This book is divided into two sections namely: synthesis and properties of herbicides and herbicidal control of weeds. Chapters 1 to 11 deal with the study of different synthetic pathways of certain ...herbicides and the physical and chemical properties of other synthesized herbicides. The other 14 chapters (12-25) discussed the different methods by which each herbicide controls specific weed population. The overall purpose of the book, is to show properties and characterization of herbicides, the physical and chemical properties of selected types of herbicides, and the influence of certain herbicides on soil physical and chemical properties on microflora. In addition, an evaluation of the degree of contamination of either soils and/or crops by herbicides is discussed alongside an investigation into the performance and photochemistry of herbicides and the fate of excess herbicides in soils and field crops.
The domain of catalytic hydrogenation continues to grow fast, reflecting the wide range of chemical applications that can be enhanced by the easy use of molecular hydrogen. The advances in ...characterization techniques and their application have improved our understanding of the catalytic processes and mechanisms occurring in both homogeneous and heterogeneous catalysis. The aim of this volume, although not exhaustive, is to provide a general overview of new progress of the hydrogenation reactions. This volume comprises a series of various contributions, as reviews or original articles, treating heterogeneously and homogeneously catalyzed hydrogenation reactions. It is composed of three parts: hydrogenation reactions in fine organic chemistry, hydrogenation reactions in environmental chemistry and renewable energy, and special topics in hydrogenation.
Provider: - Institution: Josip Juraj Strossmayer University of Osijek. FACULTY OF FOOD TECHNOLOGY. Department of Process Engineering. Sub-department of Process Design and Construction Materials. - ...Data provided by Europeana Collections- Posljednjih par desetljeća, industrijska konoplja (Cannabis sativa L.) je nepravedno zapostavljena zbog izgledom slične vrste konoplje Cannabis indica L. koja se koristi kao opojno sredstvo. Cilj ovoga rada bio je ispitati utjecaj parametara ekstrakcije ulja iz Cannabis sativa L. sjemenki procesom hladnog prešanja nakon čega je provedena ekstrakcija zaostalog ulja u pogači pomoću superkritičnog CO2. Optimiranje procesa ekstrakcije konopljinog ulja provedeno je metodom odzivnih površina. Ispitan je utjecaj temperature zagrijavanja glave preše, frekvencije elektromotora te veličine otvora pužne preše na iskorištenje i kvalitetu ulja kod procesa prešanja, kao i utjecaj tlaka ekstrakcije, temperature i protoka otapala u procesu ekstrakcije pomoću superkritičnog CO2. U proizvedenim uljima odredili su se sljedeći parametri kvalitete ulja: peroksidni broj, slobodne masne kiseline, netopljive nečistoće, voda, jodni broj, saponifikacijski broj, anisidinski broj i Totox broj. Osim navedenog, u dobivenim uljima ispitan je i sastav masnih kiselina, tokoferola, te klorofila i karotenoida. Ispitan je i utjecaj različitih prirodnih antioksidanasa i njihovih koncentracija na oksidacijsku stabilnost konopljinog ulja. Rezultati su pokazali da postoji statistički značajan utjecaj različitih procesnih parametara ekstrakcije na iskorištenje i kvalitetu ulja. Količina zaostalog ulja u pogači potpuno je ekstrahirana pomoću superkritičnog CO2 na novokonstruiranom uređaju za superkritičnu ekstrakciju. Odabirom relevantnih procesnih uvjeta superkritične ekstrakcije, kao i periodičnim frakcioniranjem, dobiveno je konopljino ulje različitih masenih koncentracija masnih kiselina, tokoferola i pigmenata. Eterično ulje origana koncentracije 0,05 % je bilo najučinkovitije u zaštiti ulja od oksidacijske degradacije. Zbog svoje kvalitete, kao i sadržaja visokokvalitetnih komponenti u sjemenkama konoplje koje pozitivno utječu na ljudsko zdravlje, ovo istraživanje je vrlo značajno s obzirom na neznatan broj objavljenih studija o konopljinom ulju.- In the past few decades, the Cannabis sativa L. hemp variety has been unfairly neglected because of its similarity to the illegal kind Cannabis indica L. used as a narcotic. The objective of this study was to evaluate the
