Industrial potential of carotenoid pigments from microalgae: Current trends and future prospects

Microalgae are rich source of various bioactive molecules such as carotenoids, lipids, fatty acids, hydrocarbons, proteins, carbohydrates, amino acids, etc. and in recent Years carotenoids from algae gained commercial recognition in the global market for food and cosmeceutical applications. However, the production of carotenoids from algae is not yet fully cost effective to compete with synthetic ones. In this context the present review examines the technologies/methods in relation to mass production of algae, cell harvesting for extraction of carotenoids, optimizing extraction methods etc. Research studies from different microalgal species such as Spirulina platensis, Haematococcus pluvialis, Dunaliella salina, Chlorella sps., Nannochloropsis sps., Scenedesmus sps., Chlorococcum sps., Botryococcus braunii and Diatoms in relation to carotenoid content, chemical structure, extraction and processing of carotenoids are discussed. Further these carotenoid pigments, are useful in various health applications and their use in food, feed, nutraceutical, pharmaceutical and cosmeceutical industries was briefly touched upon. The commercial value of algal carotenoids has also been discussed in this review. Possible recommendations for future research studies are proposed.     

Improvement of the probiotic growth-stimulating capacity of microalgae extracts by pulsed electric fields treatment

This study aimed to investigate the nutritional character (carbohydrates, proteins, pigments, and phycocyanin), total antioxidant capacity (TAC) and the capability of simulating the growth of Lactobacillus rhamnosus of different extracts from C. vulgaris and A. platensis by means of the application of conventional aqueous extraction procedure and pulsed electric field (PEF) extraction technology. It was confirmed a significantly improved nutritional profile of Chlorella and Spirulina extracts obtained by PEF technology pre-treatment (3 kV/cm, 100 kJ/kg), with specifically higher values in total carbohydrate, Chlorophyll a, Chlorophyll b, and carotenoids content, and TAC. Additionally, Spirulina PEF extract showed a probiotic's growth-stimulating capability of 1 log10 cycle when fermented by Lactobacillus rhamnosus, with a metabolomic profile specifically rich in bioactive short chain fatty acids (SCFAs) and organic acids (3-phenyl lactic acid). The present study points out the applicability of PEF extraction technology under optimized conditions to improve the nutritional and functional character of microalgae and cyanobacterial-derived ingredients.     

Recovery of carotenoids from tomato processing by-products – a review

Industrial tomato processing generates large amount of low-value by-products, primarily used as livestock feed or disposed of; however, being a rich source of natural carotenoids, tomato waste can be used to produce high value-added products for food, cosmetics, or pharmaceutical applications. The objective of this review is to summarize and give an overview of the extraction methods available for the recovery of carotenoids and, especially, lycopene from tomato processing by-products. Organic solvent extraction techniques are presented and the effect of extraction conditions on carotenoids recovery is evaluated. In particular, the use of Ultrasound Assisted (UAE), Microwave Assisted (MAE), Enzyme-Assisted (EAE) and Extraction at High Pressure (HPE) for the recovery of carotenoids is assessed. Also, this review examines the efficiency of Supercritical Fluid Extraction (SFE) and in particular the effect of process parameters on carotenoid recovery from industrial tomato waste.     

Applications and opportunities for ultrasound assisted extraction in the food industry — A review

Ultrasound assisted extraction (UAE) process enhancement for food and allied industries are reported in this review. This includes herbal, oil, protein and bioactives from plant and animal materials (e.g. polyphenolics, anthocyanins, aromatic compounds, polysaccharides and functional compounds) with increased yield of extracted components, increased rate of extraction, achieving reduction in extraction time and higher processing throughput. Ultrasound can enhance existing extraction processes and enable new commercial extraction opportunities and processes. New UAE processing approaches have been proposed, including, (a) the potential for modification of plant cell material to provide improved bioavailability of micro-nutrients while retaining the natural-like quality, (b) simultaneous extraction and encapsulation, (c) quenching of the radical sonochemistry especially in aqueous systems to avoid degradation of bioactives and (d) potential use of the radical sonochemistry to achieve targeted hydroxylation of polyphenolics and carotenoids to increase bioactivity.Industrial relevanceThe application of ultrasonic assisted extraction (UAE) in food processing technology is of interest for enhancing extraction of components from plant and animal materials. This review shows that UAE technology can potentially enhance extraction of components such as polyphenolics, anthocyanins, aromatic compounds, polysaccharides, oils and functional compounds when used as a pre-treatment step in a unit process. The higher yield obtained in these UAE processes are of major interest from an industrial point of view, since the technology is an “add on” step to the existing process with minimum alteration, application in aqueous extraction where organic solvents can be replaced with generally recognised as safe (GRAS) solvents, reduction in solvent usage, and shortening the extraction time. The use of ultrasonic for extraction purposes in high-cost raw materials is an economical alternative to traditional extraction processes, which is an industry demand for a sustainable development.     

