Infl uence of process parameters and composition of the oil phase on rheological properties of mayonnaise

Sažetak Poznavanje reoloških svojstava hrane od velikog je značenja bilo da se radi o postizanju određenih svojstava hrane ili o vođenju procesa pri proizvodnji hrane. U ovom radu istraživan je utjecaj procesnih parametara (brzina rotacije rotora homogenizatora, vrijeme pripreme majoneze) i sastava uljne faze na reološko ponašanje majoneze. Mehanički proces homogenizacije majoneze proveden je kod 10 000, 12 000 i 15 000 o/min. i vremenu 3 i 8 min. pri sobnoj temperaturi. Majoneza sadrži 70% ulja sa različitim udjelima suncokretovog ulja i Olys ulja. Mjerenja reoloških svojstava provedena su na rotacijskom viskozimetru (DV- III + Digital Rheometer-Brookfield Engineering Laboratories, USA) sa koncentričnim cilindrima pri temperaturama 10 oC i 25 oC. Iz dobivenih podataka izračunati su reološki parametri koefi cijent konzistencije, indeks tečenja i prividna viskoznost. Rezultati istraživanja su pokazali da brzina rotacije rotora homogenizatora, vrijeme trajanja procesa pripreme majoneze i sastav uljne faze utječu na reološka svojstva. Homogenizacijom kod veće brzine rotora nastaje majoneza sa većom konzistencijom i viskoznosti. Dolazi do formiranja većeg broja kapljica ulja manjeg promjera i bolje disperzije u vodenoj fazi emulzije. Porastom udjela Olys ulja u uljnoj fazi povećava se viskoznost i konzistencija majoneze pripremljene kod 15 000 o/min. Homogenizacijom majoneze tijekom 8 min. kod 12 000 o/min. dolazi do porasta viskoznosti i konzistencije.The knowledge of rheological properties of food is very important both for achieving specifi c food properties and for controlling the food production process. In this study we investigated the eff ect of process parameters (rotation speed of the rotor homogenizers, time of preparation of mayonnaise) and the oil phase composition on the rheological behavior of mayonnaise. The mechanical process of homogenization of the mayonnaise was conducted in 10 000, 12 000 and 15 000 rpm and the time 3 and 8 min. at room temperature. Mayonnaise contains 70% of oil with diff erent proportions of sunfl ower oil and Olys oil. Rheological tests were carried out in a controlled rotational viscometer (DV- III + Digital Rheometer - Brookfi eld Engineering Laboratories, USA) with concentric spindles at 10 °C and 25 °C. From the obtained data, rheological parameters: consistency coeffi cient, fl ow behavior index and apparent viscosity were calculated. The results of research showed that homogenization speed, preparation time and the composition of oil phase have infl uence on rheological properties of mayonnaise. The result of homogenization at the higher speed of the rotor is mayonnaise with greater consistency and viscosity. There appears a formation of greater number of oil droplets with minor diameter, which are more dispersible in water phase of emulsion. The higher proportion of Olys oil in the oil phase increases the viscosity and consistency of mayonnaise prepared at 15 000 rpm. Homogenization of mayonnaise for 8 min. at 12 000 rpm increases viscosity and consistency

Addition of different vegetable oils’ effect on oxidative stability of sunflower oil blend

