Ultrasound-assisted Extraction Technique Research Articles

Application of response surface methodology for the co-optimization of extraction and probiotication of phenolic compounds from pomegranate fruit peels (Punica granatum L.)

Currently, the synergistic interactions between plant polyphenols and probiotic bacteria are gaining interest with diverse perspectives of applications of both functional ingredients. This study aims to explore and optimize the interaction between pomegranate peel polyphenols and the probiotic strain Lactobacillus rhamnosus ATCC 53103, throughout the co-optimization of the extraction/probiotication techniques. In this context, the response surface methodology (RSM) was applied to find the suitable extraction conditions to obtain phenolic extracts exhibiting a synergistic interaction when fermented with the probiotic strain. A s-Cyclodextrin ultrasound-assisted extraction technique has been applied for pomegranate polyphenols extraction, followed by the probiotic fermentation of extracts. Results of RSM indicate that for all chosen design responses, the experimental values are in good agreement with the predicted one, with R squared values above 0.8 for all prediction models. Using optimal conditions predicted by the desirability function, it has been found that after probiotication of optimized phenolic extracts, the growth of probiotic strain at presence of polyphenols was possible. Moreover, a significant (p < 0.05) improvement of in vitro antioxidant activity of probioticated extracts was confirmed (an increase on in vitro free radical scavenging activity up to 51.37%). Results of this study, demonstrate for the first time, the feasibility of RSM approach to perform simultaneously the optimization of extraction and probiotication processes of phenolic compounds with the perspective to develop a new bioprocess aiming to produce functional food ingredient or novel nutraceutical products containing both bioactive polyphenols and beneficial probiotic bacteria.

Analysis of anticancer compound, indole-3-carbinol, in broccoli using a new ultrasound-assisted dispersive-filter extraction method based on poly(deep eutectic solvent)-graphene oxide nanocomposite

Indole-3-carbinol (I3C), an important anticancer compound found in broccoli, has attracted considerable attention. The rapid extraction and accurate analysis of I3C in the pharmaceutical industry in broccoli is challenging as I3C is unstable at low pH and high temperature. In this study, a rapid, accurate, and low-cost ultrasound-assisted dispersive-filter extraction (UADFE) technique based on poly(deep eutectic solvent)-graphene oxide (PDES-GO) adsorbent was developed for the isolation and analysis of I3C in broccoli for the first time. PDES-GO with multiple adsorption interactions and a fast mass transfer rate was synthesized to accelerate adsorption and desorption. UADFE was developed by combining dispersive solid-phase extraction (DSPE) and filter solid-phase extraction (FSPE) to realize rapid extraction and separation. Based on the above two strategies, the proposed PDES-GO-UADFE method coupled with high-performance liquid chromatography (HPLC) allowed the rapid (15–16 min), accurate (84.3%–96.4%), and low-cost (adsorbent: 3.00 mg) analysis of I3C in broccoli and was superior to solid-phase extraction, DSPE, and FSPE methods. The proposed method showed remarkable linearity (r=0.9998; range: 0.0840–48.0 μg/g), low limit of quantification (0.0840 μg/g), and high precision (relative standard deviation ≤5.6%). Therefore, the PDES-GO-UADFE-HPLC method shows significant potential in the field of pharmaceutical analysis for the separation and analysis of anti-cancer compounds in complex plant samples.

Optimization of ultrasound‐assisted extraction conditions for phenolics, antioxidant, and tyrosinase inhibitory activities of Vietnamese brown seaweed (Padina australis)