process of oil extraction from Cannabis sativa L. seeds by cold pressing, followed by extraction with supercritical CO2. Extraction optimization of hemp oil production was conducted using response surface methodology (RSM). The effects of temperature, temperature head presses, frequency, and nozzle size on oil recovery and quality parameters in the pressing experiments and the effects of extraction pressure, temperature and solvent flow rate in supercritical CO2 extraction experiments were investigated. In obtained hemp oils the following parameters were analysed: peroxide value, free fatty acids, insoluble impurities, moisture content, iodine value, saponification value, Anisidine value and Totox value. The composition of fatty acids, tocopherols, chlorophyll and carotene content was also determined. The influence of different natural antioxidants and their concentration on the oxidative stability of hemp seed oil was investigated. The results show that the oil recovery and quality was statistically significantly (ANOVA) affected by applied operational extraction process parameters. The residual oil in the pressed cake was extracted almost completely by supercritical CO2 in a newly designed supercritical fluid extraction system. By selecting the relevant process conditions of supercritical extraction, as well as by fractionation, it is possible to obtain hemp oil with different mass concentrations oil fatty acids, tocopherols and pigments. The essential oil of oregano in concentration of 0.05 % was the most efficient in protecting the hemp oil against oxidative deterioration. Because of the oil’s high quality, as well as the high content of high-quality components in hemp seeds which positively affect human health, this study is very significant regarding the small number of published studies on hemp seed oil.- All metadata published by Europeana are available free of restriction under the Creative Commons CC0 1.0 Universal Public Domain Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
Provider: - Institution: - Data provided by Europeana Collections- Vrednovanje poduzeća naftne i plinske industrije po mnogim je čimbenicima
specifično i teško izvedivo postojećom metodologijom i ...trenutno korištenim
pristupima vrednovanju. Identifikacija i ocjena čimbenika koji stvaraju i pokreću
vrijednost poduzeća naftne i plinske industrije temelji se na složenim izračunima
koji uključuju mnoge varijable. Međuovisnost tih varijabli prekompleksna je da bi
se izrazila jednostavnom formulom. Iz tih se razloga kod vrednovanja ovakvih
poduzeća postojeće metode vrednovanja moraju prilagođavati čime se u konačnici
brojni kvalitativni, pa čak i kvantitativni čimbenici uopće ne uzimaju u obzir. Pred
ekonomske stručnjake i znanstvenike s područja vrednovanja postavljaju se tako
novi izazovi u determiniranju odgovarajuće metodologije i pristupa kojima će se
moći otkloniti navedeni nedostaci. U ovom doktorskom radu predložen je
suvremeni pristup vrednovanju poduzeća naftne i plinske industrije na osnovi
računalne inteligencije. Takav pristup temeljen je na korištenju i prilagodbi brojnih
financijskih i nefinancijskih pokazatelja pomoću umjetnih neuronskih mreža i
neizrazite logike.- Business valuation of oil and gas companies can be described as specific and
difficult in many aspects within existing methodology and currently used
approaches in appraisal process. Identification and evaluation of the significant
factors that create and determine enterprise value in oil and gas industry is based
on complex calculations involving many variables. Regardless of this reason,
existing business valuation methods for such companies have to be improved with
taking into account a numerous qualitative and even additional quantitative
factors. Therefore, economic experts and scientists in the field of business
valuation are confronted with new challenges in determination of appropriate
approaches that should be able to eliminate the disadvantages of existing
valuation methods. In this doctoral thesis, a modern approach to business
valuation of oil and gas companies based on computational intelligence has been
suggested. This approach includes application and adaption of selected financial
and non-financial indicators by means of artificial neural networks and fuzzy
logic- All metadata published by Europeana are available free of restriction under the Creative Commons CC0 1.0 Universal Public Domain Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
Provider: - Institution: Josip Juraj Strossmayer University of Osijek. FACULTY OF FOOD TECHNOLOGY. Department of Process Engineering. Sub-department of Process Design and Construction Materials. - ...Data provided by Europeana Collections- Cilj rada bio je ispitati utjecaj tlaka (300–500 bar), temperature (40–60 °C), protoka CO2 (0,194–14,125 kg/h) i veličine čestica (0,238–1,059 mm), kao i utjecaj veličine (dimenzija) ekstraktora, na prinos ulja iz zrna soje sorte „Ika“ superkritičnim CO2. Na osnovi vanjskog koeficijenta prijenosa tvari tijekom superkritične ekstrakcije ulja s površine kvarcnog pijeska, konstruirana je nova Sherwood-ova korelacija. Iznesen je i detaljan prikaz matematičkih modela koji se koriste za opisivanje kinetike superkritične ekstrakcije biljnih ulja. Praćena je promjena kvalitete sojinog ulja tijekom provedbe ekstrakcije i to: ispitivanjem