Oksidacijska stabilnost je važan parametar za procjenjivanje kvalitete ulja i masti, daje dobru procjenu stanja njihove osjetljivosti za oksidacijsko kvarenje. Istraživano je poboljšanje oksidacijske stabilnosti suncokretovog ulja u smjesi s repičinim uljem, uljem kikirikija, uljem kukuruzne klice i rižinim uljem. Ispitivana je smjesa različitih biljnih ulja sa suncokretovim uljem (25:75, 50:50). Oksidacija smjese dvije vrste ulja inducirana je i mjerena primjenom Rancimat metode (uzorak 3,0 g, temperatura 120 oC, protok zraka 9 L/h). Rezultat oksidacije ulja izražen je indukcijskim periodom (IP). Stabilnost smjese ulja proporcionalna je indukcijskom periodu. Miješanje ispitivanih ulja sa suncokretovim uljem (25:75 i 50:50) dovodi do porasta oksidacijske stabilnosti smjese ulja. Rezultat miješanja ulja kukuruzne klice i rižinog ulja sa suncokretovim uljem (25:75, 50:50), za svako posebno, poboljšana je oksidacijska stabilnost smjese ulja u Rancimat testu od 14,4% do 34,4% s uljem kukuruzne klice i od 15,2% do 46,8% s rižinim uljem u usporedbi sa suncokretovim uljem (kontrolni uzorak). Ovo istraživanje prikazuje načine poboljšanja stabilnosti suncokretovog ulja miješanjem s repičinim uljem, uljem kikirikija, uljem kukuruzne klice i rižinim uljem.Oxidative stability is an important parameter for the estimation of oil and fats quality. It also gives a good estimation of the state of their sensitivity to oxidative decay. Improvement of oxidative stability of sunflower oil blended with rape oil, peanut oil, rapeseed oil and rice oil was researched. A blend of different vegetable oils with sunflower oil (25:75, 50:50) was analyzed. Oxidation of the blend of two types of oil was induced and measured using Rancimat method (sample 3.0 g, temperature 120°C, airflow 9 L/h). The result of oil oxidation was expressed as induction period (IP). Stability of oil blend was proportional to induction period. Blending of the researched oils with sunflower oil (25:75 and 50:50), leads to the increase of oxidative stability of the oil blend. The result of blending rapeseed oil and rice oil with sunflower oil (25:75, 50:50), for each one separately, is improved oxidative stability of oil blend in Rancimat test, from 14.4% to 34.4% with the rapeseed oil and from 15.2% to 46.8% with rice oil in comparison to the sunflower oil (control sample). This research shows the ways of improving the stability of sunflower oil by blending it with rape oil, peanut oil, rapeseed oil and rice oil

Shear rate influence ob rheological properties of apple puree at low temperatures

Poznavanje reoloških svojstava hrane od velike je važnosti za postizanje određenih svojstava hrane i za vođenje procesa pri proizvodnji hrane. Tekstura je jedan od značajnijih čimbenika koji određuju kakvoću namirnica, pa tako i onih kojima se zamrzavanjem želi očuvati veća stabilnost tijekom vremena. Cilj rada bio je istraživanje utjecaja brzine smicanja i kontinuiranog hlađenja na reološka svojstva kaše jabuke pri niskim temperaturama prije zamrzavanja i tijekom zamrzavanja. Istraživanja su provedena s kašom jabuke sorte Idared. Mjerenja reoloških svojstava provedena su na rotacijskom viskozimetru Rheotest 3 s kriostatskom jedinicom. Reološka svojstva ispitivane kaše određena su mjerenjem i grafičkim prikazom ovisnosti smičnog naprezanja i brzine smicanja pri 10 oC te izračunavanjem koeficijenta konzistencije i indeksa tečenja. Također je mjerena ovisnost smičnog naprezanja i prividne viskoznosti o temperaturi kod kontinuiranog hlađenja pri konstantnoj brzini smicanja. Određena je temperatura nakon koje dolazi do naglog povećanja smičnog naprezanja i manje brzine snižavanja temperature (Tk), kao i najniža temperatura pothlađivanja kod koje još dolazi do smicanja (Tm). Ispitivanja su pokazala da reološka svojstva kaše jabuke pri niskim temperaturama tijekom kontinuiranog hlađenja i temperature Tk i Tm ovise o brzini smicanja. Hlađenjem ispitivane kaše jabuke u području zamrzavanja dolazi do pothlađivanja kaše do temperature (Tm) koja je ovisila o brzini smicanja. Značajne su promjene reoloških svojstava kaše jabuke u području pothlađivanja zbog nastajanja kristala leda kao novih krutih čestica i njihovog rasta, a zapažene su pri temperaturama od -5,55 do -10,50 oC, ovisno o brzini smicanja.The knowledge of rheological properties is very important either for achieving specific food properties, or for designing production procedure. The texture is one of the significant factors, which specifies the quality of foodstuffs, including those, which are kept by freezing in order to preserve their stability for a longer period. The aim of this work was to investigate an influence of shear rate and continuous cooling on rheological properties of apple puree at low temperatures before freezing and during the process of freezing. Investigation was carried out with apple puree of Idared sort. Measurements of the rheological properties were made by a rotary viscosimeter Rheotest 3 with the refrigerating unit. The rheological properties of purees were measured and shown by graphic representation showing relation between shear stress and shear rate at the temperature of 10°C and by calculating the consistency coefficient and flow behaviour index. The relation between shear stress, temperature and cooling rate was also measured at the constant shear rate. The temperature was measured at which shear stress increases and the temperature (Tk) falls. The lowest temperature of cooling at which the shear (Tm) is still present was also measured. The examinations showed that at low temperatures the rheological properties of apple puree depended of shear rate. If the apple purees were cooled at a freezing temperature, their temperature (Tm) depended of the shear rate. There were some significant changes of rheological properties of apple puree while being cooled due to ice crystals formation and growth. They were formed as solid particles and observed at temperatures ranging from – 5.55 to – 10.50°C depending on the shear rate

