On-line DACC-HPLC analysis of polycyclic aromatic hydrocarbons in edible oils

In this work an HPLC method for determination of polycyclic aromatic hydrocarbons (PAH) in edible oils on a DACC (donor-acceptor complex chromatography) column coupled with an on-line HPLC system with fluorescent detection. Method was used to determine the content of individual PAHs in the refined sunflower oil, virgin olive oil, cold pressed pumpkin seed oil, dark sesame oil and pumpkin seed oil produced with roasting obtained from domestic market. Calibration and validation were conducted for 13 individual PAHs among which are all 8 PAHs that are listed as priorities for determination in food and environment by both European Commission and US Environmental Protection Agency (EPA). Correlation coefficients of calibration curves for all standards were above 0.999 in selected range and all validation parameters (limit of detection, limit of quantification, accuracy and precision) were within limits set by European regulation. Content of PAHs in cold pressed pumpkin seed oil, roasted pumpkin seed oil and especially dark sesame oil was several-fold higher than the recommendations set by different European oil research and production organizations even though for both pumpkin seed oils it was lower than limits set by official European legislation. High content of cancerogenous heavy fraction PAHs were found in dark sesame oil that advises to limitation of its consumption in human diet

Fatty Acid Composition in Oil of Recent Rapeseed Hybrids and 00 Cultivars

Fatty acid composition in oil of seven new hybrids (‘Artus’, ‘Baldur’, ‘Exact’, ‘Executive’, ‘Extra’, ‘RG 9908’, ‘RG 9909’) and eight 00-cultivars (‘Aviso’, ‘Bristol’, ‘Canary’, ‘Dexter’, ‘Ella’, ‘Kosto’, ‘Navajo’, ‘Royal’) of rapeseed was investigated in the period 2003-2005. The experiments were placed in the experimental field of the Faculty of Agriculture in Zagreb. Fatty acid composition was determined by gas chromatography of their methyl esters, and the oil iodine number was calculated as well. The studied new rapeseed hybrids and 00 cultivars contained no erucic acid or it was present far below 2%. The average content of oleic acid was 61.88±2.64% in hybrids and 62.54±3.90% in 00-cultivars, the content of linoleic acid was 20.52±1.49% and 19.57±2.51%, the content of linolenic acid was 8.39±1.50% and 7.92±2.12%, the content of palmitic acid was 5.13±0.48% and 5.50±0.51%, and the content of stearic acid was 1.48±0.16% and 1.58±0.19%, respectively. Th is ratio of fatty acids confirms the high nutritive quality of rapeseed oil. The iodine value was 112±2 in oil from hybrids and 110±4 in oil from 00-cultivars. In both investigated groups there were no differences in fatty acid composition which could influence the quality and stability of rapeseed oil. The average values in oils obtained from hybrids as well as from 00-cultivars are inside the data prescribed in law regulations. Although, there were several samples in which oleic and palmitic acid contents were above and linoleic and linolenic acid contents (as well as the iodine values) below the limit values, what ought to be incorporated into the revision of present regulations on vegetable oils. Fatty acid composition in hybrids and in 00-cultivars was greatly influenced by weather conditions. In the year with higher mean monthly air temperatures and less precipitation during May and June compared to average long-term weather conditions for these months, oil contained more oleic and less linoleic and linolenic acid

Utjecaj klimatskih uvjeta, sortnih karakteristika i postupaka proizvodnje na udjele tokoferola, plastokromanola-8 i pigmenta u lanenom ulju