Alternative Extraction Method of Bioactive Compounds from Mulberry (<Emphasis Type="Italic">Morus nigra</Emphasis> L.) Pulp Using Pressurized-Liquid Extraction

Black mulberry (Morus nigra L.) is one of the most important species of the genus Morus as its fruit contains substantial levels of anthocyanins and phenolic compounds which show a potentially positive effect on the human health. Nowadays, PLE is becoming a promising extraction technology. Therefore, the development of fast extraction methods of anthocyanins and phenolic compounds from mulberry pulp using pressurized-liquid extraction (PLE) has been studied in this paper. The operating conditions (solvent, temperature, pressure, purge time, pH, and flushing) were investigated by a Box–Behnken design. Analysis of the model clearly showed that the most influential factors were temperature and solvent composition. The optimum extraction conditions for anthocyanins were 47.2% methanol in water, a temperature of 75.5 °C, pressure of 200 atm, a purge time of 90 s, pH 3.01, and 50.2% for flushing. The best conditions for the extraction of phenolics were 74.6% methanol, 99.4 °C, 100 atm, 90 s purge, pH 7, and 100% flushing. The optimum extraction time was 10 min. The precision values of the methods were also evaluated and excellent results (RSD?<?5%) were obtained. The developed methods were successfully applied to several mulberry marmalade samples. The results using PLE were compared to those achieved by UAE methods. Similar extraction yields were obtained for anthocyanins by PLE and UAE under optimized conditions; however, PLE required less methanol consumption. Besides, PLE showed higher extraction efficiency for total phenolic compounds. From the results, it can be concluded that pressurized-liquid extraction can be considered as an efficient alternative and powerful tool for the extraction of bioactive compounds from mulberries.     

Pulsed electric fields (PEF), pressurized liquid extraction (PLE) and combined PEF + PLE process evaluation: Effects on Spirulina microstructure,biomolecules recovery and Triple TOF-LC-MS-MS polyphenol composition

This study aims at evaluating the impact of different processes-pulsed electric fields (PEF), pressurized liquid extraction (PLE) and a multistep process combining PEF + PLE on the yield of antioxidant compounds (protein, polyphenols, chlorophyll a, chlorophyll b, and carotenoids) from Spirulina. Firstly, the effects of PEF or PLE treatment on the extraction yield of Spirulina biomolecules were evaluated. To further increase the extraction yield, PEF + PLE was used, as an innovative extraction approach. The results showed that PEF + PLE greatly improved the extraction yield compared with the PEF or PLE treatments alone. Compared with Folch extraction (conventional control technique), PEF + PLE significantly (P < 0.05) shortened the extraction time (−165 min) and increased the protein, polyphenol, chlorophyll a and antioxidant capacity values of Spirulina extracts by 1328%, 979%, 11% and 47% respectively. Furthermore, Triple TOF-LC-MS-MS results showed that PEF + PLE increased both the type and content of phenolic compounds. The above results were attributed to PEF-induced damage on Spirulina helical structure, which was verified by fluorescence and scanning electron microscopy.     