Propiedades nutritivas y la seguridad microbiológica de las semillas oleaginosas y los frutos secos de cultivo orgánico

Organski uzgojene biljke uljarica i orašasti plodovi te proizvodi njihove prerade su zbog svojih nutritivnih vrijednosti, odličnog okusa i pozitivnih učinaka na zdravlje sve omiljeniji današnjim potrošačima. Mnogi od tih proizvoda se mogu dobiti uz minimalno procesiranje, a budući da nisu termički tretirani, zanimljivo je da imaju vrlo veliki stupanj mikrobiološke čistoće. U ovom radu opisani su proizvodi organski uzgojenih uljarica s obzirom na njihovu nutritivnu i energetsku vrijednost te mikrobiološku ispravnost. Opisana su svojstva ulja i maslaca biljaka uljarica i orašastih plodova te njihovi nusproizvodi, koji se dobivaju postupkom hladnog prešanja. U radu su prikazani i rezultati ispitivanja mikrobiološke ispravnosti navedenih proizvoda te usporedba dobivenih parametara s normama koje propisuje Zakon o higijeni hrane i mikrobiološkim kriterijima za hranu (NN 81/13, 115/18).Organically grown plants of oilseeds and nuts, and products of their processing, are increasingly popular with today\u27s consumers due to their nutritional value, excellent taste and positive health effects. Many of these products can be obtained with minimal processing, and since they are not thermally treated, it is interesting that they have a very large degree of microbiological purity. This paper describes the products of organically grown oilseeds with regard to their nutritional and energy value and microbiological integrity. The properties of oil and butter of oilseeds and nuts are described, as well as and their by-products, which are obtained by cold pressing process. The paper also presents the results of testing of the microbiological correctness of the products and the comparison of the obtained parameters with the standards prescribed by the Food Hygiene and Microbiological Criteria for Food.Biologisch angebaute Ölsamenpflanzen und Nüsse sowie Produkte ihrer Verarbeitung erfreuen sich bei den heutigen Verbrauchern aufgrund ihres Nährwerts, ihres ausgezeichneten Geschmacks und ihrer positiven gesundheitlichen Auswirkungen zunehmender Beliebtheit. Viele dieser Produkte können mit minimaler Verarbeitung gewonnen werden. Da sie nicht thermisch behandelt werden, ist es interessant, dass sie einen sehr hohen Grad an mikrobiologischer Reinheit aufweisen. In dieser Arbeit werden die Produkte aus Ölsaaten aus biologischem Anbau im Hinblick auf ihren Nähr- und Energiewert und ihre mikrobiologische Integrität beschrieben. Es werden die Eigenschaften von Öl und Butter von Ölsaaten und Nüssen sowie deren Nebenprodukte, die durch Kaltpressung gewonnen werden, beschrieben. In der Arbeit werden auch die Ergebnisse der Prüfung der mikrobiologischen Integrität der Produkte und der Vergleich der erhaltenen Parameter mit den Normen, die das Gesetz über die Hygiene von Lebensmitteln und die mikrobiologischen Kriterien für Lebensmittel vorschreibt (Amtsblatt Narodne novine 81/2013), dargestellt.Grazie ai loro valori nutritivi, al delizioso gusto e agli effetti positivi sulla salute, le piante oleaginose e la frutta in guscio coltivate secondo il metodo biologico come anche i prodotti da esse derivati, sono sempre più pregiati tra i consumatori di oggi. Molti di questi prodotti si possono ottenere attraverso le lavorazioni minime e, dato che non vengono trattati termicamente, curiosamente dimostrano un grado di purezza microbiologica molto elevato. Nella presente tesi vengono descritti i prodotti ottenuti dalle piante oleaginose coltivate secondo il metodo biologico con riferimento al loro valore nutritivo ed energetico nonché alla loro sicurezza microbiologica. Sono state descritte le proprietà degli oli e dei burri estratti dalle piante oleaginose e dalla frutta in guscio e dei loro sottoprodotti che si ricavano con la spremitura a freddo. La tesi riporta anche i risultati degli esami della qualità e sicurezza microbiologica dei prodotti ivi indicati, nonché il confronto tra i parametri ottenuti e le norme disposte dalla Legge sull’igiene degli alimenti e sui criteri microbiologici applicabili ai prodotti alimentari (G.U.croata 81/2013).Las semillas oleaginosas y los frutos secos cultivados orgánicamente y los productos de su procesamiento, son cada vez más populares entre los consumidores debido a su valor nutricional, el sabor excelente y los efectos positivos en la salud. Muchos de estos productos pueden obtenerse con un procesamiento mínimo y, dado que no se tratan térmicamente, es interesante que tengan un grado muy alto de pureza microbiológica. En este trabajo fueron descritos los productos de las semillas oleaginosas cultivadas orgánicamente con respecto a su valor nutricional, energético y seguridad microbiológica. Están descritas las propiedades de los aceites y mantequillas de semillas oleaginosas y frutos secos y sus subproductos, que se obtienen por prensado en frío. El documento también presenta los resultados de las pruebas de la seguridad microbiológica de estos productos y la comparación de los parámetros obtenidos con los estándares prescritos por la Ley de Higiene Alimentaria y las normas microbiológicas para los alimentos (NN 81/2013)

