IntroductionThe population of the earth is growing every year,which makes technologies for food obtaining andprocessing very important for humanity. Efficientprocessing technologies produce more useful productswhile doing less harm to the environment. The oceansare the least explored part of the earth. Every year,dozens of new compounds are isolated from marineaquatic organisms around the world. Many of thempossess various beneficial biological properties that canbe used, for instance, in pharmacology. Every year, newsecondary metabolites of great practical and fundamentalinterest are extracted from echinoderms.Starfish (Asteroidea) are widespread marineechinoderms of more than 160 species. Starfish arepredators that damage shellfish plantations and coralreefs. In the XX–XXI centuries, world fisheries havebeen busy looking for new sources of nutrients, especiallyfor marine carriers of biologically active substances thatcan be used to obtain highly effective medicines [1].The present research featured Lysastrosoma anthosticta;the research objective was to select a promising methodof supercritical extraction.Supercritical fluid extraction and supercritical fluidchromatography have been used since the late 1970sin food analysis for determining lipids and toxicants.Supercritical fluid extraction is an effective means ofnatural product extraction. The supercritical extractionprocess has potential advantages over conventionalextraction processes, such as shorter extraction time,reduced organic solvent volume, and more selectiveextraction [2].Study objects and methodsSamples of Lysastrosoma anthosticta Fisher, 1922were harvested in the Peter the Great Bay (Russia,Sea of Japan) in 2020. Starfish with a total weight of42 000 g were gutted, cut with scissors into small pieces(about 1 cm long), and stored in a plastic bag at –70°C.Frozen samples were lyophilized and crushed. The dryweight was 3630 g. After that, 30 g of aliquots was usedfor extraction. All experiments were done in triplicates.Extraction with supercritical CO2 was performed usingTHAR SFC 500 (USA). Figure 1 shows the technologicalscheme of the supercritical extraction unit. Extractionwas carried out using supercritical CO2: pressure – 200,400, and 600 bar per square inch; t – 30, 40, 50, 60,and 70°C; flow rate – 20 g/min. At the second step,the experiment extraction was carried out using CO2and 5% solvent (chloroform): pressure – 200, 400, and600 bar per square inch; t – 30, 40, 50, 60, and 70°C;flow rate – 20 g/min. The control extraction of 30 g ofdried starfish was carried out using the Folch methodwith a mix of chloroform-methanol (2:1) at the rate of20 parts of the extraction mixture per one part of thetissue at 30, 40, 50, 60, and 70°C [3].The extracts were analyzed by high-performance liquidchromatography (HPLC) with tandem mass spectrometryАннотация.Введение. Морские звезды (Asteroidea) насчитывают более 160 видов, что делает их ценным сырьем для производства белкови жиров. Настоящее исследование позволило определить химический состав морских звезд и доказало целесообразностьиспользования этого ресурса в качестве коммерческого источника жиров.Объекты и методы исследования. В ходе исследования были определены оптимальные параметры экстракциилипидной фракции Lysastrosoma anthosticta сверхкритическим диоксидом углерода, а также описан качественныйсостав полученных экстрактов.Результаты и их обсуждение. Выход жирных кислот, полученных со сверхкритическим сорастворителем диоксидауглерода, был в 1,8 раза выше, чем при стандартной экстракции по методу Фолча. Содержание примесей оказалось ниже,чем в образцах, где использовалась система хлороформ-метанол. Полиненасыщенные жирные кислоты, выделенныеиз L. anthosticta, принадлежали к ω-3 (18,0 %), ω-6 (11,7 %), ω-7 (21,2 %), ω-9 (10,1 %) и ω-11 (6,5 %). Остальноесоставляли насыщенные жирные кислоты: пальмитиновая (до 14 %) и миристиновая (до 6 %). Качественный составлипидной фракции не отличался от метода выделения. Однако сверхкритическая экстракция увеличила выход продукта,скорость экстракции и качество экстракционного остатка. Сверхкритический диоксид углерода оставил твердый осадок,который не имел характерного запаха и был достаточно хрупким для дальнейшего измельчения. В будущем такойостаток можно использовать для получения белкового концентрата.Выводы. Сверхкритическая экстракция хлороформом может быть рекомендована для выделения жирных кислот изморских организмов при 60°C и 400 бар.Ключевые слова. Морская звезда, иглокожие, ненасыщенные жирные кислоты, липиды, мореФинансирование. Работа выполнена при финансовой поддержке гранта Президента Российской Федерации(SP-3156.2019.4).Для цитирования: Применение технологии сверхкритической экстракции для получения полиненасыщенных кислотиз морской звезды Lysastrosoma anthosticta Fisher, 1922 / А. М. Захаренко [и др.] // Техника и технология пищевыхпроизводств. 2021. Т. 51. № 4. С. 753–758. (На англ.). https://doi.org/10.21603/2074-9414-2021-4-753-758.755Захаренко А. М. [и др.] Техника и технология пищевых производств. 