Computational analysis of the simultaneous application of ultrasound and electric fields in a lipid bilayer.

The combined application of electric fields and ultrasonic waves has shown promise in controlling cell membrane permeability, potentially resulting in synergistic effects that can be explored in the biotechnology industry. However, further clarification on how these processes interact is still needed. The objective of the present study was to investigate the atomic-scale effects of these processes on a DPPC lipid bilayer using molecular dynamics simulations. For higher electric fields, capable of independently forming pores, the application of an ultrasonic wave in the absence of cavitation yielded no additional effects on pore formation. However, for lower electric fields, the reduction in bilayer thickness induced by the shock wave catalyzed the electroporation process, effectively shortening the mean path that water molecules must traverse to form pores. When cavitation was considered, synergistic effects were evident only if the wave alone was able to generate pores through the formation of a water nanojet. In these cases, sonoporation acted as a mean to focus the electroporation effects on the initial pore formed by the nanojet. This study contributes to a better understanding of the synergy between electric fields and ultrasonic waves and to an optimal selection of processing parameters in practical applications of these processes.

Saline extraction assisted by ultrasound: a method to obtain purified phycocyanin.

The influence of ultrasound intensity and saline solution concentration (NH4Cl and CaCl2) on phycocyanin extraction from Arthrospira platensis was evaluated. The intensity had a significant effect on phycocyanin content and purity, while the saline solution concentration only had an effect on purity. The optimum extraction condition was obtained at 41% of intensity and 8.5 g.L-1 of CaCl2 solution. In this condition, ultrasound promoted cell disruption efficiently, increasing the extraction yield. The combination of ultrasound with CaCl2 solution reduced the co-extraction of chlorophylls and other proteins, providing more purified extracts. The freezing and thawing method was compared to the best condition obtained, and it showed no significant difference for phycocyanin content but better results for purity. Overall, ultrasound treatment may be considered a promising technology to obtain phycocyanin by the food industry without additional purification techniques due to the reduced extraction time, less use of energy, and easy scale-up.

Effect of ultrasound on Pseudoneochloris marina and Chlorella zofingiensis growth.

The present work evaluated the ultrasound (US) effects on the growth of Pseudoneochloris marina and Chlorella zofingiensis. For P. marina, US treatment did not increase cell proliferation and reduced cell density when used for 60 min (exponential phase, for 5 days), indicating a possible occurrence of cell damage. For C. zofingiensis, the application of discontinuous US for 10 min resulted in an increase of 65 % in biomass concentration compared to the control. These distinct behaviors indicate that microalgae species react differently to physical stimuli. After US treatment, a reduction of carotenoid, chlorophyll, lipid and protein concentrations was observed, which may be related to changes in the metabolic pathways to produce these compounds. Overall, the results of the present study show the potential of discontinuous US to enhance microalgae cell proliferation.

Molecular dynamics insights on temperature and pressure effects on electroporation.

Electroporation is a cell-level phenomenon caused by an ionic imbalance in the membrane, being of great relevance in various fields of knowledge. A dependence of the pore formation kinetics on the environmental conditions (temperature and pressure) of the cell membrane has already been reported, but further clarification regarding how these variables affect the pore formation/resealing dynamics and the transport of molecules through the membrane is still lacking. The objective of the present study was to investigate the temperature (288-348 K) and pressure (1-5000 atm) effects on the electroporation kinetics using coarse-grained molecular dynamics simulations. Results shown that the time for pore formation and resealing increased with pressure and decreased with temperature, whereas the maximum pore radius increased with temperature and decreased with pressure. This behavior influenced the ion migration through the bilayer, and the higher ionic mobility was obtained in the 288 K/1000 atm simulations, i.e., a combination of low temperature and (not excessively) high pressure. These results were used to discuss some experimental observations regarding the extraction of intracellular compounds applying this technique. This study contributes to a better understanding of electroporation under different thermodynamic conditions and to an optimal selection of processing parameters in practical applications which exploit this phenomenon.

