Traditional Thermal Treatment Research Articles

Improvement of radio frequency (RF) heating uniformity for peanuts with a new strategy using computational modeling

Radio frequency (RF) heating has been considered as an alternative method to traditional thermal treatments for postharvest pasteurization and disinfestations. However, the non-uniform heating in food samples is the main obstacle to be urgently solved. In this study, mica plates were placed on top of the samples with polypropylene blocks placed in between the samples as a new strategy to improve the RF heating uniformity. A computer simulation model was developed based on the commercial software COMSOL to evaluate the temperature distributions. Experiments with peanut samples placed in three dimensions of containers were conducted to validate the simulation model. The results showed that adding mica plates with the similar dimension to the cold spot of samples and increasing the plate thickness effectively improved the RF heating uniformity. Adding polypropylene blocks raised sample average temperatures and finally optimized the RF heating uniformity.

Effect of ultrasound and storage time on quality attributes of strawberry juice

AbstractThe aim of this study was to evaluate changes in quality attributes of non‐clarified strawberry juice during storage at 5 °C after ultrasonication at 40 kHz for 10 and 30 min in comparison with thermally treated juice at 90 °C for 60 s. Ultrasound treatments maintained color parameters with no significant differences (p < .05) from untreated sample, while thermally treated juice showed lower L* values and higher hue angles than the control. No significant differences in °Brix and total acidity were found between treated and untreated samples, and both parameters remained unchanged throughout storage. Compared to the control, ultrasound treatments showed no significant reductions on day 0 in mesophilic and psychrophilic bacteria, and yeast and molds counts. However, the treatments showed significant decrease in the microbial growth rate through storage time, and significant increase in both polyphenol content and antioxidant activity, compared to control.Practical applicationsWith today's tendency towards the consumption of nutritious and fresh‐like foods, non‐thermal treatments are gaining popularity. Among them, ultrasound has become a feasible alternative against traditional thermal treatments. Strawberry products are considered of great nutritional value, because of their high content in antioxidant compounds and vitamin C. In this study, ultrasound was evaluated in strawberry juice through storage time, where significant reductions on microbial growth rate were achieved; meaning that shelf‐life of the product was increased compared to control. Furthermore, physicochemical parameters were maintained through storage, and antioxidant capacity and polyphenol content showed a significant increment, which implies that nutritional value of the product was increased by ultrasound treatments. Therefore, sonication is a potential technology that can easily be applied at the fruit juice industry, replacing the traditional thermal treatment which compromises the organoleptical and nutritional quality of the final product.

Removal and recovery of o-xylene by silica gel using vacuum swing adsorption

The removal and recovery of o-xylene (a typical volatile organic compounds, VOCs) by silica gel has been systematically investigated by vacuum swing adsorption (VSA) process. Laboratory scale measurements show that the adsorption of o-xylene on silica gels could be significantly enhanced by increasing the height to diameter ratio (H/D) of adsorption bed, the inlet flowrate and o-xylene initial concentration. However, reducing the H/D and desorption pressure or increasing the amount of purging gas are observed to be favorable for the desorption of o-xylene from the silica gels. The optimized operational conditions are determined at 5:1 for H/D, 5kPa (absolute) of desorption pressure and 0.45L/min of purge gas flowrate. According to further kinetic fitting and analysis, it is found that the adsorption of o-xylene on this silica gel is film-diffusion control, which could be enhanced by increasing gas flowrate or initial o-xylene concentration. In addition, reducing the particle size of the silica gel is also found to increase the saturation of adsorbed o-xylene in silica gels. A scaled-up integrated VSA setup was applied to confirm the above results, leading to a complete o-xylene removal from the gas (100% removed) with 87% of o-xylene recovered directly as liquid. Based on a rough economic calculation, the VSA shows greater merits than those of traditional thermal treatment and absorption methods, due to its recovered VOCs as products. Additional tests by other aromatic VOCs further approved the feasibility of the VSA using silica gels. These findings indicate that the VSA with air cooling at ambient temperature would be a promising and ‘green’ technology for treating high boiling VOCs.