Stabilizzazione del grasso d\u27oca con antiossidanti e sinergizzanti

Tijekom proizvodnje, skladištenja i toplinske obrade guščja mast podliježe oksidacijskom kvarenju. U ovom radu istraživan je utjecaj dodatka prirodnih i sintetskih antioksidanasa te sinergista (ekstrakt ružmarina, ekstrakt zelenog čaja, ekstrakt kadulje, alfa tokoferol, mješavina tokoferola, propil galat, limunska kiselina, askorbinska kiselina, kofeinska kiselina, ružmarinska kiselina) na oksidacijsku stabilnost guščje masti. Oksidacijska stabilnost masti, sa i bez dodanog antioksidansa i sinergista, ispitivana je primjenom Schaal Oven testa. Rezultati testa prikazani su kao vrijednost peroksidnog broja nakon određenog vremena držanja masti pri temperaturi 63 °C. Rezultati istraživanja pokazuju da dodani antioksidansi i sinergisti uspješno stabiliziraju guščju mast, osim α-tokoferola. Od prirodnih antioksidanasa najveću antioksidacijsku aktivnost u guščjoj masti ima ekstrakt zelenog čaja. Postigao je najveću efikasnost zaštite od oksidacijskog kvarenja. Ekstrakt ružmarina u kombinaciji sa sinergistom pokazuje veću razinu zaštite masti od oksidacije u odnosu na čisti ekstrakt ružmarina. Dodatkom mješavine tokoferola postignuta je bolja stabilizacija masti u odnosu na ekstrakt kadulje. Sintetski antioksidans propil galat uspješno je povećao stabilnost guščje masti.During production, storage and heat treatment, goose fat is subject to oxidative deterioration. This paper investigated the influence of natural and synthetic antioxidants and synergists (rosemary extract, green tea extract, sage extract, alpha tocopherol, tocopherol mixture, propyl gallate, citric acid, ascorbic acid, caffeic acid, rosmarinic acid) on the oxidative stability of goose fat. Oxidation stability of fat, with and without added antioxidants and synergists, was investigated using the Schaal Oven test. The test results are presented as the value of the peroxide number after a certain time of keeping the fat at a temperature of 63 °C. The results of the study showed that applying antioxidants and synergists successfully stabilises goose fat, with exception of α-tocopherol. Of the natural antioxidants, green tea extract has the highest antioxidant activity in goose fat. It achieved the highest efficiency of protection against oxidative deterioration. Rosemary extract in combination with a synergist shows a higher level of fat protection against oxidation compared to pure rosemary extract. By adding a tocopherol mixture, a better stabilization of the fat was achieved compared to sage extract. The synthetic antioxidant propyl gallate successfully increased the stability of goose fat.Während der Herstellung, Lagerung und Wärmebehandlung unterliegt Gänseschmalz einem oxidativen Verfall. In dieser Arbeit wurde der Einfluss von natürlichen und synthetischen Antioxidantien und Synergisten (Rosmarinextrakt, Grüntee-Extrakt, Salbeiextrakt, Alpha-Tocopherol, Tocopherol-Mischung, Propylgallat, Zitronensäure, Ascorbinsäure, Kaffeesäure, Rosmarinsäure) auf die Oxidationsstabilität von Gänseschmalz untersucht. Die Oxidationsstabilität von Schmalz, mit und ohne zugesetzte Antioxidantien und Synergisten, wurde mit dem Schaal-Ofen-Test untersucht. Die Testergebnisse werden als Wert der Peroxidzahl nach einer bestimmten Zeit der Lagerung von Schmalz bei einer Temperatur von 63 °C angegeben. Die Ergebnisse der Studie zeigen, dass die Anwendung von Antioxidantien und Synergisten Gänseschmalz erfolgreich stabilisiert, nicht aber α-Tocopherol. Von den natürlichen Antioxidantien hat Grüntee-Extrakt die höchste antioxidative Aktivität in