dobivenih frakcija na sastav masnih kiselina i tokoferola, primjenom plinske kromatografije, kao i pojedinačnih triacilglicerola, primjenom tekućinske kromatografije visoke djelotvornosti. Rezultati su pokazali da su, prema statističkoj značajnosti (ANOVA) utjecaja različitih procesnih uvjeta na ekstrakciju ulja iz zrna soje, tlak ekstrakcije, protok CO2 i veličina čestica imali značajan utjecaj na prinos ulja (p < 0,05), dok temperatura ekstrakcije nije pokazala statistički značajan utjecaj (p = 0,07) na prinos ulja. Smanjenjem veličine čestica te povećanjem tlaka i protoka CO2 povećavao se prinos ulja. Pri tlaku 300 bar, u intervalu od 40 do 60 °C, temperatura nije utjecala na prinos ulja te se može smatrati da je prijelazni tlak za sustav ulje iz zrna soje – superkritični CO2 upravo pri ispitanom tlaku, ili se nalazi u nekom uskom intervalu oko navedene vrijednosti tlaka. Svi ispitani matematički modeli (Kandiah i Spiro, Brunner, Tan i Liou, Martinez i sur., te Sovová model) bili su prikladni za opisivanje kinetike superkritične ekstrakcije. Međutim, na osnovi niskih AARD vrijednosti Sovová model je pokazao najbolja slaganja eksperimentalnih i modelom predviđenih podataka. Prijenos rezultata istraživanja iz laboratorijskog u poluindustrijsko mjerilo (scale-up), uspješno je proveden na temelju geometrijske sličnosti ekstraktora i mehanizma prijenosa tvari u procesu ekstrakcije. Važnost nove Sherwood-ove korelacije je u mogućnosti procjene vanjskog koeficijenta prijenosa tvari u slučajevima superkritične ekstrakcije ulja s površine neporoznih materijala, posebice kada je u pitanju prijenos rezultata iz laboratorijskog u industrijsko mjerilo. Odabirom relevantnih procesnih uvjeta superkritične ekstrakcije, kao i periodičnim frakcioniranjem, dobiveno je sojino ulje različitih masenih koncentracija masnih kiselina, triacilglicerola i tokoferola.- The aim of this research was to determine the influence of pressure (300–500 bar), temperature (40–60 °C), CO2 flow rate (0.194–14.125 kg/h) and particle size (0.238–1.059 mm), as well as the influence of extractor size on the oil yield from soybean cultivar “Ika” by supercritical CO2. According to the external mass transfer coefficient during the supercritical extraction of soybean oil from the surface of spiked quartz sand a new Sherwood correlation was developed. A detailed review of mathematical models used to describe the kinetics of supercritical extraction of vegetable oils is also given. The quality change of soybean oil during the extraction was investigated as follows: the composition of fatty acids and tocopherols was determined in the extract fractions, using gas chromatography, as well as individual triacylglycerols, using high performance liquid chromatography. The results show that the extraction yield was statistically significantly (ANOVA) affected by applied operational extraction parameters of pressure, CO2 flow rate and particle size (p < 0.05). However, extraction temperature did not show statistically significant influence on extraction yield (p = 0.07). An increase of pressure and solvent flow rate, and decrease of particle size improved the extraction yield. At pressure of 300 bar and temperature interval from 40 to 60 °C, the temperature did not affect the oil yield. Thus, it can be considered that the above mentioned pressure (or pressure close to 300 bar) represents crossover pressure for soybean oil. All examined mathematical models (Kandiah and Spiro, Brunner, Tan and Liou, Martinez et al., and Sovová) were suitable for describing extraction kinetics. However, Sovová model showed the best accordance between experimental and model predicted data which was confirmed by very low AARD values. The extraction was successfully scaled-up to pilot plant according to the geometrical similarity of extractor and to the mass transfer mechanism involved on the extraction. The importance of the new Sherwood correlation lies in the fact that enables estimation of the external mass transfer coefficient in the case of supercritical extraction of oil from the surface of nonporous materials, particularly in scale-up of the results from the laboratory to industrial plant. By selecting the relevant process conditions of supercritical extraction, as well as by fractionation, it is possible to obtain soybean oil with different mass concentrations oil fatty acids, triacylglycerols and tocopherols.- All metadata published by Europeana are available free of restriction under the Creative Commons CC0 1.0 Universal Public Domain Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
Provider: - Institution: - Data provided by Europeana Collections- Strateški savezi su oblik suradnje koji jamči svakom partneru samostalnost, a istovremeno
omogućuje stjecanje ključnih kompetencija ...za postizanje konkurentnosti.