Alternatives to conventional thermal treatments in fruit-juice processing. Part 2: Effect on composition, phytochemical content, and physicochemical, rheological, and organoleptic properties of fruit juices

ABSTRACTTraditional thermal techniques may cause losses in nutritional quality and phytochemical contents, and also in physicochemical, rheological, and organoleptic properties of processed fruit juices. This paper provides an overview of the effect on these qualities by the use of alternatives to traditional thermal treatments in fruit-juice processing, for three key operations in fruit-juice production such as microbial inactivation, enzyme inactivation, and juice-yield improvement. These alternatives are UV light, high-intensity light pulses, γ-irradiation, pulsed electric fields, radiofrequency electric fields, Ohmic heating, microwave heating, ultrasound, high hydrostatic pressure, supercritical carbon dioxide, ozonation, and flash-vacuum expansion. Although alternatives to heat treatments seem to be less detrimental than the thermal treatment, there are many parameters and conditions that influence the output, as well as the nature of the juice itself, hampering comparisons between different studies. Additionally, future research should focus on understanding the mechanisms underlying the changes in the overall quality of fruit juices, and also on scaled-up processes, process design, and optimization that need to be deal with in detail to maximize their potential as alternative nonthermal technologies in fruit-juice processing while maintaining fruit-juice attributes to the maximum.

Individual and Combined Effects of Pomegranate Extract and Ultrasonic Treatments on Kiwifruit Juice Quality Parameters

AbstractThe objectives of this study were to report the effectiveness of ultrasound and pomegranate extract, individually and combined, on kiwifruit juice quality attributes. Fruit juices were treated with 180 μg/mL pomegranate extract and sonicated for 10 and 30 min (180 W, 40 kHz). Microbial populations, ascorbic acid retention, sensory attributes and color parameters were evaluated through refrigerated storage. By the end of storage, individual ultrasound treatments were able to reduce yeast and molds counts compared with that in control. Furthermore, combined treatments of ultrasound and pomegranate extract showed synergism, with higher reductions on yeast and molds. None of the treatments were able to increase the ascorbic acid retention through storage time. Color parameters evaluated showed that the treatments applied had significant differences from that of control. At Day 2, the treatments showed an improvement in color, with total color difference (ΔE) lower than that of untreated sample, indicating less color difference from fresh kiwifruit juice. Sensory attributes were not significantly affected by the treatments. However, a significant effect of storage time was perceived by the panelists, with a decrease in overall visual quality score throughout time, indicating the end of shelf‐life of the product at Day 7 of refrigerated storage.Practical ApplicationsUltrasonic processing technology and the application of natural antimicrobials are continuously being explored as alternatives to traditional thermal treatments in the food industry. It is necessary to study the impact of these technologies both individually and combined, in terms of microbiological stability and quality preservation. In practice, it is important to not only decrease the microbial growth on food products, but also minimize the loss of their nutritional and sensory attributes. This study suggests some processing and preservation conditions for kiwifruit juice, demonstrating the potential use of ultrasound in combination with the application of pomegranate extract as a biopreservative. This hurdle technology could be easily introduced in the fruit and vegetable juice industry, replacing thermal treatments that compromise the nutritional and sensory quality of the final product.

Citric acid facilitated thermal treatment: An innovative method for the remediation of mercury contaminated soil

Thermal treatment is a promising technology for the remediation of mercury contaminated soils, but it often requires high energy input at heating temperatures above 600°C, and the treated soil is not suitable for agricultural reuse. The present study developed a novel method for the thermal treatment of mercury contaminated soils with the facilitation of citric acid (CA). A CA/Hg molar ratio of 15 was adopted as the optimum dosage. The mercury concentration in soils was successfully reduced from 134mg/kg to 1.1mg/kg when treated at 400°C for 60min and the treated soil retained most of its original soil physiochemical properties. During the treatment process, CA was found to provide an acidic environment which enhanced the volatilization of mercury. This method is expected to reduce energy input by 35% comparing to the traditional thermal treatment method, and lead to agricultural soil reuse, thus providing a greener and more sustainable remediation method for treating mercury contaminated soil in future engineering applications.

