Chromatic characteristics and anthocyanin profile of a micro-oxygenated red wine after oak or bottle maturation

Micro-oxygenation (MOX) was applied to a red wine for 5 months following the end of alcoholic fermentation and then both a non-oxygenated control wine and the micro-oxygenated wine were matured in oak barrels or bottles. The concentration of anthocyanin and anthocyanin-derived compounds and the chromatic characteristics of the control and micro-oxygenated wines after the maturation period were studied. Anthocyanin and anthocyanin-derived compounds composition were determined by liquid chromatography-mass spectrometry; and, together with monomeric anthocyanins, compounds including direct anthocyanin-flavanol adducts, ethyl-linked anthocyanin-flavanol compounds, and pyranoanthocyanins were identified. The results showed that the improvements in the chromatic characteristics obtained by applying the MOX technique to Monastrell wines were maintained after an aging period in bottle or barrel. The color intensity of wines increased during maturation in oak barrels, whereas the color of the bottled wines decreased, although MOX wines always showed higher color intensity than the respective control wines. Bottled wines also showed a higher increase in tint and a lower quantity of compounds resistant to SO₂ discoloration than oak matured wines, indicating that the formation of these compounds is favored by the oxidative conditions in oak barrels.     

Modulus of elasticity of I-214 young poplar wood from standing trees to sawn timber: influence of the age and stand density

The poplar wood industry chain from planted forests takes a strategic position for the creation of a competitive, profitable, and highly technological bioeconomy in the world. Niche sectors such as buildings can find in poplar wood an effective ally to reduce its carbon footprint and ecological backpack. For the poplar wood, it is important to understand the huge significance of the proper silvicultural management of a plantation and to characterize the raw material. In this context, this paper carries out such characterization for the particular case of young plantations of the clone I-214 (Populus × euroamericana (Dode) Guinier), commonly used for its high growth rate. The acoustic non-destructive characterization of poplar wood is carried out from standing trees, logs and sawn timber and then compared with the one obtained through destructive mechanical tests. The study shows that growth parameters are highly affected by the age and moderately affected by stand density, while mechanical properties are strongly affected by the age and less affected by the stand density. The study also shows high values of the linear regression coefficients between the mechanical properties obtained on standing trees, logs, and sawn timber using non-destructive and destructive methods (R²?=?0.7 for all three cases), greater than those obtained for other species. A good linear fitting was obtained between the tree and log velocities (R²?=?0.76) and between the tree and log elastic moduli (R²?=?0.85). Consequently, the evaluation of the mechanical properties employing the optimized acoustic protocol provides a reliable characterization for the poplar wood.

     

Development of an antimicrobial material based on a nanocomposite cellulose acetate film for active food packaging

Nanocomposites based on biopolymers have been recognised as potential materials for the development of new ecofriendly food packaging. In addition, if these materials incorporate active substances in their structure, the potential applications are much higher. Therefore, this work was oriented to develop nanocomposites with antimicrobial activity based on cellulose acetate (CA), a commercial organoclay Cloisite30B (C30B), thymol (T) as natural antimicrobial component and tri-ethyl citrate (TEC) as plasticiser. Nanocomposites were prepared by a solvent casting method and consisted of 5% (w/w) of C30B, 5% (w/w) of TEC and variable content of T (0%, 0.5% and 2% w/w). To evaluate the effect of C30B into the CA matrix, CA films without this organoclay but with T were also prepared. All nanocomposites showed the intercalation of CA into the organoclay structure; furthermore this intercalation was favoured when 2% (w/w) of T was added to the nanocomposite. In spite of the observed intercalation, the presence of C30B inside the CA matrices increased the opacity of the films significantly. On the other hand, T showed a plasticiser effect on the thermal properties of CA nanocomposites decreasing glass transition, melting temperature and melting enthalpy. The presence of T in CA nanocomposites also allowed the control de Listeria innocua growth when these materials were placed in contact with this Gram-positive bacterium. Interestingly, antimicrobial activity was increased with the presence of C30B. Finally, studies on T release showed that the clay structure inside the CA matrix did not affect its release rate; however, this nanofiller affected the partition coefficient K_P/FS which was higher to CA nanocomposites films than in CA films without organoclay. The results obtained in the present study are really promising to be applied in the manufacture of food packaging materials.     