Phenolic profile of sugarcane juice: Effects of harvest season and processing by ohmic heating and ultrasound.

In the present work, a comprehensive phenolic analysis of fresh sugarcane juice from three different harvest seasons was performed and the effect of ohmic heating and ultrasound treatments on the phenolic content and color of the juice was evaluated. Among the 32 phenolic compounds identified, a total of 17 were quantified, comprising, in decreasing order of abundance, flavones (38-49 mg/L), dilignols (22-29 mg/L), and phenolic acid derivatives (17-30 mg/L). The main phenolic groups affected by the crop season (year and season) were flavones and phenolic acid derivatives. Juice treated by ohmic heating and ultrasound showed a total phenolic content similar to fresh juice, indicating the absence of additional non-thermal effects. Regarding color, both treatments promoted only a slight difference by visual perception. Considering these two quality parameters, ultrasound and ohmic heating seem to be a good alternative for sugarcane juice pasteurization.

Effect of pasteurization on Aspergillus fumigatus in apple juice: Analysis of the thermal and electric effects.

Fungal spoilage in fruit juices is a currently relevant issue considering that recent reports have found unacceptable fungal levels even after traditional pasteurization processes. Ohmic heating demonstrated to be a good alternative process to conventional pasteurization, as it can promote higher heating rates and additional cell damage in some scenarios (nonthermal effects). However, the application of ohmic processing for fungi inactivation has not been properly investigated. The objective of this study was to analyze the inactivation of Aspergillus fumigatus, a highly distributed fungi species, in apple juice by ohmic and conventional heating at 75, 80, 85, 90 and 94 °C. Predictive primary and secondary models were fitted and the Weibull-Mafart models were the most accurate to describe the experimental behavior considering the statistical indices applied. Statistical differences between both thermal processes were found in the three lower analyzed temperatures (75, 80 and 85 °C), which is possibly related to nonthermal effects. When ohmic heating was applied, processing time was up to 23% shorter. The resulted model was successfully validated in two distinct temperatures (83 and 92 °C) and could be applied to obtain adequate processing times for apple juice pasteurization. This study contributes to deepen the knowledge concerning the use of ohmic heating for fungi inactivation.

Extraction of valuable compounds from Arthrospira platensis using pulsed electric field treatment.

Pulsed electric field (PEF) treatment was evaluated for phycocyanin and proteins extraction from Arthrospira platensis (Spirulina platensis). PEF extractions were performed using different specific energies (28, 56 and 122 J·ml-1 of suspension) and the results were compared to the extraction with bead milling. At highest PEF-treatment energies a damage of the cell morphology could be observed and the highest yields (up to 85.2 ±â€¯5.7 mg·g-1 and 48.4 ±â€¯4.4 g·100 g-1 of phycocyanins and proteins, respectively) could be obtained at 122 and 56 J·ml-1. The yields increased with incubation time after PEF-treatment. The antioxidant capacity of the extracts obtained after PEF-treatment was higher than of those obtained after bead milling. PEF treatment is a promising technology to obtain blue-green antioxidant extracts from A. platensis in an environmental friendly process.

Sequential extraction of phenolics and pectin from mango peel assisted by ultrasound.

The present work evaluated the use of ultrasound to extract sequentially phenolics and pectin from mango peel. Initially, the influence of ethanol and ultrasound on the phenolics extraction was investigated. The results showed that the ultrasound did not affect the extraction yield of these compounds. The best total phenolics yield (67%) was obtained with an extraction solution consisting of 50% of ethanol in water (v/v) and without ultrasound application, according to the experimental design. As an innovative extraction methodology, the residue of this extraction was then used to extract pectin assisted by ultrasound. The use of ultrasound increased over than 50% of the pectin extraction yield and did not affect its quality, measured by the galacturonic acid content and the degree of esterification. The sequential extraction of phenolics and pectin shows to be an alternative to use the whole residue from mango peel.

Effect of thermal and high pressure processing on stability of betalain extracted from red beet stalks.