Electrically tunable pore morphology in nanoporous gold thin films

Nanoporous gold (np-Au) is an emerging nanostructured material that exhibits many desirable properties, including high electrical and thermal conductivity, high surface area-to-volume ratio, tunable pore morphology, well-established surface-binding chemistry, and compatibility with microfabrication. These features make np-Au a popular material for use in fuel cells, optical and electrical biosensors, drug delivery vehicles, neural electrode coatings, and as a model system for nanoscale mechanics. In each of its many applications, np-Au morphology plays an essential role in the overall device operation. Therefore, precise morphological control is necessary to attain optimal device performance. Traditionally, thermal treatment by furnaces and hot plates is used to obtain np-Au with self-similar but coarser morphologies. However, this approach lacks the ability to create different morphologies on a single substrate and requires high temperatures (> 250 °C) incompatible with most plastic substrates. Herein, we report electro-annealing as a novel method that permits control of the extent and location of pore coarsening on a single substrate in one fast treatment step. The electro-annealing entails much lower temperatures (< 150 °C) than traditional thermal treatment, putatively due to electrically assisted phenomena contributing to the thermally activated surface diffusion of gold atoms, responsible for coarsening. Overall, this approach is easily scaled to display multiple pore morphologies on a single chip, therefore enabling high-throughput screening of optimal nanostructures for specific applications.

Photocatalytic oxidation of cytostatic drugs by microwave‐treated N‐doped TiO2 under visible light

AbstractBACKGROUND5‐Fluorouracil is one of the most commonly used cytostatic drugs worldwide. However, the toxicity and persistence of 5‐fluorouracil in the environment have recently received considerable attention. In this study, 5‐fluorouracil removal was performed by photocatalytic oxidation with microwave‐treated N‐doped TiO2 under visible light.RESULTSThe microwave‐treated N‐doped TiO2 removed 5‐fluorouracil with a higher degradation efficiency than N‐doped TiO2 synthesized with the traditional thermal treatments. The most efficient N‐doped TiO2 (N6) was synthesized using 1 M NH4OH pre‐immersion and a 3 h 180°C microwave treatment, followed by 55°C calcination for 6 h. The photocatalytic degradation of 5‐fluorouracil achieved 88.8% removal within 20 h of treatment by N6 under visible light, which is higher than that obtained by Degussa P25 TiO2 (61.5%). Higher concentrations of NH4OH and longer calcination times resulted in decreased 5‐fluorouracil degradation; the particle size of the synthesized N‐doped TiO2 increased after calcination. The surface area decreased while the pore volume and pore size increased after synthesis. Furthermore, the basicity of the sites on the synthesized N‐doped TiO2 decreased after calcination.CONCLUSIONThis study, for the first time, reported that microwave‐assisted treatment for N‐doped TiO2 synthesis effectively removed 5‐fluorouracil and cyclophosphamide compared with traditional thermal treatment. © 2014 Society of Chemical Industry

Effect of a different high pressure thermal processing compared to a traditional thermal treatment on a red flesh and peel plum purée