Pressurized liquids vs. high intensity focused ultrasounds for the extraction of proteins from a pomegranate seed waste

Pomegranate processing results in a waste with high protein content and potential industrial applicability. The reuse of these proteins requires their previous extraction and characterization. Nevertheless, extraction of proteins from vegetal tissues is a difficult task, and methodologies commonly applied for this purpose are non-sustainable and show low yields. Pressurized liquids extraction (PLE) is a sustainable technique scarcely applied for the extraction of proteins. PLE and high intensity focused ultrasounds (HIFU) have been compared in this work to recover proteins from a pomegranate seed waste. PLE extracted more proteins than HIFU, but it took longer and still co-extracted phenolic compounds. Extracted proteins were also characterized. Proteins separation by isoelectrofocusing electrophoresis revealed that the extraction technique, PLE or HIFU, significantly affected the solubility of proteins. Peptides released by simulated gastrointestinal digestion of extracted proteins also showed important differences when they were identified by UHPLC-MS/MS. Many identified peptides showed common features with antioxidant, antihypertensive, and hypocholesterolemic peptides. These activities were also confirmed by in vitro studies. PLE samples demonstrated, in general, higher bioactivity than HIFU. In addition to phenolic compounds, significantly co-extracted with proteins by PLE, other interesting compounds were also identified (e.g. azelaic acid).Industrial relevanceExtraction of proteins is usually carried out using non-sustainable methods that results in low yields and protein degradation. This work purposes the use of pressurized liquids extraction (PLE) for the recovery of proteins from a pomegranate seed waste, and compares these results with the obtained using high intensity focused ultrasounds (HIFU). PLE extracted more proteins but it required longer times than HIFU and co-extracted more phenolic compounds. The extraction procedure significantly affected proteins solubility and extracts composition. Proteins, peptides, and phenolic compounds contributed to the bioactivity of extracts. This work demonstrates that this waste is a sustainable and cheap source of proteins and bioactive molecules with high potential for the preparation of bioactive compounds, nutraceuticals, and cosmetics.     

Green ultra-high pressure extraction of bioactive compounds from Haematococcus pluvialis and Porphyridium cruentum microalgae

Microalgae are considered prolific sources of bioactive compounds that can be useful for nutraceuticals. In this study, the potential of ultra-high pressure extraction (UHPE) for the simultaneous cell disruption and extraction of bioactives from two microalgae species, Haematococcus pluvialis and Porphyridium cruentum, was evaluated. The variables studied to extract carotenoids for H. pluvialis were pressure (100–600 MPa) and number of cycles (1 and 3 cycles) whereas the variables studied to obtain bioactives such as B-phycoerythrin, carotenoids, and PUFAs for P. cruentum were pressure (100–600 MPa) and different extraction solvents (water, ethanol, ethyl acetate or ethanol/d-limonene), generally recognized as safe (GRAS). The UHPE results showed significant increase on the extraction of carotenoids (109.74–119.34 mg per g extract) from H. pluvialis using 1 cycle of 20 min regardless of the pressure used. For P. cruentum, an UHPE with water provided extracts enriched in B-phycoerythrin (up to 144.43 mg per g extract), while subsequent UHPE using ethanol, ethyl acetate or ethanol/d-limonene 1:1 (v/v) provided extracts enriched in carotenoids (up to 65.05 mg per g extract) and polyunsaturated fatty acids (mainly eicosapentanoic acid and linoleic acid). Therefore, UHPE proved to be a viable green alternative for the recovery of bioactives from microalgae biomass.Industrial relevance: Microalgae are promising sources of bioactives such as B-phycoerythrin, carotenoids and polyunsaturated fatty acids. The potential of ultra-high-pressure extraction (UHPE) has been demonstrated as a fast and viable eco-friendly alternative using GRAS solvents (water, ethanol, ethyl acetate or ethanol/d-limonene) for the simultaneous cell disruption and extraction of these bioactives from Haematococcus pluvialis and Porphyridium cruentum. The bioactives obtained with one step or two step-UHPE process can be used in an array of food, cosmetic and pharmaceutical applications.     

