Energy relaxation of N2O in gaseous, supercritical, and liquid xenon and SF6

Rotational and vibrational energy relaxation (RER and VER) of N2O embedded in xenon and SF6 environments ranging from the gas phase to the liquid, including the supercritical regime, is studied at a molecular level. Calibrated intermolecular interactions from high-level electronic structure calculations, validated against experiments for the pure solvents, were used to carry out classical molecular dynamics simulations corresponding to experimental state points for near-critical isotherms. The computed RER rates in low-density solvents of krotXe=(3.67±0.25)×1010 s-1 M-1 and krotSF6=(1.25±0.12)×1011 s-1 M-1 compare well with the rates determined by the analysis of two-dimensional infrared experiments. Simulations find that an isolated binary collision description is successful up to solvent concentrations of ∼4 M. For higher densities, including the supercritical regime, the simulations do not correctly describe RER, probably due to the neglect of solvent-solute coupling in the analysis of the rotational motion. For VER, the near-quantitative agreement between simulations and pump-probe experiments captures the solvent density-dependent trends.

Experimental and theoretical characterization of the release kinetic of carvacrol as inclusion complexes with β-cyclodextrin in poly(lactic acid) and Mater-Bi® processed by supercritical impregnation

The incorporation of active compounds into polymeric matrices using traditional methods has several drawbacks mainly due to the high volatility and thermal sensitivity of these substances. A solution to this problem could be the incorporation of bioactive compounds forming inclusion complexes as a strategy to improve the chemical stability, bioactivity and achieve controlled release. In this work, β-cyclodextrin/carvacrol inclusion complex was prepared by spray drying to be incorporated into poly(lactic acid) (PLA) and Mater-Bi® films by supercritical CO2 impregnation. The impregnation process was carried out at pressures of 10, 15 and 20 MPa and at 40 °C. Both polymers showed the highest amount of incorporated inclusion complex at 15 MPa, where the percentage of impregnation varied from 0.6 % to 7.1 % in Mater-Bi® and PLA, respectively. Release tests for PLA films impregnated with inclusion complex showed a slow release of the active compound, which did not reach equilibrium after 350 h under the experimental conditions. This prolonged release was not observed in Mater-Bi® due to the lower incorporation of the inclusion complex. The release rate was described herein by a comprehensive phenomenological model considering the decomplexation kinetics combined with the equilibrium and mass transfer expressions.

Characterisation of flavourous sesame oil obtained from microwaved sesame seed by subcritical propane extraction

This study developed a novel and green method to produce fragrant sesame oil using microwaves and subcritical extraction (SBE). Sesame seeds were microwaved at 540 W for 0-9 min before subcritical propane extraction at 40 °C and 0.5 MPa. SBE caused less deformation to the cellular microstructure of sesame cotyledons while dramatically improving oil yield (96.7-97.1 %) compared to screw processing (SP) (53.1-58.6 %). SBE improved extraction rates for γ-tocopherol (381.1-454.9 μg/g) and sesame lignans (917.9-970.4 mg/100 g) in sesame oil compared to SP (360.1-443.8 μg/g and 872.8-916.8 mg/100 g, respectively). Microwaves generated aroma-active heterocyclics and phenolics faster than hot-air roasting in sesame oil with a better sensory profile. SBE had a higher extraction rate for aroma-active terpenes, alcohols, and esters while reducing the concentrations of carcinogenic PAHs and HCAs in sesame oil. The novel combination process of microwaves and subcritical extraction is promising in producing fragrant sesame oil with superior qualities.

Effect of Operational Variables on Supercritical Foaming of Caffeic Acid-Loaded Poly(lactic acid)/Poly(butylene adipate-co-terephthalate) Blends for the Development of Sustainable Materials

