“Fresh-cut” krumpir tretiran eteričnim uljem komorača tijekom skladištenja pri 8 °C

The aim of this study was to investigate the effect of treatment with fennel essential oil (FEO) on the shelf life of fresh-cut potatoes (FCP) and on the sensory characteristics of raw and subsequently boiled and fried potatoes. Peeled and sliced potatoes were immersed in an aqueous solution containing different FEO concentrations (0 (water control), 25, 125, and 250 mg L-1) for 15 min, then drained, vacuum packaged, and stored at 8 °C for 12 days. The CIELAB color parameters and aerobic mesophilic bacteria count (AMB) of the raw FCP and the sensory characteristics of the raw, boiled and fried samples were determined. AMB decreased with increasing FEO content, and this trend was generally maintained during storage. Slight negative changes in color were observed with increasing FEO content and with storage time. Fennel taste and odor in raw and boiled potatoes increased with increasing FEO content, while FEO odor after frying was only slightly pronounced in FEO-250 on day 0. Despite the antibacterial activity of FEO, spoilage of FCP was not prevented during storage. In general, after 6 days, the best results in terms of absence of browning and off-odor of raw and off-taste and sour taste of boiled and fried FCP were obtained with 25 mg L-1 FEO treatment.Cilj ovog istraživanja bio je ispitati učinak tretiranja eteričnim uljem komorača (FEO) na rok trajanja svježe rezanog krumpira (FCP) te na senzorske karakteristike sirovog te naknadno kuhanog i prženog krumpira. Oguljeni i narezani krumpiri potopljeni su 15 min u vodenu otopinu koja je sadržavala različite koncentracije FEO (0 (kontrola-voda), 25, 125 i 250 mg L-1), zatim su ocijeđeni, pakirani u vakuumu i pohranjeni pri 8 °C tijekom 12 dana. Određivan je broj aerobnih mezofilnih bakterija (AMB) sirovog FCP te su analizirani CIELAB parametri boje i senzorske karakteristike sirovih, kuhanih i prženih uzoraka. S povećanjem koncentracije FEO AMB se smanjio, a taj se trend uglavnom zadržao i tijekom skladištenja. S povećanjem koncentracije FEO i s vremenom skladištenja uočene su blage, ali negativne promjene boje. U sirovom i kuhanom krumpiru svojstva okusa i mirisa komorača povećavale su se s povećanjem udjela FEO, dok je miris FEO nakon prženja bio tek neznatno izražen i to u FEO-250 0-tog dana. Unatoč antimikrobnom djelovanju FEO, kvarenje FCP-a tijekom skladištenja nije spriječeno. Općenito, nakon 6 dana, najbolji rezultati s obzirom na boju i odsutnost neugodnog mirisa sirovog te neugodnog i kiselkastog okusa kuhanog i prženog FCP postignuti su tretmanom s 25 mg L-1 FEO

The influence of laurel essential oil treatment on the shelf-life and sensory characteristics of fresh-cut apples during storage

Fresh-cut apples provide consumers convenient, fresh, ready-to-eat product. However such products are susceptible to browning and microbiological spoilage which occurs very quickly after processing. Due to their antimicrobial properties, essential oils have a potential stabilizing effect on fresh-cut products, but could have undesirable effects on their color or taste. The aim of this study was to investigate the effect of laurel essential oil (LEO) treatment at different concentrations (25, 75, 125 and 175 mg L-1) on the shelf-life (aerobic mesophilic bacteria count) and physical (soluble dry metter, pH, color, texture) and sensory characteristics of fresh-cut apples during 10 days of storage at 8 °C. Number of aerobic mesophilic bacteria decreased with the increase of LEO concentration and it slightly increased with the increase of storage time. In general, samples treated with 75 mg L-1 LEO had the lowest and samples treated with 175 mg L-1 LEO the highest soluble dry matter, while pH trend was vice versa. Soluble dry matter, pH, and firmness increased during storage. Apples treated with 75 mg L-1 LEO after 10 days of storage showed the least color change. This study showed that LEO can be used to preserve and enrich sensory characteristics of fresh-cut apples, especially at a concentration of 75 mg L-1. Generally, this LEO concentration can be recommended regarding the results of microbiological and sensory analysis as well as results of soluble dry matter, pH, color parameters and firmness

