Heat-sensitive Compounds Research Articles

Physical Cell Disruption Technologies for Intracellular Compound Extraction from Microorganisms

This review focuses on the physical disruption techniques in extracting intracellular compounds, a critical step that significantly impacts yield and purity. Traditional chemical extraction methods, though long-established, face challenges related to cost and environmental sustainability. In response to these limitations, this paper highlights the growing shift towards physical disruption methods—high-pressure homogenization, ultrasonication, milling, and pulsed electric fields—as promising alternatives. These methods are applicable across various cell types, including bacteria, yeast, and algae. Physical disruption techniques achieve relatively high yields without degrading the bioactivity of the compounds. These techniques, utilizing physical forces to break cell membranes, offer promising extraction efficiency, with reduced environmental impacts, making them attractive options for sustainable and effective intracellular compound extraction. High-pressure homogenization is particularly effective for large-scale extracting of bioactive compounds from cultivated microbial cells. Ultrasonication is well-suited for small to medium-scale applications, especially for extracting heat-sensitive compounds. Milling is advantageous for tough-walled cells, while pulsed electric field offers gentle, non-thermal, and highly selective extraction. This review compares the advantages and limitations of each method, emphasizing its potential for recovering various intracellular compounds. Additionally, it identifies key research challenges that need to be addressed to advance the field of physical extractions.

α-Tocopherol and retinol content in Holder pasteurized versus high-pressure processed human milk during 6 months of storage

Human milk is a vital source of nutrition for infants providing essential nutrients for optimal growth and development. However, the processing methods applied to ensure its safety may affect its nutritional composition. The aim of this study was to compare the nutritional profile of α-tocopherol and retinol content in human milk, both raw and processed by Holder pasteurization or high-pressure processing. Our study followed a design that included milk samples obtained from 12 female donors (age ranged from 30 to 38) in the lactation period up to 6 months after delivery. Every milk sample was divided into four groups: (i) no treatment, (ii) subjected to Holder pasteurization (HP), (iii) and (iv) subjected to high-pressure processing (HPP), which differed in the way the pressure was applied. The results showed that both HP and HPP significantly affected the nutritional profile of the milk. Retinol level was approximately 20 % lower after both treatments than in untreated milk. The main difference was in tocopherol levels, which decreased by 46 % after HP, whereas these concentrations decreased by only 26 % in the cumulative pressure HPP-treated samples. These results suggest that the use of HPP should be considered as a prospective approach to human milk processing. Since HPP has advantages in preserving heat-sensitive compounds and the levels of vitamin E decrease less.

Optimization of process parameters of refractance window drying for aonla slices and comparison with other drying techniques.

Aonla is as a good source of antioxidants due to its high ascorbic acid and polyphenol contents. However, because of its high acidity and astringent taste, aonla is rarely consumed in its fresh form. As the constituents in aonla are heat sensitive, it is essential to find a suitable drying method for preservation. Therefore, refractance window drying (RWD) of aonla slices was studied as it has the potential of retaining heat-sensitive compounds. The effect of RWD process variables, namely water temperature (75, 82.5, 90 °C) and slice thickness (2, 4, 6 mm), on different quality parameters of dehydrated aonla was studied. Increasing water temperature resulted in significantly higher ascorbic acid content, titratable acidity and product temperature, while total phenolic content, free radical scavenging activity and moisture content decreased. With the exception of product temperature, higher slice thickness led to an increase in the values of all the parameters. At the optimized processing conditions of 83 °C water temperature and 4 mm slice thickness, the ascorbic acid content, total phenolic content, free radical scavenging activity, titratable acidity and moisture content values were found to be 269.03 mg (100 g)-1, 242.33 mg (100 g)-1, 87.11%, 3.62% and 4% respectively. The aonla slices subjected to RWD also possessed 4-6% higher phytochemical content than osmotically dried and hot-air-dried samples. This research highlights the effectiveness of RWD in preserving heat-sensitive compounds in food like aonla. The RW-dried slices had a smoother and more uniform microstructure compared to osmotically dried and hot-air-dried samples. © 2024 Society of Chemical Industry.

Effects of microwave drying on physicochemical characteristics, microstructure, and antioxidant properties of propolis extract.