This study aimed to determine the optimum ultrasound-assisted extraction (UAE) conditions for obtaining the highest yields of phenolics and antioxidants from Padina australis. The effects of extraction variables including temperature (40–60°C), extraction time (50–80 min), ethanol concentration (0%–60%) and sample-to-solvent ratio (1–5 g/100 mL) on the total phenolic content (TPC), DPPH radical scavenging activity (DRSA) and ferric reducing antioxidant power (FRAP) were determined and optimized using Box-Behnken design in conjunction with response surface methodology (RSM). The extraction temperature, ethanol concentration and sample-to-solvent ratio significantly affected TPC and DRSA, while extraction time had no impact on TPC and antioxidant activity of P. australis within the tested ranges. The optimal UAE conditions were determined to be ultrasonic temperature of 60°C, ultrasonic time of 60 min, solvent concentration of 60% (v/v) aqueous ethanol and sample-to-solvent ratio of 1 g/100 mL. The developed mathematical models were found to be reliable predictors for TPC, DRSA and FRAP, and the predicted values fit well with the experimental data (R2 = 0.86–0.96). The extract was then fractionated to generate n-hexane, ethyl acetate and aqueous fractions. Of these fractions, ethyl acetate fraction was found to possess the highest values of TPC (807.20 mg GAE/g), DPPH (1,417.01 mg TE/g), FRAP (615.07 mg TE/g dry fraction) and the strongest tyrosinase inhibitory activity (29.90 mg AAE/g). Practical applications The study employed ultrasound-assisted extraction technique, an advanced extraction method, and RSM method for maximizing the yields of phenolics and antioxidants from P. australis. In addition, the tyrosinase inhibitory activity of P. australis extract and its fractions, for the first time, was also investigated. The results suggested the optimal UAE conditions to recover phenolics and bioactive compounds with high antioxidant and tyrosinase inhibitory properties from P. australis. Moreover, this study establishes that the ethyl acetate fraction derived from P. australis was a rich source of phenolics and antioxidants; thus, it could be further isolated and purified to obtain individual bioactive compounds for the utilization in the food and cosmeceutical industries.

Optimization of oil extraction from Lallemantia iberica seeds using ultrasound-assisted extraction

The present study aims at optimising the oil extraction from Dragon’s head (Lallemantia iberica) seeds using response surface methodology. For this purpose, the working conditions (solid/liquid ratio, ultrasound intensity and extraction time) were varied in a series of experiments to determine the optimum extraction conditions, which were further verified through an independent extraction experiment. The experiments were conducted using ultrasound-assisted extraction (UAE) technique. The maximum yield obtained for UAE extraction efficiency under optimal conditions was 97.02%, taking the Soxhlet technique as a reference (corresponding to an oil content of 39.73 g/100 g dry seeds). The operation conditions for maximum extraction efficiency were: 1/16 (g/mL) solid/liquid ratio, 13.77 (W/cm2) ultrasound intensity and 12.5 min extraction time.

Enrichment of flaxseed (Linum usitatissimum) oil with carotenoids of sea buckthorn pomace via ultrasound-assisted extraction technique: Enrichment of flaxseed oil with sea buckthorn

Currently, flaxseed oil is used as an important functional food constituent owing to its large content of omega-3 fatty acids. However, flaxseed oil does not contain carotenoids that could enhance the oxidative stability of the oil. In this study, carotenoids extracted from sea buckthorn pomace were used to enrich cold-pressed flaxseed oil via an ultrasound-assisted extraction technique (UAE). The process parameters were optimized through Box-Behnken design to maximize the carotenoid content in the flaxseed oil. The results obtained by statistical analysis indicated that the yield of 14.02 mg/L of carotenoid content was found in the enriched flaxseed oil at 75.6 min, feed to oil ratio of 19.9 (wt. basis), and amplitude 80.81%. Further, UAE at optimum process parameters was compared with the conventional extraction (CE) method, and it was found that UAE had ~ 49 wt% of higher carotenoid content relative to CE. The physicochemical properties of the enriched flaxseed oil were determined to evaluate the effects of carotenoid enrichment in the flaxseed oil. Based on the outcomes of the present investigation, enriched flaxseed oil could be the potential source for the pharmaceuticals and nutraceuticals industry.

Extraction and analysis of oleanolic acid and ursolic acid from apple processing waste materials using ultrasound-assisted extraction technique combined with high performance liquid chromatography

The aim of the present study was to develop a is simple, effective, eco-friendly, reproducible and high-yield two-stage ultrasound-assisted extraction (UAE) procedure combined with quantitative determination high performance liquid chromatographic (HPLC) method for obtaining isomeric triterpene acids - oleanolic acid (OA) and ursolic acid (UA) in the crystalline dried powdered form from apple processing agro-industrial waste material. A rapid, sensitive and specific HPLC method was developed and validated with respect to robustness, specificity, linearity-range, accuracy, precision and sensitivity. The effect of the nature and the volume of the extraction solvent, the extraction time and the sample size on the extraction efficiency were investigated. The optimal conditions for high-yield extraction were found.