Pressurized liquids as an alternative process to antioxidant carotenoids' extraction from Haematococcus pluvialis microalgae

In this work, extraction of antioxidant carotenoids from Haematococcus pluvialis microalga, has been studied combining pressurized liquid extraction (PLE), using hexane and ethanol as extracting solvents, and analytical techniques such as thin layer chromatography (TLC) and HPLC with DAD. The effect of the extraction temperature (50, 100, 150 and 200 °C) and the polarity of the solvent have been studied in terms of in vitro antioxidant activity and chemical composition considering two different morphological cells (green vegetative cells and red cysts). Results demonstrate that the extraction temperature had a positive influence in the extraction yield while its effect in the antioxidant activity was negative, lowering the activity of the extracts with an increase of the extraction temperature. The best yields were obtained with ethanol at the higher extraction temperature while the best antioxidant activity was also achieved using ethanol but at lower temperatures. Chemical composition was determined by TLC and HPLC with DAD. Several compounds were identified in the samples and concentration of astaxanthin was obtained. Results pointed out that the extracts contained different carotenoids in both, the green and the red phase, and that depending on its contribution a stronger antioxidant activity would be expected.     

Application of high hydrostatic pressure and ultrasound-assisted extractions as a novel approach for pectin and polyphenols recovery from tomato peel waste

In this study, high hydrostatic pressure extraction (HHPE) and ultrasound-assisted extraction (UAE) were used for the improvement of pectin and polyphenol recovery from tomato peel waste.HHPE enhanced pectin recovery by 15% after 45 min of recycling, in comparison with the conventional extraction (CE) for 180 min. Similar mass fractions of anhydrouronic acid, total sugars and total phenols were obtained by using both methods. FTIR and ¹H NMR data confirmed that chemical composition of pectin obtained by HHPE and CE is identical, therefore it was concluded that the faster HHPE method can be used for its further isolation.Although depectinized residues subjected to UAE in 70% ethanol for 15 min contained two times lower values of total phenols (1625.7 mg/100 g) than pectinized samples (3643.9 mg/100 g), their quantities are not negligible, considering the fact that they are generated after HHPE. At the end of UAE, the residues were exploited as a source of fatty acids, among which lauric, palmitic and stearic acids are dominant.In conclusion, by shortening the extraction time using HHPE and UAE, it is possible to efficiently produce two valuable functional ingredients, pectin and polyphenols, and at the same time to reduce peel waste from tomato canning industry, which presents an environmental problem.Industrial relevanceUtilizing HHPE and UAE as novel and emerging technologies, and combining them with traditional ones (Soxhlet) is given the solution for sequential isolation of pectin, polyphenols and fatty acids from tomato peel waste, generated by canning factory.Shortening of extraction time using HHPE and UAE, it is possible to replace the conventional techniques, and achieve efficient production of pectin and polyphenols.Overall, the extraction methodology proposed in this work could provide two valuable benefits, i.e. the producers could find mode for decreasing of disposal costs of waste and consumer would take opportunity that isolated compounds could be reintroduced into food.     

Green ultrasound and microwave extraction of carotenoids from passion fruit peel using vegetable oils as a solvent: Optimization,comparison, kinetics,and thermodynamic studies

The aim of this study was to examine the effect of green processes like ultrasonication assisted extraction (UAE) and microwave assisted extraction (MAE) using olive oil (OO) and sunflower oil (SO) as solvents on the extractability of carotenoids from passion fruit peel (PEP) that is discarded as waste. Using optimized conditions of UAE, 91.4% (OO) and 86.7% (SO) of the carotenoids present were extracted while MAE extracted 86.9% in OO. Comparison of energy density revealed that UAE is more efficient than MAE. UAE treated OO was acceptable for different quality parameters and the oil was enriched with carotenoids by more than three times and phenolic content by fifteen times. The extraction kinetics and thermodynamic studies for carotenoids extracted from PEP using UAE and CE (conventional extraction) processes with OO as solvent were performed at different combinations of extraction time and temperature. The extraction rate constant (k_s) for UAE and CE was in the range of 0.0022–0.0048 100 g/μg carotenoids min and 4.02 × 10⁻⁵ − 6.85 × 10⁻⁵ 100 g d.w./μg carotenoids min, respectively. The effective diffusion coefficient of UAE and CE for the extraction of carotenoids varied between 2.3740 ×10⁻¹³ and 2.8260 ×10⁻¹³ m²/s and 0.997×10⁻¹⁴and 2.336 ×10⁻¹⁴ m²/s, respectively and corresponding mass transfer rate ranged from 1.625 ×10⁻⁷ – 1.8731 ×10⁻⁷ m/s and 0.0728 ×10⁻⁸ – 0.1714 ×10⁻⁸ m/s. The kinetics information mainly rate constant, effective diffusivity and mass transfer coefficient obtained from the green extraction process using ultrasonication would allow the prediction of operation conditions for industrial implementation.     

