Probiotication of cooked sausages employing agroindustrial coproducts as prebiotic co-encapsulant in ionotropic alginate–pectin gels

Cooked sausages were formulated inoculating alginate–pectin microcapsules containing agroindustrial coproducts, cactus pear peel flour or apple marc flour, seeking to enhance the nutritional value of cooked meat products. The microcapsules increased total moisture (from 66 to 75% in average), but water was not being physically retained since higher expressible moisture values in inoculated samples were observed (20% as compared to 15% in control). Inoculated samples presented higher lactic acid bacteria populations, since in addition to the thermotolerant capacity of the bacteria, encapsulation added a protective barrier for the bacteria to survive. Higher lactic acid bacteria counts were reflected in fewer coliforms in inoculated samples (<0.001 log CFU after 15 days of storage), with no detrimental effect on texture. Natural antioxidants present in agroindustrial coproducts decreased the oxidative rancidity of lipids for storage. The results imply that agroindustrial coproducts are a good alternative to formulate symbiotic functional ingredients that can be employed to improve the nutritional properties of nondairy thermal processed food products, like cooked emulsified meat products.     

Preliminary Mechanical Characterization of Thermal Filters for the X-IFU Instrument on Athena

The X-ray Integral Field Unit (X-IFU) is one of the two instruments of the Athena astrophysics space mission approved by ESA in the Cosmic Vision Science Program. The X-IFU consists of a large array of TES microcalorimeters that will operate at?~?50 mK inside a sophisticated cryostat. A set of thin filters, highly transparent to X-rays, will be mounted on the cryostat thermal shields in order to attenuate the IR radiative load, to attenuate RF electromagnetic interferences, and to protect the detector from contamination. In this paper, we present the current thermal filters design, describe the filter samples developed/procured so far, and present preliminary results from the ongoing characterization tests.     

Two 20-Residue-Long Peptides Derived from Plasmodium vivax Merozoite Surface Protein 10 EGF-Like Domains Are Involved in Binding to Human Reticulocytes

Plasmodium parasites’ invasion of their target cells is a complex, multi-step process involving many protein-protein interactions. Little is known about how complex the interaction with target cells is in Plasmodium vivax and few surface molecules related to reticulocytes’ adhesion have been described to date. Natural selection, functional and structural analysis were carried out on the previously described vaccine candidate P. vivax merozoite surface protein 10 (PvMSP10) for evaluating its role during initial contact with target cells. It has been shown here that the recombinant carboxyl terminal region (rPvMSP10-C) bound to adult human reticulocytes but not to normocytes, as validated by two different protein-cell interaction assays. Particularly interesting was the fact that two 20-residue-long regions (³⁸⁸DKEECRCRANYMPDDSVDYF⁴⁰⁷ and ⁴¹⁵KDCSKENGNCDVNAECSIDK⁴³⁴) were able to inhibit rPvMSP10-C binding to reticulocytes and rosette formation using enriched target cells. These peptides were derived from PvMSP10 epidermal growth factor (EGF)-like domains (precisely, from a well-defined electrostatic zone) and consisted of regions having the potential of being B- or T-cell epitopes. These findings provide evidence, for the first time, about the fragments governing PvMSP10 binding to its target cells, thus highlighting the importance of studying them for inclusion in a P. vivax antimalarial vaccine.     

Thermal stability of some commercial synthetic antioxidants

Synthetic antioxidants are widely applied substances in human food and in animal feed industries. These products, which are mainly derived from phenolic structures, were developed to avoid or retard the oxidative rancidity of fats and oils when added either to raw material or to end-products. Synthetic antioxidants such as butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA), tertiary butylhydroxyquinone (TBHQ), and ethoxyquin (EQ) are frequently applied during the cooking of the by-products (viscera, blood, and feathers) in the poultry feed industry. However, results in terms of oxidative prevention are unequal and usually modest. Because information about the thermal stability of synthetic antioxidants is scarce, we developed a laboratory model that simulates the cooking of poultry by-products to study the effectiveness of BHT, BHA, TBHQ, and EQ. The antioxidants were thermally treated at 100–200°C, over 1 or 2 h. The effectiveness of each antioxidant after the thermal treatment was assessed with the Rancimat test by measuring the modification of the induction period for the oxidation of sardine oil and comparing it to the oxidation kinetics of the oil without added antioxidants. Within our experimental conditions, all antioxidants assayed showed different degrees of thermal instability. BHT and TBHQ were effective as antioxidants at temperatures up to 175°C, exhibiting only 25 to 30% inactivation. However, BHA and EQ were inactivated by 70 and 60%, respectively, at 150°C. Heating time (1 and 2 h) at a given temperature did not significantly modify the behavior of the antioxidants assayed. EQ is the most frequently applied antioxidant to prevent oxidative rancidity in the cooking of poultry by-products. However, according to our results, EQ and BHA, which is another antioxidant frequently used by the poultry industry, are less suitable     