Strateški savezi u farmaceutskoj industriji najčešće nastaju u procesu istraživanja i razvoja
novog lijeka te prilikom komercijalizacije lijeka. S tim u vezi udružuju se farmaceutska
poduzeća meñusobno i farmaceutska i biotehnološka poduzeća.
Istraživanjem najboljih poslovnih praksi na meñunarodnom tržištu utvrñeno je da veliki broj
farmaceutskih poduzeća koristi prednosti strateških saveza.
Farmaceutska industrija u Republici Hrvatskoj nalazi se pred velikim izazovom. Inozemna
farmaceutska poduzeća su jaka konkurencija na hrvatskom farmaceutskom tržištu. Hrvatska
farmaceutska poduzeća pokrivaju manje od polovice domaćeg tržišta. Nadalje, položaj
domaćih farmaceutskih poduzeća dodatno otežava problem nelikvidnosti, oskudni izvori
kapitala i nedostatak novih tehnologija.
Doktorska disertacija pod naslovom Strateški savezi u funkciji rasta i razvoja farmaceutske
industrije u Republici Hrvatskoj ima za cilj odgovoriti na pitanje mogu li strateški savezi
pomoći farmaceutskoj industriji u učvršćivanju tržišne pozicije hrvatskih farmaceutskih
poduzeća na domaćem, ali i inozemnom tržištu.
Stoga se provelo anketno istraživanje na farmaceutskim poduzećima u Republici Hrvatskoj.
Rezultati pokazuju da strateški savezi mogu biti u funkciji rasta i razvoja farmaceutske
industrije u Republici Hrvatskoj. Od devet postavljenih hipoteza, osam hipoteza je potvrñeno,
a jedna je opovrgnuta.
Strateški savezi pozitivno utječu na sljedeće faktore rasta i razvoja farmaceutske industrije u
republici Hrvatskoj: nove tehnologije, nova znanja, proširenje proizvodnog asortimana, veći
udio na domaćem i inozemnom tržištu i bolji poslovni rezultat. Strateški savezi, meñutim,
nemaju utjecaja na inovaciju proizvoda.
U skladu sa dobivenom rezultatima konstruiran je model utjecaja strateških saveza na rast i
razvoj farmaceutske industrije u Republici Hrvatskoj.- Strategic alliances are a form of cooperation that guarantees independence to every partner,
and at the same time enables the acquiring of key competencies for achieving
competitiveness.
Strategic alliances in pharmaceutical industry are most commonly forged in the process of
research and development of a new drug and during commercialization of the drug. With
regard to this, pharmaceutical companies join together amongst each other, as well as with
biotechnological companies.
Research of the best business practices in the international market has shown that a large
number of pharmaceutical companies take advantage of strategic alliances.
Pharmaceutical industry in Croatia faces a great challenge. Foreign pharmaceutical companies
present a fierce competition on Croatian pharmaceutical market. Croatian pharmaceutical
companies cover less than a half of the domestic market. Furthermore, the market position of
domestic pharmaceutical companies is additionally jeopardised by the problem of insolvency,
meagre sources of capital and lack of new technologies.
The purpose of doctoral dissertation entitled Strategic alliances in the function of growth and
development of pharmaceutical industry in Croatia is to answer the following question: can
strategic alliances help the pharmaceutical industry in consolidating the market position of
Croatian pharmaceutical companies on the domestic, but also in the foreign market?
Consequently, a survey was carried out and the respondents were pharmaceutical companies
in Croatia.
The results have shown that strategic alliances can function as the catalysts of growth and
development of pharmaceutical industry in Croatia. Eight out of nine hypotheses have been
confirmed, and one has been refuted.
Strategic alliances have a positive effect on the following factors of growth and development
of pharmaceutical industry in Croatia: new technologies, new knowledge, expansion of the
product lines, larger market share in the domestic and foreign markets and better business
outcome. However, strategic alliances have no effect on product innovation.