Evaluation of Direct Ultrasound-Assisted Extraction of Phenolic Compounds from Potato Peels

Potato peels (PPs) are generally considered as agriculture waste. The United States alone generates over one million tons of PPs a year. However, PPs contain valuable phenolic compounds with antioxidant activities. In this study, we evaluated the efficiency of ultrasound-assisted extraction techniques in recovering antioxidants from PPs. These techniques included a direct ultrasound-assisted extraction (DUAE), an indirect ultrasound-assisted extraction (IUAE), and a conventional shaking extraction (CSE). Results of this study showed that DUAE was more effective in extracting phenolic compounds than IUAE and CSE. We also evaluated the factors affecting the yield of total phenolic compounds (TPC) in DUAE, including the temperature, time, acoustic power, ratio of solvent to solids, and size of PPs particles. TPC yield of DUAE was higher, and the extraction rate was faster than IUAE and CSE. Furthermore, TPC yield was strongly correlated to the temperature of the mixture of PPs suspension. SEM images revealed that the irradiation of ultrasound energy from DUAE caused micro-fractures and the opening of PPs cells. The extract obtained from DUAE was found to have antioxidant activity comparable to commercial synthetic antioxidants. Results of this preliminary study suggest that DUAE has the potential to transform PPs from agricultural waste to a valuable ingredient. A future systematic research study is proposed to advance the knowledge of the impact of processing parameters in the kinetics of phenolic compounds extraction from potato peels using various extraction methods.

Extraction of Phenolics and Flavonoids from Four Hosta Species Using Reflux and Ultrasound-Assisted Methods with Antioxidant and α-Glucosidase Inhibitory Activities.

The total phenolic and flavonoid contents (TPC and TFC) from the genus Hosta with antioxidant and α-glucosidase inhibitory activities were reported for the first time. Sixteen extracts from the aboveground and underground parts of the four Hosta species, including H. plantaginea, H. ventricosa, H. ensata, and H. albofarinosa, using reflux extraction (RE) and ultrasound-assisted extraction (UAE) techniques have high TPC and TFC with good antioxidant and α-glucosidase inhibitory activities. Furthermore, no significant differences on extraction yields, TPC, and TFC were found between RE and UAE techniques. Additionally, extracts from the aboveground parts of the four Hosta species had higher TPC, TFC, antioxidant, and α-glucosidase inhibitory activities compared to the underground parts by means of RE or UAE techniques. Lastly, the extracts of H. albo-marginata displayed a very remarkable α-glucosidase inhibitory activity compared to the positive control acarbose. The relationships of sixteen extracts of the four Hosta species were analyzed by RE and UAE techniques between extraction yields, TPC, TFC, antioxidant activity, and α-glucosidase inhibitory activity. The present study demonstrated that H. plantaginea, H. ventricosa, H. ensata, and H. albofarinosa could be new sources of natural antioxidants and antidiabetes for pharmaceutical and industrial purposes.

Ultrasound assisted extraction of selected edible macroalgae: Effect on antioxidant activity and quantitative assessment of polyphenols by liquid chromatography with tandem mass spectrometry (LC-MS/MS)

Despite vast coastline and huge cultivation of macroalgae in India, bioactive compounds in the edible macroalgae have not been well characterized. Ultrasound assisted extraction and conventional extraction techniques were compared & characterized by extracting three edible macroalgae, viz., Sargassum wightii, Ulva rigida and Gracilaria edulis in methanol. Ultrasound assisted extract (120 min) of S. wightii showed significantly higher (p < 0.05) phenolic (19.27 ± 0.05 mg gallic acid equivalent/g) and flavonoid content (14.94 ± 0.65 mg quercetin equivalent/g) as well as antioxidant activity [evaluated by ferric reducing antioxidant power (8.21 ± 0.02 mg Trolox/g) and by 2,2-Diphenyl-1-picrylhydrazyl (87.79 ± 0.13%RSA) assay] when compared with conventional extraction. G. edulis showed highest yield (4.77 ± 0.24%) with conventional extraction at 120 min. Further, extracts of all macroalgae (ultrasound assisted extraction/120 min) characterized by liquid chromatography with tandem mass spectrometry for bioactives showed highest phloroglucinol (69.86 ± 5.25 mg/kg), fucoxanthin (1.45 ± 0.22 mg/kg) and gallic acid in the S. wighti; highest quercetin (0.07 ± 0.00 mg/kg) and ferulic acid (0.21 ± 0.04 mg/kg) in the U. rigida and the highest vanillin (0.39 ± 0.01 mg/kg) in the G. edulis. Liquid chromatography with tandem mass spectrometry results corroborated higher antioxidant activity seen with the ultrasound assisted extract. This study seems the first report on use of ultrasound assisted extraction for the selected Indian edible macroalgae & quantification of their bioactives. Results are highly relevant to the functional food & nutraceuticals industry for the potential exploitation of these edible macroalgae, especially, the brown seaweed, S. wightii.

