Search

Anthocyanins have received considerable attention for the development of food products with attractive colors and potential health benefits. However, anthocyanin applications have been hindered by stability issues, especially in the context of complex food matrices and diverse processing methods. From the natural microenvironment of plants to complex processed food matrices and formulations, there may happen comprehensive changes to anthocyanins, leading to unpredictable stability behavior under various processing conditions. In particular, anthocyanin hydration, degradation, and oxidation during thermal operations in the presence of oxygen represent major challenges. First, this review aims to summarize our current understanding of key anthocyanin stability issues focusing on the chemical properties and their consequences in complex food systems. The subsequent efforts to examine plenty of cases attempt to unravel a universal pattern and provide thorough guidance for future food practice regarding anthocyanins. Additionally, we put forward a model with highlights on the role of the balance between anthocyanin release and degradation in stability evaluations. Our goal is to engender updated insights into anthocyanin stability behavior under food processing conditions and provide a robust foundation for the development of anthocyanin stabilization strategies, expecting to promote more and deeper progress in this field.

DNA methylation is increasingly known to be essential for fruit ripening and senescence. Currently, 5-azacytidine (AZ) was selected as an effective demethylator and it successfully shaped the genomic hypomethylation in harvested strawberries. This was associated with the reprogramming of global gene expressions, which influenced downstream food traits. The alleviation of decay and softening, as well as the deceleration of soluble solid accumulation, were included. Coloration was also delayed as a result of the AZ-induced hypomethylation. Our examinations of anthocyanin biosynthesis and transport revealed that they were markedly minimized, which was probably involved with the decreased abscisate level and its weakened metabolism. Additionally, under AZ, the retarded postharvest senescence process was observed and it might be induced by the inhibited ROS accumulation accompanying the peroxidase and catalase activities alteration. Overall, these findings underlined the importance of methylation in strawberries and suggested the potential role of epigenetic regulators in the postharvest industry.

Sulfur dioxide (SO

After the iconic outburst of Zonag Lake in Hoh Xil of Tibetan Plateau (TP) in 2011, the causes of the collapse and its impact on the volume of water contained by the downstream lakes have highly been concerned, but the overall changes of the hydrological ecosystem and its impacts on the basin are yet not clear. This paper analyzes the hydrological system (lake area and hydrological connection) and ecosystem (sandstorm activity and vegetation growth status) changes and their impacts on the regional ecological environment after the outburst event, based on remotely sensed images from 2000 to 2020, meteorological observations, and field surveys. The results show that the outburst of Zonag Lake has not only changed the regional hydrology and ecosystem pattern but also caused a trend of degradation in the ecological environment of Zonag Lake Basin. Some lambing areas and active areas of Tibetan antelope in the area are being buried and eroded by the sandstorm. The downstream Yanhu Lake has risen to the highest level and overflowed through the emergency diversion engineering. These impacts are continuously threatening the health of the ecological environment of the world natural heritage site in Hoh Xil, the safety of Qinghai-Tibet highway, Qinghai-Tibet railway, and other engineering facilities, as well as the stability of fluvial geomorphology in the northern most sources of Yangtze River.

Particle-laden jet flow is important to both jet-related industry applications and transmission of the virus through violent expiratory events, such as coughing and sneezing. To help understand its dynamics from the particle level, we develop a time-resolved, three-dimensional (3D), particle tracking velocimetry method, coupled with particle image velocimetry measurement of gas flow, and perform experiments on a dilute particle-laden gas jet. The spatial distributions of velocity and fluctuating velocity of the gas and particles are obtained. It is found that the presence of particles significantly changes the gas turbulence and stretch the gas flow field to the downstream. The probability density function of axial particle velocity shows non-Gaussian distribution and deviates much from those of the spanwise velocities, indicating strong non-equilibrium and anisotropic states. A new drag model is derived based on the reconstructed particle trajectories and gas flow field near the ejector exit with particle Reynolds numbers between 30 and 300. It is found in better agreement with the experimental data than the standard single-particle drag model. A simple model relating the particle volume fraction with particle displacement is developed based on the self-similarity theory of jet, showing good agreement with the experimental measurement.

Graphical abstract, Highlights • Citrus segment membrane removal during canning was improved for clean process. • The improved process using mixed acid (alkali) showed good membrane removal result. • The processing water was fully used for preparing a new healthy electrolyte drink. • The bioactive compounds in the canning processing water were completely recoverd. • This green process with economic viability has great society benefits., In the production of canned citrus, large amounts of processing water were discharged during the segment membrane removal process, causing severe pollution. In order to reduce pollution and recover the bioactive compounds in the processing water, the production of canned satsuma mandarin, sweet orange and grapefruit were studied, and improved acid (0.1% HCl, 0.4% citric acid) and alkali (0.1% KOH, 0.2% NaOH) were used to conduct the new chemical hydrolysis process to remove the segment membrane. The obtained acid and alkali processing water were firstly explored the potential to make novel beverages, which contain electrolytes (Na: 472–945 ppm; K: 208–279 ppm; Cl: 364–411 ppm; citrate: 1105–1653 ppm) and potential prebiotics such as pectin and flavonoids. The improved segment membrane removal process realized the conversion of wastewater into drinkable beverages at low costs. The bioactive compounds were fully recovered without wastewater discharging, which produced great environmental, economic and health value.