The heat sensitivity of phenolics and flavonoids leads to considerable losses of these compounds during conventional drying. Microwave drying has the advantage of shorter drying time and rigorous process control, minimizing damage to heat-sensitive compounds. Microwave drying kinetics and the impacts of microwave drying on physicochemical characteristics, morphological structure, antioxidant properties, total phenolics, and flavonoid content of propolis extract were investigated. Increasing the microwave power output from 180 to 900 W resulted in a 67% reduction in drying time. Morphological changes were more noticeable at higher microwave power levels as shown in scanning electron microscopy images. Water activity values of microwave dried propolis extracts were below 0.4, which satisfied the requirement for shelf-stable dry products. The solubility of microwave dried propolis extract increased with increasing microwave power level, and the highest solubility was achieved for the propolis extract microwave dried at 900 W. Microwave dried propolis extracts exhibited lower total phenolic content levels than fresh propolis extract. The microwave power level did not affect the total flavonoid content but it affected 2,2-diphenyl-1-picrylhydrazyl (DPPH) free-radical scavenging activity of microwave dried propolis extracts. The DPPH free-radical scavenging activity closest to the fresh propolis extract was obtained for the microwave dried propolis extract at 900 W. This also showed the highest 6-hydroxy-2,5,7,8-tetramethyl-2-carboxylic acid (Trolox) equivalent antioxidant capacity. Microwave drying of propolis extract at 900 W was found to be the most efficient drying condition because it yielded the shortest drying time, the highest effective moisture diffusivity, and phenolic and flavonoid content levels that were very similar to those in fresh propolis extract. © 2023 Society of Chemical Industry.

Technological Processing of Dried Powdered Rosehips to Tablets Through Wet Granulation

Abstract The pseudo-fruits of Dog Rose are a rich source of L-ascorbic acid and several other active substances, which means their high supportive therapeutic potential. The study aimed to examine the impact of the chosen technological procedure for the preparation of tablets containing rosehip powder on the amount of L-ascorbic acid in the final pharmaceutical form. Drying of the plant drug was performed at room temperature to avoid possible thermal degradation of this heat-sensitive compound. Similarly, drying of the granules after wet granulation in the oven was replaced by natural drying at room temperature. The composition of two types of prepared granule formulations differed in the filler – lactose (LAC) or microcrystalline cellulose (MCC). Apart from the disintegration test, they meet the technological requirements for granules or tablets. Lactose was confirmed as a more suitable filler, which despite the unsuccessful disintegration of the granules, ensures the disintegration of tablets within 15 minutes even without the addition of a special excipient acting as a disintegrant. The content of L-ascorbic acid detected using isotachophoresis – capillary zone electrophoresis was 87.16 ± 5.06 µg in LAC tablets and 63.33 ± 2.83 µg in MCC tablets.

Mass transfer parameters and quality characteristics of aonla slices under refractance window drying

This study investigates the effects of refractance window (RW) drying process parameters on mass transfer and quality characteristics of dried aonla slices. RW drying of aonla slices was carried out at three levels of water temperature (75, 82 and 90 °C) and slice thickness (2, 4 and 6 mm). In terms of quality characterization, the total phenolic content, ascorbic acid content, and browning index were determined. Higher retention of ascorbic acid (64.49 ± 0.34%) and phenolic content (37.84 ± 0.08 mg GAE/g dry matter) was found at 90 and 82 °C water temperature, respectively with inconsequential variation in browning index. Mass transfer parameters such as Biot number, effective moisture diffusivity and mass transfer coefficient were estimated using Dincer and Dost model. Effective moisture diffusivity during drying varied from 4.27 × 10−10 to 1.09 × 10−09 m2s−1 and Biot number was observed to be in the range of 0.268 to 8.666 for different drying conditions. XRD pattern suggested that RW dried aonla slices had semi-crystalline structure. The changes in crystalline structure to amorphous was pronounced more at high water temperature. It was also revealed by the disintegration of cell wall/membrane and connecting surfaces, which resulted into smooth and flaky microstructures with sharp edges. The gamut of crystallite size was obtained as 49.12 ± 0.26 to 99.12 ± 1.19 nm. The presence of bound water after completion of drying was represented by FTIR peaks centered around 3577 cm−1. The infrared spectroscopy of RW dried aonla postulated that peak intensity of absorption bands negligibly changed with varying processing conditions, but minor peak shift was observed. This study elucidates the suitability of RW drying for retention of heat-sensitive compounds in food produce such as aonla with better quality retention and morphological characteristics.