The objective of this study is to compare the influence of genotype, environmental conditions and processing methods after maturation and harvesting of four varieties of flaxseed (Altess, Biltstar, Niagara and Oliwin) on the levels of tocochromanols, carotenoids and chlorophyll in flaxseed oil. Samples were produced by cold pressing of dry seeds and seeds heated for 30 min at 60 °C. Temperature, sunshine and rainfall were primary environmental conditions included. Grand mean of mass fraction of γ-tocopherol was (522±29), of plastochromanol-8 (305±2) and total tocochromanols (831±3) mg per kg of oil. The highest levels of these compounds and strongest antioxidant activity were found in cold-pressed oil of Biltstar variety. During seed maturation, levels of γ-tocopherol and plastochromanol-8 increased with average temperature and total sunshine and decreased with total rainfall. Fifth week after flowering was identified as the maturation period with best climate conditions to achieve optimal tocochromanol content. Grand mean of mass fraction of carotenoids expressed as β-carotene was (1.83±0.01) and of chlorophyll expressed as pheophytin a (0.43±0.10) mg per kg of oil. Altess variety had the highest levels of pigments. Antioxidant activity decreased with the increase of chlorophyll, while correlations with carotenoids were not determined. Generally, oil obtained by cold pressing had higher levels of tocochromanols and lower levels of pigments but similar antioxidant activity to the oil after seed conditioning. The results of this study contribute to identifying the flaxseed variety that is the best for oil production with the highest antioxidant activity and nutritive value, and provide better understanding of tocochromanol biosynthesis depending on different climate conditions.Svrha je ovoga rada bila ispitati utjecaj genotipa, uvjeta okoliša i različitih načina obrade nakon dozrijevanja i žetve četiri sorte lana (Altess, Biltstar, Niagara i Oliwin) na udjele tokokromanola, karotenoida i klorofila u ulju dobivenom od tih sorata. Uzorci su proizvedeni hladnim prešanjem i kondicioniranjem sjemenki lana tijekom 30 min na 60 °C. Praćeni su glavni okolišni čimbenici, i to temperatura, padaline i insolacija. Prosječni udjel γ-tokoferola u uzorcima bio je (522±29) mg/kg, plastokromanola-8 (305±2) mg/kg, a ukupnih tokokromanola (831±3) mg/kg. Hladno prešano ulje sorte Biltstar imalo je najveći udjel tih spojeva te najizraženiji antioksidacijski učinak. Udjeli γ-tokoferola i plastokromanola-8 povećavali su se s porastom prosječne temperature i trajanjem insolacije, a smanjivali s povećanjem količine oborina u periodu sazrijevanja sjemena. Utvrđeno je da su za postizanje optimalnog udjela tokokromanola u ulju najbolji klimatski uvjeti bili pet tjedana nakon cvatnje. Prosječni udjel karotenoida u svim uzorcima ulja, izražen kao β-karoten, bio je (1.83±0.01) mg/kg, a klorofila, izražen kao feofitin a, (0.43±0.10) mg/kg. Ulja dobivena od sorte Altess imala su najveće udjele pigmenata. Antioksidacijska aktivnost ulja smanjivala se s povećanjem udjela klorofila, dok udjel karotenoida nije imao bitan utjecaj. Hladno prešana ulja imala su veće udjele tokokromanola i manje udjele pigmenata od ulja dobivenih od kondicioniranih sjemenki, no slična antioksidacijska svojstva. Ovo je istraživanje omogućilo identifikaciju najbolje sorte lana za dobivanje ulja najveće antioksidacijske aktivnosti i hranjive vrijednosti, što pridonosi spoznajama o utjecaju klimatskih uvjeta na biosintezu tokokromanola

Polycyclic aromatic hydrocarbons bioaccessibility in seafood: Culinary practices effects on dietary exposure

This work aimed to determine the effect of culinary practices on the contamination level and bioaccessibility of polycyclic aromatic hydrocarbons (PAHs) in seafood. The selected farmed seafood species (marine shrimp, clams and seaweed) were commercially available in Portugal. The mean concentrations of PAHs varied between 0.23 and 51.8 µg kg-1, with the lowest value being observed in raw shrimp and the highest in dried seaweed. The number of compounds detected in seaweed and clams (naphthalene, acenaphthene, fluorene, phenanthrene, benzo(b)fluoranthene and benzo(j)fluoranthene) were higher than in shrimp (fluorene and pyrene). Among the PAHs measured, fluorene was the predominant one. There was a significant interaction effect between species and culinary treatment (p < 0.05), thus boiled and dried seaweed samples presented the lowest and the highest levels of fluorene (0.13 and 1.8 µg kg-1), respectively. The daily intake of PAHs decreased with bioaccessibility, varying from 22% for benzo(k)fluoranthene (in raw clam) to 84% for phenanthrene (in steamed clam). According to the potency equivalent concentrations, screening values and bioaccessibility of PAHs, the consumption of marine shrimp, clam and seaweed is considered as safe for consumers.This work received financial support from European (FEDER funds through COMPETE) and Portuguese funds (Fundação para a Ciência e Tecnologia Project UID/QUI/50006/2013). The Portuguese Foundation for Science and Technology supported the Ph.D. Grant of ALM (SFRH/BD/103569/2014) as well as the post-doc Grant of P.A. (SFRH/BPD/100728/2014) and the IF2014 contract of AM.info:eu-repo/semantics/publishedVersio

The influence of processing conditons of pumpkin cucurbita pepo l. Seed on bioactive compounds and oil stability