Red beet stalks are a potential source of betalain, but their pigments are not widely used because of their instability. In the present work, the applicability of high pressure processing (HPP) and high temperature short time (HTST) thermal treatment was investigated to improve betalain stability in extracts with low and high concentrations. The HPP was applied at 6000 bar for 10, 20 and 30 min and HTST treatment was applied at 75.7 °C for 80 s, 81.1 °C for 100 s and 85.7 °C for 120 s, HPP treatment did not show any improvement in the betalain stability. In turn, the degradation rate of the control and the HTST thermal treatment at 85.7 °C for 120 s of the sample with high initial betalain concentration were 1.2 and 0.4 mg of betanin/100 ml of extract per day respectively. Among the treatments studied, HTST was considered the most suitable to maintain betalain stability from red beet stalks.

Ultrasound as an alternative technology to extract carotenoids and lipids from Heterochlorella luteoviridis.

The present work evaluated the use of ultrasound as a pre-treatment to lipid and carotenoid extraction from the microalgae Heterochlorella luteoviridis. The pre-treatment was performed in the presence of ethanol (25%, v/v) with the ultrasound intensity varying from 0 to 100% (435kJkg-1). After the pre-treatment, a diffusive step was performed in order to evaluate different ethanol concentrations (50-75%, v/v). The results regarding carotenoid extraction showed that there is an optimal extraction region: 40-80% of ultrasound intensity and 60-75% of ethanol concentration. The lipid extraction was not influenced by the ultrasound pre-treatment and increased with the increase of ethanol concentration.

Evaluation of non-thermal effects of electricity on ascorbic acid and carotenoid degradation in acerola pulp during ohmic heating.

The effect of electric field on ascorbic acid and carotenoid degradation in acerola pulp during ohmic heating was evaluated. Ascorbic acid kinetic degradation was evaluated at 80, 85, 90 and 95°C during 60 min of thermal treatment by ohmic and conventional heating. Carotenoid degradation was evaluated at 90 and 95°C after 50 min of treatment. The different temperatures evaluated showed the same effect on degradation rates. To investigate the influence of oxygen concentration on the degradation process, ohmic heating was also carried out under rich and poor oxygen modified atmospheres at 90°C. Ascorbic acid and carotenoid degradation was higher under a rich oxygen atmosphere, indicating that oxygen is the limiting reagent of the degradation reaction. Ascorbic acid and carotenoid degradation was similar for both heating technologies, demonstrating that the presence of the oscillating electric field did not influence the mechanisms and rates of reactions associated with the degradation process.

Characterization of rice starch and protein obtained by a fast alkaline extraction method.

This study evaluated the characteristics of rice starch and protein obtained by a fast alkaline extraction method on rice flour (RF) derived from broken rice. The extraction was conducted using 0.18% NaOH at 30°C for 30min followed by centrifugation to separate the starch rich and the protein rich fractions. This fast extraction method allowed to obtain an isoelectric precipitation protein concentrate (IPPC) with 79% protein and a starchy product with low protein content. The amino acid content of IPPC was practically unchanged compared to the protein in RF. The proteins of the IPPC underwent denaturation during extraction and some of the starch suffered the cold gelatinization phenomenon, due to the alkaline treatment. With some modifications, the fast method can be interesting in a technological point of view as it enables process cost reduction and useful ingredients obtention to the food and chemical industries.

Pinhão starch and coat extract as new natural cosmetic ingredients: Topical formulation stability and sensory analysis.

The objective of this study was to use pinhão derivatives, starch and coat extract, as new natural ingredients to develop cosmetic formulations. Two types of formulation, gel and emulgel, and their controls were developed. The formulations were characterized by stability studies using thermal stress. The parameters analyzed were resistance to centrifugation, pH, spreadability, rheology, content of phenolic compounds and antioxidant activity. Sensory analysis was also performed to verify the acceptability of the ingredients to potential consumers. The pH was kept the same after heating/freezing cycles for all formulations, and the formulations showed stability by resistance to centrifugation. The formulations did not induce any skin irritation or cutaneous pH alteration. The pinhão starch addition improved spreadability stability and increased viscosity when compared with control formulations. The pinhão coat extract used in these formulations is a good source of phenolic compounds and antioxidant activity. Moreover, sensory analysis indicates that the emulgel formulation is the best vehicle for adding pinhão starch and pinhão coat extract.