EFFECT OF SAMSKARA ON FOOD W.S.R.T FRYING (SNEHA BHARJANA): A REVIEW

The use of different processes to transform the properties of food items is termed as Samskara in Ayurveda. These methods or processes are aimed at improving the nutritive value, palatability, compatibility, digestibility, and bioavailability of the food. Frying food in any kind of lipid (sneha) is a very popular, old and easy method of cooking. Fried foods have both positive and negative effects on the health of an individual. It can make the food tastier, more nutritive and give good texture, which are desirable qualities. Frying also can be undesirable for health as it makes the food heavy for digestion, high calorie and can sometimes lead to degradation of important heat sensitive nutritional compounds as well as the generation of toxic molecules. Frying in different sneha (Fats) like ghee and oil, gives different results. The use of frying as a food process is to be done after proper consideration of its pros and cones and assessment of the person consuming such food.

Impact of pre-treatment methods on the drying kinetics, product quality, and energy consumption of electrohydrodynamic drying of biological materials

Electrohydrodynamic (EHD) drying is an energy-efficient drying method. This novel drying technology operates at room temperature, which makes it particularly suitable for drying biomaterials that contain heat-sensitive compounds. It has a higher drying rate than other low-temperature methods, such as solar and freeze-drying. However, its drying rate is not high enough to compete with other conventional thermal methods, such as hot-air drying. For industrial applications requiring high product throughput, the drying rate of EHD drying should be improved. One way to do this is to combine EHD with pre-treatment methods. Therefore, this study evaluated the impact of different pre-treatment methods on drying kinetics, energy consumption, and product quality attributes of apple slices dried using EHD drying. Pulsed electric fields (PEF), ultrasound, and blanching are the studied pre-treatment methods. Results show that only PEF pre-treatment could significantly decrease the EHD drying time by 39%. However, it resulted in a 26% higher browning index than the untreated EHD-dried apples, which is not appealing to consumers. The applied pre-treatment methods did not significantly affect other quality attributes, such as antioxidant activity, total phenolics, and rehydration ratio. In conclusion, using the studied pre-treatments for EHD drying increases the complexity of the process, whereas it is arguable whether the added values outweigh the energetic and quality downsides or not.

A Cold-Active Flavin-Dependent Monooxygenase from Janthinobacterium svalbardensis Unlocks Applications of Baeyer-Villiger Monooxygenases at Low Temperature.

Cold-active enzymes maintain a large part of their optimal activity at low temperatures. Therefore, they can be used to avoid side reactions and preserve heat-sensitive compounds. Baeyer-Villiger monooxygenases (BVMO) utilize molecular oxygen as a co-substrate to catalyze reactions widely employed for steroid, agrochemical, antibiotic, and pheromone production. Oxygen has been described as the rate-limiting factor for some BVMO applications, thereby hindering their efficient utilization. Considering that oxygen solubility in water increases by 40% when the temperature is decreased from 30 to 10 °C, we set out to identify and characterize a cold-active BVMO. Using genome mining in the Antarctic organism Janthinobacterium svalbardensis, a cold-active type II flavin-dependent monooxygenase (FMO) was discovered. The enzyme shows promiscuity toward NADH and NADPH and high activity between 5 and 25 °C. The enzyme catalyzes the monooxygenation and sulfoxidation of a wide range of ketones and thioesters. The high enantioselectivity in the oxidation of norcamphor (eeS = 56%, eeP > 99%, E > 200) demonstrates that the generally higher flexibility observed in the active sites of cold-active enzymes, which compensates for the lower motion at cold temperatures, does not necessarily reduce the selectivity of these enzymes. To gain a better understanding of the unique mechanistic features of type II FMOs, we determined the structure of the dimeric enzyme at 2.5 Å resolution. While the unusual N-terminal domain has been related to the catalytic properties of type II FMOs, the structure shows a SnoaL-like N-terminal domain that is not interacting directly with the active site. The active site of the enzyme is accessible only through a tunnel, with Tyr-458, Asp-217, and His-216 as catalytic residues, a combination not observed before in FMOs and BVMOs.

