Wednesday, 31 January 2018

Fungicide residues affect the sensory properties and flavonoid composition of red wine

Journal of Food Composition and Analysis, 66 (2018) 185-192


The influence of four fungicide treatments [viz., metrafenone, boscalid + kresoxim-methyl, fenhexamid and mepanipyrim, which are typically used to control downy mildew (Plasmopara viticola) and grey mould (Botrytis cinerea)] on the composition of Tempranillo red wines was assessed by examining changes in phenolic composition, colour and aroma profile in wines from pesticide-treated grapes in relation to control wines made from untreated grapes. The results were also compared with those for wine of a previous vintage in order to ascertain whether fungicide-related changes were comparable to vintage-related changes. Only the boscalid + kresoxim-methyl treatment led to significant differences in wine of the 2013 vintage; thus, it increased the contents in monomeric anthocyanins (58%) and flavan-3-ols (36%), and also colour lightness (20%), but decreased the contribution of the ripe (42%) and fresh fruits (59%) odorant series. These results seemingly confirm that the presence of boscalid + kresoxim-methyl residues in must impairs the sensory quality of the resulting wine by diminishing its brightness and aroma. Differences varied markedly between years, which suggests that the course of the fermentation process is influenced not only by the composition of the grapes but also by the presence of the fungicide.

Evaluation of the neuroprotective and antidiabetic potential of phenol-rich extracts from virgin olive oils by in vitro assays

Food Research International, 106, 558-567, 2018


In this work, phenol-rich extracts from ‘Cornicabra’ and ‘Picual’ virgin-olive oils (EVOOs) were examined, for the first time, to establish their capacity to inhibit key enzymes involved in Alzheimer's disease (AD) (acetylcholinesterase (AChE), butyrylcholinesterase (BuChE) and 5-lipoxygenase (LOX)), major depressive disorder (MDD) and Parkinson's disease (PD) (monoamine oxidases: hMAO-A and hMAO-B respectively), and diabetes mellitus (DM) (α-glucosidase and α-amylase). ‘Cornicabra’ displayed the best inhibitory activity against all enzymes, when compared to ‘Picual’: BuChE (IC50 = 156 ± 4 and 308 ± 33 mg mL−1), LOX (IC50 = 26 ± 0.5 and 37 ± 3 mg mL−1), hMAO-A (IC50 = 20 ± 2 and 37 ± 0.2 mg mL−1), hMAO-B (IC50 = 131 ± 7 and 215 ± 13 mg mL−1) and α-glucosidase (IC50 = 154 ± 17 and 251 ± 31 mg mL−1), respectively. The behaviour observed can be associated with the higher content of secoiridoids, lignans and phenolic acids in ‘Cornicabra’ EVOO.

Monday, 8 January 2018

Genotypic and phenotypic identi cation of olive cultivars from north-western Spain and characterization of their extra virgin olive oils in terms of fatty acid composition and minor compounds

Scientia Horticulturae, 2018


Galicia (NW Spain) is emerging as a new olive-growing region. Galician oil producers are currently striving to recover old autochthonous cultivars with a view to obtaining high quality extra virgin olive oil (EVOO). In this work, a total of 32 trees were studied in order to established their identity and genetic relationships to the main cultivated material in the Iberian Peninsula. The analysis of 11 morphological features of the endocarp and 14 microsatellite markers allowed three different cultivars to be identi ed among the sampled trees. Compar- ison with the morphological and molecular pro les available in the World Olive Germplasm Bank of Cordoba (WOGBC) revealed that 24 trees (75%) were of the ‘Brava’ cultivar and 7 (22%) of the ‘Mansa’ cultivar. The other tree, labelled as Picuda, matched no speci c cultivar in WOGBC. Characterizing the oils obtained from the studied cultivars revealed a high potential for producing high-quality EVOOs of speci c origin.

