Changes in lipids during different sterilizing conditions in canning albacore (Thunnus alalunga) in oil

The effects on muscle lipid deterioration of initial cooking and of three time/temperature processing combinations after 4 months storage of albacore tuna canned in oil were studied. Conjugated dienes only increased slightly on cooking but thiobarbituric acid index increased and fell on canning; free fatty acids (FFA) increased with some canning. Polyene index and polyunsaturated fatty acids (PUFA) content provided higher values with higher temperature, shorter time processing.     

Copper, iron, manganese and zinc levels in turrón from Jijona and Alicante

The aim of this study was to determine the ash and trace element contents (copper, iron, manganese and zinc) of two traditional types of turrón (a typical Spanish Christmas sweet made from almonds, honey, egg white and sugar), popularly known as ‘hard’ or Alicante turrón and ‘soft’ or Jijona turrón. Samples and ‘soft’ or Jijona turrón. Samples. Samples of turrón were incinerated, the ashes dissolved in HCl/HNO₃ and the mineral contents determined using atomic absorption spectroscopy. Ash samples of Jijona turrón showed greater mineral contents than did Alicante tur and 164g %, respectively) since the former has a greater almond content. Copper and manganese were present in the smallest quantities. They also showed most variation between the types and categories of the turrón investigated, both experimentally and statistically. Mean iron and zinc values were similar in both types of     

Effect of slurry ice on chemical changes related to quality loss during European Hake (Merluccius merluccius) chilled storage

Slurry ice is a biphasic system consisting of small spherical ice crystals surrounded by seawater at subzero temperature. Its employment was evaluated in the present work as a new chilled storage method for whole European Hake (Merluccius merluccius) and compared to traditional flake icing. Different chemical analyses (nucleotide degradation, formaldehyde formation, lipid hydrolysis and oxidation, interaction compound formation, and electrophoretic protein profiles) related to quality changes were analysed and compared to sensory evaluation. An inhibitory effect on quality loss mechanisms was observed for the slurry ice treatment, according to nucleotide degradation (K value), free formaldehyde content, browning development, and sarcoplasmic protein profiles. No differences in lipid hydrolysis and oxidation could be distinguished by a comparison between both icing conditions. The sensory analysis showed a higher shelf-life time for slurry icing than flake icing (12 days and 5 days, respectively). Results confirm the practical advantages of using slurry ice as a chilled storage method.     

Semiconductor-to-metallic phase transition of VO<Subscript>2</Subscript> by laser excitation

VO₂ thin films deposited on MgO and fused silica glass substrates were prepared by the pulsed laser deposition (PLD) technique, which shows phase transition (PT) from the monoclinic semiconductor phase to a metallic tetragonal rutile structure at temperatures over 68°C. The observed PT is reversible, showing a typical hysteresis. The PT can also be induced through optical pumping by laser excitation. In this case, it was found that the optically induced PT is ultrafast and passive, but not thermally initiated. In order to understand the PT mechanism, a study of transient holography using degenerate-four-wavemixing (DFWM) measurement was conducted. A Nd:YAG pulsed laser with pulse duration of 30 psec operating at 532 nm was employed as the coherent light source. This showed that the observed transient holography in VO₂ thin film is associated with the excited state dynamical process, which essentially causes the structural change, or so-called optically induced PT. The observed extremely large polarizability is believed to relate to the large offset in the potential well minimum between the ground state and excited state. Through an unidentified intermediate state, the transient lattice distortion triggered the structural change.     

Activation of the K-ras oncogene in colorectal neoplasms is associated with decreased apoptosis

BACKGROUND: Recent in vitro data indicate that the oncogenic effects of activated ras genes may be mediated, at least in part, through inhibition of apoptotic cell death. To examine this proposition in vivo, the relationship between mutations of the K-ras gene and the frequency of apoptosis was studied in a series of 69 sporadic colorectal neoplasms (11 adenomas and 58 carcinomas). METHODS: Mutations in codon 12 of K-ras were determined by a single tube, enriched polymerase chain reaction. Apoptotic cells in tumor sections were identified by in situ end-labeling of fragmented DNA, whereas levels of bcl-2 and p53 proteins were determined by immunohistochemistry. RESULTS: Tumors with mutant K-ras had a significantly lower apoptotic index than those with the wild-type allele (P < 0.05). They were also more likely to exhibit positive bcl-2 staining (P < 0.05). Adenomas showed significantly greater bcl-2 positivity than carcinomas (89% and 51%, respectively; P < 0.05). The frequency of apoptosis in these tumors was not related to either bcl-2 positivity or p53 status. CONCLUSIONS: These findings suggest that activation of K-ras in colorectal carcinoma may inhibit apoptosis and thus favor tumor progression. Alternatively, this association may reflect an accumulation of K-ras mutations in cells in which normal apoptotic pathways have been impaired.     

Quality retention during the chilled distribution of farmed turbot (Psetta maxima): effect of a primary slurry ice treatment

The quality and shelf‐life of chilled farmed turbot (Psetta maxima) was evaluated by sensory, microbiological and biochemical procedures after being subjected to a two‐step refrigeration storage in slurry ice and flake ice, respectively. Turbot specimens were stored for 10 or 17 days in slurry ice, and then were transferred to flake ice for 1–3 days to simulate the sale conditions in the market. The results were compared with control batches stored only in flake ice and processed in parallel. Storage of turbot in the two‐step strategy resulted in a better maintenance of sensory quality, especially with regard to its mucus production and gill odour development, better control of microbial activity, especially of aerobes, and the slowing down of some biochemical degradation mechanisms such as the nucleotide degradation pathway and trimethylamine production. As a consequence, the shelf‐life was extended significantly. From these results it can be concluded that the refrigerated transport of farmed turbot in slurry ice enhances its shelf‐life, before its transfer into flake ice in the retail market.     

Biosurfactant-and-Bioemulsifier Produced by a Promising Cunninghamella echinulata Isolated from Caatinga Soil in the Northeast of Brazil

A Mucoralean fungus was isolated from Caatinga soil of Pernambuco, Northeast of Brazil, and was identified as Cunninghamella echinulata by morphological, physiological, and biochemical tests. This strain was evaluated for biosurfactant/bioemulsifier production using soybean oil waste (SOW) and corn steep liquor (CSL) as substrates, added to basic saline solution, by measuring surface tension and emulsifier index and activity. The best results showed the surface water tension was reduced from 72 to 36 mN/m, and an emulsification index (E₂₄) of 80% was obtained using engine oil and burnt engine oil, respectively. A new molecule of biosurfactant showed an anionic charge and a polymeric chemical composition consisting of lipids (40.0% w/w), carbohydrates (35.2% w/w) and protein (20.3% w/w). In addition, the biosurfactant solution (1%) demonstrated its ability for an oil displacement area (ODA) of 37.36 cm², which is quite similar to that for Triton X-100 (38.46 cm²). The stability of the reduction in the surface water tension as well as of the emulsifier index proved to be stable over a wide range of temperatures, in pH, and in salt concentration (4%–6% w/v). The biosurfactant showed an ability to reduce and increase the viscosity of hydrophobic substrates and their molecules, suggesting that it is a suitable candidate for mediated enhanced oil recovery. At the same time, these studies indicate that renewable, relatively inexpensive and easily available resources can be used for important biotechnological processes.