Development of a method for genetic identification of four species of anchovies: E. encrasicolus, E. anchoita, E. ringens and E. japonicus

Cytochrome b has been successfully employed for genetic identification of four species of anchovies (Engraulis spp) using two methodologies: PCR–RFLP and FINS. The first method allowed the identification of Engraulis anchoita, Engraulis ringens and Engraulis japonicus–Engraulis encrasicolus. In some cases, with a determined restriction profile, this technique was able to differentiate E. japonicus from E. encrasicolus. The second method allowed the identification of those four species and demonstrates that FINS is a suitable technique for the identification of all species studied in this work. Phylogenetic trees show that sequences of E. encrasicolus are grouped into two different clusters. These results are consistent with the previously published data which suggest that some species of genus Engraulis could be cryptic species, being one specie or population distributed in the oceanic habitat and the other one around the coast.     

Characterisation of avocado (Persea americana Mill) honeys by their physicochemical characteristics

The quality of 12 avocado (Persea americana Mill) honeys from Spain was evaluated. Eight common physicochemical parameters were analysed, namely water content, pH, acidity (free, lactonic and total), sugar content, ash content and electrical conductivity. In addition, the honey samples were analysed using inductively coupled plasma optical emission spectrometry (ICP‐OES), and six minerals were quantified for each honey, namely potassium (K), calcium (Ca), magnesium (Mg), sodium (Na), phosphorus (P) and sulphur (S). Most samples showed proper maturity considering the medium water content (mean 17.7%). The total acidity (below 50 meq kg^?1 except for one sample) indicated absence of undesirable fermentation; also, the mean pH of around 4.77 is usual in this kind of honey. The values for ash content and electrical conductivity were high (0.77% and 798 µS cm^?1 respectively) and typical of dark honeys. K was the predominant mineral (accounting for 73% of the total minerals quantified), followed by Na (10%). Copyright © 2004 Society of Chemical Industry     

Influence of different aging systems and oak woods on aged wine color and anthocyanin composition

The evolution of a red wine, Cigales appellation in origin, was studied during its storage in three different aging systems (barrels, chips, and staves) made of different kinds of oak wood (American, French, and Hungarian). The results obtained were analyzed in order to determine the content of anthocyanins in wine according to the aging system used. The studied variables were monoglucosides of delphidin, cyanindin, peonidin, petunidin and malvidin (as acetic and p-coumaric esters), as well as vitisin A, malvidin-3-O-caffeylglucoside, and color variables. The relationship between the anthocyanins and color variables stressed the importance of these compounds during the formation of pigments characteristic of aged wine, and highlighted how they are affected by the aging system chosen.Analysis of the results allowed us to define the evolution of the wine accordingly to the aging system and the botanical species of wood used. Wine treated with chips evolved more quickly than wines treated with the other two systems, because there was a higher loss of anthocyanins and an increase in brownish tonalities. On the other hand, wine treated with Hungarian oak wood suffered a slightly higher loss of anthocyanins than those aged with French and American oak wood.     

Reduction of Escherichia coli O157:H7 viability on leafy green vegetables by treatment with a bacteriophage mixture and trans-cinnamaldehyde

Enterohemorrhagic Escherichia coli (EHEC) O157:H7 has been recognized as a major foodborne pathogen responsible for frequent gastroenteritis outbreaks. Phages and essential oils can be used as a natural antimicrobial method to reduce bacterial pathogens from the food supply. The objective of this study was to determine the effect of a bacteriophage cocktail, BEC8, alone and in combination with the essential oil trans-cinnameldehyde (TC) on the viability of a mixture of EHEC O157:H7 strains applied on whole baby romaine lettuce and baby spinach leaves. The EHEC O157:H7 strains used were Nal^R mutants of EK27, ATCC 43895, and 472. Exponentially growing cells from tryptic soy (TS) broth cultures were spot inoculated on leaves and dried. EHEC cells were placed at low, medium, and high inoculum levels (10⁴, 10⁵, and 10⁶ CFU/mL, respectively). Appropriate controls, BEC8 (approx. 10⁶ PFU/leaf), and TC (0.5% v/v) were applied on treated leaves. The leaves were incubated at 4, 8, 23, and 37 °C in Petri dishes with moistened filter papers. EHEC survival was determined using standard plate count on nalidixic acid (50 μg/mL) Sorbitol MacConkey agar. No survivors were detected when both leaves were treated with BEC8 or TC individually at low inoculum levels after 24 h at 23 and 37 °C. When the EHEC inoculum size increased and/or incubation temperature decreased, the efficacy of BEC8 and TC decreased. However, when the two treatments were combined, no survivors were detected after 10 min at all temperatures and inoculum levels on both leafy greens. These results indicated that the BEC8/TC combination was highly effective against EHEC on both leafy greens. This combination could potentially be used as an antimicrobial to inactivate EHEC O157:H7 and reduce their incidence in the food chain.