Thursday, 4 January 2018

Bioaccessibility and potential bioavailability of phenolic compounds from achenes as a new target for strawberry breeding programs

Food Chemistry 248 (2018) 155-165


Strawberry is a major natural source of bioactive compounds. Botanically, strawberry is an aggregate fruit consisting of a fleshy floral receptacle that bears a cluster of real dry fruits (achenes). Existing knowledge on the phenolic composition of achenes and its contribution to that of the whole fruit is limited. Also, the gastric and intestinal bioavailability of phenols is poorly known. In this work, a combination of spectrophotometric and HPLC–DAD methods was used to analyse the phenolic composition of whole fruits and achenes before and after in vitro digestion. Five different phenol families were identified. Also, achenes were found to contribute a sizeable fraction of phenolic acids and hydrolysable tannins in the whole fruit. Because the mere presence of phenolic compounds in a food matrix does not ensure their ready absorption and bioavailability, polyphenol potential bioavailability could be an effective selection criterion for strawberry breeding programs aimed at improving dietary healthiness.


Wednesday, 3 January 2018

Aldehydes as additives in AOT-based microemulsions: influence upon electrical percolation

Tenside, Surfactants & Detergents, 2018



The influence of alkyl-aldehydes upon electric percolation of AOT-based microemulsions has been studied. The number of carbons in the hydrocarbon chain was varied between 0 and 5 atoms (chain length between 0 and 7.33Å). Two different behaviors were found, while the presence in the microemulsion of short chains aldehydes implies a decrease in the percolation temperature, aldehydes with 4 or 5 carbon atoms in the hydrocarbon chain increase the percolation threshold. These opposite behavior has ben justified in terms of aldehyde location in the microheterogeneous system.

Tuesday, 2 January 2018

Screening of organic pollutants in pet hair samples and the significance of environmental factors

Science of The Total Environment, 625 (2018) 311–319


Organic pollutants (OPs) represent a wide range of chemicals that are potentially harmful for human and wildlife health. Many of these pollutants have been identified as endocrine disruptors that can alter hormonal balance producing adverse biological effects such as neurotoxicity, reproductive disorders, carcinogenicity and hepatotoxicity. For years, hair has been selected as a non-invasive source to assess levels of animal contamination. In the present study, a multiclass screening method for determining about 60 organic pollutants in pet hair was designed and validated for qualitative and quantitative purposes. Concentrations from different classes of organochlorine, and organophosphate pesticides (OCPs, and OPPs), polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (NDL-PCBs and DL-PCBs), polybrominated diphenyl ethers (PBDEs) and organophosphate esters (OPEs) were identified in the selected pet hair samples from Ourense (NW, Spain). We detected most of these pollutants in the selected hair pets. The mean concentrations found ranged from 89 to 6556 ng/g for OPEs, from 8.6 to 1031 ng/g for PAHs, from 8.6 to 256 ng/g for PBDEs, from 29 to 184 ng/g for OPPs, from 0.29 to 139 for OCPs, from 0.30 to 59 ng/g for NDL-PCBs and from 1.2 to 14 ng/g for DL-PCBs. To our knowledge, this is the first study to document the presence of OPs in pets from North-West Spain and it could provide baseline information for future monitoring of OPs in the area.

Monday, 1 January 2018

Changes of the shelf life of candelilla wax/tarbush bioactive based-nanocoated apples at industrial level conditions

Scientia Horticulturae  231 (2018) 43-48


The aim of this study was to determine the efficacy of the candelilla wax-based nanocoating for increase the shelf life of apples at industrial level. Phytomolecules of tarbush were obtained and were added in the nanocoating for morphological characterization and quantification of nanoparticles. Phytomolecules of tarbush promoted a high amount of nanoparticles and a surface uniform and free from heterogeneity in the nanocoating. Apples fruit dipped for 10 s in nanocoating with phytomolecules of tarbush and without phytomolecules then were stored on marketing conditions at 22 ± 2 °C and refrigeration at 5 ± 2 °C, 90% RH at industrial level, while the uncoated fruit served as controls. Physicochemical changes were monitored during 8 weeks. A sensory evaluation of preference in taste and appearance was performed in the apples. Candelilla wax-based nanocoating with phytomolecules of tarbush was able to reduce significantly (P ˂ 0.05) the physicochemical changes in the apples. The results of the overall preference indicated that control apples were the most preferred in taste and appearance. Apples coated with nanocoating with phytomolecules of tarbush were the least preferred in appearance and taste. According to the results, phytomolecules of tarbush incorporated into the candelilla wax-based nanocoating is an alternative for increase shelf life of Golden delicious apples in marketing conditions and refrigeration at industrial level.