Utjecaj UV-C zračenja na trajnost svježe rezanog krumpira i njegova senzorna svojstva nakon termičke obrade

Research background. Potato tissue is damaged during fresh-cut production, which makes fresh-cut potato susceptible to the quality loss and microbiological spoilage. At the same time, such products are desirable due to their convenience; however, they are extremely sensitive and have short shelf life. The main challenge of the fresh-cut potato industry is to find possibilities to overcome these drawbacks. UV-C treatment, known for its antibacterial activity, is a promising technique and it shows a potential to improve shelf life of fresh-cut potato products. Experimental approach. The influence of the UV-C treatment on the safety and quality, as well as sensory traits of fresh-cut potato (Solanum tuberosum L. cv. Birgit) during storage was examined. For this purpose, 0-, 3-, 5- and 10-min UV-C irradiation was applied on vacuum-packed potato slices pretreated with sodium ascorbate solution. During 23 days of storage at (6±1) °C, microbiological, physicochemical and sensory properties of raw samples were monitored, along with sensory properties of boiled and fried fresh-cut potatoes. Results and conclusions. The 5- and 10-min UV-C treatments significantly reduced microbial growth, increased total solids and lightness (L*), and positively affected odour and firmness of raw potatoes. Cooked UV-C-treated samples were described with more pronounced characteristic potato odour and taste. Overall, UV-C-treated fresh-cut potato retained its good quality and sensory traits up to 15 days at (6±1) °C. Novelty and scientific contribution. To the best of our knowledge, this is the first scientific article dealing with the effect of UV-C light on durability (safety, quality and sensory traits) of fresh-cut potato cv. Birgit and its suitability for boiling and frying. In general, UV-C treatment is a known antimicrobial technique, but its application on fresh-cut potato is poorly explored. Results confirmed that vacuum-packed fresh-cut potato treated only with UV-C and sodium ascorbate as anti-browning agent, without the addition of chemical preservatives, had twofold longer shelf-life at (6±1) °C than the fresh-cut potato not treated with UV-C. Fresh-cut potato treated with UV-C retained good overall quality and sensory properties either raw, boiled or fried. Results of this study could also be useful for producers in terms of potential UV-C application as a strategy for prolonging the shelf-life of fresh-cut potato.Pozadina istraživanja. Tijekom proizvodnje svježe rezanog krumpira dolazi do oštećenja tkiva krumpira, što ga čini osjetljivim na gubitak kakvoće i mikrobiološko kvarenje. Istodobno, takvi su proizvodi poželjni zbog svoje praktičnosti, no izrazito su osjetljivi i imaju kratki rok trajanja. Glavni izazov industrije svježe rezanog krumpira je pronaći mogućnosti za prevladavanje ovih nedostataka. Obrada UV-C zrakama, poznatima po svom antibakterijskom djelovanju, je obećavajuća tehnika i pokazuje potencijal za poboljšanje trajnosti svježe rezanih proizvoda od krumpira. Eksperimentalni pristup. Ispitivan je utjecaj UV-C zraka na sigurnost i kakvoću, kao i senzorna svojstva svježe rezanog krumpira (Solanum tuberosum L. cv. Birgit) tijekom skladištenja. U tu svrhu primijenjeno je 0-, 3-, 5- i 10-minutno UV-C zračenje na vakuumirane kriške krumpira prethodno obrađene otopinom natrijevog askorbata. Tijekom 23 dana skladištenja na (6±1) °C praćena su mikrobiološka, fizikalno-kemijska i senzorna svojstva sirovih uzoraka, te senzorna svojstva kuhanog i prženog svježe rezanoga krumpira. Rezultati i zaključci. Obrada UV-C zrakama u trajanju od 5 i 10 minuta značajno je smanjila rast mikroba, povećala ukupnu suhu tvar i svjetlinu (L*), te pozitivno utjecala na miris i čvrstoću sirovog krumpira. Kuhani uzorci tretirani UV-C zrakama opisani su kao uzorci s izraženijim karakterističnim mirisom i okusom krumpira. Sveukupno, svježe rezani krumpir tretiran UV-C zrakama zadržao je svoju dobru kakvoću i senzorna svojstva do 15 dana na (6±1) °C. Novina i znanstveni doprinos. Koliko je nama poznato, ovo je prvi znanstveni članak koji se bavi učinkom UV-C svjetla na trajnost (sigurnost, kakvoću i senzorna svojstva) svježe rezanog krumpira cv. Birgit i njegovu prikladnost za kuhanje i prženje. Općenito, obrada UV-C zrakama je poznata antimikrobna tehnika, ali je njegova primjena na svježe rezani krumpir slabo istražena. Rezultati su potvrdili da svježe rezani krumpir pakiran u vakuumu i tretiran samo UV-C zrakama i natrijevim askorbatom kao sredstvom protiv posmeđivanja, bez dodatka kemijskih konzervansa, ima dvostruko dužu trajnost pri (6±1) °C od svježe rezanoga krumpira koji nije tretiran UV-C zrakama. Svježe rezani krumpir tretiran UV-C zrakama zadržao je dobru ukupnu kakvoću i senzorna svojstva, kako sirov tako i kuhan ili pržen. Rezultati ovog istraživanja mogli bi biti korisni i proizvođačima u smislu moguće primjene UV-C svjetla kao strategije za produljenje trajnosti svježe rezanog krumpira

