Soft and hard wall in a stochastic reaction diffusion equation

We consider a stochastically perturbed reaction diffusion equation in a bounded interval, with boundary conditions imposing the two stable phases at the endpoints. We investigate the asymptotic behavior of the front separating the two stable phases, as the intensity of the noise vanishes and the size of the interval diverges. In particular, we prove that, in a suitable scaling limit, the front evolves according to a one-dimensional diffusion process with a non-linear drift accounting for a "soft" repulsion from the boundary. We finally show how a "hard" repulsion can be obtained by an extra diffusive scaling.Comment: 33 page

Phase fluctuations in the ABC model

We analyze the fluctuations of the steady state profiles in the modulated phase of the ABC model. For a system of $L$ sites, the steady state profiles move on a microscopic time scale of order $L^3$. The variance of their displacement is computed in terms of the macroscopic steady state profiles by using fluctuating hydrodynamics and large deviations. Our analytical prediction for this variance is confirmed by the results of numerical simulations

Bioactive potential and chromatographic characterization of body mucus from Portugal coastal fish halobatrachus didactylus

The body mucus in fish provides a stable physical or chemical barrier against invading pathogens. In mucus, antimicrobial peptides are secreted as a response to immune stimulation. Studies have shown antimicrobial activity against multidrug-resistant pathogens and low toxicity to eukaryotic cells. Previously, body mucus from five captive Halobatrachus didactylus individuals was collected. We aim to explore the mucus studying molecules with bioactive potential. Size exclusion high­performance liquid chromatography (SE­HPLC) analyses were performed on the five body mucus samples showing a similar molecular size distribution with a maximum peak of ca. 800 Da. These five mucus samples were pooled to assess the following bioactivities: antioxidant (ABTS and ORAC), antimicrobial (minimal inhibitory concentration), and cytotoxicity (Caco­2 and HaCaT human cell lines). The protein content in the mucus, determined by the bicinchoninic acid methodology, was 16836 ± 1020 µg BSA/mL. The antioxidant activity resulted in 268 ± 11 µmol TE/g mucus protein for ABTS and 306 ± 11 µmol TE/g mucus protein for ORAC. The antibacterial activity was assessed against five pathogenic bacteria: Escherichia coli, Listeria monocytogenes, Pseudomonas aeruginosa, Salmonella enterica, Staphylococcus aureus, within minimal inhibitory concentrations of 421 to 105 µg mucus protein/mL. Moreover, the mucus showed non­cytotoxic for Caco­2 cells in concentrations between 196 to 25 µg mucus protein/mL, while it showed cytotoxicity for HaCaT cells. In the future, liquid chromatography­tandem mass spectrometry (LC­MS/MS) analysis will be performed to determine the molecules behind these bioactivities, namely antimicrobial peptides.info:eu-repo/semantics/publishedVersio

Chemical composition, antioxidant capacity and phenolic contents of carob (Ceratonia siliqua L.) flour as related to seed presence and roasting effects

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Composição química, capacidade antioxidante e conteúdo polifenólico da farinha de alfarroba (Ceratonia siliqua L.) em relação à presença de semente e efeito de torrefação

Carob is the fruit of an evergreen tree (Ceratonia siliqua L.) cultivated in the Mediterranean area, where Portugal has a high-cultivated extent with relevant production and low prices. Carob is well known for its valuable locust bean gum. However, carob pods contain various relevant nutrients, including proteins, carbohydrates and fiber, and phytochemicals such as polyphenols, which position carob flour with great potential to be used as a functional ingredient. This study aimed to evaluate the impact of different roasting processes of carob flour (with and without seeds) on its nutritional composition and antioxidant activity. Seed presence led to a higher content of macronutrients in carob flour. The roasting processing affected the total content of polyphenols (TPC), determined by Folin-Ciocalteau, since the content at 150 ºC was twice of that obtained at 80 ºC, probably due to the formation of certain Maillard reaction products (MRPs), or certain phenolics that may degrade during roasting. The antioxidant activity is correlated with TPC, increasing when the flour was roasting at 150ºC. Regarding the total fiber content, a significant increase was observed in samples processed at 150 ºC. These findings confirm the importance of understanding the impact of processing on the nutritional value and bioactive properties of carob flours, to use them efficiently as a functional food ingredient.Alfarroba é um fruto de árvore perene (Ceratonia siliqua L.) cultivada na área mediterrânea, na qual Portugal compreende alta extensão de cultivo com produção relevante e baixo custo. Alfarroba é usualmente conhecida pela goma de alfarroba, contudo as vagens de alfarroba contêm variados nutrientes relevantes, incluindo proteínas, hidratos de carbono e fibra, e fitoquímicos tais como polifenóis, conferindo à farinha de alfarroba potencial para ser usada como ingrediente funcional. Este estudo focou-se na avaliação do impacto de diferentes processos de torrefação da farinha de alfarroba (com e sem semente) na sua composição nutricional e capacidade antioxidante. A presença de semente levou a alto conteúdo de macronutrientes na farinha de alfarroba. O processo de torrefação afetou o conteúdo total de polifenóis (CTP), determinado por FolinCiocalteau, uma vez que para 150 ºC o conteúdo obtido foi o dobro daquele obtido para 80 ºC, possivelmente devido à formação de certos produtos de reações Maillard (PRMs) ou certos fenóis que possam degradar durante a torrefação. A atividade antioxidante correlaciona-se com o CTP, aumento na farinha de alfarroba processada a 150 ºC. Relativamente ao conteúdo de fibras totais, observou-se um aumento significativo nas amostras processadas a 150 ºC. Os resultados obtidos comprovam a importância em analisar o impacto do processamento ao nível do valor nutricional e das propriedades bioativas da farinha de alfarroba, de forma a ser usada eficientemente como ingrediente funcional em alimentos.info:eu-repo/semantics/publishedVersio