Tuesday, 17 October 2017

Antioxidant and antimicrobial properties of encapsulated guava leaf oil in hydroxypropyl-beta-cyclodextrin

Industrial Crops and Products
https://doi.org/10.1016/j.indcrop.2017.10.027


The essential oil from guava leaves has low physicochemical stability and low solubility in water, what limits its application in food formulations. This study aimed to characterize the physicochemical properties and the antioxidant and antimicrobial activities of encapsulated guava leaf oil in hydroxypropyl-β-cyclodextrin (HPβCD). Inclusion complex formation of guava leaf oil and HPβCD was determined by several techniques. Antioxidant activity of encapsulated guava leaf oil was more stable to sunlight exposure than free guava leaf oil by 26–38%. The antibacterial activity of guava leaf oil against Staphylococcus aureus and Escherichia coli was improved by 4 and 2 times after encapsulation in HPβCD, respectively.

Tuesday, 26 September 2017

Improved 1,3-propanediol production with maintained physical conditions and optimized media composition: Validation with statistical and neural approach

Biochemical Engineering Journal


This work is aimed at assessing the use of response surface methodology (RSM) and artificial neural networks (ANNs) for modelling, and predicting, the optimum parameters for 1,3-Propanediol production by Lactobacillus brevis N1E9.3.3 from glycerol and glucose co-fermentation. A preliminary study of physical parameters was conducted using Plackett-Burman design to reduce the number of input variables up to seven; i) beef extract, ii) yeast extract, iii) MgSO4·7H2O, iv) MnSO4·H2O, v) vitamin B12, vi) glycerol and vii) glucose. The traditional RSM models were improved by ANN models between a 54.08% and 12.19% in terms of root mean square error (RMSE). This study suggested that RSM and ANN can be considered as effective tools to model and predict optimum parameters for 1,3-Propanediol production by L. brevis N1E9.3.3.



Monday, 25 September 2017

Dietary exposure and neurotoxicity of the environmental free and bound toxin β-N-methylamino-l-alanine

Food Research International, 100, 2017, Pages 1-13


The growing evidence supporting a link between exposure to the naturally occurring toxin β-N-methylamino-l-alanine (BMAA) and progressive neurodegenerative diseases, has recently arisen the interest of the scientific community. Latest investigations suggest that dietary exposure to this algal toxin may have been largely underestimated. This paper reviews the state of the art regarding BMAA, with special attention paid to its neurotoxicity, its concentration levels in food, and human exposure. As for other environmental toxins, dietary intake is most likely the main route of exposure to BMAA for the general population. However, data concerning BMAA levels in foodstuffs are still scarce. It is concluded that further investigations on dietary intake and potential human health effects are clearly necessary to assess the risks to public health associated with BMAA exposure. Some critical remarks and recommendations on future research in this area are provided, which may help to identify approaches to reduce dietary BMAA exposure.

Wednesday, 20 September 2017

Chromatographic Fingerprinting with Multivariate Data Analysis for Detection and Quantification of Apricot Kernel in Almond Powder

Food Analytical Methods


Adulteration of almond powder samples with apricot kernel was solved by gas chromatographic fatty acid fingerprinting combined with multivariate data analysis methods (principal component analysis (PCA), PCA-linear discriminant analysis (PCA-LDA), partial least squares (PLS), and LS support vector machine (LS-SVM). Different almond and apricot kernel samples were mixed at concentrations ranging from 10 to 90% w/w. PCA and PCA-LDA methods were applied for the classification of almonds, apricot kernels, and mixtures. PLS and LS-SVM were used for the quantification of adulteration ratios of almond. Models were developed using a training data set and evaluated using a validation data set. The root mean square error of prediction (RMSEP) and coefficient of determination (R2) of validation data set obtained for PLS and LS-SVM were 5.01, 0.964 and 2.29, 0.995, respectively. The results showed that the methods can be applied as an effective and feasible method for testing almond adulteration.

