Study of star-forming galaxies in SDSS up to redshift 0.4: I. Metallicity evolution

The chemical composition of the gas in galaxies versus cosmic time provides a very important tool for understanding galaxy evolution. Although there are many studies at high redshift, they are rather scarce at lower redshifts. However, low redshift studies can provide important clues about the evolution of galaxies, furnishing the required link between local and high redshift universe. In this work we focus on the metallicity of the gas of star-forming galaxies at low redshift, looking for signs of chemical evolution. To analyze the metallicity contents star-forming galaxies of similar luminosities and masses at different redshifts. With this purpose, we present a study of the metallicity of relatively massive (log(M_star/M_sun)>10.5) star forming galaxies from SDSS--DR5 (Sloan Digital Sky Survey--Data Release 5), using different redshift intervals from 0.04 to 0.4. We used data processed with the STARLIGHT spectral synthesis code, correcting the fluxes for dust extinction, estimating metallicities using the R_23 method, and segregating the samples with respect to the value of the [NII]6583/[OII]3727 line ratio in order to break the R_23 degeneracy selecting the upper branch. We analyze the luminosity and mass-metallicity relations, and the effect of the Sloan fiber diameter looking for possible biases. By dividing our redshift samples in intervals of similar magnitude and comparing them, significant signs of metallicity evolution are found. Metallicity correlates inversely with redshift: from redshift 0 to 0.4 a decrement of ~0.1 dex in 12+log(O/H) is found.Comment: 11 pages, 9 figures, Accepted for publication in A&

Correction of defective textures in packaged dry-cured pork ham by applying conventional and ultrasonically-assisted mild thermal treatments

Pastiness is a textural defect characterized by an excessive softness and loss of elasticity which lacks corrective actions at industrial level. The objective of this study was to evaluate the textural and microstructural changes of dry-cured pork ham, with different pastiness levels, subjected to conventional and ultrasonically-assisted corrective mild thermal treatments. Pastiness was assessed by an expert sensory panel and hams were classified into three categories: high (HP), medium (MP) and no (NP) pastiness. Ham samples (n = 108) were heated (40 and 50 °C) with power ultrasound (PuS) and without (CV) PuS application. After heating, all of the textural parameters assessed were improved. Hardness increased by 102% and adhesiveness decreased by 55% and the ham became less viscoelastic. The largest modifications were found in the samples heated at 50 °C and no differences were found between CV and PuS treatments. The microstructure of pasty samples revealed that the treatment produced a shrinkage of the myofibrils, which could explain the increase in hardness and the improvement in texture of defective ham.info:eu-repo/semantics/acceptedVersio

Application of temperature and ultrasound as corrective measures to decrease the adhesiveness in dry-cured ham. Influence on free amino acid and volatile compound profile

The impact of low temperature treatment and its combination with ultrasound has been evaluated in order to correct texture defects in dry-cured hams. A total of 26 dry-cured hams, classified as high proteolysis index (PI>36%), were used. From these hams, ten slices from each ham sample were cut, vacuum packed and submitted to three different treatments: control (without treatment), conventional thermal treatments (CV) and thermal treatment assisted by power ultrasound (US). The impact of these treatments on instrumental adhesiveness, free amino acid and volatile compounds profile were assessed. Statistical analysis showed that both US and CV treatments, significantly (P < .001) decreased the instrumental adhesiveness of dry-cured hams from 85.27 g for CO to 40.59 and 38.68 g for US and CV groups, respectively. The total free amino acid content was significantly (P < .001) affected by both treatments, presenting higher values the samples from the US group (6691.5 vs. 6067.5 vs. 5278.2 mg/100 g dry matter for US, CV and CO groups, respectively). No significant differences were observed between US and CV treatments. All the individual free amino acids were influenced by ultrasound and temperature treatments, showing the highest content in sliced dry-cured ham submitted to ultrasounds at 50 °C, except for isoleucine which presented the highest level in samples from CV group. Similarly, significant differences (P < .05) were also detected in the total volatile compound content between CO and US groups, with a higher concentration in the CO batch (56,662.84 AU × 103/g of dry-cured ham) than in the US treatment (45,848.47 AU × 103/g of dry-cured ham), being the values in the CV treatment intermediate (48,497.25 AU × 103/g of dry-cured ham). Aldehydes, ethers and esters, carboxylic acids and sulphur compounds were more abundant in the CO group, while CV group showed higher concentrations of ketones, alcohols and nitrogen compounds.info:eu-repo/semantics/acceptedVersio

