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.

Friday, 28 April 2017

Optimization of selective pressurized liquid extraction of organic pollutants in placenta to evaluate prenatal exposure

Journal of Chromatography A


The early exposure to organic pollutants (OPs) related to dietary habit or environmental exposure is a concern of growing interest in environmental health. When OPs enter the body, they can accumulate in fatty tissue and even travel through the bloodstream being able to cross the placenta and reach the fetus through the substance exchange between the mother and the child. Epidemiologic and clinical data affirm that these chemicals increase the risk of adverse effects during childhood. This article reviews and addresses one of the most relevant analytical methods for determining OPs in placenta. We discuss and critically evaluate procedures, such as solid-liquid and selective pressurized liquid extraction (SPLE). Clean-up of extracts was performed by solid-phase extraction (SPE) using EZ-POP cartridges. Detection of OPs was carried out by gas chromatography (GC) coupled to tandem mass spectrometry (MS/MS). Recoveries ranged from 52% to 94% by SPLE with estimated quantification limits between 0.15 and 2.2 ng/g for organochlorine pesticides (OCPs), between 0.083 and 0.50 for organophosphate pesticides (OPPs), between 0.025 and 0.15 ng/g for polychlorinated biphenyl (PCBs), between 0.015 and 0.10 ng/g for polybromodiphenyl ethers (PBDEs), between 0.33 and 0.66 ng/g for pyrethroids and between 0.022 and 0.87 ng/g for polycyclic aromatic hydrocarbons (PAHs). Most of the target OPs were detected in twenty real placenta samples studied, with pyrethroids, PAHs and OPPs representing most of the 90% of OPs with means of 13–18 ng/g versus PCBs, OCPs, and PBDEs with means <4.0 ng/g. The rsults of this work indicate a prenatal exposure to OPs in Galicia.

Saturday, 1 April 2017

Physico-chemical characterization and evaluation of bio-efficacies of black pepper essential oil encapsulated in hydroxypropyl-beta-cyclodextrin

Food Hydrocolloids


Encapsulation of essential oils with cyclodextrins can protect their active compounds from environmental conditions and improve their aqueous solubility, hence increasing their functional capabilities as additives. The purpose of this study was to characterize the physico-chemical properties and bio-efficacies, antioxidant and antibacterial activities, of the encapsulated black pepper essential oil in hydroxypropyl-β-cyclodextrin (HPβCD), in comparison with the major ingredient in the oil, β-caryophyllene. The difference in encapsulation efficiency of the pure compound and the black pepper oil results from the presence of other components in the black pepper oil such as limonene, δ-3-carene and pinene. Although the inclusion complexes increase their stability, they gave slightly lower antioxidant activity as a result of the HPβCD was blocking the functional groups of active compounds during reaction with DPPH radicals. Instead, after encapsulated in HPβCD, the antibacterial activity of black pepper oil was improved by 4 times against both S. aureus and E. coli.

Monday, 20 March 2017

State of the Art on Functional Virgin Olive Oils Enriched with Bioactive Compounds and Their Properties

Int. J. Mol. Sci. 2017, 18(3), 668. 


 Virgin olive oil, the main fat of the Mediterranean diet, is per se considered as a functional food—as stated by the European Food Safety Authority (EFSA)—due to its content in healthy compounds. The daily intake of endogenous bioactive phenolics from virgin olive oil is variable due to the influence of multiple agronomic and technological factors. Thus, a good strategy to ensure an optimal intake of polyphenols through habitual diet would be to produce enriched virgin olive oil with well-known bioactive polyphenols. Different sources of natural biological active substances can be potentially used to enrich virgin olive oil (e.g., raw materials derived from the same olive tree, mainly olive leaves and pomaces, and/or other compounds from plants and vegetables, mainly herbs and spices). The development of these functional olive oils may help in prevention of chronic diseases (such as cardiovascular diseases, immune frailty, ageing disorders and degenerative diseases) and improving the quality of life for many consumers reducing health care costs. In the present review, the most relevant scientific information related to the development of enriched virgin olive oil and their positive human health effects has been collected and discussed.

Friday, 17 March 2017

A Critical Review of Bioactive Food Components, and of their Functional Mechanisms, Biological Effects and Health Outcomes.