The clustering is critical to understanding the multiscale behavior of fluidization. However, its time-resolved evolution on the particle level is seldom touched. Here, we explore both the time-averaged and time-resolved dynamics of clusters in a quasi-2D fluidized bed. Particle tracking velocimetry is adopted and then clusters are identified by using the Voronoi analysis. The time-averaged results show that the cluster hydrodynamic parameters depend highly on the cluster size and the distance from the wall. The number distribution of the cluster size follows a power law (~n)) of the percolation theory except for large clusters (n>100). The time-resolved analysis shows that the cluster coalescence can be simplified as a collision between two inelastic clusters, during which the net external force is roughly zero, and a snowplow model is proposed to predict its energy loss, ΔE ~ t. The cluster rupture is suggested to be caused by increasing torque.

We developed a novel method of microwave irradiation to deal with Escherichia coli (E. coli), realized the trans-membrane and trans-wall direct electron transfer of Guanine in viable E. coli. Typical surface controlled irreversible electrode process of E. coli was achieved by cyclic voltammetry with the participating of two electrons and two protons. The method of bacterium culture and colony count showed that the direct electrochemistry of E. coli could be realized with its biological activity maintained. In addition, the electrochemical parameters of E. coli were further achieved, which provided a paradigm for direct electrochemical study of other bacteria.

The hydrodynamic conservation equations and constitutive relations for a binary granular mixture composed of smooth, nearly elastic spheres with non-equipartition energies and different mean velocities are derived. This research is aimed to build three-dimensional kinetic theory to characterize the behaviors of two species of particles suffering different forces. The standard Enskog method is employed assuming a Maxwell velocity distribution for each species of particles. The collision components of the stress tensor and the other parameters are calculated from the zeroth- and first-order approximation. Our results demonstrate that three factors, namely the differences between two granular masses, temperatures and mean velocities all play important roles in the stress–strain relation of the binary mixture, indicating that the assumption of energy equipartition and the same mean velocity may not be acceptable. The collision frequency and the solid viscosity increase monotonously with each granular temperature. The zeroth-order approximation to the energy dissipation varies greatly with the mean velocities of both species of spheres, reaching its peak value at the maximum of their relative velocity.

This paper proposes a synchronized measurement method of analyzing collapsing granular piles using a high-speed camera and a grid-based tactile pressure sensor. The method is developed with a pressure sensor comprising 2016 individual sensels and a granular pile consisting of approximately 24,000 ceramsite spheres. Geometric, kinetic, and mechanical quantities (i.e., packing fraction ϕ, mean speed v ¯ , and pressure P) are simultaneously measured for a more detailed analysis of collapse processes. Collapses last for about 3.3τc where the characteristic time τ c = h 0 / g , h0 is the initial height of the granular pile, and g is acceleration due to gravity. The failure angle is measured as φf ≈ 51°. The relation between packing fraction and flow speed in μ(I) rheology, which is a previous theoretical predication, is validated in the experimental measurements of this work. Pressure distributions beneath the granular pile are recorded in time. Results show that the probability density function of the scaled contact pressure exhibits the power-law for small stresses, whilst a Gaussian distribution for large pressures beneath the granular pile at the initial state. As the pile is agitated, a large drop in pressure is observed during the stage when many particles fall freely, and pressure propagation is compared with mean speed.

International audience; Purpose - The purpose of this paper is to investigate the local feature of driven granular gases in event-driven molecular dynamic simulation, in order to achieve spatial profiles of local velocity distribution and granular temperature, and the local state with various coefficients of restitution.Design/methodology/approach - Event-driven molecular dynamic simulation is performed to study a vibro-fluidized granular gas system. Triangular-wave vibration is adopted in the simulation. The authors focus on the steady state of a driven granular gas.Findings - The simulation finds the local velocity distribution is asymmetric along vibration direction in this driven granular gas system, which agrees with the experimental results obtained in micro-gravity. A nonlinear spatial profile of the skewness of local velocity distribution in vibration direction is found in the simulation. Furthermore, it is found that the value of skewness increases with the system dissipation. It is also found that the two temperature components T+ and T- differ from each other. This shows breakdown of energy equipartition. The ratio between them drops exponentially along y direction in various coefficients of restitution. All results confirm that the bulk boundary effect relates to the dissipation properties of granular gases.Originality/value - This is the first MD simulation that investigates the bulk boundary effect to the local velocity distribution. The spatial profiles of the skewness of local velocity distribution are also investigated when changing the coefficient of restitution to study the influence of the system dissipative nature.