LC-ESI-MS/MS Analysis and Extraction Method of Phenolic Acids from Gluten-Free Precooked Buckwheat Pasta

In many countries, common buckwheat (Fagopyrum esculentum Möench) has been cultivated for its nutritive value as food ingredient. This plant is a rich source of vitamins and exogenic amino acids. Many of the health-promoting effects of F. esculentum have been attributed to a large amount of phenolic compounds. Presented in this paper, precooked buckwheat pasta, produced by extrusion cooking, is a gluten-free product without any technological additives. Moreover, it contains natural polyphenolic antioxidants and therefore could be classified as convenience food. The phenolic acid compositions of precooked buckwheat pasta were as follows: gallic, protocatechuic, gentisic, 4-OH-benzoic, vanillic, trans-caffeic, cis-caffeic, trans-p-coumaric, cis-p-coumaric, trans-ferulic, cis-ferulic, and salicylic. A very important step of sample pretreatment before quantitative analysis is the choice of extraction conditions. Therefore, in this study, before quantitative analysis (liquid chromatography-mass spectrometry, LC-ESI-MS/MS), optimization of ultrasound-assisted extraction (UAE) of phenolic acids from precooked buckwheat pasta was performed. The most effective conditions for the isolation of phenolic acids from precooked buckwheat pasta with the use of UAE were as follows: 80 % aqueous ethanol, 60 °C, ultrasound frequency 20 kHz, power 100 W, and time 40 min.     

Ultrasound‐assisted extraction of polyphenols from potato peels: profiling and kinetic modelling

Ultrasound‐assisted extraction (UAE) at 33 and 42 kHz has been investigated in the extraction of polyphenols from peels of two potato varieties, cream‐skinned Lady Claire (LC) and pink‐skinned Lady Rosetta (LR), commonly used in snack food production. Extraction efficacy between the UAE‐untreated (control) and the UAE‐treated extracts was assessed on the total phenolic content and antioxidant capacities (DPPH and FRAP). Application of UAE showed significantly higher recovery of phenolic compounds compared to solid–liquid extraction process alone. Lower ultrasonic frequency (33 kHz) was more effective in recovering polyphenols compared to 42 kHz ultrasonic treatment. The liquid chromatography‐tandem mass spectrometry revealed that chlorogenic acid and caffeic acid were the most prevalent phenolics in LR peels, whereas caffeic acid was dominant in LC peels. Peleg's equation showed a good correlation (R² > 0.92) between the experimental values and the predicted values on the kinetics of UAE of phenolic compounds.     

Functional food oil coloured by pigments extracted from microalgae with supercritical CO2

A functional food oil, rich in fatty acids and antioxidants, coloured with pigments (carotenoids) extracted with supercritical CO₂ from the microalga Chlorella vulgaris, was produced, having in view its use in food industry (namely for derived seafood). The supercritical fluid extraction (SFE) was carried out in order to study the effect of several modifiers (oil mixed with the microalga and ethanol with the supercritical CO₂), the degree of crushing of the microalga and the supercritical fluid flow rate, at a pressure of 300 bar and temperature of 40 °C. Moreover, the microalga pigments were also extracted with acetone and with vegetable oil at room and high temperature. The recovery of carotenoids was 100% with oil at room temperature for 17 h, 70% with oil at 100 °C for 30 min, 69% with supercritical CO₂ at 40 °C and 300 bar. In SFE the degree of crushing strongly influenced the extraction recovery and higher pigment recoveries were obtained with well crushed biomass.     