Thermosonication applied to kiwi peel: a healthy source of nutrients

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Thermosonication applied to kiwi peel: impact on nutritional and microbiological indicators

The peels of many fruits are rich sources of nutrients, although they are not commonly consumed. If they are properly decontaminated, they can be used as healthy food ingredients reducing food waste. The objective was to apply thermosonication processes to kiwi peel and evaluate the impact on Listeria innocua survival (a non-pathogenic surrogate of L. monocytogenes) and key nutrients and quality indicators: proteins, fibers, minerals (Ca, K, Mg, Na, and P), chlorophylls, and phenolic contents. Kiwi peels were artificially inoculated with L. innocua and thermal and thermosonication treatments were performed at 55 °C and 60 °C for 30 and 15 min maximum, respectively. Bacteria were enumerated through treatment time, and quality indicators were assessed before and at the end of treatments. A Weibull model with a decimal reduction time (D-value) was successfully used in L. innocua survival data fits. Results showed that coupling temperature to ultrasound had a synergistic effect on bacteria inactivation with significant decreases in D-values. Thermosonication at 60 °C was the most effective in terms of protein, fiber, chlorophylls, and phenolics retention. Minerals were not significantly affected by all treatments. Applying thermosonication to kiwi peel was more effective for decontamination than thermal treatments at the same temperature while allowing the retention of healthy compounds.info:eu-repo/semantics/publishedVersio

Dobrushin states in the \phi^4_1 model

We consider the van der Waals free energy functional in a bounded interval with inhomogeneous Dirichlet boundary conditions imposing the two stable phases at the endpoints. We compute the asymptotic free energy cost, as the length of the interval diverges, of shifting the interface from the midpoint. We then discuss the effect of thermal fluctuations by analyzing the \phi^4_1-measure with Dobrushin boundary conditions. In particular, we obtain a nontrivial limit in a suitable scaling in which the length of the interval diverges and the temperature vanishes. The limiting state is not translation invariant and describes a localized interface. This result can be seen as the probabilistic counterpart of the variational convergence of the associated excess free energy.Comment: 34 page

Super-hydrodynamic limit in interacting particle systems

This paper is a follow-up of the work initiated in [3], where it has been investigated the hydrodynamic limit of symmetric independent random walkers with birth at the origin and death at the rightmost occupied site. Here we obtain two further results: first we characterize the stationary states on the hydrodynamic time scale and show that they are given by a family of linear macroscopic profiles whose parameters are determined by the current reservoirs and the system mass. Then we prove the existence of a super-hyrdrodynamic time scale, beyond the hydrodynamic one. On this larger time scale the system mass fluctuates and correspondingly the macroscopic profile of the system randomly moves within the family of linear profiles, with the randomness of a Brownian motion.Comment: 22 page

Sugar, total phenolic content and antioxidant activity of integral carob (Ceratonia siliqua L.) powder during the simulated gastrointestinal tract digestion as related to the particle-size effect

Carob (Ceratonia siliqua L.) fruit is obtained from the evergreen carob tree, native to the Mediterranean region 1,2 and produced mainly in Portugal, Italy, Morocco and Turkey 3– 5. Portugal has a high-cultivated extent with relevant carob fruit production at low prices. Carob products containing phenolic substances exhibit antioxidant capacity and can promote human health, and aid in preventing chronic diseases 6,7. Currently, carob powder (CP) production is mainly achieved after the pulp separation despite having been demonstrated that seeds improve the extraction efficiency of bioactive compounds like polyphenols 4. This study aimed to produce an integral CP through an innovative process and assess its physicochemical and bioactive properties in different particle sizes throughout a simulated gastrointestinal tract (GIT) digestion. The sugar content profile obtained throughout GIT digestion indicates that the highest present sugar in undigested carob powders is digested and broken into simple sugars like glucose and fructose, potentiating CPs as a functional and within healthy food intake recommendations ingredient to use. The total phenolic content and antioxidant activity obtained for the ≤100 μm fraction are correlated and gastric digestion promotes the increase in TPC value compared to chemically extracted samples (undigested). The >100 μm fractions display a distinct profile from ≤100 μm, possibly due to higher content in insoluble fibers, which hinders the release of these bioactive compounds from the carob matrix. This study showed that the particle-size affects the sugar, antioxidant and total phenol content under gastrointestinal tract digestion. The ≤100 μm fraction obtained the best suitable profile as a functional food ingredient.info:eu-repo/semantics/publishedVersio