Amino acid-decarboxylase activity in bacteria associated with Mediterranean hake spoilage

We examined the amino acid-decarboxylase activity of bacteria isolated throughout the ice storage of Mediterranean hake. Pseudomonas was the main microbial group in the fresh samples. Its number increased by up to 2 logarithmic units during the storage and 20% of the isolates showed the ability to produce putrescine. Shewanella putrefaciens was the most prolific organism and became the dominant microbial group on day 6 of storage. It also had the highest proportion of aminogenic isolates and the strongest decarboxylase potential as a tyramine- and cadaverine-producing microorganism. A competitive procedure in biogenic amine production seems to have occurred when trimethylamine oxide was available in the culture medium. The abundance of Enterobacteriaceae increased gradually throughout the storage but never reached high counts and their isolates produced small amounts of cadaverine only. Although the counts of micrococci and staphylococci were considerably high, only two isolates were ornithine-decarboxylase positive. Neither lactic acid bacteria nor enterococci were positive.     

Analysis of 41 kb of the DNA sequence from the right arm of chromosome II of Schizosaccharomyces pombe

We report the complete sequence of cosmid c18A7 (41 046 bp insert), located on the right arm of chromosome II of the Schizosaccharomyces pombe genome. The sequence, which partially overlaps with cosmids SPBC4F6 and SPBC336, contains 16 open reading frames (ORFs) capable of coding for proteins of at least 100 amino acid residues in length (one partial) and one small nucleolar RNA (snoRNA). Four known genes were found: swi10 (encoding a mating-type switching protein also involved in nucleotide excision repair); dim1 (encoding a dimethyladenosine transferase); arf1 (encoding ADP-ribosylation factor 1); and pol3 (cdc6) the partial fragment, encoding the 125 kDa catalytic subunit of the DNA polymerase type B. Six ORFs similar to known proteins were found. They include a transporter of the major facilitator superfamily class, a vacuolar sorting protein, an asparagine synthase, a nuclear protein, a reticulum oxidoreductin and a heat shock protein. Each protein product of the other six ORFs has conserved domains and can be assigned a molecular, but not a biological, function. The sequence has been submitted to the EMBL database under Accession No. AL080287.     

Peptidase and proteinase activity ofLactococcus lactis,Lactobacillus casei andLactobacillus plantarum

The proteolytic system of several non-commercial strains of lactococci and lactobacilli that were isolated directly from traditional-Spanish, semi-hard, goats' milk cheese was studied. The aminopeptidase, X-prolyldipeptidyl aminopeptidase, dipeptidase and proteinase activity of these new strains was measured for the cytoplasmic, cell-wall/membrane and spontaneously released fractions. The aminopeptidase activity was exclusively intracellular and higher forLactobacillus casei subsp.casei than forLactococcus lactis subsp.lactis. Lactobacillus plantarum showed higher dipeptidase activity thanL. casei. The highest level of proteinase activity was recorded for the cell-wallmembrane fraction ofLactococcus lactis subsp.lactis IFPL 359, and was higher on β-casein than on α_s-casein for all the strains studied. These results suggest some different contribution of these strains to the proteolysis of cheese during ripening and they seem to complement each other when used together in the starter culture.     

Inactivation of Staphylococcus aureus in Oat and Soya Drinks by Enterocin AS‐48 in Combination with Other Antimicrobials

The presence of toxicogenic Staphylococcus aureus in foods and the dissemination of methicillin‐resistant S. aureus (MRSA) in the food chain are matters of concern. In the present study, the circular bacteriocin enterocin AS‐48, applied singly or in combination with phenolic compounds (carvacrol, eugenol, geraniol, and citral) or with 2‐nitro‐1‐propanol (2NPOH), was investigated in the control of a cocktail made from 1 methicillin‐sensitive and 1 MRSA strains inoculated on commercial oat and soya drinks. Enterocin AS‐48 exhibited low bactericidal activity against staphylococci in the drinks investigated when applied singly. The combinations of sub‐inhibitory concentrations of enterocin AS‐48 (25 μg/mL) and phenolic compounds or 2NPOH caused complete inactivation of staphylococci in the drinks within 24 h of incubation at 22 °C. When tested in oat and soya drinks stored for 7 d at 10 °C, enterocin AS‐48 (25 μg/mL) in combination with 2NPOH (5.5 mM) reduced viable counts rapidly in the case of oat drink (4.2 log cycles after 12 h) or slowly in soya drink (3.8 log cycles after 3 d). The same combined treatment applied on drinks stored at 22 °C achieved a fast inactivation of staphylococci within 12 to 24 h in both drinks, and no viable staphylococci were detected for up to 7 d of storage. Results from the study highlight the potential of enterocin AS‐48 in combination with 2NPOH for inactivation of staphylococci.     

Growth,carcass traits and palatability: Can the influence of the feeding regimes explain the variability found on those attributes in different Uruguayan genotypes?

It is well known what genetic and nutritional factors affect growth and meat quality, but there is less information related to interactive importance of them during the productive process. These systems are mainly based on rangelands affecting animal growth in early stages of life thus producing smaller cattle and reduced retail yield comparing with well grown calves. During the last ten years, Uruguayan livestock production systems have been intensified using improved pastures, concentrates and better genetic. The main breeds in Uruguay are Hereford, Angus and their crosses. These British breeds are under genetic evaluation programs which consider carcass trait parameters. It is important for beef industry to know if interactions between genotype and nutrition during growth and fattening phases are influencing production, efficiency, carcass weight and meat quality attributes. The aim of this article is to present information obtained under different feeding strategies during the post weaning and fattening and their influence on those attributes.     