Abstract The effect of the application of different high pressure thermal (HPT) treatments on the instrumental color, the activity of the polyphenoloxidase (PPO) enzyme, bioactive compounds (total polyphenols and anthocyanins) content and the antioxidant activity were was evaluated after processing a red flesh and peel plum puree and compared to an equivalent thermal treatment (TT). Different pressure levels (300, 600, and 900 MPa) at different initial processing temperatures (60, 70, and 80 °C) were applied. HPT treatments produced a similar inactivation of the PPO as the TT (~ 50%). In addition, HPT treatment was more effective than the TT in preserving the original colour, the anthocyanins content and the antioxidant activity of the processed purees. The application of pressures at 600 MPa combined with initial temperatures of 70 °C was the treatment which gave the highest inactivation of the PPO and best maintained the bioactive compounds of purees. Industrial relevance The exploration of new technologies, such as the combination of pressure and heating for short times (high pressure thermal or HPT treatments), could be a new way to extend the shelf-life of fruit-derived products. HPT treatments can better preserve bioactive compared to most traditional thermal treatment. While there are currently no HPT-processed shelf-stable foods commercially available, it's possible to provide a viable process for heat-sensitive products such as fruit-derived products that would suffer a severe loss of quality by the application of a traditional thermal process. A previous study (Gonzalez-Cebrino et al., 2013) showed that high pressure processing (HPP) did not inactivate polyphenoloxidase enzyme in plum puree. Results of this paper could allow production of a plum puree with an enzyme activity similar to a thermally treated puree.

Chemical Reactions in Food Systems at High Hydrostatic Pressure

The combination of high hydrostatic pressure and temperature has become a valuable alternative to produce superior quality products in cases where the traditional thermal treatments have failed to deliver high-quality products. Unfortunately, the impact of pressure on chemical reactions in food systems is often overlooked. This review summarizes studies on chemical reactions in various food systems that have been qualitatively and quantitatively evaluated under high pressure at either ambient, moderate, or elevated temperatures. In addition, a critical discussion on the current approaches was used to evaluate the reaction rates, and therefore, the reaction mechanisms of some food systems are provided. Activation volume and activation energy of various food systems treated by high hydrostatic pressure are also provided. Finally, the need of kinetic studies in food systems is highlighted.

Low‐Temperature Synthesis of Crystalline Inorganic/Metallic Nanocrystal‐Halloysite Composite Nanotubes

AbstractWe have demonstrated a facile approach for the low‐temperature synthesis of crystalline inorganic/metallic nanocrystal‐halloysite composite nanotubes by employing the bulk controlled synthesis of inorganic/metallic nanocrystals on halloysite nanotubes. The halloysite clay nanotubes can adsorb the target precursor and induce inorganic/metallic nanocrystals to grow in situ. The crystalline phase and morphology of the composite clay nanotubes is tunable. By simply tuning the acidity of the titania sol, the crystalline titania‐clay nanotubes with tunable crystalline phases of anatase, a mixture of anatase and rutile or rutile are achieved. The approach is general and has been extended to synthesize the representative perovskite oxide (barium and strontium titanate)‐halloysite composite nanotubes. Metallic nickel nanocrystal can also be grown on the surface of halloysite nanotubes at low temperature. The traditional thermal treatment for crystallite transformation is not required, thus intact contour of halloysite nanotubes and the crystallinity structure of halloysite nanotubes can be guaranteed. The combined properties from inorganic/metallic nanocrystal (high refractive index, high dielectric constant and catalytic ability) and the halloysite clay nanotubes are promising for applications such as photonic crystals, high‐k‐gate dielectrics, photocatalysis and purification.

Effect of ion irradiation on tensile ductility, strength and fictive temperature in metallic glass nanowires

Ion irradiation of thermoplastically molded Pt57.5Cu14.3Ni5.7P22.5 metallic glass nanowires is used to study the relationship between glass structure and tensile behavior across a wide range of structural states. Starting with the as-molded state of the glass, ion fluence and irradiated volume fraction are systematically varied to rejuvenate the glass, and the resulting plastic behavior of the metallic glass nanowires probed by in situ mechanical testing in a scanning electron microscope. Whereas the as-molded nanowires exhibit high strength, brittle-like fracture and negligible inelastic deformation, ion-irradiated nanowires show tensile ductility and quasi-homogeneous plastic deformation. Signatures of changes to the glass structure owing to ion irradiation as obtained from electron diffraction are subtle, despite relatively large yield strength reductions of hundreds of megapascals relative to the as-molded condition. To reconcile changes in mechanical behavior with glass properties, we adapt previous models equating the released strain energy during shear banding to a transit through the glass transition temperature by incorporating the excess enthalpy associated with distinct structural states. Our model suggests that ion irradiation increases the fictive temperature of our glass by tens of degrees – the equivalent of many orders of magnitude change in cooling rate. We further show our analytical description of yield strength to quantitatively describe literature results showing a correlation between severe plastic deformation and hardness in a single glass system. Our results highlight not only the capacity for room temperature ductile plastic flow in nanoscaled metallic glasses, but also processing strategies capable of glass rejuvenation outside of the realm of traditional thermal treatments.