Changes of bioactive components in berry seed oils during supercritical CO2 extraction

The objective of the work was to elucidate the chemical composition of fractions of oil extracts obtained during the supercritical extraction on a semi‐industrial scale from strawberry (Fragaria x ananassa Duch.), chokeberry [Aronia melanocarpa (Michx.)], and raspberry (Rubus idaeus L.) seeds from industrial press cake. The oil extracts differed in terms of their content of bioactive components: carotenoids, tocopherols, chlorophylls, and fatty acids. Raspberry seed oil was the richest source of tocopherols (620.1–2166.7 mg kg^?1) and α‐linolenic acid (above 37%). Chokeberry seed oil had the highest content of linoleic acid (above 70%), and α‐tocopherol (166.0–1104.8 mg kg^?1). Strawberry oil was characterized by the highest content of chlorophylls and α‐linolenic acid (above 30%). It was showed that the oil fraction collected at the beginning of extraction is characterized by a high acid value, which requires purification steps to be used for food purposes.

Practical applications

Strawberry, raspberry, and chokeberry by‐products left over from the production of concentrated juice are a valuable source of oils rich in n‐3 and n‐6 polyunsaturated fatty acids, tocopherols, and carotenoids. The research showed that the fractionation of extracts in the course of supercritical extraction leads to oils with varying amounts of different bioactive compounds, and thus to products with potentially wide applications. Seeds oils have high potential utility as a source of unconventional oil for cosmetic and pharmaceutical sectors and biodiesel. Their targeted utilization may be exploited for economic, environmental and health benefits.     

Recovery of Aromatic Aglycones from Grape Pomace Winemaking By-Products by Using Liquid-Liquid and Pressurized-Liquid Extraction

The potential of winemaking grape pomace by-products as a source of glycosidic aroma precursors that under enzymatic hydrolysis might release aroma compounds has been evaluated. Two different extraction methodologies, liquid–liquid and pressurized liquid extraction (LLE and PLE) were employed. Solid phase extraction (SPE)-GC-MS analysis of the hydrolyzed LLE glycosidic extract revealed 22 aroma compounds belonging to different chemical families (terpenes, C13 norisoprenoids, vanillines, etc.). Response surface methodology was employed to study the effect of the most significant PLE experimental variables (temperature and solvent composition) on the extraction of aromatic aglycones. The parameters of the model were estimated by multiple linear regressions. Most of the aroma compounds showed an adequate fit to the calculated model (18 compounds from 22 with R ²?>?0.8). The application of the optimized PLE conditions (50 % of ethanol in the hydroalcoholic solution) and 90 °C showed higher extraction yield of aglycones when comparing with the extraction yield obtained by LLE.     

Validation of a Method for Analysis of Aroma Compounds in Red Wine using Liquid–Liquid Extraction and GC–MS

An analytical method for determination of volatile composition of wines using sample preparation by liquid–liquid extraction and gas chromatography coupled to mass spectrometry for separation and detection has been developed and validated. Extraction of volatile compounds was performed in dichloromethane, and 1-octanol was added as an internal standard. Kékfrankos red wine produced in Villány wine region in Hungary was used as a model wine for testing and validation of the method. The developed method allowed satisfactory determination of 33 volatile compounds in the wines. Compounds analyzed include alcohols, esters, lactones, fatty acids, furans, and nitrogen compounds. The calibration curves of the four reference compounds used (2-phenyl ethanol, ethyl nonanoate, butyrolactone, and tyrosol) were linear in all cases with correlation coefficients (R ²) ranging from 0.9951 to 0.9992. The accuracy of the method was checked with a standard addition method (recovery 92.2–103 %), showing good repeatability and reproducibility (RSD?<?10 %).     

Emerging opportunities for the effective valorization of wastes and by-products generated during olive oil production process: Non-conventional methods for the recovery of high-added value compounds