Expanded polystyrene will account for 5.3% of total global plastic production in 2021 and is widely used for food packaging due to its excellent moisture resistance and thermal insulation. However, some of these packages are often used only once before being discarded, generating large amounts of environmentally harmful plastic waste. A very attractive alternative to the conventional methods used for polymer processing is the use of supercritical carbon dioxide (scCO2) since it has mass-transfer properties adapted to the foam morphology, generating different path lengths for the diffusion of active compounds within its structure and can dissolve a wide range of organic molecules under supercritical conditions. The objective of this research was to evaluate the effect of operational variables on the process of caffeic acid (CA) impregnation and subsequent foaming of polylactic acid (PLA) as well as two PLA/poly(butylene-co-terephthalate-adipate) (PBAT) blends using scCO2. The results showed an increase in the degree of crystallinity of the CA-impregnated samples due to the nucleation effect of the active compound. On the other hand, SEM micrographs of both films and foams showed significant differences due to the presence of PBAT and its low miscibility with PLA. Finally, the results obtained in this work contribute to the knowledge of the important parameters to consider for the implementation of the impregnation and foaming process of PLA and PLA/PBAT blends with potential use in food packaging.

Carotenoids and Fatty Acids Obtained from Paprika Capsicum annuum by Supercritical Carbon Dioxide and Ethanol as Co-Extractant

Paprika Capsicum annuum L. contains useful molecules such as carotenoids and polyunsaturated fatty acids, which are considered high-value functional and health ingredients. To obtain these compounds, paprika was extracted using different methods (Soxhlet, SC-CO_2, and SC-CO₂ with co-extractant) and at different parameters. The results showed that the carotenoid content decreased with the addition of the co-extractant while the fatty acid content and yield increased. It was found that the highest carotenoid content (capsanthin > β-carotene > capsorubin > zeaxanthin > β-cryptoxanthin > violaxanthin) was obtained at 50 °C/45 MPa for SC-CO₂ extraction. Paprika extract rich in polyunsaturated fatty acids (linoleic, oleic, and α-linolenic acid) was obtained at 40 °C/25 MPa for SC-CO₂ with co-extractant. The PUFA/SFA ratios for paprika extract were in agreement with the recommendations of nutritional guidelines. The use of SC-CO₂ for the extraction of Capsicum annuum allowed us to obtain a high-quality, rich in carotenoids and polyunsaturated fatty acids, extract that can be used as a substrate in the industry.

Structural modification of plum (Prunus domestica L) kernel protein isolate by supercritical carbon-dioxide treatment: Functional properties and in-vitro protein digestibility

The effect of supercritical carbon dioxide (SC-CO₂) treatment at different processing temperatures (30-70 °C) on the physico-functional properties, structural features, and in-vitro digestibility (IVPD) of plum kernel protein isolates (PKPI) was examined. The results revealed remarkable changes in the secondary structures of SC-CO₂-treated PKPIs, including a decrease in α-helix proportion, a concomitant increase in β-sheet content, and a considerable variation in random coils and β-turn structures. The temperature rise increased the negative zeta potential to a maximum of 31.35 mV at 60 °C, exhibiting the colloidal stability of PKPI dispersions. SDS-PAGE analysis showed variations in the intensities of protein bands, indicating denaturation and aggregation at higher temperatures. These structural and molecular changes improved water-binding capacity (1.22-fold) and oil binding capacity (1.11-fold), wettability (1.12-fold), and the highest value in all the properties was recorded at 60 °C. Moreover, the highest IVPD value (21.58 %) and a distinguishable colour difference (∆E) of 8.11 was also obtained at 60 °C of the processing temperature. Therefore, SC-CO₂ treatment-induced modification of PKPI contributed to the enhanced digestibility and techno-functional properties, which offered new prospects to extend its use in food applications.

Investigating the Effect of Supercritical Carbon Dioxide Treatment on the Rheological, Thermal, and Functional Properties of Plum (Prunus domestica L.) Kernel Protein Isolates

Plum kernels are a promising source of dietary proteins that are irretrievably lost during processing. The recovery of these underexploited proteins could be eminently vital for human nutrition. Plum kernel protein isolate (PKPI) was prepared and exposed to a targeted supercritical carbon dioxide (SC-CO₂) treatment to diversify its effectiveness in industrial applications. The impacts of SC-CO₂ treatment at different processing temperatures (30-70 °C) on dynamic rheology, microstructure, thermal, and techno-functional characteristics of PKPI were investigated. The results revealed that the dynamic viscoelastic characteristics of SC-CO₂-treated PKPIs showed higher storage modulus, loss modulus, and lower tan δ value than native PKPI, indicating greater strength and elasticity of the gels. Microstructural analysis showed that the proteins experienced denaturation at elevated temperatures and resulted in the formation of soluble aggregates, which increased the heat requirement for thermal denaturation of SC-CO₂-treated samples. SC-CO₂-treated PKPIs demonstrated a decline of 20.74% and 30.5% in crystallite size and crystallinity. PKPIs treated at 60 °C showed the highest dispersibility, which was 1.15-fold higher than the native PKPI sample. SC-CO₂ treatment offers a novel path to improve the techno-functional properties of PKPIs and extend its use in food and non-food applications.