Gänseschmalz. Er erreichte die höchste Schutzwirkung gegen oxidativen Verfall. Rosmarinextrakt in Kombination mit einem Synergisten zeigt im Vergleich zu reinem Rosmarinextrakt einen höheren Schutz von Schmalz gegen Oxidation. Durch Zugabe einer Tocopherolmischung wurde eine bessere Stabilisierung von Schmalz erreicht als mit Salbeiextrakt. Das synthetische Antioxidans Propylgallat erhöhte erfolgreich die Stabilität von Gänseschmalz.Durante la producción, el almacenamiento y el tratamiento térmico, la grasa de ganso está sujeta a deterioro oxidativo. En este trabajo se analiza la influencia de la adición de antioxidantes y sinergistas naturales y sintéticos (el extracto de romero, el extracto de té verde, el extracto de salvia, el a-tocoferol, la mezcla de tocoferoles, el galato de propilo, el ácido cítrico, el ácido ascórbico, el ácido cafeico, el ácido rosmarínico) sobre la estabilidad oxidativa de la grasa de ganso. La estabilidad a la oxidación de la grasa, con y sin antioxidantes y sinergistas añadidos, fue investigada mediante la prueba del Schaal. Los resultados de la prueba se presentan como el valor del número de peróxido después de un cierto tiempo de mantenimiento de la grasa a una temperatura de 63 °C. Los resultados de la investigación muestran que los antioxidantes y sinergistas agregados estabilizan con éxito la grasa de ganso, excepto el α-tocoferol. De los antioxidantes naturales, el extracto de té verde tiene la mayor actividad antioxidante en la grasa de ganso. Logró la más alta eficiencia de protección contra el deterioro oxidativo. El extracto de romero en combinación con un sinergista muestra un mayor nivel de protección de las grasas contra la oxidación en comparación con el extracto de romero puro. Al agregar una mezcla de tocoferoles, se logró una mejor estabilización de la grasa en comparación con el extracto de salvia. El antioxidante sintético galato de propilo aumentó con éxito la estabilidad de la grasa de ganso.Durante la produzione, lo stoccaggio e il trattamento termico, il grasso d\u27oca è soggetto a irrancidimento ossidativo. In questo lavoro, è stata studiata l\u27influenza dell\u27aggiunta di antiossidanti e sinergizzanti naturali e sintetici (estratto di rosmarino, estratto di tè verde, estratto di salvia, alfa tocoferolo, miscela di tocoferoli, gallato di propile, acido citrico, acido ascorbico, acido caffeico, acido rosmarinico) sulla stabilità ossidativa del grasso d\u27oca. La stabilità ossidativa del grasso, con e senza l\u27aggiunta di antiossidanti e sinergizzanti, è stata studiata utilizzando il test Schaal Oven. I risultati del test sono presentati come il valore del numero di perossidi dopo che il grasso è stato mantenuto per un certo tempo alla temperatura di 63 °C. I risultati della ricerca mostrano che gli antiossidanti e i sinergizzanti aggiunti stabilizzano efficacemente il grasso d\u27oca, ad eccezione dell\u27α-tocoferolo. Tra gli antiossidanti naturali, l\u27estratto di tè verde ha evidenziato la più alta attività antiossidante rispetto al grasso d’oca; ha raggiunto, infatti, la massima efficienza di protezione contro l’irrancidimento ossidativo. L\u27estratto di rosmarino, in combinazione con un sinergizzante, mostra un livello di protezione dei grassi contro l\u27ossidazione più elevato rispetto all\u27estratto di rosmarino puro. Aggiungendo una miscela di tocoferolo, si ottiene una migliore stabilizzazione del grasso rispetto a quella ottenuta con l\u27estratto di salvia. L\u27antiossidante sintetico gallato di propile ha aumentato efficacemente la stabilità ossidativa del grasso d\u27oca