2021. Т. 51. № 4 С. 753–758(LC-MS/MS). Reverse-phase HPLC was performed usinga Shimadzu LC-20 liquid chromatograph (Shimadzu,Japan) equipped with a CTO-20A thermostat (Shimadzu,Japan) and a UV-VIS SPD-20A detector (Shimadzu,Japan). ZORBAX Eclipse XDB C18 (150×4.6 mm,particle size: 5 microns) was used as an analyticalcolumn at a temperature of 30°C and a total flow rate of0.22 mL/min. Gradient elution with two mobile phasesFigure 1. Technological scheme of the supercritical extraction unitFigure 2. HPLC and ion trap joint system with tandem mass spectrometry50 60 70756Zakharenko A.M. et al. Food Processing: Techniques and Technology, 2021, vol. 51, no. 4, pp. 753–758(A – deionized water; B – acetonitrile with formic acid0.1% v/v) was programed as follows: 0 min 0% V,25 min 100% V, 60 min 100% V. The chromatographand the mass spectrometric detector were linked by theCompass software, which made it possible to integratethe entire system into a single complex (Fig. 2).The mass spectra of electrospray ionization massspectrometry (ESI-MS) and electrospray ionizationtandem mass spectrometry (ESI-MSN) were performedusing an Amazon SL ion trap (Bruker, Germany) equippedwith an electrospray ionization source. The ESI MSionization parameters were optimized as follows: capillaryvoltage of 4500 V, nitrogen spraying at 29 psi, dry gasconsumption of 10 l/min at 160°C. Mass spectra wererecorded in the mass range m/z 50–2000 in the modeof negative and positive ions. The mass spectra of theions were recorded in the auto MS/MS mode.Results and discussionAn analysis of yields of lipids fraction fromLysastrosoma anthosticta under various conditionsshowed that the extraction with supercritical carbondioxide with no co-solvent was less effective than thestandard extraction according to the Folch method(Fig. 3). However, when extra 5% chloroform was addedto the extraction system as a co-solvent, it significantlyincreased the yields of the total fatty acid fraction. Thechoice of the solvent and the extraction range parameterswas based on the results of previous works where starfishmaterial was treated with a plant matrix [4, 5]. Despitethe fact that the main target components are soluble inliquid CO2 only above 200 bar, it is possible to separatesignificant amounts of the lipid fraction [6, 7]. Thelipid fraction obtained by supercritical extraction withchloroform was 1.8 times higher than in the standardFolch method. The extraction was found to be quiteeffective only when a co-solvent was used. The optimalparameters for extraction with a co-solvent included atemperature of 60°C and a pressure of 400 bar. The dataobtained correlated with the most frequently selectedparameters. Most often, when using this technology, theauthors chose a pressure of 300–350 bar as the optimalone [8–11]. With these parameters, a good yield oflipids can be obtained as quickly as possible; a furtherincrease in the temperature and extraction pressure didnot lead to a significant increase in the yield.Obtaining chemical profiles is an extremely importantresult for any biological analysis system. In this work,we used the HPLC-ESI-MS/MS method with additionalionization and analysis of fragmented ions. High accuracymass spectrometric data were recorded on an ion trapamaZon SL BRUKER DALTONIKS equipped withan ESI source in the mode of negative and positiveions. The experiment used a four-stage ion separationmode (MS/MS mode). A qualitative analysis showedthat the ratio of polyunsaturated to saturated fatty acidsdid not depend on the extraction method (Table 1). Ananalysis of polyunsaturated fatty acids isolated fromL. anthosticta showed that they mainly belonged toω-3 (18.0%), ω-6 (11.7%), ω-7 (21.2%), ω-9 (10.1%),and ω-11 (6.5%). The rest was saturated fatty acids,mainly palmitic (up to 14%) and myristic (up to 6%).Figure 3. Effect of extraction conditions on the yield of the fatty acid: a – extraction with supercritical CO2;b – extraction with supercritical CO2 with a solvent (chloroform); c – extraction accordingto the Folch method at various temperatures02430 40 50 60 70a bc d757Захаренко А. М. [и др.] Техника и технология пищевых производств. 2021. Т. 51. № 4 С. 753–758The predominance of polyunsaturated acids is typicalof starfish [12, 13].A review of scientific publications showed thatstarfish can be considered as a valuable source offeed additives for agricultural animals and birds.For instance, Danish compound feed producers areconsidering the possibility of industrial use of starfishto produce additives for compound feeds. Accordingto recent studies, such compound feed can reduce theexcretion of nitrogen in pigs. Scientists from the Centerfor Aquatic Animals in Denmark proved that starfishcan be an effective alternative to traditional sources offeed protein, e.g. soybeans. Starfish meal could replacethe most commonly used protein sources and increasethe weight gain in piglets. In fact, starfish-based animalfeed may be more economically rational than traditionalprotein sources. In addition, starfish are being rigorouslytested as a possible protein source for bird nutrition. Ifthe results are confirmed, starfish will become a richsource of protein, which will create high demand fromegg producers, who are constantly searching for newsources of protein [14].ConclusionStarfish are a valuable raw material for proteinand lipid production. The chemical composition ofstarfish makes it possible to use it in food and feedindustry. The content of proteins was 9.5–14.0%, lipids– 0.5–3.5%, minerals – 1.5–32.0%. In comparison withthe integumentary tissue, the internal organs of starfishhave a higher content of potassium and iron [15, 16].The yields of fatty acids obtained under conditions ofsupercritical carbon dioxide co-solvent were 1.8 timeshigher than those obtained with the standard Folchmethod, while the content of impurities was lower thanwhen the extraction was performed using a chloroformmethanolsystem. The analysis of polyunsaturated fattyacids isolated from Lysastrosoma anthosticta showedthat they mainly belonged to ω-3 (18.0%), ω-6 (11.7%),ω-7 (21.2%), ω-9 (10.1%), and ω-11 (6.5%). The restwas saturated fatty acids: palmitic (14%) and myristic(6%). Thus, isolating fatty acids from marine organismsusing supercritical extraction with chloroform can berecommended as an effective commercial method.In addition, supercritical carbon dioxide with a solventleft a dry residue, brittle enough for further grinding andwithout typical smell. Such a residue can presumablybe used to produce protein concentrate.ContributionAll the authors contributed equally to the study andbear equal responsibility for information published inthis article.Conflict of interestsThe authors declare that there is no conflict of interestsregarding the publication of this article.