Improved Sustainability in Wine Industry Byproducts: A Scale-up and Economical Feasibility Study for High-Value Compounds Extraction Using Modified SC-CO2

The objective of the present work was to optimize the operating conditions (P, T cosolvent %) and to study the scale-up and the feasibility of the supercritical fluid extraction (SFE) process for polyphenols from grape pomace, the main solid byproduct of the wine industry. Pilot-scale equipment (1 L extraction vessel) was used to study the scale-up prediction for extraction vessels of 50, 100, 500, and 1000 L capacity. The adopted scale-up criteria consisted of maintaining and keeping constant the solvent mass-to-feed mass ratio and the bed geometry dimension. The results indicated an excellent predictive level obtained by Sovová's model and success of the adopted scale-up criteria. At industrial scale, yields were close to 2.3 g_GAE/100 g_DM, a value obtained using the pilot-scale equipment. High concentrations of high-added-value phenols such as cis-resveratrol glucoside, cis-coutaric acid, trans-p-coumaric acid, quercetin, and proanthocyanidins were found in the extract. An economic evaluation of the process indicated the feasibility of an industrial SFE plant with a capacity of 500 L for producing in 60 min an extract with an expected phenolics' concentration of approximately 133 g_GAE/kg _extract at an estimated 67€ /kg_extract cost of manufacturing. Notably, all values are better than those currently reported in the literature.

Extraction of High-Value Chemicals from Plants for Technical and Medical Applications

Plants produce a variety of high-value chemicals (e.g., secondary metabolites) which have a plethora of biological activities, which may be utilised in many facets of industry (e.g., agrisciences, cosmetics, drugs, neutraceuticals, household products, etc.). Exposure to various different environments, as well as their treatment (e.g., exposure to chemicals), can influence the chemical makeup of these plants and, in turn, which chemicals will be prevalent within them. Essential oils (EOs) usually have complex compositions (>300 organic compounds, e.g., alkaloids, flavonoids, phenolic acids, saponins and terpenes) and are obtained from botanically defined plant raw materials by dry/steam distillation or a suitable mechanical process (without heating). In certain cases, an antioxidant may be added to the EO (EOs are produced by more than 17,500 species of plants, but only ca. 250 EOs are commercially available). The interesting bioactivity of the chemicals produced by plants renders them high in value, motivating investment in their production, extraction and analysis. Traditional methods for effectively extracting plant-derived biomolecules include cold pressing and hydro/steam distillation; newer methods include solvent/Soxhlet extractions and sustainable processes that reduce waste, decrease processing times and deliver competitive yields, examples of which include microwave-assisted extraction (MAE), ultrasound-assisted extraction (UAE), subcritical water extraction (SWE) and supercritical CO2 extraction (scCO2). Once extracted, analytical techniques such as chromatography and mass spectrometry may be used to analyse the contents of the high-value extracts within a given feedstock. The bioactive components, which can be used in a variety of formulations and products (e.g., displaying anti-aging, antibacterial, anticancer, anti-depressive, antifungal, anti-inflammatory, antioxidant, antiparasitic, antiviral and anti-stress properties), are biorenewable high-value chemicals.