Use of Different Kinds of Solutes Alternative to Sucrose in Osmotic Dehydration of Yacon

The present work aimed to evaluate glycerol, maltodextrin, polydextrose and sorbitol for the osmotic dehydration of yacon for diabetics, keeping its properties as prebiotic. Osmotic dehydration was carried out using a yacon to 33% concentrated syrup weight ratio of 1:12, with magnetic stirring at 23ºC and atmospheric pressure. The best results were achieved for glycerol and sorbitol with 80 ± 4% and 81± 1% of water removal and increase of 3.73 ± 0.11 and 4.30 ± 0.16 times in total soluble solids respectively. Maltodextrin did not promote dehydration.

Evaluation of non-thermal effects of electricity on anthocyanin degradation during ohmic heating of jaboticaba (Myrciaria cauliflora) juice.

This study investigated the non-thermal effects of electricity on anthocyanin degradation during ohmic heating of jaboticaba juice. For this, temperature profiles during conventional and ohmic heating processes were matched, and the degradation kinetics of anthocyanins were compared at temperatures ranging from 70 to 90°C. The monomeric anthocyanin content was quantified by UV-Visible spectroscopy using the pH-differential method. Anthocyanin degradation was fitted to a first-order model. The rate constants ranged from 1.7 to 7.5 × 10(-3)min(-1) and from 1.8 to 7.6 × 10(-3)min(-1) for ohmic and conventional heating, respectively. The analysis of variance (α=0.05) showed no significant differences between rate constants of the ohmic and conventional heating at the same temperatures. All kinetic and thermodynamic parameters evaluated showed similar values for both technologies. These results indicate that the presence of the oscillating electric field did not affect the degradation rates of anthocyanins during ohmic heating.

Effect of the electric field frequency on ascorbic acid degradation during thermal treatment by ohmic heating.

In this work, the influence of the electric field frequency and solids content on the degradation kinetics of ascorbic acid during ohmic heating of acerola pulp and acerola serum was investigated. The degradation percentage of ascorbic acid in the pulp after 120 min of heating varied between 12 and 17%. For the serum, the degradation percentage was in the range of 13 and 18%. The results were fitted to the first-order model, and the kinetic rate constants ranged from 1.1 to 1.6×10(-3) min(-1) and from 1.1 to 1.5×10(-3) min(-1) for pulp and serum, respectively. D values ranged between 1480 and 2145 min for the pulp and between 1524 and 1951 min for the serum. A distinct behavior between the kinetic parameters of the pulp and serum in electric field frequencies ranging from 10 to 1000 Hz indicates that the presence of distinct amounts and types of solids might affect the rate of the electron transfer in electrochemical reactions. These variables may also affect the polarization process stimulated by the oscillating electric field. The non-achievement of the equilibrium of the polarization process may have an influence on oxidation reactions, affecting the predisposition to hydrogen donation from the ascorbic acid molecule.

Caracterização física, química e sensorial de sobremesas à base de soja, elaboradas com mucilagem de chia / Physical, chemical and sensory characterization of soy-based desserts made with chia mucilage

No desenvolvimento de produtos, é de suma importância o conhecimento da influência das modificações da formulação nas propriedades sensoriais, físicas e químicas destes. O objetivo deste trabalho foi caracterizar sobremesas à base de soja com e sem adição de mucilagem de chia, utilizada como espessante alimentar. As formulações foram caracterizadas quanto as suas propriedades reológicas, °Brix, pH e cor. O perfil sensorial foi determinado por Análise Descritiva Quantitativa (ADQ), utilizando-se uma equipe de 10 julgadores treinados. Os resultados mostraram que as amostras não diferiram quanto aos valores de pH, °Brix e coordenada cromática a*. Quanto aos outros parâmetros de cor e reológicos, foram detectadas diferenças significativas entre as amostras, o que mostra a influência do tipo de espessante nestas características. Os resultados da ADQ mostraram que as amostras não apresentaram diferenças estatísticas quanto aos atributos, cor rosa, sabor de goiaba, sabor de soja e cremosidade, porém diferiram quanto à consistência. Com isso, conclui-se que a adição da mucilagem de chia pode ser feita sem causar grandes modificações ao produto.