In accordance with the results obtained, a model of Strategic alliances influence on the
growth and development of pharmaceutical industry in Croatia was proposed.- All metadata published by Europeana are available free of restriction under the Creative Commons CC0 1.0 Universal Public Domain Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
Provider: - Institution: Josip Juraj Strossmayer University of Osijek. FACULTY OF FOOD TECHNOLOGY. Department of Process Engineering. Sub-department of Unit Operations. - Data provided by Europeana ...Collections- U radu se istraživao utjecaj omjera-kruto-tekuće (10, 20, 30 i 40 mL/g), otapala (vode, te 50,
70 i 96%-tnog etanola), vremena (10-200 minuta) te veličine čestica (> 0,63 mm; 0,63 - 0,4 mm;
0,4 - 0,16 mm i < 0,16 mm) na prinos ekstrakcije ukupnih fenola iz sjemenki grožđa, kao i
utjecaj temperature (25, 40, 50, 60, 70 i 80 °C) na kinetiku ekstrakcije ukupnih i individualnih
fenolnih tvari. Istraživao se i utjecaj različitih načina ekstrakcije (ekstrakcija uz zagrijavanje u
vodenoj kupelji s tresilicom, ekstrakcija na univerzalnom sustavu za ekstrakciju, kombinacija
ekstrakcije superkritičnim fluidima i ekstrakcije otapalom) na ekstraktibilnost fenolnih tvari,
antioksidacijsku aktivnost i boju ekstrakata.
Prijenos fenolnih tvari tijekom kruto-tekuće ekstrakcije odvijao se difuzijom, a određene
vrijednosti koeficijenata efektivne difuzije ukupnih (0,2 - 1,96·10-10 m2/min) i individualnih
fenolnih tvari (0,02 - 0,69·10-10 m2/min) povećavale su se s porastom temperature ekstrakcije.
Svi ispitani eksponencijalni matematički modeli (modificirani Fickov II, modificirani
Henderson-Pabisov i Pageov model) te neeksponencijalni Pelegov model bili su prikladni za
opisivanje kinetike kruto-tekuće ekstrakcije, međutim, na osnovi više statističkih pokazatelja
Pageov model je pokazao najbolja slaganja eksperimentalnih i modelom predviđenih podataka.
Ekstrakcijom u vodenoj kupelji, najveći prinos ukupnih fenolnih tvari ostvaren je
ekstrakcijom iz čestica manjih od 0,63 mm pri omjeru kruto-tekuće 40 mL/g i temperaturi 80 °C
pomoću 50% -tnog etanola u trajanju 200 minuta, dok je za iste uvjete ekstrakcija na
univerzalnom sustavu za ekstrakciju dala veći prinos fenolnih tvari od 6 do 35 %.
Oduljavanje sjemenki grožđa pod različitim procesnim uvjetima superkritične ekstrakcije
(tlakovi: 300 i 450 bara i temperature 40 i 60 °C) imalo je pozitivan utjecaj na ekstraktibilnost
fenolnih tvari tijekom ekstrakcije otapalom, kao i na antioksidacijsku aktivnost dobivenih
ekstrakata.
Procesni uvjeti i način kruto-tekuće ekstrakcije utjecali su na antioksidacijsku aktivnost i
boju ekstrakta. Utvrđena je visoka korelacija između antioksidacijske aktivnosti ekstrakata
sjemenki grožđa i masenog udjela individualnih fenolnih spojeva te ukupnih fenolnih tvari kao i
postojanje povezanosti boje ekstrakata i masenog udjela fenolnih tvari u ekstraktima.- This study was aimed to investigate the influence of solvent (water and aqueous ethanol: 50,
70 and 96%), solid-liquid ratio (10, 20, 30 and 40 mL/g), extraction time (10-200 minutes) and
particle size (> 0.63mm, 0.63 - 0.4 mm, 0.4 - 0.16 mm and < 0.16 mm) on yield of solid-liquid
extraction as well as influence of temperature (25, 40, 50, 60, 70 and 80 °C) on extraction
kinetics of total and individual phenolic compounds. The effect of extraction method (water bath
extraction, universal extraction system, combined supercritical fluid extraction and water bath
extraction) on phenolic extractability, antioxidant activity and colour of extract was also
investigated.
The main mechanism of mass transfer during solid-liquid extraction was diffusion. The
values of effective diffusion coefficient for total (0.2 - 1.96·10-10 m2/min) and individual
(0.02 - 0.69·10-10 m2/min) phenolic compound increased with extraction temperature. All
examined exponential mathematical models (modified Fick II, modified Henderson-Pabis and
Page) and non-exponential model proposed by Peleg were suitable for describing extraction
kinetics. However, Page model showed the best accordance between experimental and model
predicted data which was confirmed by several relevant statistical criteria.
The highest phenolic yield was obtained from grape seed particle lower than 0.63 mm during
200 minutes of extraction in water bath at 80 °C and solid-liquid ratio 40 mL/g by using 50%
aqueous ethanol. Results obtained by universal extraction system were higher in average 6 - 35%
in relation to water bath extraction.
Oil elimination from grape seed under different regimes of supercritical fluid extraction (300
and 450 bar; 40 and 60 °C) had the positive effect on phenolic extractability by conventional
solid-liquid extraction and on antioxidant activity of extracts.