Supercritical Fluid and Conventional Extractions of High Value-Added Compounds from Pomegranate Peels Waste: Production, Quantification and Antimicrobial Activity of Bioactive Constituents

This study is focused on different extractions (Cold Maceration (CM), Ultrasonic Extraction (UE), Soxhlet Extraction (SE) and Supercritical Fluid Extraction (SFE)) of bioactive compounds from pomegranate (Punica Granatum L.) fruit peels using methanol, ethanol, and acetone as solvents in conventional extractions and changing operating pressure (10, 15, 20, 25 MPa) in SFE, respectively. The extraction yields, total phenols (TP) and proanthocyanidins (PAC) contents, and antioxidant activity of different extracts are revealed. TP and PAC recovered by extracts ranged from 24.22 to 42.92 mg gallic acid equivalents (GAE)/g and 2.01 to 5.82 mg PAC/g, respectively. The antioxidant activity of extracts ranged from 84.70% to 94.35%. The phenolic compound identification and quantification in selective extracts was done using the LC-MS/MS method. The contents of different flavonoids and phenolic acids have been determined. SFE extract, obtained at 20 MPa, contained the highest content (11,561.84 μg/g) of analyzed total polyphenols, with predominant ellagic acid (7492.53 μg/g). For the first time, Microbial Growth Inhibition Rates (MGIRs) were determined at five different concentrations of pomegranate SFE extract against seven microorganisms. Minimal Inhibitory Concentration (MIC₉₀) was determined as 2.7 mg/mL of SFE pomegranate peel extract in the case of five different Gram-negative and Gram-positive bacteria.

Lignocellulose-Degrading Enzymes: A Biotechnology Platform for Ferulic Acid Production from Agro-Industrial Side Streams

Biorefining by enzymatic hydrolysis (EH) of lignocellulosic waste material due to low costs and affordability has received enormous interest amongst scientists as a potential strategy suitable for the production of bioactive ingredients and chemicals. In this study, a sustainable and eco-friendly approach to extracting bound ferulic acid (FA) was demonstrated using single-step EH by a mixture of lignocellulose-degrading enzymes. For comparative purposes of the efficiency of EH, an online extraction and analysis technique using supercritical fluid extraction-supercritical fluid chromatography-mass spectrometry (SFE-SFC-MS) was performed. The experimental results demonstrated up to 369.3 mg 100 g^-1 FA release from rye bran after 48 h EH with Viscozyme L. The EH of wheat and oat bran with Viscoferm for 48 h resulted in 255.1 and 33.5 mg 100 g^-1 of FA, respectively. The release of FA from bran matrix using supercritical fluid extraction with carbon dioxide and ethanol as a co-solvent (SFE-CO₂-EtOH) delivered up to 464.3 mg 100 g^-1 of FA, though the extractability varied depending on the parameters used. The 10-fold and 30-fold scale-up experiments confirmed the applicability of EH as a bioprocessing method valid for the industrial scale. The highest yield of FA in both scale-up experiments was obtained from rye bran after 48 h of EH with Viscozyme L. In purified extracts, the absence of xylose, arabinose, and glucose as the final degradation products of lignocellulose was proven by high-performance liquid chromatography with refractive index detection (HPLC-RID). Up to 94.0% purity of FA was achieved by solid-phase extraction (SPE) using the polymeric reversed-phase Strata X column and 50% EtOH as the eluent.

Natural antimicrobials and antioxidants added to polylactic acid packaging films. Part I: Polymer processing techniques

Currently, reducing packaging plastic waste and food losses are concerning topics in the food packaging industry. As an alternative for these challenges, antimicrobial and antioxidant materials have been developed by incorporating active agents (AAs) into biodegradable polymers to extend the food shelf life. In this context, developing biodegradable active materials based on polylactic acid (PLA) and natural compounds are a great alternative to maintain food safety and non-toxicity of the packaging. AAs, such as essential oils and polyphenols, have been added mainly as antimicrobial and antioxidant natural compounds in PLA packaging. In this review, current techniques used to develop active PLA packaging films were described in order to critically compare their feasibility, advantages, limitations, and relevant processing aspects. The analysis was focused on the processing conditions, such as operation variables and stages, and factors related to the AAs, such as their concentrations, weight losses during processing, and incorporation technique, among others. Recent developments of active PLA-based monolayers and bi- or multilayer films were also considered. In addition, patents on inventions and technologies on active PLA-based films for food packaging were reviewed. This review highlights that the selection of the processing technique and conditions to obtain active PLA depends on the type of the AA regarding its volatility, solubility, and thermosensitivity.