Design and Characterization of High-Performance Electrodes for Dye-Sensitized Solar Cells

Dye-sensitized solar cells (DSSC) have attracted much attention recently due to its potential as a cost-effective alternative for silicon-based solar cells. Three major components are involved to make a highly efficient DSSC: a working electrode containing dye-sensitized nanostructured TiO2 layers, a counter electrode containing platinum-coated TCO substrate, and a composite electrolyte solution to fill between the two electrodes. In this lecture, I will present our recent developments on novel electrodes for highly efficient DSSC. For the counter electrodes, novel platinum nanostructures were fabricated according to a cyclic electro-deposition (CED) method for the Pt films with uniform nanograss structure having great electro-catalytic performance and intrinsic light-scattering, perfectly suitable for use as counter electrodes for DSSC. we have developed a strategy of nanofabrication to prepare monolayers of platinum nanoparticles self-assembled on a rough surface of TCO in two steps: first, preparation of a well dispersed Pt NP solution from polyol reduction at a pH well controlled on adding NaOH; second, dipping the SAM-functionalized TCO substrate, prepared beforehand using ‘piranha’ and MPTMS surface treatments in turn, into the Pt NP solution near 295 K to complete the fabrication of the SAM-Pt CE for DSSC. The uniform SAM-Pt film with a narrow distribution of size can be produced on TCO without a stabilizer, so that the traditional thermal treatment at high temperatures is no longer necessary. The uniform nature of the SAM-Pt film has the advantages of minimizing the amounts of Pt loading and optimizing the catalytic function on the TCO surface. The DSSC devices prepared according to this SAM-Pt approach attained notable photovoltaic performance (η = 9.2 %) comparable to those fabricated with a conventional TD method (η = 9.1 %) or a CED method (η = 9.3 %) under the same experimental conditions. For the working electrodes, we constructed photoanodes, containing titania nanostructures of varied types – spherical nanoparticles (NP), one-dimensional nanorods (NR), and octahedron-like nanocrystals of varied size (HD1-HD3), in either a bi-layer (BL) or a multi-layer (ML) film configuration. The ML devices were fabricated based on the NP-BL system with additional HDP layers inserted between the two components, NP and SL, to enhance J SC so as to attain the best performance, with efficiency of power conversion (PCE) = 10.1 %, at film thickness (L) 26 mm. Because of the robust structural feature of the HD films, the devices fabricated with a simple BL film configuration, HD1/SL = 6/3, exhibited the best performance, PCE = 10.2 % at L = 29 mm, which is a promising advance for Z907-based solar cells with a superior and enduring stability of performance for commercialization.

Influence of low-energy plasma annealing on structural and optical properties of silver nanoclusters grown by magnetron sputtering deposition

Structural and optical modifications induced by low-energy (≤80 eV) bias-plasma annealing of silver nanoclusters (2–25 nm) grown by magnetron sputtering deposition are reported. By combining postmortem structural characterizations and real-time optical measurements, we show that etching effects associated with enhanced Ag mobility result in progressive and irreversible changes of both the morphology and organization of the nanoclusters (i.e., decrease of the cluster size and intercluster distance as well as increase of their out-of-plane aspect ratio). Surface plasmon resonance bands of the nanoclusters are also modified by plasma treatment, which causes a blue-shift together with an amplitude decrease and a narrowing of the band. In addition, the kinetics of plasma-induced modifications can be easily controlled by varying the applied bias voltage. Therefore, plasma annealing could emerge as an efficient alternative to more traditional thermal annealing treatments for tuning the plasmonic properties of noble metal nanoclusters with great flexibility.