Influence of degumming process on rheological properties of crude sunflower seed oil

Deguminacija je postupak tretiranja sirovog ulja vodom, razrijeđenim kiselinama (fosforna, limunska) radi uklanjanja fosfolipida i gumastih, sluzavih tvari. Svrha ovog rada je ispitati utjecaj vrste kiseline i parametara kiselinsko-vodene deguminacije (temperatura kontakta kiseline i ulja, temperatura kontakta i vrijeme trajanja miješanja ulja s vodom) na reološka svojstva sirovog suncokretovog ulja. Proces deguminacije proveden je različitim kiselinama (limunska kiselina, askorbinska kiselina, vinska kiselina; udjela 0,3% na masu ulja, u koncentraciji 50%), temperaturama kontakta kiseline i ulja (50 oC, 70 oC, 80 oC), dodatkom 2% vode, temperature kontakta vode i ulja (25 oC, 40 oC, 70 oC) te vrijeme kontakta s vodom (30, 60 i 90 minuta s miješanjem). Efikasnost deguminacije ulja praćena je određivanjem reoloških svojstava ulja i određivanjem prinosa i gubitka ulja. Mjerenja reoloških svojstava degumiranog ulja provedena su rotacijskim viskozimetrom primjenom sustava koncentričnih cilindara pri temperaturi 25 oC. Reološki parametri određeni su primjenom Newtonovog zakona. Rezultati istraživanja pokazuju da su svi ispitivani sustavi imali Newtonovski karakter. Deguminacijom suncokretovog ulja limunskom kiselinom postiže se veća efikasnost uklanjanja fosfolipida (manja viskoznost ulja) u odnosu na vinsku i askorbinsku kiselinu. Bolji rezultat procesa postignut je kod temperature kontakta ulja s kiselinom pri 80 oC i temperaturi kontakta ulja s vodom pri 70 oC tijekom 60 minuta miješanja ulja.Degumming is the treatment of crude oils with water, dilute acids (phosphoric or citric acid) to remove the phosphatides and mucilaginous material from the crude oil. The aim of this paper is to examine the influence of acid type and degumming process parameters (contact temperature of acid and oil, contact temperature and time of agitation of oil and water) on rheological properties of crude sunflower oil. Diverse degumming agents (citric acid, ascorbic acid, tartaric acid- amount 0.3% of mass oil), all used in a concentration of 50%, acid and oil contact temperature (50oC, 70oC, 80oC), 2% of water was added, water and oil contact temperature (25oC, 40oC, 70oC), contact time with water (30, 60 and 90 minutes with agitation) were used. Efficiency of oil degumming was monitored by determining rheological properties of oil and yield and loss of oil. Measurements of rheological properties of degumming oil were performed using rotational viscosimeter at 25oC. The rheological parameters were determined by the Newton law. The results of the research have shown that all the investigated systems had Newtonian characteristics. Degumming of sunflower oil with citric acid results in a better efficiency in removing of phospholipids (lower viscosity of oil) with regard to tartaric and ascorbic acid. Best results were obtained at contact temperature of acid and oil at 80oC and temperature contact of oil with water 70oC using 60 minute agitation

Treatment possibilities of vegetative water appearing in the process of olive oil extraction