Utjecaj sorte i industrijske obrade na sastav polifenola u koncentriranom soku višnje (Prunus cerasus L.)

The objective of this study is to investigate the infl uence of cultivar and industrial processing on total polyphenols, anthocyanins, hydroxycinnamic acids and antioxidant activity in concentrated sour cherry (Prunus cerasus L., cvs. Marasca and Oblačinska) juices. Samples were collected during four processing steps: from fresh fruit prior to processing, then from pressed, fi ltered and concentrated juices. The content of total phenols was the same in both cultivars, but antioxidant activity (Oblačinska>Marasca) and total monomeric anthocyanins (Marasca>Oblačinska) diff ered. All processing steps significantly influenced the content of total phenols, total monomeric anthocyanins and antioxidant activity. In all samples four major anthocyanins were identifi ed by HPLC with UV/VIS PDA detector, listed in the descending order based on their abundance: cyanidin-3-glucosylrutinoside, cyanidin-3-rutinoside, cyanidin-3-sophoroside and cyanidin-3-glucoside. Marasca cv. contained more total anthocyanins, and contents of cyanidin-3-sophoroside and cyanidin-3-glucosylrutinoside. The content of total hydroxycinnamic acids was also higher in Marasca than Oblačinska cv. Aft er processing, the concentration of all identifi ed anthocyanins increased in both cultivars. Majority of the highest values of polyphenols were detected in the juice aft er pressing. The content of polyphenols and their antioxidant activity were considerably stable during industrial processing to concentrated juice. Although Marasca had higher polyphenolic content than Oblačinska, both cultivars showed promising industrial potential for processing to concentrated juice.Svrha je ovoga rada bila ispitati utjecaj sorte i industrijske obrade na ukupne polifenole, antocijanine, hidroksicinamične kiseline i antioksidacijsku aktivnost u koncentriranom soku višnje (Prunus cerasus L., sorte Maraska i Oblačinska). Uzorci su prikupljeni tijekom četiri koraka obrade: iz svježeg voća prije prerade, te iz prešanog, filtriranog i koncentriranog soka. Ukupni je udjel fenola bio jednak u obje sorte, ali su se antioksidacijska aktivnost (Oblačinska>Maraska) i ukupni udjel monomernih antocijanina razlikovali. Svi su koraci obrade bitno utjecali na ukupni udjel fenola, monomernih antocijanina i antioksidacijsku aktivnost soka višnje. Visokodjelotvornom tekućinskom kromatografijom (HPLC) uz UV/VIS PDA detekciju u svim su uzorcima identificirana četiri glavna antocijanina, i to redom od najzastupljenijeg: cijanidin-3-glukozilrutinozid, cijanidin-3-rutinozid, cijanidin-3-soforozid i cijanidin-3-glukozid. Kultivar Maraska sadržavao je više antocijanina, te veće udjele cijanidin-3-soforozida i cijanidin-3-glukozilrutinozida. Ukupni je udjel hidroksicinamičnih kiselina također bio veći u sorti Maraska nego u sorti Oblačinska. Koncentracija se svih identificiranih antocijanina povećala u obje sorte nakon obrade. Najveći su udjeli polifenola uglavnom izmjereni u soku nakon prešanja. Udjeli polifenola i njihov antioksidacijski učinak bili su uglavnom isti tijekom ugušćivanja soka. Iako je sorta Maraska imala veći udjel polifenola od sorte Oblačinska, obje su sorte prikladne za industrijsku proizvodnju koncentriranog soka od višnje