Tuesday, 29 August 2017

Diseñando aceites de oliva “gourmet” en Galicia

Lección Inaugural
Curso 2017-2018




Resumen


Pretendo exponer alguno de los principales resultados obtenidos por nuestro grupo a lo largo de varios años de investigación sobre la caracterización aromá- tica y fenólica de aceitunas y aceites de oliva producidos en Galicia, y –de esta manera- visualizar una de nuestras apuestas científicas, de gran interés y rele- vancia actual en Galicia. El objetivo último es contribuir a diseñar una estrategia que permita potenciar la puesta en el mercado de aceites de oliva “gourmet” con valor diferencial.

Monday, 31 July 2017

Combination of food wastes for an efficient production of nisin in realkalized fed-batch cultures

Biochemical Engineering Journal


Nisin production by Lactococcus lactis CECT 539 was studied in four realkalized fed-batch cultures in diluted whey with feeding with lactose- and glucose-containing substrates. The first and third cultures were fed with mixtures of whey (W) and a 400 g/L concentrated glucose (CG), or with a concentrated mussel processing waste (CMPW) and CG, respectively.
The second and fourth cultures were respectively performed under the same conditions as in the first and third fermentations. However, these cultures were supplemented with mixtures of W plus a 2% (w/v) yeast extract (WYE2) and CG (second culture), or with CMPW plus a 2% (w/v) yeast extract (CMPWYE2) (fourth culture) after sample extractions at 132 and 168 h, respectively. From these times, each culture was fed with mixtures of WYE2 and CG, or CMPWYE2 and CG, respectively.
The final concentrations of nisin obtained in the third (223.98 BU/mL) and fourth (350.61 BU/mL) cultures, fed with glucose-containing substrates (CG and CMPW), were considerably higher than those obtained in the first (108.00 BU/mL) and second (158.53 BU/mL) cultures fed with the mixture of lactose- and glucose-containing substrates (W and CG).

Sunday, 30 July 2017

High hydrostatic pressure as pretreatment and adjuvant for the enzymatic release of ferulic acid from corn cob

Process Biochemistry


Bioprocesses based on the use of enzymes can be employed for the obtainment of ferulic acid by its solubilization from corn cob, which is a natural source of this phenolic compound. In order to overcome the limitations caused by the recalcitrance of biomass, the application of pretreatments is advisable. The utilization of high hydrostatic pressure on the enzymatic release of ferulic acid from corn cob with three feruloyl esterase extracts was studied applying pressurization at 600 MPa as a pretreatment in combination with a mild thermal treatment at 130 °C/2 h. Additionally, pressurization at 200 MPa during the enzymatic hydrolysis step was assessed to increase the ferulic acid yield. The results showed that the application of a high pressure pretreatment at 600 MPa/40 °C/15 min to thermally treated corn cob increased by 20% the ferulic acid release in comparison with the thermal treatment for Ultraflo® L, but not for the Aspergillus extracts. Pressurization at 200 MPa during the hydrolysis stage affected differently the enzymes stability and ferulic acid release depending on the extract and the pretreatments applied, showing that the effects of pressurization are complex and must be assessed in each case.

Thursday, 15 June 2017

A critical review on the applications of artificial neural networks in winemaking technology

Critical Reviews in Food Science and Nutrition


Since their development in 1943, artificial neural networks were extended into applications in many fields. Last twenty years have brought their introduction into winery, where they were applied following four basic purposes: authenticity assurance systems, electronic sensory devices, production optimization methods, and artificial vision in image treatment tools, with successful and promising results. This work reviews the most significant approaches for neural networks in winemaking technologies with the aim of producing a clear and useful review document.