Design Based Ultrasound-Assisted Extraction of Marrubium vulgare Linn and Comparative Evaluation of Extracts for Furan Labdane Diterpene (Marrubiin) Concentration and Antihypertensive Potential

Background: Improvement in extract quality in terms of concentration of secondary metabolites and pharmacological activity has always been the need of the hour. In the present research, the target was to extract the selected medicinal herb using the ultrasound waves and to optimize the extraction conditions for the improvement in the quality of extract with respect to furan labdane diterpene (marrubiin) concentration and antihypertensive potential. Methods: The whole plant of Marrubium vulgare Linn. was collected from the fields of Pulwama district of Jammu and Kashmir state in India and extracted by cold maceration (MVM) and ultrasound assisted extraction techniques (MVU). The response surface methodology coupled with the central composite design was employed to optimize the selected extraction parameters in UAE method. The marrubiin concentration in different extracts was determined by HPTLC. The extracts were also evaluated for the antihypertensive potential by non-invasive blood pressure monitoring (NIBPM) method. Results: The extract yield (14.2 ± 0.9%) and concentration of marrubiin (0.91 ± 0.04%) were significantly improved at the optimized UAE conditions (Ultrasound power 467 W, sonication time of 47 minutes and solvent concentration of 33 mL per g of drug) as compared to the conventional method. Furthermore, the MVU extract (200 mg/kg) along with ethanol significantly (p&lt;0.01) prevented the rise in mean systolic blood pressure (MSBP) of animals and also the GSH was significantly (p&lt;0.05) enhanced as compared to ethanol-treated animals. Conclusion: The elevation in MSBP and decrease in reduced glutathione concentration (GSH) by the chronic ethanol consumption were significantly altered by MVU extract as compared to MVM extract. The enhanced antihypertensive effect of selected herb may be attributed to the improved concentration of secondary metabolites (marrubiin) in MVU extract obtained at optimized conditions.

Pectin from sunflower by-product: Optimization of ultrasound-assisted extraction, characterization, and functional analysis

In the current study, sunflower by-product pectin (SFBP) was obtained using ultrasound-assisted extraction (UAE) technique. The UAE variables were successfully optimized, and the optimal condition (irradiation time 30 min, temperature 33 °C and ultrasound power 400 W) yielded 11.15%. Under this condition, SFBP was rich in low-esterified galacturonic acid content (72.94%), and had long side branches of galactan, arabinogalactan, and arabinan, with an average molecular weight of 175.353 kDa. The structural properties were characterized using FTIR, NMR, XRD spectroscopies. The thermal analysis by DSC and TGA suggested suitable thermal stability for SFBP. The solubility, water and oil holding capacities, emulsifying capacity, emulsifying stability (vs various conditions), foam capacity, foam stability, DPPH and ABTS inhibitions, and reducing power assay were measured to evaluate the potential of SFBP to be considered as a food ingredient.