Hydrogen engineering via plasma immersion ion implantation and flash lamp annealing in silicon-based solar cell substrates

Higher conversion efficiencies while reducing costs at the same time is the ultimate goal driving the advancement of solar cell development. In this work, solar cell emitters are formed in Si substrates by plasma immersion ion implantation (PIII) of phosphine and posterior millisecond-range flash lamp annealing (FLA). In Si-based solar cells, hydrogen plays a fundamental role due to its excellent passivation properties. The optical and electrical properties of the fabricated emitters will be studied, with particular interest in their dependence on the hydrogen content present in the samples. The influence of different FLA annealing parameters and a comparison with traditional thermal treatments such as rapid thermal annealing (RTA) and furnace annealing (FA) will be presented. The samples treated by FLA at 1200 °C for 20 ms in forming gas show sheet resistance values of the order of 60 Ω/◻, and minority carrier diffusion lengths in the range of ∼200 μm without the use of a capping layer for surface passivation. Those results are significantly better than the ones observed from RTA or FA annealed samples. The simultaneous implantation of hydrogen during the doping process, combined with optimal FLA annealing parameters, gave promising results for the application of this technology in replacing the conventional POCl3 deposition and diffusion.

Comparative effect of high pressure processing and traditional thermal treatment on the physicochemical, microbiology, and sensory analysis of olive jam

In the present work the effect of the processing by high hydrostatic pressures (HPP) was assessed as an alternative to the thermal treatment of pasteurization in olive jam. The effects of both treatments on the product after processing were compared and stability during storage under refrigeration was assessed through the characterization of physicochemical, microbiological and sensory aspects. To assess the effect of processing, two HPP treatments (450 and 600MPa) and thermal pasteurization (80 °C for 20 min) were applied, comparing them with the unprocessed product. HPP 600MPa versus the rest of treatments showed a reduction in microorganisms, greater clarity and less browning, and sensory acceptance. The shelf-life of the refrigerated product would indicate the feasibility of the application of the HPP technology for food with similar shelf-life to that obtained with the traditional treatment of pasteurization, but with a better sensory quality.

Effect of Hydrostatic High Pressure and Thermal Treatments on Two Types of Pumpkin Purée and Changes during Refrigerated Storage

High pressure processing (HPP) is an alternative to the traditional thermal treatment. The physicochemical composition, instrumental color and bioactive compounds (carotenoid and phenolic compounds) were evaluated in two pumpkin purées after processing (HPP: 400–600 MPa and thermal treatment) and after storage. One sample of purée was taken in the industry after the first sieve and before the thermal blanching, and the other was taken after deaeration and before pasteurization. HPP of pumpkin purée presented some advantages compared to the thermal treatment such as lower color modifications after processing and during storage, and higher nutritional value (some carotenoid and polyphenol contents were higher in HPP). The application of initial pretreatments reduces the original color intensity of the purées, and thus diminishes the differences of HPP and the thermal treatment in this aspect. However, the application of pretreatments is a necessary step for the stabilization of pumpkin purées during storage. Practical Applications Hydrostatic high pressure is a real alternative to thermal processing in determinate food products. Every year, new high pressure-processed products are in the market. However, only a few studies have evaluated the application of this technology in an industrial line of vegetable processing, which present some particularities (thermal pretreatments and additives are usually added). This paper presents valuable information for the application of high pressure processing at industrial level.