In product development is important to study the influence of ingredients in the physical, chemical and sensory properties of the product. The aim of this study was to characterize soy-based desserts with and without addition of chia mucilage, used as food thickener. The formulations were characterized for their rheological properties, °Brix, pH and color. The sensory profile was determined by Quantitative Descriptive Analysis (QDA) using 10 trained judges. The results regarding to pH, ° Brix and color coordinate a* did not differ. Unlike these parameters, the other chromaticity coordinates and the rheological properties presented significant statistical differences between the samples. The QDA results showed that the samples did not differ as to the attributes, color, pink guava flavor, creaminess and flavor of soy, but differed in consistency. Thus, it is concluded that the addition of mucilage chia can be made without causing major changes to the product.

Degradation kinetics of anthocyanins in acerola pulp: comparison between ohmic and conventional heat treatment.

Degradation kinetics of monomeric anthocyanins in acerola pulp during thermal treatment by ohmic and conventional heating was evaluated at different temperatures (75-90°C). Anthocyanin degradation fitted a first-order reaction model and the rate constants ranged from 5.9 to 19.7 × 10(-3)min(-1). There were no significant differences between the rate constants of the ohmic and the conventional heating processes at all evaluated temperatures. D-Values ranged from 116.7 to 374.5 for ohmic heating and from 134.9 to 390.4 for conventional heating. Values of the free energy of inactivation were within the range of 100.19 and 101.35 kJ mol(-1). The enthalpy of activation presented values between 71.79 and 71.94 kJ mol(-1) and the entropy of activation ranged from -80.15 to -82.63 J mol(-1)K(-1). Both heating technologies showed activation energy of 74.8 kJ mol(-1) and close values for all thermodynamic parameters, indicating similar mechanisms of degradation.

Study on the stability of ß-carotene microencapsulated with pinhão (Araucaria angustifolia seeds) starch.

Native and hydrolyzed pinhão starches were used as coating materials for ß-carotene microencapsulation by freeze-drying. The purpose of the present study was to evaluate the stability of ß-carotene encapsulated under three different conditions: in the presence of ultraviolet light at 25±2 °C, in the dark at 25±2 °C and in the dark at 10.0±0.2 °C. The color of the samples was also analyzed. Microcapsules prepared with native starch showed the lowest stability during storage. In contrast, microcapsules encapsulated with 12 dextrose equivalent (DE) hydrolyzed starch exhibited the highest stability. First-order kinetic and Weibull models were applied to describe the degradation of ß-carotene over time. The R(2) values of the Weibull model were greater than those of the first-order kinetic model. Moreover, multivariate analyses (principal component and cluster analyses) were also conducted.

Degradation kinetics of anthocyanin in blueberry juice during thermal treatment.

The kinetics of anthocyanin degradation in blueberry juice during thermal treatment at 40, 50, 60, 70, and 80 degrees C were investigated in the present study. Anthocyanin degradation was analyzed up to the level of 50% retention using a pH differential method. The degradation of anthocyanin at each temperature level followed a first-order kinetic model, and the values of half-life time (t(1/2)) at temperatures of 40, 50, 60, 70, and 80 degrees C were found to be 180.5, 42.3, 25.3, 8.6, and 5.1 h, respectively. The activation energy value of the degradation of the 8.9 degrees Brix blueberry juice during heating was 80.4 kJ.mol(-1). The thermodynamic functions of activation (DeltaG, DeltaH, and DeltaS) have been determined as central to understanding blueberry degradation.