Development and application of green and sustainable analytical methods for flavonoid extraction from Passiflora waste

Brazilian biodiversity and favourable environmental conditions open up possibilities not yet explored, showing potential to shift the country’s monochromatic economy into an emancipated, diversified and sustainable economic environment. This can be made possible through the integral use of its resources, exploring every functional fraction to create novel solutions to modern problems. Biorefineries present an interesting strategy to fully use the potential of agricultural feedstocks and together with green separation methods can contribute to the generation of sustainable processes and products. Passion Fruit (Passiflora edulis Sims f. flavicarpa Deg species) is produced on a large scale in Brazil and in other tropical countries, and its processing plants generate tons of residues that basically consist of peel, seeds and bagasse, which account for around 75% of its mass. These fractions of P. edulis can contain significant amounts of flavonoids, secondary metabolites that are the main compounds responsible for the fruit’s bioactivity (antioxidant, anti-inflammatory, pesticide and biocide, in general). Therefore, this work aims to develop, apply and compare the best conditions for the extraction of isoorientin, orientin and isovitexin from passion fruit applying solid–liquid methodologies, followed by analyte quantification using UHPLC-PDA. Homogenizer-assisted (HAE), ultrasound-assisted (UAE) and microwave-assisted (MAE) extraction techniques were used, as well as a full factorial design to reach optimal parameters concerning the extraction yield and energy and solvent efficiencies. According to the results, the procedure based on HAE presented the best conditions for the extraction of selected flavonoids (1.07, 0.90 and 0.33 mg g−1 of isoorientin, orientin and isovitexin, respectively) and was considered the best method according to the green and sustainable described factors.

Ultrasound assisted extraction of phytochemicals from Coccinia indica fruits and its characterization

Ultrasound assisted extraction (UAE) technique was employed for the extraction of phytochemicals from Coccinia indica fruit. Twenty-two compounds were identified post extraction process by GCMS analysis. Temperature, time of extraction, solvent concentration and solid-solvent (SS) ratio were considered as important process parameters for UAE. Response surface method was applied for optimizing the extraction process. The study focussed on the yield of extract, antioxidant activity (DPPH and ABTS), total phenolic content and total flavonoid content as the dependent variables. The optimum values of process parameters were obtained to be 30 °C temperature, 42 min of extraction time, 63% solvent (ethanol) concentration and SS ratio of 1:60. At these optimum conditions, the extract yield was 18.58%. The DPPH activity of 83.42%, 27.18% ABTS radical scavenging ability, 12.82 mg Gallic acid equivalent (GAE)/g of phenolic content and 79.81 mg Rutin equivalent (RE)/g of flavonoid content were obtained. Major compounds identified by GCMS were rutin, naringenin, apigenin and kaempferol. Resveratrol was also identified in the extract of C. indica fruits.

The Chemical and Biological Profiles of Leaves from Commercial Blueberry Varieties.

Blueberries have seen an ascending production line boosted by World Health Organization (WHO) approvals for their contributions to a healthy diet and the evidence that they act against different diseases. This increase resulted in significant amounts of discarded leaves, which could be a valuable source of bioactive compounds. In the present study, ultrasound-assisted extraction technology was used to determine and compare the chemical and biological profiles of leaves from six commercial blueberry (Vaccinium corymbosum L.) varieties. Feruloylquinic acid was the major compound identified, ranging from 19.23 ± 0.18 mg/g (at the lowest level, registered in the Spartan variety) to 49.62 ± 0.41 mg/g (at the highest level, registered in the Nelson variety). Rutin was the second major compound identified, for which Toro, Nelson, and Elliot leaves registered the highest values, with 35.77 ± 0.19 mg/g, 32.50 ± 0.20 mg/g, and 31.53 ± 0.1 mg/g, respectively. Even though analogous polyphenols were detected in the six cultivars, their concentrations and amounts were different. The leaf extracts of the cultivars Toro, Elliot, and Nelson appear to be good sources of antioxidants, registering high percentage inhibitions of DPPH radicals, of 70.41%, 68.42%, and 58.69%, respectively. The blueberry leaf extracts had a strong antibacterial activity and a low antifungal capacity, and a low-to-moderate antimutagenic capacity towards Salmonella typhimurium TA98 and TA100 strains, with Toro leaf being the best candidate. All of these biological activities indicate health-related benefits, recommending them as suitable candidates for medical and pharmaceutical applications. The present paper adds significant knowledge to the field of blueberry leaves via chemical and biological profiles, supporting the ultrasound-assisted extraction technique as a useful and green method to provide alternative sources of bioactive compounds.

