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

A general framework for stochastic traveling waves and patterns, with application to neural field equations

In this paper we present a general framework in which to rigorously study the effect of spatio-temporal noise on traveling waves and stationary patterns. In particular the framework can incorporate versions of the stochastic neural field equation that may exhibit traveling fronts, pulses or stationary patterns. To do this, we first formulate a local SDE that describes the position of the stochastic wave up until a discontinuity time, at which point the position of the wave may jump. We then study the local stability of this stochastic front, obtaining a result that recovers a well-known deterministic result in the small-noise limit. We finish with a study of the long-time behavior of the stochastic wave.Comment: 43 pages, 3 figure

Front fluctuations for the stochastic Cahn–Hilliard equation

We consider the Cahn–Hilliard equation in one space dimension, perturbed by the derivative of a space and time white noise of small intensity, and we investigate the effect of the noise on the solutions when the initial condition is a front that separates the two stable phases. We prove that, given with probability going to one as the noise intensity vanishes, the solution remains close to a front for long times, and we study the fluctuations of the front in this time scaling. They are given by a one dimensional continuous process, self similar of order one and non-Markovian, related to a fractional Brownian motion and for which a couple of representations are given

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

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

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

Exploring non-edible parts of pineapples as fat replacers in cake formulations

Non-edible parts of many fruits, such as peel and seeds, are sources of compounds with important nutritional properties. They are also rich in fibres, which gives them the potential to be used as functional ingredients since fibres may be fat replacers in many food formulations. If these parts of fruits are properly transformed into edible forms, there will be potential reuse and recovery of food waste. In the case of pineapple, approximately 70% of the total weight of the fruit is not consumed, being rinds, core, and crown usually discarded. This work aimed to transform pineapples' non-edible parts (rinds and crowns) into powders by freeze-drying with posterior micronization. The objective was to use the powders as fat replacers in a traditional cupcake recipe and assess the texture profile of the baked cakes. Pineapples (Ananas comosus L.) rinds and crowns were removed, cut into small pieces, and freeze-dried. The dried samples were ground in a hammer mill to obtain powders/flours. They were characterized in terms of water activity, water and oil absorption capacity (WAC and OAC), proteins, and total dietary fibre content (on a dry basis, d.b.). These powders were used in a cupcake recipe (control), replacing the fat (butter) with the powders in different proportions: 25, 50, and 75%. Relevant textural parameters such as hardness, cohesiveness, chewiness, and springiness were assessed in the baked cupcakes. Water activity values of rind and crown powders were 0.36±0.02 and 0.49±0.03, respectively. Regarding functional properties, crown flours presented a considerably higher OAC (6.11±0.39 g oil/g d.b.) than the rind (2.45±0.47 g oil/g d.b.); WAC of both flours was similar, averaging 2.30±0.34 g water/g d.b. Protein content was significantly higher in the crown (8.14±0.89 g/100 g d.b.) than in the rind flours (4.43±0.38 g/100 g d.b.). Dietary fibres were mainly insoluble; the crown had 18% and the skin 37%.The texture of cupcakes with 25% of both types of flour was similar to the control. However, as the proportions of the flours increased, texture differed mainly in crown-based recipes, becoming the cakes harder with springiness and adhesiveness decay. These findings suggest that incorporating pineapple waste parts in a traditional cake recipe may serve as healthier ingredients with improved functional properties.info:eu-repo/semantics/publishedVersio

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

Particle size effect of integral carob flour on bioaccessibility of bioactive compounds during simulated gastrointestinal digestion

Carob fruit is native to the Mediterranean region and produced mainly in Portugal, Italy, Morocco and Turkey. The production of the carob fruit in Portugal is highly extensive and sustainable. Currently, carob flour (CF) production is mainly achieved after pulp separation, despite it having been demonstrated that the seeds improve the extraction efficiency of bioactive compounds such as polyphenols, promoting human health. This study aimed to produce an integral CF through an innovative process and assess its physicochemical and bioactive properties at different particle sizes throughout simulated gastrointestinal tract (GIT) digestion. The sugar content profile obtained throughout GIT digestion indicated that sucrose, the sugar present at the highest concentration in undigested CF, was digested and broken down into simple sugars, namely glucose and fructose. The total phenolic content (TPC) and antioxidant activity obtained for the ≤100 µm fraction were in accordance and gastric digestion promoted an increase in the TPC value compared to the undigested sample. The >100 µm fractions displayed a distinct profile from the ≤100 µm fraction. This study showed that the particle size affects the sugar, antioxidant and total phenolic content of CFs and also their gastrointestinal tract digestion. The ≤100 µm fraction demonstrated the most suitable profile as a functional food ingredient.info:eu-repo/semantics/publishedVersio