Key Parameters Impacting the Crystal Formation in Antisolvent Membrane-Assisted Crystallization.

Antisolvent crystallization is commonly used in the formation of heat-sensitive compounds as it is the case for most active pharmaceutical ingredients. Membranes have the ability to control the antisolvent mass transfer to the reaction medium, providing excellent mixing that inhibits the formation of local supersaturations responsible for the undesired properties of the resulting crystals. Still, optimization of the operating conditions is required. This work investigates the impact of solution velocity, the effect of antisolvent composition, the temperature and gravity, using glycine-water-ethanol as a model crystallization system, and polypropylene flat sheet membranes. Results proved that in any condition, membranes were consistent in providing a narrow crystal size distribution (CSD) with coefficient of variation (CV) in the range of 0.5-0.6 as opposed to 0.7 obtained by batch and drop-by-drop crystallization. The prism-like shape of glycine crystals was maintained as well, but slightly altered when operating at a temperature of 35 °C with the appearance of smoother crystal edges. Finally, the mean crystal size was within 23 to 40 µm and did not necessarily follow a clear correlation with the solution velocities or antisolvent composition, but increased with the application of higher temperature or gravity resistance. Besides, the monoclinic form of α-glycine was perfectly maintained in all conditions. The results at each condition correlated directly with the antisolvent transmembrane flux that ranged between 0.0002 and 0.001 kg/m2. s. In conclusion, membrane antisolvent crystallization is a robust solution offering consistent crystal properties under optimal operating conditions.

Study of stingless bee (Heterotrigona itama) propolis using LC-MS/MS and TGA-FTIR

Propolis, especially meliponini propolis is getting more popular in the functional food market, mainly due to its pharmacological importance. The quality of propolis is largely dependent upon the extraction technology and its solvent system. The present study investigated the performance of propolis extraction from maceration with and without ultrasonic pretreatment (30 min) in both water and 20% ethanol systems. Maceration was chosen to avoid degradation of heat sensitive compounds. Ultrasonic pretreatment was introduced to enhance propolis extraction from recalcitrant raw material. The yield of propolis was 4.0-5.5%. The results found that maceration with ultrasonic pretreatment, especially in aqueous ethanol increased the phenolics (17.043 mg GA/g), tannins (5.411 mg GA/g) and flavonoids (0.83 mg Q/g) content, as well as antioxidant capacity of propolis (80% at 1 mg/mL). Mass spectral based principal component analysis revealed that solvent system had higher effect (> 30%) on the variance of propolis quality rather than extraction technology. The variance of chemical composition had also led to the difference of antioxidant capacity among propolis samples. Alcohol precipitation would remove polymeric substance from propolis which was then characterised by thermogravimetric analysis coupled with Fourier transform infrared spectrometer (TGA-FTIR) after acid hydrolysis. The substance was putatively identified as hygroscopic lignocelluloses (14.4% moisture, 36.6% hemicelluloses and celluloses, 40% lignins), and started to decompose at 203°C, involving 4 steps of degradation mechanism at the highest derivative weight of 12.09%/min.

Optimization of vitamin c extraction of roselle petals (Hibiscus sabdariffa) assisted with microwaves using response surface methodology

Vitamin C contained in roselle petals acts as an antioxidant that provides health benefits. In order to make it easier to use, vitamin C needs to be extracted out of the roselle petal cells in the form of extracted raw roselle juice. The commonly used conventional method has disadvantages that can damage heat-sensitive compounds such as vitamin C. An alternative extraction method used was microwave-assisted extraction. The success of this method in extracting vitamin C was influenced by a few factors, such as the ratio of the roselle petals-water, microwave power, and extraction time. The purpose of this study was to determine the optimum conditions for microwave-assisted extraction of vitamin C in roselle extract and to determine the physical and chemical characteristics of roselle extract produced in the optimum conditions. This study utilized response surface methodology (RSM) in a central composite design (CCD). The optimized factors included the roselle petals-water ratio (5 - 10%), microwave power (150 - 350 W), and extraction time (3 - 7 mins). The parameter response tested in this study was vitamin C. While the extract produced under optimum conditions was also characterized by the total anthocyanin content, total phenols, antioxidant activity, pH value and colour (L, a* and b*). The results showed that the recommended optimum conditions were a 5% roselle petals-water ratio, 250 W of microwave power, and 6.09 mins of extraction time. The verification results show that this optimum condition produced vitamin C higher than the conventional method. The characteristics of roselle extract produced by microwave-assisted extraction at optimum conditions were vitamin C at 9.973±0.508 mg/g, total anthocyanins at 1.771±0.124 mg/100 g, phenol at 30.848±1;899 m/g, IC50 at 6.699±0.627 ppm, pH at 2.133±0.057, colour with an L value of 31.033±0.404, a* value of 1.066±0.155, and b* value of 18.100±0.458.