BackgroundA large amount of wastes and by-products are generated during olive oil production process. Traditionally, these products have been considered as a problem. However, they constitute a great source of high-added value compounds, which have the potential to be used as food additives and/or nutraceuticals. Therefore, valorization of wastes and by-products from food industry kills two birds with one stone and addresses both the use of waste and by-products and societal health, thus greatly contributing for a sustainable food chain from an environmental and economical point of view.Scope and approachIn the present review, current and new insights in the recovery of high-added value compounds from wastes and by-products generated during olive oil production process will be discussed. Several conventional (solvent, heat, grinding) and non-conventional methodologies (ultrasounds, microwaves, sub- and supercritical fluid extractions, pressurized liquid extraction, pulsed electric fields and high voltage electrical discharges) have been investigated for the recovery of high-added value compounds (polyphenols, fatty acids, coloring pigments (chlorophylls and carotenoids), tocopherols, phytosterols, squalene, volatile and aromatic compounds) from wastes and by-products generated during olive oil production process.Key findings and conclusionsNon-conventional technologies can constitute a promising tool to recover high-added value compounds from olive oil wastes and by-products. However, the content of these valuable compounds can vary greatly depending on the matrix and the efficiency in the recovery of these compounds is highly dependent of the technology used for extraction.     

微藻生物活性物质在食品工业中的应用进展

微藻能产多种生物活性物质,其中一些可以作为功能性食品的添加剂。一些微藻能积累大量人体所需的超长链不饱和脂肪酸,包括花生四烯酸(ARA)、二十碳五烯酸(EPA)和二十二碳六烯酸(DHA)。尽管利用微藻生产DHA技术已得到商业化应用,其他超长链不饱和脂肪酸仍尚不能通过微藻商业化生产。微藻中的多糖是微藻的细胞结构成分、储能物质或充当其他生理功能,它们通常具有粘弹性等流变特性,因此它们不仅可以作为保健食品的功能因子,还适合作果冻和饮料的配料。类胡萝卜素、藻胆蛋白和叶绿素等色素,具有生物活性,可作为具有保健作用的食品着色剂。一些微藻类胡萝卜素已经能够商业化生产,但是像叶绿素等其他微藻色素的工业化生产技术仍待开发。微藻还能合成多种具有抗病毒、抗氧化和血管紧张素转换酶抑制活性的肽,一些生物活性肽也可通过水解微藻蛋白获得。本文综述了微藻的生物活性物质以及这些活性成分在功能性食品中应用的可能性。     

Integration of pressurized liquids and ultrasound in the extraction of bioactive compounds from passion fruit rinds: Impact on phenolic yield,extraction kinetics and technical-economic evaluation

Passion fruit rind is a by-product rich in bioactive compounds that can be recovered by high pressure extractions and ultrasound using nontoxic solvents in shorter process times. This work investigated Pressurized Liquid Extraction (PLE) and its combination with ultrasound (Ultrasound-Assisted Pressurized Liquid Extraction, UAPLE) to intensify the recovery of phenolic compounds from passion fruit rinds. The influences of process parameters such as temperature, pressure, ultrasonic intensity and solvent mass flow rate on the global yield (X₀), total phenolic content (TPC) and antioxidant capacity were evaluated. The major phenolics were determined by UHPLC-QE HRMS. Kinetic extraction curves adjusted by the Spline and two-site models showed that in UAPLE (60 °C, 10 MPa and 360 W/cm²) with solvent flow rate of 10 g/min, 100% of TPC was recovered in 68.54 min of extraction. This condition also provided the greatest economic viability concerning total phenolics, with the lowest estimated manufacturing cost.Industrial relevanceSynthetic compounds in processed food have been increasingly rejected by consumers, who look for natural compounds that promote health benefits and are obtained with sustainable technologies. The bioactive compounds found in passion fruit rinds can meet this industrial demand as potential colorants, additives and natural preservatives in foods or beverages, incorporated in cosmetics, functional food and pharmaceutical supplements. In order to successfully recover bioactive compounds, it is recommended to apply selective extraction techniques in the target compound, thus providing final products with greater added value. In addition, the process optimization is crucial to achieve optimal extraction conditions to maximize the yield of the targent compounds. Given this context, searching for a more sustainable destination of the passion fruit agroindustrial waste and to increase its commercial value, this work proposes the combination of two extraction techniques, Ultrasound and Pressurized Liquid Extraction (UAPLE), to intensify the recovery of bioactive compounds from passion fruit rinds. The findings of this work reveal that UAPLE can enhance the extraction of phenolic compounds from passion fruit rinds even at moderate temperatures, thus encouraging the application of this technique for other agroindustrial by-products. Moreover, the economic evaluation of the UAPLE at the optimal conditions indicates its viability for industrial scale application.