanine and l-tryptophan. Validation studies were carried out via enzyme-linked immunosorbent analysis technique in order to demonstrate the applicability and superiority of the l-phenylalanine imprinted SPR sensor

Molecular Imprinted Based Quartz Crystal Microbalance Nanosensors For Mercury Detection

Mercury(II) ions are emerging as a result of more human activity, especially coal‐fired power plants, industrial processes, waste incineration plants, and mining. The mercury found in different forms after spreading around diffuses the nature of other living things. Although the damage to health is not yet clear, it is obvious that it is the cause of many diseases. This work detects the problem of mercury(II) ions, one of the active pollutants in wastewater. For this purpose, it is possible to detect the smallest amount of mercury(II) ions by means of the mercury(II) ions suppressed quartz crystal microbalance nanosensor developed. Zinc(II) and cadmium(II) ions are chosen as competitor elements. Developed nanosensor technology is known as the ideal method in the laboratory environment to detect mercury(II) ions from wastewater because of its low cost and precise result orientation. The range of linearity and the limit of detection are measured as 0.25 × 10−9–50 × 10−9 m. The detection limit is found to be 0.21 × 10−9 m. The mercury(II) ions imprinted nanosensors prepared according to the obtained experimental findings show high selectivity and sensitivity to detect mercury(II) ions from wastewater.PubMe

Surface plasmon resonance-based immunosensor for igm detection with gold nanoparticles

In this work, a surface plasmon resonance (SPR) based immunosensor was prepared by the immobilization of the amine-functionalized gold nanoparticles (N-AuNPs) on the sensing surface to sense immunoglobulin M (IgM) antibodies in the aqueous solution and artificial plasma. The characterization studies of SPR based immunosensor for IgM detection were performed with scanning electron microscope (SEM), contact angle measurements, and ellipsometry. Kinetic studies for the IgM immunosensor were carried out in the range of 1.0 to 200 ng/mL IgM concentrations in an aqueous solution. The total IgM analysis time including adsorption, desorption, and regeneration cycles was nearly 10 min for the prepared immunosensor. The limit of detection (LOD) and limit of quantification (LOQ) were found as 0.08 and 0.26 ng/mL, respectively. The reusability of the proposed immunosensor was tested with 6 consecutive adsorption-desorption, and regeneration cycles. Also, enzyme-linked immunosorbent assay (ELISA) method was utilized in the validation of the immunosensor

Plastic antibody based surface plasmon resonance nanosensors for selective atrazine detection

WOS: 000394064800071PubMed: 28183651This study reports a surface plasmon resonance (SPR) based affinity sensor system with the use of molecular imprinted nanoparticles (plastic antibodies) to enhance the pesticide detection. Molecular imprinting based affinity sensor is prepared by the attachment of atrazine (chosen as model pesticide) imprinted nanoparticles onto the gold surface of SPR chip. Recognition element of the affinity sensor is polymerizable form of aspartic acid. The imprinted nanoparticles were characterized via FTIR and zeta-sizer measurements. SPR sensors are characterized with atomic force microscopy (AFM), scanning electron microscopy (SEM), Fourier transform infrared spectrophotometry (FTIR) and contact angle measurements. The imprinted nanoparticles showed more sensitivity to atrazine than the non-imprinted ones. Different concentrations of atrazine solutions are applied to SPR system to determine the adsorption kinetics. Langmuir adsorption model is found as the most suitable model for this affinity nanosensor system. In order to show the selectivity of the atrazine-imprinted nanoparticles, competitive adsorption of atrazine, simazine and amitrole is investigated. The results showed that the imprinted nanosensor has high selectivity and sensitivity for atrazine. (C) 2016 Elsevier B.V. All rights reserved.Ministry of Food, Agriculture and Livestock, of Republic of Turkey [TAGEM 12/AR-GE/35]This research has been carried out with supports from the Ministry of Food, Agriculture and Livestock, of Republic of Turkey with grant number TAGEM 12/AR-GE/35