Effect of pulsed electric field parameters on the alkaline extraction of valuable compounds from perilla seed meal and optimization by central composite design approach

Perilla seed meal (PSM) is the by-product of the oil extraction industry and a potential source of bioactive compounds. Pulsed electric field, a non-thermal technology, can be used to recover heat labile bioactive compounds from plant materials such as perilla seed meal. This study found that pulsed electric field (PEF) assisted alkaline extraction influenced the protein content and antioxidant activity of perilla seed meal (PSM). Among all PEF parameters, electric field strength (EFS) and pulse width (PW) were found to be the most significant as judged by F-value. Consequently, a central composite rotatable experimental design was applied to investigate the effect of electric field strength (EFS) and pulse width against protein content, antioxidant activity, and total phenolic content (TPC) of PEF treated PSM extract. Compared to conventional alkaline extraction, an increase in the yield of protein content by 10.58%, antioxidant activity by 7.48%, and total phenolic content by 21.59% was recorded at the optimal values of electric field strength (4 kV/cm) and pulse width (120 µs). Moreover, Karl pearson correlational analysis revealed a strong relationship (linear, R2=0.963) between antioxidant activity and total phenolic content. The validation was done at 95% confidence level for which the predicted values were compared with the actual experimental values, and the means were found to be insignificantly different from each other (p > 0.05). Industrial relevanceNon-thermal extraction techniques such as pulsed electric field used in this study can be used for the recovery of valuable compounds from the food materials especially heat sensitive compounds. PEF treatment increased the extractability of the water-soluble compounds from the perilla seed meal (PSM) samples and increased the recovery of valuable compounds from PSM while maintaining the nutritional and functional viability. Hence, this technology is having the potential to be used as assistant technology for the extraction of heat sensitive components from the plant cells which may find its applications in neutraceutical and pharmaceutical industries.

Optimization of Ultrasound-Assisted Garlic Extraction using Response Surface Methodology

The different nutrients in garlic provide numerous health benefits. As the most active and important bioactive compound found in garlic, allicin offers antimicrobial, anticancer, antioxidant, cholesterol-lowering and cardiovascular-preventive effects.Considering water as the solvent, garlic extraction was studied using ultrasonic bath technology based on the response surface methodology (RSM) for treatments created in Design-Expert 10 software package. The study was carried out at different temperatures (30-60°C), durations (10-30 min), powers (40-100 W) and frequencies (37 and 80 Hz). The extractions were evaluated for total phenolic content, DPPH test, and extraction efficiency. The optimum conditions were found to be 10 min, 30°C, 40 W and 37 Hz (R2= 0.99 for total phenolic content, R2= 0.93 for DPPH test and R2= 0.94 for extraction efficiency). Temperature and duration of sonication were the most influential parameters on the responses.It was concluded that ultrasonic apparatus can be conveniently used for extraction as it speeds up the process and reduces the required time, improving the quality of the extract in terms of antioxidant properties, the possibility of extraction of heat-sensitive compounds, etc.