Maslinarstvo Republike Hrvatske u snažnom je usponu. Razlog su tome prirodne blagodati koje omogućuju proizvodnju ekstra djevičanskih maslinovih ulja visoke kakvoće. Površine pod kulturom masline rastu iz godine u godinu. Kako se većina plodova masline prerađuju u maslinovo ulje, porastom količine prerađenih plodova raste i količina dobivenih nusprodukata tijekom procesa ekstrakcije maslinovog ulja. Nusprodukti su u prvom redu komina i vegetabilna voda. U Hrvatskoj se godišnje prema gruboj procjeni proizvede oko 55,250,000 litara vegetabilne vode. U radu su na osnovi citata iz znanstvenih i stručnih radova opisane glavne tehnologije zbrinjavanja vegetabilne vode: biološke, kemijske, fizikalne, mikrobiološke, biotehnološke metode te metoda ekstrakcije korisnih spojeva iz vegetabilne vode i njeno direktno izlijevanje na poljoprivredne površine. Od opisanih metoda za uvjete u Hrvatskoj preporučene su: anaerobna razgradnja, neutralizacija pomoću kalcija, izlijevanje na poljoprivredne površine i ekstrakcija korisnih tvari.Olive growing is on the constant rise in the Republic of Croatia. Natural benedictions which enable the production of extra virgin olive oils of high quality are the reason for this. Surfaces under olive culture grow from year to year. As most of olive fruits are processed into olive oil, along with the increase in quantity of processed fruits grows the quantity of obtained by- products during the process of extraction of olive oil. Primary by- products are olive cake and vegetative water. It is roughly estimated that the annual production of vegetative water in Croatia is about 55.235.000 l. Based on quotations from scientific and professional papers, this paper describes the major technologies of vegetative water treatment. They are: biological, chemical, physical, microbiological, biotechnological methods, and the method of extraction of useful compounds from vegetative water and its direct pouring out on agricultural surfaces. Out of described methods, the following are recommended for Croatian conditions: anaerobic decomposition, neutralization by calcium, pouring out on agricultural surfaces and extraction of useful compounds

Addition of different vegetable oils’ effect on oxidative stability of sunflower oil blend

Oksidacijska stabilnost je važan parametar za procjenjivanje kvalitete ulja i masti, daje dobru procjenu stanja njihove osjetljivosti za oksidacijsko kvarenje. Istraživano je poboljšanje oksidacijske stabilnosti suncokretovog ulja u smjesi s repičinim uljem, uljem kikirikija, uljem kukuruzne klice i rižinim uljem. Ispitivana je smjesa različitih biljnih ulja sa suncokretovim uljem (25:75, 50:50). Oksidacija smjese dvije vrste ulja inducirana je i mjerena primjenom Rancimat metode (uzorak 3,0 g, temperatura 120 oC, protok zraka 9 L/h). Rezultat oksidacije ulja izražen je indukcijskim periodom (IP). Stabilnost smjese ulja proporcionalna je indukcijskom periodu. Miješanje ispitivanih ulja sa suncokretovim uljem (25:75 i 50:50) dovodi do porasta oksidacijske stabilnosti smjese ulja. Rezultat miješanja ulja kukuruzne klice i rižinog ulja sa suncokretovim uljem (25:75, 50:50), za svako posebno, poboljšana je oksidacijska stabilnost smjese ulja u Rancimat testu od 14,4% do 34,4% s uljem kukuruzne klice i od 15,2% do 46,8% s rižinim uljem u usporedbi sa suncokretovim uljem (kontrolni uzorak). Ovo istraživanje prikazuje načine poboljšanja stabilnosti suncokretovog ulja miješanjem s repičinim uljem, uljem kikirikija, uljem kukuruzne klice i rižinim uljem.Oxidative stability is an important parameter for the estimation of oil and fats quality. It also gives a good estimation of the state of their sensitivity to oxidative decay. Improvement of oxidative stability of sunflower oil blended with rape oil, peanut oil, rapeseed oil and rice oil was researched. A blend of different vegetable oils with sunflower oil (25:75, 50:50) was analyzed. Oxidation of the blend of two types of oil was induced and measured using Rancimat method (sample 3.0 g, temperature 120°C, airflow 9 L/h). The result of oil oxidation was expressed as induction period (IP). Stability of oil blend was proportional to induction period. Blending of the researched oils with sunflower oil (25:75 and 50:50), leads to the increase of oxidative stability of the oil blend. The result of blending rapeseed oil and rice oil with sunflower oil (25:75, 50:50), for each one separately, is improved oxidative stability of oil blend in Rancimat test, from 14.4% to 34.4% with the rapeseed oil and from 15.2% to 46.8% with rice oil in comparison to the sunflower oil (control sample). This research shows the ways of improving the stability of sunflower oil by blending it with rape oil, peanut oil, rapeseed oil and rice oil

Shear rate influence ob rheological properties of apple puree at low temperatures