Analytical study of apple liqueurs

In the present work the composition of apple liqueurs has been analysed, since the consumption of these beverages in Spain has increased during the last years. Twenty-five samples, belonging to the most representative five brands of the Spanish market have been analysed. The following determinations were carried out: alcoholic grade, total acidity, methanol, furfurol, dry extract, reducing sugars, sucrose, ash contact, macroelements (Na, K, Ca, Mg) and microelements (Cu, Fe, Mn, Zn). These parameters enable the quality evaluation of these beverages and contribute to their characterization with respect to the fruit used in their elaboration. To complete the experimental study, a BMDP 7M discriminant statistical analysis has been applied to the results obtained. The variables that best discriminate the groups have been determined and all the samples have been classified and differentiated.

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Analytisches Studium der Apfelsaftliköre

Zusammenfassung Es wurde die Zusammensetzung von Apfelsaftlikören analysiert, weil diese Getränke öfter in Spanien getrunken werden. Fünfundzwanzig Proben von fünf bestimmten, spanischen Markengetränken wurden analysiert. Es wurden folgende Bestimmungen ausgeführt: Alkoholkonzentration, Gehalt an Säure, Methanol, Extrakt, Zucker, Sucrose, Asche, Macroelemente (Na, K, Ca, Mg) und Mikroelemente (Cu, Fe, Mn, Zn). Diese Parameter erlauben die Qualität dieser Getränke zu schätzen und ihre Charakterisierung auf Grund des Fruchtgehaltes. Weiterhin wurde eine BMDP 7M diskriminant-statistische Analyse der Resultate angewandt. Die diskriminant-Variablen der Gruppe wurden bestimmt und alle Proben konnten klassifiziert und unterschieden werden.

     

DNA sequencing and analysis of a 40 kb region from the right arm of chromosome II from Schizosaccharomyces pombe

We have determined the complete nucleotide sequence of a 39,648 bp segment, contained in cosmid c32F12, derived from the right arm of chromosome II from the fission yeast Schizosaccharomyces pombe. Computer analysis of the sequence revealed the presence of 15 non-overlapping open reading-frames (ORFs) longer than 300 bp and one tRNA-Thr gene. Six ORFs correspond to the previously known rec14+, tug1+, rum1+, pch1+, gpd1+ and cyr1+ genes. Five ORFs code for putative proteins with significant homology to proteins from other organisms. SPBC32F12.01c shows considerable similarity to human neutral sphingomyelinase, whereas SPBC32F12.03c, SPBC32F12.10 and SPBC32F12.14 exhibit strong homology to glutathione peroxidase, phosphoglucomutase and ubiquitin protein ligase E-3 components from various organisms, respectively. The four remaining ORFs identified show weak or non-significant homology to previously sequenced genes. The nucleotide sequence has been submitted to the EMBL database under Accession Number AL023796.     

A Novel Functional Wrapping Design by Complexation of ε-Polylysine with Liposomes Entrapping Bioactive Peptides

An innovative edible wrapping with potential use for designing functional foods with antimicrobial capacity was developed by complexation of ε-polylysine with peptide-loaded liposomes. Unmarketable long-term frozen cooked shrimp (Litopenaeus vannamei) muscle was used as a source of both bioactive peptides and complex liposomal suspension carrier, producing a sustainable value-added protein wrapping material with desirable sensory properties. A <10-kDa peptide fraction (SH) with antioxidant and angiotensin-converting enzyme inhibitory capacity was encapsulated in partially purified phosphatidylcholine (PC) liposomes (LSH) with an entrapment efficiency of 85 %. The average size and zeta potential of LSH were 164?±?2 nm and –37.0?±?1.7 mV, respectively. The LSH surface changed from electronegative to electropositive upon adsorption of ε-polylysine (PL) with an optimal concentration of 0.5 %. The average diameter and zeta potential of the resulting complex ε-polylysine-adsorbed liposomes containing the peptide hydrolysate (PL-LSH) were 216?±?5 nm and +51.1?±?1.1 mV, respectively. The ε-PL proved to be effective as liposome stabilizing and antimicrobial agent. The PL-LSH suspension was incorporated in the formulation of the protein wrapping to provide it with both bioactive and antimicrobial properties. The wrapping showed low water solubility (≈30 %) and low mechanical resistance (tensile strength?=?0.23?±?0.06 MPa; elongation at break?=?0.91?±?0.19 %) properties that allowed it to be very versatile for varied food design and was effective against Listeria monocytogenes, Escherichia coli, Staphylococcus aureus and Yersinia enterocolitica.     

Development and Evaluation of a Film and Edible Coating Obtained from the <Emphasis Type="Italic">Cajanus cajan</Emphasis> Seed Applied to Fresh Strawberry Fruit

The aim of this work was to develop and evaluate the effect of an edible coating produced with protein isolate and gum from the Cajanus cajan seed to be applied to strawberries (Fragaria spp.). The films were formulated using 1 and 2% gum, and 5 and 10% protein isolate, as well as glycerol (2%) as a plasticizer. The formulated films were evaluated in terms of water vapor permeability (WVP), opacity, color, scanning electron microscopy, and texture. Once the ideal formulation with sufficiently low WVP and opacity was selected, it was applied to the strawberries, which were evaluated in terms of mass loss, color, firmness, acidity, pH, soluble solids, anthocyanin content, vitamin C content, and acceptability degree by an untrained consumer panel. Results showed that film made from 5% of protein isolate and 1% of gum had the lowest WVP of all treatments. Applied to strawberries, the coating resulted in a reduction of the total soluble solid content, the consumption of citric acid, and the mass loss of coated with respect to uncoated strawberries after 10 days of storage at 5 °C, without causing sensorial changes.