Peptide characteristics of sunflower protein hydrolysates

Protein isolate from sunflower seeds was used as the starting material for preparation of an extensively hydrolyzed peptide product. Protein was hydrolyzed using an endopeptidase (Alcalase), an exopeptidase (Flavourzyme), or both enzymes sequentially. Combined use of these proteases generated the highest degree of hydrolysis, 54.2%, and highest solubility, around 90%, between pH 2.5 and 7. Molecular weight profiles of the hydrolysates were characterized by gel filtration chromatography and denaturing electrophoresis. Amino acid compositions and solubilities of the different hydrolysates also were studied.     

Nitrate stimulation of indigenous nitrate-reducing, sulfide-oxidising bacterial community in wastewater anaerobic biofilms

The role of the nitrate-reducing, sulfide-oxidising bacteria (NR-SOB) in the nitrate-mediated inhibition of sulfide net production by anaerobic wastewater biofilms was analyzed in two experimental bioreactors, continuously fed with the primary effluent of a wastewater treatment plant, one used as control (BRC) and the other one supplemented with nitrate (BRN). This study integrated information from H(2)S and pH microelectrodes, RNA-based molecular techniques, and the time course of biofilm growth and bioreactors water phase. Biofilms were a net source of sulfide for the water phase (2.01 micromol S(2-)(tot)m(-2)s(-1)) in the absence of nitrate dosing. Nitrate addition effectively led to the cessation of sulfide release from biofilms despite which a low rate of net sulfate reduction activity (0.26 micromol S(2-)(tot)m(-2)s(-1)) persisted at a deep layer within the biofilm. Indigenous NR-SOB including Thiomicrospira denitrificans, Arcobacter sp., and Thiobacillus denitrificans were stimulated by nitrate addition resulting in the elimination of most sulfide from the biofilms. Active sulfate reducing bacteria (SRB) represented comparable fractions of total metabolically active bacteria in the libraries obtained from BRN and BRC. However, we detected changes in the taxonomic composition of the SRB community suggesting its adaptation to a higher level of NR-SOB activity in the presence of nitrate.     

Exploiting a new electrochemical sensor for biofilm monitoring and water treatment optimization

Bacterial biofilm development is a serious problem in many fields, and the existing biofilm monitoring sensors often turn out to be inadequate. In this perspective, a new sensor (ALVIM) has been developed, exploiting the natural marine and freshwater biofilms electrochemical activity, proportional to surface covering. The results presented in this work, obtained testing the ALVIM system both in laboratory and in an industrial environment, show that the sensor gives a fast and accurate response to biofilm growth, and that this response can be used to optimize cleaning treatments inside pipelines. Compared to the existing biofilm sensors, the proposed system show significant technological innovations, higher sensitivity and precision.     

HPLC-fluorimetric method for analysis of amino acids in products of the hive (honey and bee-pollen)

An optimization of the OPA method has made feasible separation and quantification of 23 amino acids, which include 5 infrequently searched for. Detection limits ranged from 0.24 to 10.1 pmol in honey and from 29.1 to 0.42 pmol in bee-pollen; reproducibility (C.V.) ranged from 5.3% to 20.4%; recoveries were above 78.8%. Forty monovarietal honey samples from ilex, oak, heather and chestnut-tree were analyzed for their free amino acid profiles. α-Aminoadipic acid and homoserine are reported for the first time in honeys. Thirty-two samples of Spanish bee-pollen, made of a majority of pellets from Cistus Ladanifer (67.1%) and Echium plantagineum (8.9%), were analyzed for their free and total amino acid profiles. Free γ-aminobutyric acid was extensively found with an average of 0.53 mg/g, while Hser and Orn were infrequent. Manually separated monofloral pellets from Cistus ladanifer and Echium plantagineum were analyzed for their free amino acid contents (including proline): 32.46 and 21.87 mg/g for the former and 22.18 and 12.23 mg/g for the latter. In contrast, the total amino acid percentage (on a dry weight basis) was 13.95% for Cistus ladanifer and 32.22% for Echium plantagineum.