The influence of process parameters and extraction method on antioxidant activity and colour of
extract was observed. Antioxidant activity of grape seed extracts was strongly correlated with
total and individual phenolic content. Relationship between phenolic content and colour of
extracts was observed.- All metadata published by Europeana are available free of restriction under the Creative Commons CC0 1.0 Universal Public Domain Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
Provider: - Institution: Josip Juraj Strossmayer University of Osijek. FACULTY OF FOOD TECHNOLOGY. Department of Food Technologies. Sub-department of Fruits and Vegetables Technology. - Data provided ...by Europeana Collections- Zahtjevi potrošača za što kvalitetnijim prehrambenim proizvodima danas su izraženiji
nego ikada. Kako bi se udovoljilo zahtjevima potrošača, velika pažnja se posvećuje razvoju
novih proizvoda ili pak poboljšavanju svojstava, a time i kvalitete, već postojećih proizvoda
(npr. dodatkom različitih sastojaka, poboljšanjem procesa proizvodnje, uključujući pakiranje i
drugo). Najznačajniji čimbenici kvalitete su aroma, boja i tekstura.
Paste od jagoda se koriste kao punilo za čokolade, energetske pločice i druge
proizvode koji sadrže voće. U industriji se paste od jagode pripremaju procesom evaporacije i
bez dodatka šećera trehaloze. Kako bi se poboljšala kvaliteta voćne paste osim industrijskog
postupka pripreme upotrijebljena je i liofilizacija, te je ispitivan utjecaj dodatka različitih
koncentracija trehaloze na aromu, teksturu, boju, sadržaj antocijana i antioksidativna
aktivnost. Također je praćen utjecaj različitih načina pakiranja (u atmosferi dušika i u zraku)
tijekom skladištenja na sobnoj temperaturi tijekom 5 mjeseci na aromu, boju i teksturu.
Trehaloza je jedan od najstabilnijh šećera. S obzirom da je razvijen enzimski proces
njezine proizvodnje koji je uvelike smanjio njenu cijenu, očekuje se sve veća primjena
trehaloze u prehrambenoj industriji zbog njezinog pozitivnog djelovanja na različita svojstva
kvalitete proizvoda.
Dodatak trehaloze uzrokovao je promjenu svojstava paste od jagode bez obzira jesu li
uzorci bili podvrgnuti evaporiraciji ili liofilizaciji u odnosu na uzorke bez dodatka trehaloze.
Sadržaj voćnih estera se je povisio dodatkom trehaloze u odnosu na uzorke bez dodatka
trehaloze. Trehaloza je također pozitivno djelovala na teksturu, očuvanje boje i sadržaj
antocijana u uzorcima.
Liofilizirani uzorci su bili kvalitetniji u odnosu na uzorke proizvedene evaporiranjem.
Sadržaj voćnih estera, očuvanje boje i sadržaj antocijana je bio veći u liofiliziranim uzorcima
nego u evaporiranim.
Nakon skladištenja (5 mjeseci), uzorci s dodanom trehalozom su i dalje imali veći
sadržaj voćnih estera i antocijana.- Today, costumer’s demands for higher quality of food products are more pronounced
than ever. To satisfy costumer’s demands, high attention is paid to new product development
or improvement of properties of existing product (by addition of different ingredients,
improvement of processing, packaging ect.). The most important quality factors are aroma,
texture and colour.
Strawberry pastes are used as fillings for chocolates, energy bars and other products
that contain fruit. In industry, strawberry pastes are prepared by evaporation and without
trehalose addition. To improve quality of this product, next to industrial process of
preparation, freeze-drying was used. Its influence and influence of different concentrations of
trehalose addition on aroma, texture, colour, anthocyanin content and free radical scavenging
activity were studied. Influence of different atmospheres (nitrogen and air) for packaging
during storage for 5 months at room temperature on mentioned properties were also studied.
Trehalose is one of most stable sugars. Since enzymatic process for its production is
developed its price is lower, so it is expected that its use in food industry will grow because
trehalose have positive effect on different quality properties of products.
Addition of trehalose caused property change of strawberry pastes in both evaporated
and freeze-dried samples in comparation to samples without trehalose addition. Fruity esters
content was higher in samples when trehalose was added. Trehalose also had positive effect
on texture, colour degradation and retention of anthocyanins in samples.
Freeze-drying also improves quality of product. Fruity esters content, retention of
anthocyanins and retention of colour were higher in freeze-dried samples.