Curr Pharm Des. 2017;23(19):2731-2741


Background:
Eating behaviours are closely related to some medical conditions potentially leading to death such as cancer, cardiovascular disease and diabetes. Healthy eating practices, maintaining a normal weight, and regular physical activity could prevent up to 80% of coronary heart disease, 90% of type-2 diabetes and onethird of all cancers.

Method:
Over the last two decades, the food industry has invested much effort in research and development of healthier, more nutritious foods. These foods are frequently designated "functional" when they contain nutritional components required for healthy living or "nutraceuticals" when intended to treat or prevent disease or disorders through a variety of bioactive (e.g., antioxidant, antimicrobial, immunomodulatory, hypocholesterolaemic) functions that are performed by functional enzymes, probiotics, prebiotics, fibres, phytosterols, peptides, proteins, isoflavones, saponins or phytic acid, among other substances.

Results:
Some agricultural and industrial residues have proven to be excellent choices as raw materials for producing bioactive compounds and have been proposed as potentially safe natural sources of antimicrobials and/or antioxidants for the food industry. Functional food ingredients containing bioactive compounds could be used as plant extracts by pharmaceutical and food industries.

Conclusion:
Bioactive food components influence health outcomes.

Wednesday, 15 March 2017

Perspective on pre- and post-natal agro-food exposure to persistent organic pollutants and their effects on quality of life

Environment International


Background

Adipose tissue constitutes a continual source of internal exposure to organic pollutants (OPs). When fats mobilize during pregnancy and breastfeeding, OPs could affect foetal and neonatal development, respectively.

Scope and approach

The main aim of this review is to deal with pre- and post-natal external exposure to organic pollutants and their effects on health, proposing prevention measures to reduce their risk. The goal is the development of a biomonitoring framework program to estimate their impact on human health, and prevent exposure by recommending some changes in personal lifestyle habits.

Key findings and conclusions

It has been shown that new studies should be developed taking into account their cumulative effect and the factors affecting their body burden. In conclusion, several programs should continuously be developed by different health agencies to have a better understanding of the effect of these substances and to develop a unified public policy.

Wednesday, 1 March 2017

Approach of Different Properties of Alkylammonium Surfactants using Artificial Intelligence and Response Surface Methodology

Tenside, Surfactants and Detergents


Response surface methodology (RSM) and artificial neural networks (ANNs) architectures to predict the density, speed of sound, kinematic viscosity, and surface tension of aqueous solutions were developed. All models implemented using the root mean square error (RMSE) for training and validation phase were evaluated. The ANN models implemented show good values of R2 (upper than 0.974) and low errors in terms of average percentage deviation (APD) (lower than 2.92 %). Nevertheless, RSM models present low APD values for density and speed of sound prediction (lower than 0.31 %) and higher APD values around 5.18 % for kinematic viscosity and 14.73 % for surface tension. The results show that the different individual artificial neural networks implemented are a useful tool to predict the density, speed of sound, kinematic viscosity, and surface tension with reasonably accuracy.



Tuesday, 21 February 2017

Encapsulation of yarrow essential oil in hydroxypropyl-beta-cyclodextrin: physiochemical characterization and evaluation of bio-efficacies

CyTA - Journal of Food


Essential oil from yarrow (Achillea millefolium L. s. l.) has a broad spectrum of pharmacological activities. However, active chemical components of yarrow oil are sensitive to environmental factors such as, light, oxygen and temperature. Encapsulation of essential oil offers solutions for the limitation. Yarrow oil was encapsulated in hydroxypropyl-β-cyclodextrin (HPβCD) through freeze-drying technique with encapsulation efficiency of 45%. Inclusion complex formation was examined by scanning electron microscope, Fourier transformed infrared spectroscopy and UV–vis analysis and phase solubility study. Yarrow oil gave strong antioxidant activity of 72% DPPH scavenging at 50 μg/mL. HPβCD could protect active compounds of essential oil and retained antioxidant activity after sunlight exposure. Yarrow oil also exhibited antibacterial activity against Staphylococcus aureus and Escherichia coli with the minimum inhibitory concentration (MIC) values of 250 μg/mL and 500 μg/mL, respectively. The antibacterial efficacy was much improved after encapsulation against both S. aureus and E. coli with the MIC value of 62.5 μg/mL.