Ultrasound-Assisted and Microwave-Assisted Extraction, GC-MS Characterization and Antimicrobial Potential of Freeze-dried L. camara Flower

Lantana camara is known to have anti-bacterial properties which can be exploited to develop a natural food preservative. There is huge demand for natural preservatives in food industry due to the increased health risks associated with synthetic preservatives, development of effecient extraction methods are essential to retain heat sensitive bioactive compounds. This aim of this study was to compare the performance of microwave-assisted extraction (MAE), ultrasound-assisted extraction (UAE), and conventional solvent extraction (CSE) methods for extraction of freeze-dried lantana flower. The phytochemicals in freeze-dried flowers were characterized by GC-MS analysis and antibacterial properties were tested at different concentrations (50, 100, and 150 µl) against E.coli, Salmonella, and S. aureus. It was evident that the UAE offered the highest yield (64%), followed by MAE (53%) and CSE (49%) with distilled water as solvent. The freeze-dried extract possessed a high amount of tannins (417 µg/g), followed by flavonoids such as catechol (88 µg/g) and quercetin (9.2 µg/g). The antibacterial potential results revealed that only distilled water-based extraction techniques offered positive inhibition zones of 2.0-2.67 mm (MAE), 1.67-2.67 mm (UAE), and 1.67-2.17 mm (CSE) against all three organisms, while the chloroform based extracts had no inhibition effect. The microwave-assisted extract at 150 µl concentration offered a significant inhibitory effect against all three pathogens. The GC-MS profiling of bioactive compounds in flower extract revealed the presence of hexadecanoic acid as the major phytochemical compound in all three extraction techniques. The study revealed that the chloroform extract failed to exhibit an antibacterial effect due to the absence of alkaloids, saponins, and anthraquinones as a result of its neutralizing effect.

Identification and Verification of the Prodigiosin Biosynthetic Gene Cluster (BGC) in Pseudoalteromonas rubra S4059.

ABSTRACTPseudoalteromonas rubra S4059 produces the red pigment prodigiosin, which has pharmaceutical and industrial potential. Here, we targeted a putative prodigiosin-synthesizing transferase PigC, and a pigC in-frame deletion mutant did not produce prodigiosin. However, extractions of the pigC mutant cultures retained antibacterial activity, and bioassay-guided fractionation found antibacterial activity in two fractions of blue color. A precursor of prodigiosin, 4-methoxy-2,2′-bipyrrole-5-carbaldehyde (MBC), was the dominant compound in both the fractions and likely caused the antibacterial activity. Also, a stable blue pigment, di-pyrrolyl-dipyrromethene prodigiosin, was identified from the two fractions. We also discovered antibacterial activity in the sterile filtered (nonextracted) culture supernatant of both wild type and mutant, and both contained a heat-sensitive compound between 30 and 100 kDa. Deletion of prodigiosin production did not affect growth rate or biofilm formation of P. rubra and did not change its fitness, as the mutant and wild type coexisted in equal levels in mixed cultures. In conclusion, a prodigiosin biosynthetic gene cluster (BGC) was identified and verified genetically and chemically in P. rubra S4059 and a stable blue pigment was isolated from the pigC mutant of S4059, suggesting that this strain may produce several prodigiosin-derived compounds of pharmaceutical and/or industrial potential.IMPORTANCE Pigmented Pseudoalteromonas strains are renowned for their production of secondary metabolites, and genome mining has revealed a high number of biosynthetic gene clusters (BGCs) for which the chemistry is unknown. Identification of those BGCs is a prerequisite for linking products to gene clusters and for further exploitation through heterologous expression. In this study, we identified the BGCs for the red, bioactive pigment prodigiosin using genomic, genetic, and metabolomic approaches. We also report here for the first time the production of a stable blue pigment, di-pyrrolyl-dipyrromethene prodigiosin (Dip-PDG), being produced by the pigC mutant of Pseudoalteromonas rubra S4059.

Antimicrobial Activity of Mentha piperita, Rosmarinus officinalis, and Withania somnifera Prepared by Ultrasound Against Escherichia coli Isolated from Poultry Stool

Background: Extraction by conventional methods such as Soxhlet requires a long time and the possibility of damage to heat-sensitive compounds. Objectives: In this study, modern ultrasound methods used to perform and investigate the antibacterial properties of plant extracts were compared. Methods: The extracts of Mentha piperita, Rosmarinus officinalis, and Withania somnifera were prepared by an ultrasound device. Ten Escherichia coli strains were isolated from poultry stool samples. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) plant extracts against E. coli were determined using the microdilution method. Results: The results showed that the lowest inhibitory concentrations of rosemary, peppermint, and wind cheese extracts prepared by ultrasound were equal to 3.1 mg/mL, while the highest inhibitory concentrations of these extracts were equal to 25, 25, and 50 mg/mL, respectively. The lowest lethal concentrations of rosemary, peppermint, and wind cheese extracts were 6.25 mg/mL, while the highest inhibitory concentrations of these extracts were 25, 25, and 50 mg/mL, respectively. The lowest bactericidal concentrations of rosemary, peppermint, and wind cheese extracts prepared by ultrasonic waves were equal to 6.25 mg/mL, while the highest lethal concentrations of these extracts were equal to 50, 25, and 100 mg/mL, respectively. Conclusions: According to the findings of the study, it can be concluded that the use of ultrasonic waves is a fast, effective, and economical method for extracting plant components. In addition, the methanolic extract of peppermint has the most inhibitory and lethal properties.