After storage, samples with trehalose added had higher content of fruity esters and
anthocyanin content.- All metadata published by Europeana are available free of restriction under the Creative Commons CC0 1.0 Universal Public Domain Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
Provider: - Institution: Josip Juraj Strossmayer University of Osijek. FACULTY OF FOOD TECHNOLOGY. Department of Process Engineering. Sub-department of Unit Operations. - Data provided by Europeana ...Collections- Istraživan je utjecaj temperature sušenja (60-90 °C) i načina dovođenja topline materijalu
(konvekcijski uz fluidizaciju; infracrvenim zračenjem) na kinetiku i efektivni koeficijent difuzije
vlage tijekom sušenja i rehidratacije uzoraka mrkve i krumpira, kao i utjecaj izbora jednočlanog
matematičkog modela na vrijednosti efektivnog koeficijenata difuzivnosti (Def) vlage
procijenjenih prema eksperimentalnim podacima.
Predložena je modifikacija Henderson-Pabisova modela (uvođenjem trećeg parametra, N),
koja je uz Pageov model dala krivulje sušenja s najmanjim odstupanjima od eksperimentalnih
podataka za sve pokuse sušenja i rehidratacije.
Procijenjene vrijednosti Def bile su ovisne o temperaturi i načinu sušenja te o
matematičkom modelu, a neovisne o vrsti povrća za oba procesa difuzije. Vrijednosti
procijenjene iz parametara Henderson-Pabisova modela i njegove modifikacije (prema
prijedlogu Dincer-Dosta) bile su i do 30 puta veće u odnosu na vrijednosti određene prema
pojednostavljenom Fikovom, Lewisovom i Pageovom modelu. Određeno kritično vrijeme (tk)
najvjerojatnije odgovara vremenu u procesu sušenja/rehidratacije kada dolazi do promjene
prevladavajućeg mehanizma difuzije vlage.
Sušenje i rehidratacija očekivano su uzrokovali promjene kvalitativnih svojstava povrća u
odnosu na svježe povrće, pri čemu je značajnost utjecaja temperature i načina sušenja na
pojedina svojstva bile različita. Općenito, “stroži” uvjeti sušenja utjecali su na pad
rehidratacijske sposobnosti i smanjenje ukupne promjene boje, te na povećanje sadržaja ukupnih
fenolnih tvari u sušenom povrću.- Influence of drying temperature (60-90 °C) and heating method (fluid-bed, infrared) on
drying/rehydration kinetics and effective diffusion coefficient (Def) of vegetables were
investigated. Choose of mathematical model for assessment of Def was tested, too.
Drying and rehydration data are the best describes by proposed modification of
Henderson-Pabis model that include addition parameter (N) and by Page model at all
experimental runs.
The estimated values of Def are depending on drying temperature, draying method and on
mathematical model from which are derived as well as vegetable independent for both diffusion
processes. Values estimated from Henderson-Pabis model and its modification were up to 30
times enhanced than values approximated by Fick, Lewis and Page models. The critical time (tk),
which probably correspond to drying/rehidration time when change of dominate diffusion
mechanisms occurred, was define according to used mathematical models.
Drying and rehydration are expected courses of qualitative properties changes of products
in regard to row vegetables. Generally, rigorous drying regimes were purchase products with
lower rehidration ability and total colour changes as well as higher content of total phenolic
compounds.- All metadata published by Europeana are available free of restriction under the Creative Commons CC0 1.0 Universal Public Domain Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
Provider: - Institution: Josip Juraj Strossmayer University of Osijek. FACULTY OF FOOD TECHNOLOGY. Department of Food Technologies. Sub-department of Carbohydrates Technology. - Data provided by ...Europeana Collections- Ciljevi ovoga istraživanja bili su: (a) prirediti modifikate škroba kukuruza i tapioke
primjenom acetilacije acetanhidridom, (b) istražiti reološka i termofizikalna svojstva nativnih
škrobova i dobivenih modifikata te (c) istražiti utjecaj pektina, karagena, guara, brašna
sjemenki rogača, glukoze, fruktoze, saharoze, trehaloze, laktoze i sirutke na reološka i
termofizikalna svojstva nativnih škrobova kukuruza i tapioke. Reološka svojstva te svojstva
želatinizacije i retrogradacije pripravljenih modificiranih i nativnih škrobova bez i sa
dodacima mjerena su pomoću Brookfield-ovog rotacijskog viskozimetra i diferencijalnog
motridbenog kalorimetra (DMK).