The Mastic Tree (Pistacia lentiscus L.) Leaves as Source of BACs: Effect of Growing Location, Phenological Stage and Extraction Solvent on Phenolic Content

Pozadina istraživanja. Tršlja (Pistacia lentiscus L.) je zimzeleni grm iz porodice Anacardiaceae, rasprostranjen u mediteranskim zemljama, gdje se koristi u narodnoj medicini. Dosadašnja istraživanja ekstrakata lista, stapke, ploda i korijena P. lentiscus pokazuju da biljka sadržava veliku koncentraciju sekundarnih metabolita (flavonoida, fenolnih kiselina i tanina), što upućuje na zaključak da ima izvrstan biološki potencijal. Stoga je svrha ovoga rada bila procijeniti utjecaj okolišnih čimbenika i vrste ekstrakcijskog otapala na koncentraciju fenola u listu tršlje uzgojene na četiri različite lokacije duž Jadranske obale (Barbariga, Lun, Hvar i Vela Luka) tijekom tri fenološke faze (faze cvatnje, ranog ploda i zrelog ploda). Eksperimentalni pristup. Budući da listovi tršlje sadržavaju fenolne spojeve koji se razlikuju po strukturi i kemijskim svojstvima, ispitivanje etanolnih i metanolnih ekstrakata provedeno je visokodjelotvornom tekućinskom kromatografijom (HPLC) s UV-Vis PDA detektorom. Fenolni spojevi su identificirani usporedbom retencijskih vremena i dobivenih spektara s odgovarajućim standardima pri 280 i 340 nm. Rezultati i zaključci. U svim su uzorcima određene koncentracije fenolnih kiselina i flavonol glikozida, dok je koncentracija katehina određena samo u metanolnim ekstraktima. Prevladavajući fenolni spoj bila je 5-O-galoilkininska kiselina, zatim su slijedili monogaloil-glukoza, 3,5-di-O-galoilkininska kiselina, 3,4,5-tri-O-galoilkininska kiselina i galna kiselina. Dominantni flavonol glikozid bio je miricetin-3-O-ramnozid, zatim miricetin-3-O-glukozid, miricetin-3-O-glukuronid, kvercetin-3-O-ramnozid i derivat flavonol glikozida. Rezultati pokazuju da masene koncentracije navedenih spojeva variraju ovisno o fenološkoj fazi, lokaciji i korištenom otapalu. Najveće masene koncentracije fenola utvrđene su u uzorcima lista tršlje ubranim na lokaciji Hvar te ekstrahiranim s 80 %-tnom otopinom metanola. Najveće masene koncentracije ukupnih fenola pronađene su u uzorcima lista tršlje ubranim tijekom fenološke faze cvatnje, a ukupnih flavonoida u uzorcima lista tršlje ubranim tijekom fenološke faze ranog ploda. Novina i znanstveni doprinos. Dobiveni rezultati omogućuju bolje razumijevanje fenolnog sadržaja vrste P. lentiscus, što može potaknuti daljnja ispitivanja valorizacije lista tršlje kao farmaceutskog pripravka ili hrane s dodanom vrijednošću.Research background. Mastic tree (Pistacia lentiscus L.) of the Anacardiaceae family is an evergreen shrub from Mediterranean countries where it is used in traditional medicine. Analysis of P. lentiscus leaf, stem, fruit and root extracts showed high concentrations of principal groups of secondary metabolites (flavonoids, phenolic acids and tannins), suggesting the plant possesses great biological potential. Therefore, the aim of this research is to evaluate the impact of environmental parameters and the extraction solvent type on the concentration of phenols in mastic tree leaf extracts grown at four different locations along the Adriatic coast (Barbariga, Lun, Hvar and Vela Luka) during three phenological stages (early flowering, early fruiting and late fruiting). Experimental approach. Since mastic tree plant has phenolic compounds with different structures and chemical properties, ethanolic and methanolic leaf extracts were analysed using high-performance liquid chromatography (HPLC) coupled with UV/Vis PDA detector. Phenolic compounds were identified by comparing the retention times and spectral data with those of standards at 280 and 340 nm. Results and conclusions. In all samples, phenolic acids and flavonol glycosides were quantified, while catechin was quantified only in methanolic extracts. The 5-O-galloylquinic acid was determined as a predominant phenolic compound in all samples followed by monogalloyl glucose, 3,5-di-O-galloylquinic acid, 3,4,5-tri-O-galloylquinic acid and gallic acid, respectively. Myricetin-3-O-rhamnoside was found to be the predominant flavonol glycoside followed by myricetin-3-O-glucoside, myricetin-3-O-glucuronide, quercetin-3-O-rhamnoside and derivative of flavonol glycoside. The mass concentration of these compounds significantly varied during different phenological stages, at different growing locations and used extraction solvents. The highest phenolic mass concentration was determined in the samples harvested at Hvar growing location and extracted in 80 % methanol. The highest total phenolic acid mass concentration was obtained in the samples harvested during the flowering phenological stage and the highest total flavonoid mass concentration in the samples harvested during the early fruiting stage. Novelty and scientific contribution. The obtained data provide a better understanding of the P. lentiscus species phenolic concentration, which can lead to further investigations regarding the valorisation of mastic tree leaves as pharmaceutical products or as food products with added value