Assessing the textural defect of pastiness in dry-cured pork ham using chemical, microstructural, textural and ultrasonic analyses

The dry-cured pork ham industry lacks non-destructive quality control techniques able to characterize relevant textural defects, such as pastiness or softness. The aim of this study is to analyze the feasibility of using different destructive and non-destructive techniques to characterize pastiness in dry-cured ham. Dry-cured ham processing was modified in order to induce different pastiness intensities over a wide range of moisture and salt contents. Afterwards, pastiness was assessed by sensory analysis and samples classified as non-pasty, medium-pasty and highly-pasty. Finally, chemical, textural, microstructural (LM and TEM) and ultrasonic analyses (velocity and attenuation coefficient) were carried out. Samples with a high degree of pastiness experienced an increase of 16.8% and 16.7% as regards the proteolysis index and relaxation capacity, respectively, and a 67.7% decrease in hardness compared to non-pasty hams. The microstructural analysis revealed that pastiness brought about great structural degradation. Ultrasonic velocity was significantly related to the salt (r = 0.79) and moisture contents (r = 0.69), but no influence of pastiness was found on the velocity. However, the attenuation coefficient increased as the pastiness rose and could be considered as a useful parameter for characterizing this complex textural defect. Therefore, ultrasound could be used not only to carry out a non-destructive characterization of dry-cured ham composition but also to assess pastiness.info:eu-repo/semantics/acceptedVersio

Bi-LSTM neural network for EEG-based error detection in musicians’ performance

Electroencephalography (EEG) is a tool that allows us to analyze brain activity with high temporal resolution. These measures, combined with deep learning and digital signal processing, are widely used in neurological disorder detection and emotion and mental activity recognition. In this paper, a new method for mental activity recognition is presented: instantaneous frequency, spectral entropy and Mel-frequency cepstral coefficients (MFCC) are used to classify EEG signals using bidirectional LSTM neural networks. It is shown that this method can be used for intra-subject or inter-subject analysis and has been applied to error detection in musician performance reaching compelling accuracy.This work has been funded by Junta de Andalucía in the framework of Proyectos I+D+I en el marco del Programa Operativo FEDER Andalucia 2014–2020 under Project No.: UMA18-FEDERJA-023, Proyectos de I+D+i en el ámbito del Plan Andaluz de Investigación, Desarrollo e Innovación (PAIDI 2020) under Project No.: PY20_00237 and Universidad de Málaga, Campus de Excelencia Internacional Andalucia Tech . Funding for open access charge: Universidad de Málaga/CBU

Application of temperature and ultrasound as corrective measures to decrease the adhesiveness in dry-cured ham. Influence on free amino acid and volatile compound profile