Effect of High‐Pressure Processing and Thermal Treatment on Quality Attributes and Nutritional Compounds of “Songold” Plum Purée

The application of hydrostatic high pressure on a "Songold" plum purée was assessed in comparison with heat pasteurization. To simulate industrial conditions, one-half of the total purée was manufactured with a pretreatment of thermal blanching (TB) and the other half without it (nonthermally blanched, NTB). Changes after thermal treatment and high-pressure processing (HPP: 400, 600 MPa) and after 20 d of refrigerated storage were evaluated. HPP maintained the microbial stability of the purées until the end of the storage period. Polyphenol oxidase activity was lower in TB purées than NTB purées. No treatment was completely effective to stop the enzyme activity, although a significant reduction was reached. Thermally treated purées showed more intense color changes after processing and storage than HP-treated purées. After processing, high-pressure (HP) purées treated at 600 MPa (TB and NTB) increased the extractability of carotenoids compared with initial untreated purée. Nevertheless, at the end of the storage, the highest carotenoid content was found in the TB purée treated at 400 MPa. After processing, total polyphenol levels were similar in all purées. TB and 600 MPa processing was more effective in the maintenance of the polyphenols than the other purées. TB increased the level of antioxidants after storage, compared to NTB purées. A previous TB step is necessary to inactivate browning enzymes before HPP to maintain the levels of bioactive compounds. HPP of plum purée could be a suitable alternative to traditional thermal processing, but more studies are necessary to ensure a major inactivation of polyphenol oxidase. High-pressure processing is one of the most successful technologies to obtain high-quality fruit purées without appreciable losses in taste, flavor, color, and nutritive value. However, for the introduction of a new technology, some advantages compared to the traditional thermal treatment need to be emphasized. The application of this technology could be reduced due to resistance of certain enzymes to pressurization. For this reason, in some cases the application of a previous thermal blanching can be necessary at industrial level. However, this can reduce the advantages of HPP application. This paper provides interesting information about the storage stability of plum purées after high-pressure treatments and assesses the need for applying heat pretreatments.

Efecto de las altas presiones hidrostáticas respecto a la pasteurización térmica en los aspectos microbiológicos, sensoriales y estabilidad oxidativa de un paté de aceituna

The present study examines the effect of high hydrostatic pressure processing (HHP) as an alternative to thermal pasteurization treatments for the conservation of olive pate and its stability during refrigerated storage, through the characterization of microbiological, physico-chemical and sensory aspects. The olive pate was made with green, pitted table olives packed in brine. Orange juice, olive oil, spices and potassium sorbate were added to the olives after being washed in water. To evaluate the effects of processing, four treatments of APH (450 and 600MPa for 5 and 10 min) and a thermal pasteurization (80 °C for 20 min) were applied to compare them with the unprocessed product. APH-treated samples showed a further reduction in the presence of microorganisms, an increase in oxidative stability, a higher sensory acceptance, greater clarity and less browning regarding the colorimetric coordinates, in comparison with those treated by thermal pasteurization. The study of the shelf life of the product in refrigeration would indicate the feasibility to implement APH technology in order to obtain food with a similar shelf life to foods obtained through the traditional thermal pasteurization treatment, but with better sensory quality.

Systematic Study on the Effect of Solvent Removal Rate on the Morphology of Solvent Vapor Annealed ABA Triblock Copolymer Thin Films

Nanoscale self-assembly of block copolymer thin films has garnered significant research interest for nanotemplate design and membrane applications. To fulfill these roles, control of thin film morphology and orientation is critical. Solvent vapor annealing (SVA) treatments can be used to kinetically trap morphologies in thin films not achievable by traditional thermal treatments, but many variables affect the outcome of SVA, including solvent choice, total solvent concentration/swollen film thickness, and solvent removal rate. In this work, we systematically examined the effect of solvent removal rate on the final thin film morphology of a cylinder-forming ABA triblock copolymer. By kinetically trapping the film morphologies at key points during the solvent removal process and then using successive ultraviolet ozone (UVO) etching steps followed by atomic force microscopy (AFM) imaging to examine the through-film morphologies of the films, we determined that the mechanism for cylinder reorientation from substrate-parallel to substrate-perpendicular involved the propagation of changes at the free surface through the film toward the substrate as a front. The degree of reorientation increased with successively slower solvent removal rates. Furthermore, the AFM/UVO etching scheme permitted facile real-space analysis of the thin film internal structure in comparison to cross-sectional transmission electron microscopy.