Bioprospecting of Microalgae Isolated from the Adriatic Sea: Characterization of Biomass, Pigment, Lipid and Fatty Acid Composition, and Antioxidant and Antimicrobial Activity

Marine microalgae and cyanobacteria are sources of diverse bioactive compounds with potential biotechnological applications in food, feed, nutraceutical, pharmaceutical, cosmetic and biofuel industries. In this study, five microalgae, Nitzschia sp. S5, Nanofrustulum shiloi D1, Picochlorum sp. D3, Tetraselmis sp. Z3 and Tetraselmis sp. C6, and the cyanobacterium Euhalothece sp. C1 were isolated from the Adriatic Sea and characterized regarding their growth kinetics, biomass composition and specific products content (fatty acids, pigments, antioxidants, neutral and polar lipids). The strain Picochlorum sp. D3, showing the highest specific growth rate (0.009 h−1), had biomass productivity of 33.98 ± 0.02 mg L−1 day−1. Proteins were the most abundant macromolecule in the biomass (32.83–57.94%, g g−1). Nanofrustulum shiloi D1 contained significant amounts of neutral lipids (68.36%), while the biomass of Picochlorum sp. D3, Tetraselmis sp. Z3, Tetraselmis sp. C6 and Euhalothece sp. C1 was rich in glycolipids and phospholipids (>75%). The lipids of all studied microalgae predominantly contained unsaturated fatty acids. Carotenoids were the most abundant pigments with the highest content of lutein and neoxanthin in representatives of Chlorophyta and fucoxanthin in strains belonging to the Bacillariophyta. All microalgal extracts showed antioxidant activity and antimicrobial activity against Gram-negative E. coli and S. typhimurium and Gram-positive S. aureus