[EN] The impact of low temperattire treatment and its combination with ultrasound has been evaluated in order to correct texture defects in dry-cured hams. A total of 26 dry-cured hams, classified as high proteolysis index (PI > 36%), were used. From these hams, ten slices from each ham sample were cut, vacuum packed and submitted to three different treatments: control (without treatment), conventional thermal treatments (CV) and thermal treatment assisted by power ultrasound (US). The impact of these treatments on instrumental adhesiveness, free amino acid and volatile compounds profile were assessed. Statistical analysis showed that both US and CV treatments, significantly (P<.001) decreased the instrumental adhesiveness of dry-cured hams from 85.27 g for CO to 40.59 and 38.68 g for US and CV groups, respectively. The total free amino acid content was significantly (P<.001) affected by both treatments, presenting higher values the samples from the US group (6691.5 vs. 6067.5 vs. 5278.2 mg/100 g dry matter for US, CV and CO groups, respectively). No significant differences were observed between US and CV treatments. All the individual free amino acids were influenced by ultrasound and temperature treatments, showing the highest content in sliced dry-cured ham submitted to ultrasounds at 50 degrees C, except for isoleucine which presented the highest level in samples from CV group. Similarly, significant differences (P<.05) were also detected in the total volatile compound content between CO and US groups, with a higher concentration in the CO batch (56,662.84 AU x 10(3)/g of dry-cured ham) than in the US treatment (45,848.47 AU x 10(3)/g of dry-cured ham), being the values in the CV treatment intermediate (48,497.25 AU x 10(3)/g of dry-cured ham). Aldehydes, ethers and esters, carboxylic acids and sulphur compounds were more abundant in the CO group, while CV group showed higher concentrations of ketones, alcohols and nitrogen compounds.This research was supported by Grant RTA 2013-00030-CO3-03 from INIA (Spain). Acknowledgements to INIA for granting Cristina Perez Santaescolastica with a predoctoral scholarship (grant number CPD2015-0212). Jose M. Lorenzo is member of the MARCARNE network, funded by CYTED (ref. 116RT0503).Pérez-Santaescolástica, C.; Carballo, J.; Fulladosa, E.; Garcia-Perez, J.; Benedito Fort, JJ.; Lorenzo, J. (2018). Application of temperature and ultrasound as corrective measures to decrease the adhesiveness in dry-cured ham. Influence on free amino acid and volatile compound profile. Food Research International. 114:140-150. https://doi.org/10.1016/j.foodres.2018.08.006S14015011

Effect of proteolysis index level on instrumental adhesiveness, free amino acids content and volatile compounds profile of dry-cured ham

[EN] Defective textures in dry-cured ham are a common problem that causes important economic losses in the ham industry. An increase of proteolysis during the dry-cured ham processing may lead to high adhesiveness and consumer rejection of the product. Therefore, the influence of proteolysis index (PI) on instrumental adhesiveness, free amino acids and volatile profile of dry-cured ham was assessed. Two hundred Spanish dry-cured ham units were firstly classified according to their PI: low PI ( 36%). Instrumental adhesiveness was affected by PI, showing the lowest values in the batch with low PI. Significant differences (P < 0.05) among groups were found in six amino acids: serine, taurine, cysteine, methionine, isoleucine and leucine. The content of leucine, serine, methionine, and isoleucine significantly (P < 0.05) increased as the proteolysis index rose. However, taurine and cysteine content showed an opposite behaviour, reaching the highest values in the dry-cured hams with low PI. Significant differences (P < 0.001) in the total content of volatile compounds among ham groups were observed, with the highest concentration in the batch with low PI, and decreasing the concentration as the PI increased. Regarding the different chemical families of volatiles, the hydrocarbons (the main family), alcohols, aldehydes, ketones and acids were more abundant in the hams showing the lowest PI. Esters did not show significant differences among the three batches of hams studied. The present study demonstrated that, apart from the effect on the adhesiveness, an excessive proteolysis seems to be associated with negative effects on the taste and aroma of the dry-cured ham.This research was supported by Grant RTA 2013-00030-CO3-03 from INIA (Spain). Acknowledgements to INIA for granting Cristina Perez Santaescolastica with a predoctoral scholarship. Jose M. Lorenzo is member of the MARCARNE network, funded by CYTED (ref. 116RT0503).Pérez-Santaescolástica, C.; Carballo, J.; Fulladosa, E.; Garcia-Perez, J.; Benedito Fort, JJ.; Lorenzo, J. (2018). Effect of proteolysis index level on instrumental adhesiveness, free amino acids content and volatile compounds profile of dry-cured ham. Food Research International. 107:559-566. https://doi.org/10.1016/j.foodres.2018.03.001S55956610