Technological properties of chickpea (Cicer arietinum): Production of snacks and health benefits related to type-2 diabetes

Chickpea (Cicer arietinum) is one of the most consumed pulses worldwide (over 2.3 million tons enter the world market annually). Some chickpea components have shown, in preclinical and clinical studies, several health benefits, including antioxidant capacity, and antifungal, antibacterial, analgesic, anticancer, antiinflammatory, and hypocholesterolemic properties, as well as angiotensin I-converting enzyme inhibition. In the United States, chickpea is consumed mostly in the form of hummus. However, the development of new products with value-added bioactivity is creating new opportunities for research and food applications. Information about bioactive compounds and functional properties of chickpea ingredients in the development of new products is needed. The objective of this review was to summarize available scientific information, from the last 15 years, on chickpea production, consumption trends, applications in the food industry in the elaboration of plant-based snacks, and on its bioactive compounds related to type 2 diabetes (T2D). Areas of opportunity for future research and new applications of specific bioactive compounds as novel food ingredients are highlighted. Research is key to overcome the main processing obstacles and sensory challenges for the application of chickpea as ingredient in snack preparations. The use of chickpea bioactive compounds as ingredient in food products is also a promising area for accessibility of their health benefits, such as the management of T2D.

Applications of Nonconventional Green Extraction Technologies in Process Industries: Challenges, Limitations and Perspectives

This study reviewed five different nonconventional technologies which are aligned with green concepts of product recovery from raw materials on industrial scale, with minimal energy consumption and chemical use. Namely, this study reviewed supercritical fluid extraction (SCFE), pressurized liquid extraction (PLE), microwave-assisted extraction (MAE), ultrasound extraction (UAE) and pulsed electric fields extraction (PEFE). This paper provides an overview of relevant innovative work done in process industries on different plant matrices for functional value-added compounds and byproduct production. A comparison of the five extraction methods showed the supercritical CO2 (SC-CO2) process to be more reliable despite some limitations and challenges in terms of extraction yield and solubility of some bioactive compounds when applied in processing industries. However, these challenges can be solved by using ionic liquids as a trainer or cosolvent to supercritical CO2 during the extraction process. The choice of ionic liquid over organic solvents used to enhance extraction yield and solubility is based on properties such as hydrophobicity, polarity and selectivity in addition to a safe environment.

Green Chemistry Extractions of Carotenoids from Daucus carota L.-Supercritical Carbon Dioxide and Enzyme-Assisted Methods

Multiple reviews have been published on various aspects of carotenoid extraction. Nevertheless, none of them focused on the discussion of recent green chemistry extraction protocols, especially for the carotenoids extraction from Daucus carota L. This group of bioactive compounds has been chosen for this review since most of the scientific papers proved their antioxidant properties relevant for inflammation, stress-related disorders, cancer, or neurological and neurodegenerative diseases, such as stroke and Alzheimer's Disease. Besides, carrots constitute one of the most popular sources of carotenoids. In the presented review emphasis has been placed on the supercritical carbon dioxide and enzyme-assisted extraction techniques for the relevant tetraterpenoids. The detailed descriptions of these methods, as well as practical examples, are provided. In addition, the pros and cons of each method and comparison with the standard solvent extraction have been discussed.

Supercritical impregnation for food applications: a review of the effect of the operational variables on the active compound loading

The scCO₂-assisted impregnation process has arisen as an effective method to impregnate solid materials. Its multiple advantages include high diffusion, it allows to obtain free-solvent materials and to operate under low temperatures, which permits to process thermolabile solutes. These characteristics have allowed its application at industrial scale for the impregnation of wood with fungicides and in the last years for textile dyeing. Meanwhile, other numerous applications are still being studied at laboratory scale. One potential field of application corresponds to the food-related industry, which includes the use of scCO₂-assisted impregnation process to develop active materials for food packaging and to generate food-grade materials loaded with nutraceuticals for functional food applications. In this framework, this article summarizes the advantages and the main drawbacks with the scCO₂-assisted impregnation process. The effect of the processing variables of the scCO₂-assisted impregnation process is discussed in terms of the incorporation of active compounds within polymer structures. Including the principles and description of the process and a review of the investigated systems for a better understanding.