Fresh-cut Potatoes Treated with Fennel Essential Oil during Storage at 8 °C

The aim of this study was to investigate the effect of treatment with fennel essential oil (FEO) on the shelf life of fresh-cut potatoes (FCP) and on the sensory characteristics of raw and subsequently boiled and fried potatoes. Peeled and sliced potatoes were immersed in an aqueous solution containing different FEO concentrations (0 (water control), 25, 125, and 250 mg L-1) for 15 min, then drained, vacuum packaged, and stored at 8 °C for 12 days. The CIELAB color parameters and aerobic mesophilic bacteria count (AMB) of the raw FCP and the sensory characteristics of the raw, boiled and fried samples were determined. AMB decreased with increasing FEO content, and this trend was generally maintained during storage. Slight negative changes in color were observed with increasing FEO content and with storage time. Fennel taste and odor in raw and boiled potatoes increased with increasing FEO content, while FEO odor after frying was only slightly pronounced in FEO-250 on day 0. Despite the antibacterial activity of FEO, spoilage of FCP was not prevented during storage. In general, after 6 days, the best results in terms of absence of browning and off-odor of raw and off-taste and sour taste of boiled and fried FCP were obtained with 25 mg L-1 FEO treatment

Effect of UV-C Irradiation, Storage and Subsequent Cooking on Chemical Constituents of Fresh-Cut Potatoes

UV-C irradiation successfully reduces the growth of microorganisms, but it can also affect the content of phenolics and sugars of fresh-cut potatoes (FCP). This could consequently alter antioxidant capacity of FCP or its potential for acrylamide formation. Therefore, this paper investigates the influence of UV-C irradiation on the content of phenolics [chlorogenic acid (CA)] and individual sugars during storage of FCP as well as after cooking. Acrylamide was also monitored in FCP after frying. Potato slices pre-treated with sodium ascorbate solution and vacuum-packaged were UV-C irradiated for 0, 3, 5, and 10 min in order to obtain irradiation doses of 0, 1.62, 2.70, and 5.40 kJ m−2, respectively, stored for 23 days (+6 °C), and subsequently boiled and fried. As the applied dose and storage duration increased, the CA content in raw FCP decreased (it retained for 75.53–88.34%), while the content of sugars as well as acrylamide in fried FCP increased. Although the increase was the most noticeable at the applied dose of 2.70 kJ m−2, the acrylamide content was always below proposed limit. Boiling and frying reduced the content of CA and sugars. In spite of certain alterations, applied doses of irradiation can ensure acceptable product in regard to phenolics and sugars, and acrylamide content particularly

Influence of Cultivar and Industrial Processing on Polyphenols in Concentrated Sour Cherry (Prunus cerasus L.) Juice

The objective of this study is to investigate the infl uence of cultivar and industrial processing on total polyphenols, anthocyanins, hydroxycinnamic acids and antioxidant activity in concentrated sour cherry (Prunus cerasus L., cvs. Marasca and Oblačinska) juices. Samples were collected during four processing steps: from fresh fruit prior to processing, then from pressed, fi ltered and concentrated juices. The content of total phenols was the same in both cultivars, but antioxidant activity (Oblačinska>Marasca) and total monomeric anthocyanins (Marasca>Oblačinska) diff ered. All processing steps significantly influenced the content of total phenols, total monomeric anthocyanins and antioxidant activity. In all samples four major anthocyanins were identifi ed by HPLC with UV/VIS PDA detector, listed in the descending order based on their abundance: cyanidin-3-glucosylrutinoside, cyanidin-3-rutinoside, cyanidin-3-sophoroside and cyanidin-3-glucoside. Marasca cv. contained more total anthocyanins, and contents of cyanidin-3-sophoroside and cyanidin-3-glucosylrutinoside. The content of total hydroxycinnamic acids was also higher in Marasca than Oblačinska cv. Aft er processing, the concentration of all identifi ed anthocyanins increased in both cultivars. Majority of the highest values of polyphenols were detected in the juice aft er pressing. The content of polyphenols and their antioxidant activity were considerably stable during industrial processing to concentrated juice. Although Marasca had higher polyphenolic content than Oblačinska, both cultivars showed promising industrial potential for processing to concentrated juice

Ružička days : International conference 18th Ružička Days “Today Science – Tomorrow Industry” : Proceedings

Proceedings contains articles presented at Conference divided into sections: chemical analysis and synthesis, chemical and biochemical engineering, food technology and biotechnology, medical chemistry and pharmacy, environmental protection and meeting of young chemists