Friday, 26 May 2017

Redispersion and Self-Assembly of C60 Fullerene in Water and Toluene

ACS Omega



This work aims at assessing the influence of two different solvents, bidistilled water and toluene, on dispersions of carbon-based engineered nanomaterials, namely, fullerenes, and their self-assembly behavior. The obtained self-assembled carbon-based materials were characterized using UV–vis spectrophotometry and transmission electron microscopy techniques. The results obtained were unexpected when toluene was used for dispersing fullerene C60, with the formation of two different types of self-assembled structures: fullerene C60 nanowhiskers (FNWs) and a type of quasispherical nanostructure. The FNWs ranged between 1 and 6 μm in length, whereas the quasispherical fullerene C60 nanoaggregates ranged between 10 and 50 nm in diameter. Aggregates obtained in toluene showed a well-formed crystal structure. When using water, the obtained aggregates were amorphous and showed a no well-defined shape. Their sizes ranged between 20 and 40 nm for nanosized structures and between 0.4 and 4.8 μm for micron-sized self-aggregates.

Monday, 22 May 2017

Climate-induced changes in river water temperature in North Iberian Peninsula

Theor Appl Climatol 


This study evaluates the effects of climate change on the thermal regime of 12 rivers in the Northern Iberian Peninsula by using a non-linear regression model that employs air temperature as the only input variable. Prediction of future air temperature was obtained from five regional climate models (RCMs) under emission scenario Special Report on Emissions Scenarios A1B. Prior to simulation of water temperature, air temperature was bias-corrected (B-C) by means of variance scaling (VS) method. This procedure allows an improvement of fit between observed and estimated air temperature for all climate models. The simulation of water temperature for the period 1990–2100 shows an increasing trend, which is higher for the period of June-August (summer) and September-November (autumn) (0.0275 and 0.0281 °C/year) than that of winter (December-February) and spring (March-May) (0.0181 and 0.0218 °C/year). In the high air temperature range, daily water temperature is projected to increase on average by 2.2–3.1 °C for 2061–2090 relative to 1961–1990. During the coldest days, the increment of water temperature would range between 1.0 and 1.7 °C. In fact, employing the numbers of days that water temperature exceeded the upper incipient lethal temperature (UILT) for brown trout (24.7 °C) has been noted that this threshold is exceeded 14.5 days per year in 2061–2090 while in 1961–1990, this values was exceeded 2.6 days per year of mean and 3.6 days per year in observation period (2000–2014).

Monday, 1 May 2017

Challenges in relating concentrations of aromas and tastes with flavor features of foods

Critical Reviews in Food Science and Nutrition 


Flavor sensations in food are highly influenced by the aroma and taste compounds. Reviewing the extensive literature of recent years in this field has shown that the reconstitution of flavor based on aroma and taste compounds poses numerous problems. These are of different nature and include among others (a) chemical transformations among these compounds, (b) changes in the concentrations of the compounds responsible for the perceived flavor, (c) interactions among the chemical compounds that enhance or reduce a specific flavor sensation, and finally, (d) the complexity of the different food matrices and its influence in the flavor perception. Another difficulty that flavor scientists must face is how to properly model and visualize the complex relationships existing between the chemical composition of foods and the flavor perception. These problems have repercussions on the reconstitution of the flavor signature of food based on the natural concentrations of its key aroma and taste compounds. Therefore, the main aim of this review is to deal with all these issues to propose potential solutions for a robust transformation in a science-based quality approach.

Saturday, 29 April 2017

Revisiting the Schönbein ozone measurement methodology

Geophysical Research Abstract


Trough the XIX century the Schönbein method gained a lot of popularity by its easy way to measure tropospheric ozone. Traditionally it has been considered that Schönbein measurements are not accurate enough to be useful. Detractors of this method argue that it is sensitive to meteorological conditions, being the most important the influence of relative humidity. As a consequence the data obtained by this method have usually been discarded. Here we revisit this method taking into account that values measured during the 19th century were taken using different measurement papers. We explore several concentrations of starch and potassium iodide, the basis for this measurement method. Our results are compared with the previous ones existing in the literature. The validity of the Schönbein methodology is discussed having into account humidity and other meteorological variables.