Protein C recognition by ion-coordinated imprinted monolithic cryogels

WOS: 000399782900021PubMed: 28195421The protein C imprinted monolithic cryogel was synthesized using 2-hydroxyethyl methacrylate by redox cryo-polymerization method. The prepared monolithic cryogel was characterized by Fourier transform infrared spectroscopy, swelling test, surface area measurements, and scanning electron microscopy. The nonimprinted cryogel was prepared as well for control. Adsorption of protein C from aqueous solutions was investigated in a continuous mode and several parameters affecting adsorption performance were optimized. The maximum protein C adsorption amount was 30.4 mg/g. The selectivity studies were performed by monolithic column studies and fast protein liquid chromatography, using hemoglobin and human serum albumin as competing proteins. The relative selectivity coefficients were 2.37 and 8.89 for hemoglobin and human serum albumin, respectively. Reusability was tested for ten consecutive adsorption-desorption cycles, and no significant change in adsorption capacity was recorded. A pseudo-second-order model was suitable to interpret kinetic data, and the Langmuir model suited the adsorption isotherms well

[PHEMA/PEI]-Cu(II) based immobilized metal affinity chromatography cryogels: Application on the separation of IgG from human plasma

The immobilized metal-affinity chromatography (IMAC) has gained significant interest as a widespread separation and purification tool for therapeutic proteins, nucleic acids and other biological molecules. The enormous potential of IMAC for proteins with natural surface exposed-histidine residues and for recombinant proteins with histidine clusters. Cryogels as monolithic materials have recently been proposed as promising chromatographic adsorbents for the separation of biomolecules in downstream processing. In the present study, IMAC cryogels have been synthesized and utilized for the adsorption and separation of immunoglobulin G (IgG) from IgG solution and whole human plasma. For this purpose, Cu(II)-ions were coupled to poly(hydroxyethyl methacrylate) PHEMA using poly(ethylene imine) (PEI) as the chelating ligand. In this study the cryogels formation optimized by the varied proportion of PEI from 1% to 15% along with different amounts of Cu (II) as chelating metal. The prepared cryogels were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis. The [PHEMA/PEI]-Cu(II) cryogels were assayed for their capability to bind the human IgG from aqueous solutions. The IMAC cryogels were found to have high affinity toward human IgG. The adsorption of human IgG was investigated onto the PHEMA/PEI cryogels with (10% PEI) and the concentration of Cu (II) varied as 10, 50,100 and 150 mg/L. The separation of human IgG was achieved in one purification step at pH 7.4. The maximum adsorption capacity was observed at the [PHEMA/PEI]-Cu(II) (10% PEI) with 72.28 mg/g of human IgG. The purification efficiency and human IgG purity were investigated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). (C) 2016 Elsevier B.V. All rights reserved

Selective Detection of Penicillin G Antibiotic in Milk by Molecularly Imprinted Polymer-Based Plasmonic SPR Sensor

Molecularly imprinted polymer-based surface plasmon resonance sensor prepared using silver nanoparticles was designed for the selective recognition of Penicillin G (PEN-G) antibiotic from both aqueous solution and milk sample. PEN-G imprinted sensors (NpMIPs) SPR sensor was fabricated using poly (2-hydroxyethyl methacrylate-N-methacroyl-(L)-cysteine methyl ester)-silver nanoparticles-N-methacryloyl-L-phenylalanine methyl ester polymer by embedding silver nanoparticles (AgNPs) into the polymeric film structure. In addition, a non-imprinted (NpNIPs) SPR sensor was prepared by utilizing the same polymerization recipe without addition of the PEN-G template molecule to evaluate the imprinting effect. FTIR-ATR spectrophotometer, ellipsometer, contact angle measurements were used for the characterization of NpMIPs SPR sensors. The linear concentration range of 0.01–10 ng/mL PEN-G was studied for kinetic analyses. The augmenting effect of AgNPs used to increase the surface plasmon resonance signal response was examined using polymer-based PEN-G imprinted (MIPs) sensor without the addition of AgNPs. The antibiotic amount present in milk chosen as a real sample was measured by spiking PEN-G into the milk. According to the Scatchard, Langmuir, Freundlich and Langmuir–Freundlich adsorption models, the interaction mechanism was estimated to be compatible with the Langmuir model

Preparation of cryogel columns for depletion of hemoglobin from human blood

WOS: 000376136500005PubMed: 26772759In this study, we aimed to prepare the metal chelate affinity cryogels for the hemoglobin (Hb) depletion. Poly(2-hydroxyethyl methacrylate) (PHEMA) cryogels were selected as base matrix because of their blood compatibility, osmotic, chemical, and mechanical stability. Cryogels are also useful when working with the viscous samples such as blood, because of their interconnected macroporous structure. Iminodiacetic acid (IDA), the chelating agent, was covalently coupled with PHEMA cryogels after activation with the epichlorohydrin and then the Ni(II) ions were chelated to the IDA-bound cryogels. The depletion of the Hb from hemolysate was shown by SDS-PAGE