The aims of this work were to identify and characterize for some important technological properties the yeast species present throughout the ripening process of Pecorino Crotonese, a traditional ...cheese produced in a well defined area of Southern Italy. In particular, the strain technological properties considered include fermentation/assimilation of galactose and lactose, assimilation of lactate and citrate in the presence of different NaCl concentrations, hydrolysis of butter fat, skim milk, gelatine and casein, production of brown pigments in cheese agar and ability to produce biogenic amines. High yeast levels were recorded in cheese samples already after 5
h of brining (about 5
log
cfu/g) and these concentration remained constant during ripening. The yeast isolates belonged to restrict number of yeast species. While
Kluyveromyces lactis and
Saccharomyces cerevisiae were isolated prevalently in the first stages of Pecorino Crotonese production,
Yarrowia lipolytica and
Debaryomyces hansenii dominated during the later stages of maturation. Otherwise, the latter two were very NaCl resistant species. In fact,
D. hansenii strains conserved the ability to assimilate lactose and galactose in the presence of 10% NaCl, while almost all the strains of
Y. lipolytica isolated assimilated citrate and lactate up to 7.5% NaCl.
Y. lipolytica isolates evidenced also the highest proteolytic and lipolytic activities and the capability to catabolize tyrosine producing brown pigment. In addition they resulted in the highest aminobiogenic potential decarboxylating ornithine, phenylalanine, tyrosine and lysine. However, they were not able to produce histamine, biogenic amine produced by three strains of
D. hansenii.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The aim of this research was the evaluation of the effects of milkfat content, nonfat milk solids content, and high-pressure homogenization on 1) fermentation rates of the probiotic strain ...Lactobacillus paracasei BFE 5264 inoculated in milk; 2) viability loss of this strain during refrigerated storage; and 3) texture parameters, volatile compounds, and sensorial properties of the coagula obtained. The data achieved suggested a very strong effect of the independent variables on the measured attributes of fermented milks. In fact, the coagulation times were significantly affected by pressure and added milkfat, and the rheological parameters of the fermented milk increased with the pressure applied to the milk for added nonfat milk solids concentrations lower than 3%. Moreover, the polynomial models and the relative response surfaces obtained permitted us to identify the levels of the 3 independent variables that minimized the viability loss of the probiotic strain used during refrigerated storage.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Different species of
Lactobacillus involved in dairy product fermentation and ripening were considered in order to study the effect of high pressure homogenization (HPH) on: (i) fermentation kinetics ...of HPH treated cells inoculated in milk; (ii) metabolic profiles; (iii) release of intracellular proteolytic enzymes; and (iv) enhance of the activity of extracellular or cellular wall located proteolytic enzymes. The HPH treatments applied were 50, 100, 150
MPa, 2 cycles at 50 and at 100
MPa. The viability loss did not exceed 1.3
log
cfu/ml after the higher treatments applied. The electrophoretic profiles of α- or β-casein incubated with the different cell free filtrates shown that HPH positively affected the proteolytic activity of some strains. Moreover, HPH affected the acidification rates of the milk inoculated with the processed cells and the primary metabolism of some strains. Regarding volatile compounds, ethanol, acetoin and 2-methyl butyric acid were subjected to the major changes when the inoculum had been processed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The principal aim of this work was to compare Caciotta cheeses obtained from cow milk previously subjected to high pressure homogenisation (HPH) at 100 MPa with those produced from raw (R) or ...heat-treated (P) cow milk. HPH had both direct and indirect effects on cheese characteristics and their evolution during ripening. In particular, HPH treatment of milk induced a significant increase of the cheese yield; moreover, it affected the microbial ecology of both curd and cheese. Compared with the thermal treatment, the HPH treatment resulted in a decrease of about one log cfu/g of yeast and lactobacilli cell loads of the curd. The initial milk treatment also affected the evolution over time and the levels attained at the end of ripening of all the microbial groups studied. In fact, lactobacilli, microstaphylococci and yeast cell loads remained at lower levels in the cheeses obtained from HPH milk with respect to the other cheese types over the whole ripening period. Moreover, HPH of milk induced marked and extensive lipolysis. Cheeses from HPH milk showed the presence of high amounts of free fatty acids immediately after brining. The electrophoretic patterns of the different cheese types showed that Caciotta made from HPH-treated milk was characterized by a more extensive and faster proteolysis as well as a significant modification of its volatile molecule profile. The results obtained and the sensory analysis indicated that HPH treatment of milk was able to differentiate Caciotta cheese or to modify its ripening patterns.
Abstract
Hydrophilic silver nanoparticles (AgNPs) are widely used in advanced biotechnologies, due to their versatile, easy, cheap preparations and due to their peculiar physico-chemical properties. ...It is well known that their surface functionalization plays a key role in defining the chemical-physical behaviour of AgNPs. If used for monitoring and remediation of heavy metals polluted water, the surface functionalization can direct the selectivity and sensitivity of the nanomaterial. Moreover, different capping agents can also induce different ecotoxicity. In this framework AgNPs are synthetises and properly functionalized using different capping agent, such as citrate (Cit), sodium 3 mercapto-1-propansulphonate (3MPS), L-cysteine (Lcys) and glutathione (GSH). The opportune choice of these capping agents induces size control (in the range of Ø = 2-30 nm) and make available selectively detection of heavy metal ions, such as Co(II), Hg (II) or Fe (III). These investigations confirmed that the multiple functionalized AgNPs are amazing and promising systems for monitoring and treatment of heavy metals polluted water.