Bioactive Compounds in Bael Fruit Pulp Waste: Ultrasound-Assisted Extraction, Characterization, Modeling, and Optimization Approaches

Bael fruit is an abundant source of bioactive compounds that have importance in the food and pharmaceutical industries. The process of extraction of the bael fruit juice produced a higher percentage of bael fruit pulp waste (BFPW) (37.33 %), which was recycled for the extraction of bioactive compounds. Thus the bioactive compounds like polyphenols, flavonoids, and carotenoids were extracted from BFPW by using the ultrasound-assisted extraction (UAE) technique. The modeling and optimization of the extraction process were carried out by using the experimental design of response surface methodology (RSM). The ethanol concentration of 51.22 %, ultrasound amplitude of 51.45 %, and ultrasound treatment time of 6.11 minutes were obtained to be an RSM optimized values of extraction process variables. The lower values of root mean squared error (RMSE) and mean absolute error (MAE) and higher values of coefficient of determination (R2) indicated admissibility and acceptability of RSM. This extraction process of bioactive compounds has the potential to implement it on an industrial scale for the formulation of food additives and medicines.

Application of Tea Extract in Food Industry

Background and Objectives: Tea is considered one of the most consumed drinks around the world and the health benefits of it have recently attracted the attention of different researchers. It has also been proven beneficial in preventing the danger of some diseases like cancer and cardiovascular problems. Further, lipid oxidation is one of the major problems in food products. Considering the above-mentioned issues, the present review focused on various techniques used to extract polyphenols from different kinds of tea, as well as their use in the food industry. Results and Conclusion: Based on our findings in this review, the main components of tea are polyphenols that have health benefits and include catechins, epicatechin, epigallocatechin, epicatechin gallate, epigallocatechin gallate, gallic acid, flavonoids, flavonols, and theophlavins. From these components, catechin is regarded as the most beneficial component. Many techniques have been discovered and reformed to extract tea compounds such as solvent-based extraction, microwave-assisted water extraction, and ultrasound-assisted extraction techniques. Overall, the microwave-assisted water extraction method is a useful method for extracting tea polyphenols, which may be used in the meat, oil, and dairy industries.

Enhanced extraction of essential oil from Cinnamomum cassia bark by ultrasound assisted hydrodistillation

Cinnamon essential oil with many bioactivities is an important raw material for the production of various chemicals, and the conventional hydrodistillation (HD) for cinnamon oil extraction always require a longer extraction time. In this work, ultrasound-assisted hydrodistillation extraction (UAHDE) technique was employed to enhance the extraction efficiency of essential oils from cinnamon barks. The parameters with significant effects on the essential oil extraction efficiency (ultrasound time, ultrasound power, extraction time, liquid–solid ratio) were optimized, and the proposed UAHDE was compared with the conventional HD extraction in terms of the extraction time, extraction yield, and physicochemical properties of extracted oils. Compared to the HD extraction, the UAHDE resulted in a shorter extraction time and a higher extraction yield. Using GC–MS analysis, the UAHDE provided more valuable essential oil with a high content of the vital trans-cinnamaldehyde compounds compared with the HD. Scanning electron micrograph (SEM) confirmed the efficiency of ultrasound irradiation for cinnamon oil extraction. In addition, the analysis of electric consumption and CO2 emission shows that the UAHDE process is a more economic and environment-friendly approach. Thus, UAHDE is an efficient and green technology for the cinnamon essential oil extraction, which could improve the quantity and quality of cinnamon oils.

Comparative larvicidal effect of Pterodon spp. extracts obtained by different extraction methods

Pterodon spp. is a native Brazilian tree species of Fabaceae family, popularly known as sucupira. In the present study, the extraction methods of Soxhlet, supercritical fluid extraction (SFE) and ultrasound assisted extraction (UAE) were conducted at different conditions to recover compounds from “sucupira” with larvicidal activity against Aedes aegypti larvae. The influence of temperature and pressure on SFE with CO2 was compared to Soxhlet and UAE techniques, performed with hexane and ethanol as solvents. The use of ethanol as solvent provided better yields, but lower larvicidal activity. The extraction yields obtained with CO2 and hexane as solvents (non-polar) were similar, regardless the extraction method. Non-polar solvents showed better larvicidal activity with chances of having practical applications in fighting disease vectors. The chemical composition of these extracts presented as major components, trans-geranylgeraniol, germacrene-D-ol and caryophyllene, which showed to be responsible for the activity.