Gas–solid fluidization is a typical nonlinear nonequilibrium system with multiscale structure. In particular, the mesoscale structure in terms of bubbles or clusters, which can be characterized by nonequilibrium features in terms of bimodal velocity distribution, energy nonequipartition, and correlated density fluctuations, is the critical factor. Traditional two-fluid model (TFM) and relevant closures depend on local equilibrium and homogeneous distribution assumptions, and fail to predict the dynamic, nonequilibrium phenomena in circulating fluidized beds even with fine-grid resolution. In contrast, the mesoscale modeling, as exemplified by the energy-minimization multiscale (EMMS) model, is consistent with the nonequilibrium features in multiphase flows. Thus, the structure-dependent multifluid model conservation equations with the EMMS-based mesoscale modeling greatly improve the prediction accuracy in terms of flow, mass transfer, and reactions as well as the understanding of flow regime transitions. Such discrepancies raise the question of the applicability of the local equilibrium assumption underlying the TFM and further shed light to the necessity of mesoscale modeling.

An event driven molecular dynamics simulation of granular gases in a rectangle container in the high frequency boundary vibration limit is performed. The local velocity distribution spatial profiles under various vibration velocities are presented. Two peaks of local velocity distribution in the marginal layers are observed. To quantify the spatial transformation of the local velocity distribution, we fit the major peak by a Gaussian function(with the mean ξ and the standard deviation σ). The results show that the fitting parameters of the major peaks, such as ξ and σ, can be well scaled by the vibration velocity.

A microgravity experimental study of vibrofluidized granular gas with intermediate number density is performed. Local velocity distributions are investigated, and are found to deviate measurably from a symmetric distribution for the velocity component in the direction of vibration due to the boundary heating mechanism. One generalized granular hydrodynamic theory (GSH) is used for a phenomenological model to describe this extended boundary effect by introducing additional variables to the two-peak distribution profile, which provides an account for the understanding of the bulk boundary effect.

The free path of a vibro-fluidized two-dimensional (2D) inelastic granular gas confined in a rectangular box is investigated by 2D event-driven molecular simulation. By tracking particles in the simulation, we analyze the local free path. The probability distribution of the free path shows a high tail deviating from the exponential prediction. The anisotropy of the free path is found when we separate the free path to x and y components. The probability distribution of y component is exponential, while x component has a high tail. The probability distribution of angle between the relative velocity and the unit vector joined two particle centers deviates from the distribution of two random vectors, indicating the existence of the dynamic heterogeneities in our system. We explain these results by resorting to the kinetic theory with two-peak velocity distribution. The kinetic theory agrees well with the simulation result.

Within the past few years, organizations in diverse industries have adopted MapReduce-based systems for large-scale data processing. Along with these new users, important new workloads have emerged which feature many small, short, and increasingly interactive jobs in addition to the large, long-running batch jobs for which MapReduce was originally designed. As interactive, large-scale query processing is a strength of the RDBMS community, it is important that lessons from that field be carried over and applied where possible in this new domain. However, these new workloads have not yet been described in the literature. We fill this gap with an empirical analysis of MapReduce traces from six separate business-critical deployments inside Facebook and at Cloudera customers in e-commerce, telecommunications, media, and retail. Our key contribution is a characterization of new MapReduce workloads which are driven in part by interactive analysis, and which make heavy use of query-like programming frameworks on top of MapReduce. These workloads display diverse behaviors which invalidate prior assumptions about MapReduce such as uniform data access, regular diurnal patterns, and prevalence of large jobs. A secondary contribution is a first step towards creating a TPC-like data processing benchmark for MapReduce., VLDB2012

Vibrating walls, frequently employed to maintain the temperature (i.e., average velocity) in a granular gas, modify the system strongly, rendering it dissimilar to a molecular one in various aspects. As evidenced by microgravity experiments employing a quasi-two-dimensional (quasi-2D) rectangular box and by 2D simulations, the one-peak velocity distribution is split into two, rendering the stress both nonuniform and anisotropic-without a shear flow and in the absence of gravitation. To account for this, granular hydrodynamics (as first proposed by Haff and later derived employing the kinetic theory) is generalized by introducing two additional variables, with one accounting for the distance between the two peaks and a second for the difference between the average velocities along different directions. The hydrodynamic theory thus generalized relates the velocity distribution to the stress, yielding results that agree with experiments and simulations.