The design of hybrid poly-ε-caprolactone (PCL)-self-assembling peptides (SAPs) matrices represents a simple method for the surface functionalization of synthetic scaffolds, which is essential for ...cell compatibility. This study investigates the influence of increasing concentrations (2.5%, 5%, 10% and 15% w/w SAP compared to PCL) of three different SAPs on the physico-chemical/mechanical and biological properties of PCL fibers. We demonstrated that physico-chemical surface characteristics were slightly improved at increasing SAP concentrations: the fiber diameter increased; surface wettability increased with the first SAP addition (2.5%) and slightly less for the following ones; SAP-surface density increased but no change in the conformation was registered. These results could allow engineering matrices with structural characteristics and desired wettability according to the needs and the cell system used. The biological and mechanical characteristics of these scaffolds showed a particular trend at increasing SAP concentrations suggesting a prevailing correlation between cell behavior and mechanical features of the matrices. As compared with bare PCL, SAP enrichment increased the number of metabolic active h-osteoblast cells, fostered the expression of specific osteoblast-related mRNA transcripts, and guided calcium deposition, revealing the potential application of PCL-SAP scaffolds for the maintenance of osteoblast phenotype.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The limitations and difficulties that nerve autografts create in normal nerve function recovery after injury is driving research towards using smart materials for next generation nerve conduits (NCs) ...setup. Here, the new polymer partially oxidized polyvinyl alcohol (OxPVA) was assayed to verify its future potential as a bioactivated platform for advanced/effective NCs. OxPVA-patterned scaffolds (obtained by a 3D-printed mold) with/without biochemical cues (peptide IKVAV covalently bound (OxPVA-IKVAV) or self-assembling peptide EAK (sequence: AEAEAKAKAEAEAKAK), mechanically incorporated (OxPVA+EAK) versus non-bioactivated scaffold (peptide-free OxPVA (PF-OxPVA) supports, OxPVA without IKVAV and OxPVA without EAK control scaffolds) were compared for their biological effect on neuronal SH-SY5Y cells. After cell seeding, adhesion/proliferation, mediated by (a) precise control over scaffolds surface ultrastructure; (b) functionalization efficacy guaranteed by bioactive cues (IKVAV/EAK), was investigated by MTT assay at 3, 7, 14 and 21 days. As shown by the results, the patterned groove alone stimulates colonization by cells; however, differences were observed when comparing the scaffold types over time. In the long period (21 days), patterned OxPVA+EAK scaffolds distinguished in bioactivity, assuring a significantly higher total cell amount than the other groups. Experimental evidence suggests patterned OxPVA-EAK potential for NCs device fabrication.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Polyetheretherketone (PEEK) is a thermoplastic polymer that has been recently employed for bone tissue engineering as a result of its biocompatibility and mechanical properties being comparable to ...human bone. PEEK, however, is a bio-inert material and, when implanted, does not interact with the host tissues, resulting in poor integration. In this work, the surfaces of 3D-printed PEEK disks were functionalized with: (i) an adhesive peptide reproducing 351-359 h-Vitronectin sequence (HVP) and (ii) HVP retro-inverted dimer (D2HVP), that combines the bioactivity of the native sequence (HVP) with the stability toward proteolytic degradation. Both sequences were designed to be anchored to the polymer surface through specific covalent bonds via oxime chemistry. All functionalized PEEK samples were characterized by Water Contact Angle (WCA) measurements, Atomic Force Microscopy (AFM), and X-ray Photoelectron Spectroscopy (XPS) to confirm the peptide enrichment. The biological results showed that both peptides were able to increase cell proliferation at 3 and 21 days. D2HVP functionalized PEEK resulted in an enhanced proliferation across all time points investigated with higher calcium deposition and more elongated cell morphology.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Medical applications stimulate the need for materials with broad potential. Chitosan, the partially deacetylated derivative of chitin, offers many interesting characteristics, such as ...biocompatibility and chemical derivatization possibility. In the present study, porous scaffolds composed of electrospun interwoven nanometric fibers are produced using chitosan or chitosan functionalized with aliphatic chains of twelve, fourteen or sixteen methylene groups. The scaffolds were thoroughly characterized by SEM and XPS. The length of the aliphatic tail influenced the physico-chemical and dynamic mechanical properties of the functionalized chitosan. The electrospun membranes revealed no interaction of Gram+ or Gram- bacteria, resulting in neither antibacterial nor bactericidal, but constitutively sterile. The electrospun scaffolds demonstrated the absence of cytotoxicity, inflammation response, and eryptosis. These results open the door to their application for blood purification devices, hemodialysis membranes, and vascular grafts.
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