Advanced Extraction of Lipids with DHA from Isochrysis galbana with Enzymatic Pre-Treatment Combined with Pressurized Liquids and Ultrasound Assisted Extractions.

Microalgal biomass is a sustainable and valuable source of lipids with omega-3 fatty acids. The efficient extraction of lipids from microalgae requires fast and alternative extraction methods, frequently combined with biomass pre-treatment by different procedures. In this work, Pressurized liquid extraction (PLE) was optimized and compared with traditional lipid extraction methods, Folch and Bligh and Dyer, and with a new Ultrasound Assisted Extraction (UAE) method for lipids from microalgae Isochrysis galbana. To further optimize PLE and UAE, enzymatic pre-treatment of microalga Isochrysis galbana was studied with commercial enzymes Viscozyme and Celluclast. No significant differences were found for lipid yields among different extraction techniques used. However, advanced extraction techniques with or without pre-treatment are a green, fast, and toxic solvent free alternative to traditional techniques. Lipid composition of Isochrysis was determined by HPLC-ELSD and included neutral and polar lipids, showing that each fraction comprised different contents in omega-3 polyunsaturated fatty acids (PUFA). The highest polar lipids content was achieved with UAE (50 °C and 15 min) and PLE (100 °C) techniques. Moreover, the highest omega-3 PUFA (33.2%), eicosapentaenoic acid (EPA) (3.3%) and docosahexaenoic acid (DHA) (12.0%) contents were achieved with the advanced technique UAE, showing the optimized method as a practical alternative to produce valuable lipids for food and nutraceutical applications.

Identification of Fungal Pathogens of Mango and Soursop Fruits Using Morphological and Molecular Tools and Their Control Using Papaya and Soursop Leaf and Seed Extracts

Fruit and vegetable products are susceptible to the attack of fungi during postharvest handling. Chemical fungicides are the most commonly used technique to control fungal diseases. However, an alternative product is the use of plant extracts, which have been reported in in vitro and in vivo conditions. The objective of this investigation was to identify one of the main pathogens of mango and soursop fruits using morphological and molecular tools as well as to evaluate the in vitro inhibitory effect of papaya and soursop leaf and seed extracts. Two pathogens were isolated and identified by their morphological and molecular characteristics from mango and soursop fruits. We obtained extracts from leaves and seeds of soursop and papaya using five solvents of increasing polarity (hexane, acetone, ethanol, methanol, and water) through the ultrasound-assisted extraction technique at a frequency of 35 kHz and 160 W for 14 min. In vitro evaluations of the extracts were performed using the Kirby–Bauer technique. The extracts with the highest percentage of inhibition were analyzed qualitatively and quantitatively using standardized techniques of colorimetry and spectrophotometry. Furthermore, we determined the content of total phenols, flavonoids, alkaloids, terpenoids, anthraquinones, coumarins, and saponins. As a result, we identified the pathogens as Colletotrichum fructicola and Nectria haematococca. Aqueous extracts (water as a solvent) showed a higher percentage of inhibition of both pathogens compared with the other extracts. Furthermore, the aqueous extract of papaya leaf was the most effective among all extracts. The aqueous papaya leaf extract exhibited a percentage of inhibition of 49.86% for C. fructicola and 47.89% for N. haematococca. The aqueous extracts of papaya leaf and seed (AqEPL and AqEPS) presented the greatest amount of metabolites (except anthraquinones and coumarins). The aqueous soursop leaf extract (AqESL) presented the greatest amount of phenols, tannins, and flavonoids (219.14 ± 8.52 mg GAE/L, 159.84 ± 10 mg GAE/g dm and 0.13 ± 1.12 × 10−4, respectively). The aqueous soursop seed extract (AqESS) had the highest saponin content with 1.2 ± 0.1 mg QSES/g dm and the papaya leaf accusative extract (AqEPL) had the highest alkaloid content (6.413 ± 1 × 10−3 mg AE/g dm) compared with the other extracts. The AqESS had a lower content of secondary metabolites (sterols, alkaloids, and saponins), while AqESL showed no presence of alkaloids and coumarins.