A Review of the Current Knowledge of Thermal Stability of Anthocyanins and Approaches to Their Stabilization to Heat.

Anthocyanins are colored valuable biocompounds, of which extraction increases globally, although functional applications are restrained by their limited environmental stability. Temperature is a critical parameter of food industrial processing that impacts on the food matrix, particularly affecting heat-sensitive compounds such as anthocyanins. Due to the notable scientific progress in the field of thermal stability of anthocyanins, an analytical and synthetic integration of published data is required. This review focuses on the molecular mechanisms and the kinetic parameters of anthocyanin degradation during heating, both in extracts and real food matrices. Several kinetic models (Arrhenius, Eyring, Ball) of anthocyanin degradation were studied. Crude extracts deliver more thermally stable anthocyanins than purified ones. A different anthocyanin behavior pattern within real food products subjected to thermal processing has been observed due to interactions with some nutrients (proteins, polysaccharides). The most recent studies on the stabilization of anthocyanins by linkages to other molecules using classical and innovative methods are summarized. Ensuring appropriate thermal conditions for processing anthocyanin-rich food will allow a rational design for the future development of stable functional products, which retain these bioactive molecules and their functionalities to a great extent.

Supercritical CO2 extraction of oil from Arctic charr side streams from filleting processing

Although Arctic charr side streams contain limited amounts of fish flesh, they are a rich fish oil source (46.3 ± 0.6%). The aim of the study was to investigate the potential for valorization of Arctic charr filleting side streams through the extraction of oil by supercritical CO2 technology. The effect of temperature (40 °C and 80 °C) and pressure (20, 35 and 45 MPa) on the final extract after supercritical fluid extraction (SFE) was evaluated. Temperature increase enhanced the yield but decreased the antioxidant activity at 45 MPa, did not affect the yield and the antioxidant activity at 35 MPa, whereas yield was limited at 20 MPa and 80 °C. Extracts were rich in monounsaturated fatty acids (56.7–58.3%, especially oleic acid 37.2–38.0%), and polyunsaturated fatty acids (20.2–26.1%, especially DHA 7.3–11.4%). The presence of astaxanthin significantly preserved the extracts from oxidation. Industrial relevanceSupercritical carbon dioxide extraction is a green technology appropriate for the recovery of non-polar and heat sensitive compounds. The extracted Arctic charr oils were rich in polyunsaturated fatty acids and astaxanthin which inhibited oxidation in combination with the absence of oxygen and light during the process. This technology could be an excellent alternative for more sustainable valorization of fish processing side streams.

Recent advances in the extraction of polyphenols from eggplant and their application in foods

The extraction of bioactive compounds from plant materials, such as eggplant, has been commonly carried out using classical extraction processes, based on solid-liquid extraction such as hydrodistillation and Soxhlet extraction. However, a series of disadvantages of these methods, such as long operating times or excessive organic solvents consumption, have caused the necessity to gradually replace them by other modern extraction technologies. Emerging extraction technologies has advantages over conventional extraction methods and are being increasingly used for the recovery of bioactive compounds from plants, such as eggplant, rich in phenolic compounds with antioxidant activity. This article presents the main polyphenols in eggplant and reviews the latest advances in their extraction. In addition, the incorporation of eggplant in the formulation of functional foods is also described. Ultrasound-assisted technology (UAE) is a suitable technology for the recovery of very abundant heat-sensitive compounds in eggplant, such as anthocyanins and phenolic acids. In addition, these compounds present several bio-activities and health-related properties so their incorporation into the preparation of different foods is a good strategy to produce functional foods.