Rezultati su pokazali da dodatak hidrokoloida znakovito utječe na porast viskoznosti
tijekom zagrijavanja suspenzija škroba kukuruza i tapioke, te konzistenciju škrobnih pasti.
Viskoznost navedenih škrobova, također je porasla dodatkom glukoze, fruktoze, saharoze,
trehaloze, laktoze te sirutke.
Dodatak glukoze, fruktoze, saharoze, trehaloze, laktoze i sirutke u prahu doveo je do
porasta temperature želatinizacije nativnih škrobova kukuruza i tapioke. Nasuprot tome,
hidrokoloidi nisu imali značajniji utjecaj na temperaturu želatinizacije ispitivanih škrobova.
Škrob tapioke imao je manju tendenciju retrogradacije u usporedbi sa kukuruznim
škrobom. Pektin, karagen, guar i brašno sjemenki rogača usporili su retrogradaciju škroba
kukuruza i tapioke, pri čemu je efikasnost ovisila o vrsti hidrokoloida, vrsti škroba te vremenu
i temperaturi skladištenja. Dodatak glukoze, fruktoze, saharoze, trehaloze, laktoze i sirutke u
prahu utjecao je na porast ili sniženje retrogradacije škroba kukuruza i tapioke, ovisno o vrsti
škroba, vrsti dodatka te vremenu i temperaturi skladištenja.
Acetiliranje škroba provedeno je dodatkom 4, 6 i 8 % acetanhidrida. Postotak
acetiliranja pripravljenih škrobova povećavao se srazmjerno s povećanjem koncentracije
acetanhidrida. Tako su postoci acetiliranja iznosili 1,257, 1,739 i 2,212 % za kukuruzni škrob
te 1,065, 1,532 i 1,979 % za škrob tapioke
Acetilirani škrobovi želatinizirali su pri nižim temperaturama i imali su nižu entalpiju
retrogradacije u usporedbi sa nativnim škrobovima. Također, imali su i znatno manju
tendenciju retrogradacije tijekom skadištenja i pri 4 i pri 25 °C.
Acetiliranjem škrobova kukuruza i tapioke dobiveni su modifikati s višim kapacitetom
bubrenja i topljivosti, a od njih pripravljeni gelovi imali su manju čvrstoću, silu pucanja te
adheziju.- The objectives of this work were to: (a) prepare modified maize and tapioca starches
by acetylation with acetic anhydride, (b) analyse the rheological and thermophysical
properties of native and prepared modified maize and tapioca starches and (c) investigate the
effects of pectin, carrageenan, guar, locust bean gum, glucose, fructose, sucrose, trehalose,
lactose and whey on the rheological and thermophysical properties of native maize and
tapioca starches. Gelatinisation, retrogradation and rheological characteristics of prepared
modified and native starches with and without additives were studied with differential
scanning calorimeter (DSC) and Brookfield rotational viscometer.
Results showed that the addition of hydrocolloids to maize and tapioca starch
suspensions resulted in increased viscosity during starch pasting and consistency of starch
pastes. Viscosity of mentioned starches increased on the addition of glucose, fructose,
sucrose, trehalose, lactose and whey also.
It was observed that addition of glucose, fructose, sucrose, trehalose, lactose and whey
increased gelatinisation temperature of native maize and tapioca starches. In contrast,
gelatinisation temperature did not vary significantly in starch-hydrocolloid systems.
Maize starch had higher tendency of retrogradation comparing to tapioca starch.
Pectin, carrageenan, guar, locust bean gum slowed the retrogradation process of maize and
tapioca starch, where efficiency depended on type of hydrocolloid, storage time and
temperature of storage. Addition of glucose, fructose, sucrose, trehalose, lactose and whey
increased or decreased retrogradation of maize and tapioca starches, depending on type of
starches, type of additives, storage time and temperature of storage.
Acetylation was carried out with 4, 6 and 8 % (w/w) of acetic anhydride. The
acetylation percent increased proportionally with the concentration of acetic anhydride used.
The percentages of acetylation were 1.257, 1.739 and 2.212 % for maize starch and 1.065,
1.532 and 1.979 % for tapioca starch.
Acetylated starches gelatinised at lower temperatures and had lower values of
gelatinisation enthalpy in comparison with native starches. Comparing to acetylated starches
(stored both at 4 °C and 25 °C), native starch had significantly higher tendency of
retrogradation.
The acetylation increased the swelling power of starches, and the similar behaviour
was found for solubility, but decreased hardness, fracturability and adhesiveness of starch
gels.- All metadata published by Europeana are available free of restriction under the Creative Commons CC0 1.0 Universal Public Domain Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