Istraživan je utjecaj godine uzgoja i uvjeta prerade bučinih koštica (beskorke i obične) i miješanja bučinih ulja s rafiniranim uljima na njegovu kvalitetu i održivost. Uvjeti prerade nisu jednako utjecali na sve sastojke, ali je održivost bila najbolja u uljima iz termički obrađenih koštica. Udjel i sastav nekih spojeva razlikovao se i s obzirom na vrstu koštice i godinu uzgoja. Dodatak rafiniranih ulja utjecao je na održivost bučinog ulja, a već 2% ovih ulja moguće je identificirati putem sastava sterola.The influence of crop season and processing conditions of pumpkin seeds (naked and husk) and mixture of pumpkin seed oils with refined oils on its quality and oxidative stability was investigated. Processing conditions didn't show the same influence on every ingredient, whereas oxidative stability was the highest in oils from thermally processed seeds. Content and composition of some compounds differed depending of the seed type and crop season. Addition of refined oils influenced the stability of pumpkin seed oil, while even 2% of these oils were identified by means of sterol composition

Application of intelligent systems in sports

U sklopu ovog rada istražuju se mogućnosti primjene umjetne inteligencije u domeni sporta. U praktičnom dijelu rada izrađuje se sustav koji služi kao savjetnik u predviđanju ishoda sportskih rezultata

Automatic system management for transport and processing protection of seamless pipes

Tema ovog diplomskog rada je upravljanje automatskim sustavom za transport i procesnu zaštitnu obradu bešavnih cijevi. Krajnji cilj ovog diplomskog rada je upoznati čitatelja s problematikom automatizacije procesa proizvodnje čeličnih bešavnih cijevi. U uvodnim poglavljima objašnjen je tehnološki postupak proizvodnje bešavnih cijevi. Obrađeni su postupci testiranja i završna obrada bešavnih cijevi. Opisani su svi uređaji koji čine električni pogonski sustav za procesnu zaštitnu obradu i transport bešavnih cijevi. Nakon toga je izrađen upravljački program i HMI sučelje koristeći programski alat TIA Portal i PLC Siemens SIMATIC S7-1500.The subject of this graduate thesis is the management of the automatic transport system and the process protection of seamless pipes. The main goal is to present the problems of automation of the process of the steel seamless tubes manufacturing. In the introductory chapters the technological manufacturing process of seamless pipes is explained, as well as seamless tube testing and finishing operations which are used. All components of the electric drive system are also described. Program application and HMI interface are presented using the TIA Portal programming tool and PLC Siemens SIMATIC S7-1500

The influence of processing conditons of pumpkin cucurbita pepo l. Seed on bioactive compounds and oil stability

Istraživan je utjecaj godine uzgoja i uvjeta prerade bučinih koštica (beskorke i obične) i miješanja bučinih ulja s rafiniranim uljima na njegovu kvalitetu i održivost. Uvjeti prerade nisu jednako utjecali na sve sastojke, ali je održivost bila najbolja u uljima iz termički obrađenih koštica. Udjel i sastav nekih spojeva razlikovao se i s obzirom na vrstu koštice i godinu uzgoja. Dodatak rafiniranih ulja utjecao je na održivost bučinog ulja, a već 2% ovih ulja moguće je identificirati putem sastava sterola.The influence of crop season and processing conditions of pumpkin seeds (naked and husk) and mixture of pumpkin seed oils with refined oils on its quality and oxidative stability was investigated. Processing conditions didn't show the same influence on every ingredient, whereas oxidative stability was the highest in oils from thermally processed seeds. Content and composition of some compounds differed depending of the seed type and crop season. Addition of refined oils influenced the stability of pumpkin seed oil, while even 2% of these oils were identified by means of sterol composition

Automatic system management for transport and processing protection of seamless pipes

Tema ovog diplomskog rada je upravljanje automatskim sustavom za transport i procesnu zaštitnu obradu bešavnih cijevi. Krajnji cilj ovog diplomskog rada je upoznati čitatelja s problematikom automatizacije procesa proizvodnje čeličnih bešavnih cijevi. U uvodnim poglavljima objašnjen je tehnološki postupak proizvodnje bešavnih cijevi. Obrađeni su postupci testiranja i završna obrada bešavnih cijevi. Opisani su svi uređaji koji čine električni pogonski sustav za procesnu zaštitnu obradu i transport bešavnih cijevi. Nakon toga je izrađen upravljački program i HMI sučelje koristeći programski alat TIA Portal i PLC Siemens SIMATIC S7-1500.The subject of this graduate thesis is the management of the automatic transport system and the process protection of seamless pipes. The main goal is to present the problems of automation of the process of the steel seamless tubes manufacturing. In the introductory chapters the technological manufacturing process of seamless pipes is explained, as well as seamless tube testing and finishing operations which are used. All components of the electric drive system are also described. Program application and HMI interface are presented using the TIA Portal programming tool and PLC Siemens SIMATIC S7-1500