Poznavanje reoloških svojstava hrane od velike je važnosti za postizanje određenih svojstava hrane i za vođenje procesa pri proizvodnji hrane. Tekstura je jedan od značajnijih čimbenika koji određuju kakvoću namirnica, pa tako i onih kojima se zamrzavanjem želi očuvati veća stabilnost tijekom vremena. Cilj rada bio je istraživanje utjecaja brzine smicanja i kontinuiranog hlađenja na reološka svojstva kaše jabuke pri niskim temperaturama prije zamrzavanja i tijekom zamrzavanja. Istraživanja su provedena s kašom jabuke sorte Idared. Mjerenja reoloških svojstava provedena su na rotacijskom viskozimetru Rheotest 3 s kriostatskom jedinicom. Reološka svojstva ispitivane kaše određena su mjerenjem i grafičkim prikazom ovisnosti smičnog naprezanja i brzine smicanja pri 10 oC te izračunavanjem koeficijenta konzistencije i indeksa tečenja. Također je mjerena ovisnost smičnog naprezanja i prividne viskoznosti o temperaturi kod kontinuiranog hlađenja pri konstantnoj brzini smicanja. Određena je temperatura nakon koje dolazi do naglog povećanja smičnog naprezanja i manje brzine snižavanja temperature (Tk), kao i najniža temperatura pothlađivanja kod koje još dolazi do smicanja (Tm). Ispitivanja su pokazala da reološka svojstva kaše jabuke pri niskim temperaturama tijekom kontinuiranog hlađenja i temperature Tk i Tm ovise o brzini smicanja. Hlađenjem ispitivane kaše jabuke u području zamrzavanja dolazi do pothlađivanja kaše do temperature (Tm) koja je ovisila o brzini smicanja. Značajne su promjene reoloških svojstava kaše jabuke u području pothlađivanja zbog nastajanja kristala leda kao novih krutih čestica i njihovog rasta, a zapažene su pri temperaturama od -5,55 do -10,50 oC, ovisno o brzini smicanja.The knowledge of rheological properties is very important either for achieving specific food properties, or for designing production procedure. The texture is one of the significant factors, which specifies the quality of foodstuffs, including those, which are kept by freezing in order to preserve their stability for a longer period. The aim of this work was to investigate an influence of shear rate and continuous cooling on rheological properties of apple puree at low temperatures before freezing and during the process of freezing. Investigation was carried out with apple puree of Idared sort. Measurements of the rheological properties were made by a rotary viscosimeter Rheotest 3 with the refrigerating unit. The rheological properties of purees were measured and shown by graphic representation showing relation between shear stress and shear rate at the temperature of 10°C and by calculating the consistency coefficient and flow behaviour index. The relation between shear stress, temperature and cooling rate was also measured at the constant shear rate. The temperature was measured at which shear stress increases and the temperature (Tk) falls. The lowest temperature of cooling at which the shear (Tm) is still present was also measured. The examinations showed that at low temperatures the rheological properties of apple puree depended of shear rate. If the apple purees were cooled at a freezing temperature, their temperature (Tm) depended of the shear rate. There were some significant changes of rheological properties of apple puree while being cooled due to ice crystals formation and growth. They were formed as solid particles and observed at temperatures ranging from – 5.55 to – 10.50°C depending on the shear rate

Effect of salinity and alkalinity on germination and root growth in industrial hemp (Cannabis sativa L.)

Salinitet i alkalitet pripadaju abiotičkim stresnim čimbenicima koji ograničavaju opskrbu biljke vodom te uzrokuju ionski stres čime narušavaju ionsku ravnotežu stanice. Oba stresna čimbenika negativno utječu na sve razvojne faze, no faza klijanja je najosjetljivija jer klica dolazi u direktni kontakt s vodenom otopinom soli u tlu. Industrijska konoplja (Cannabis sativa L.) dobro podnosi salinitet uzrokovan povišenom koncentracijom NaCl ali je relativno malo dostupnih podataka koji se bave tolerancijom konoplje na različite vrste solnoga stresa. Sjeme kultivara konoplje (Santhica 70 i Futura 83) bilo je izloženo djelovanju saliniteta izazvanog otopinama NaCl i Na2SO4 te alkaliteta izazvanog otopinama NaHCO3 i Na2CO3 tijekom četiri dana. Obje vrste solnog stresa inhibirale su klijanje i rast korijena u oba genotipa u odnosu na kontrolu. Stres izazvan otopinom Na2SO4 nakon 2. dana uzgoja uzrokovao je redukciju klijavosti za 97,6% (Santhica 70) i 90,6% (Futura 83) te pokazao najniže vrijednosti germinacijskog indeksa tolerantnosti na sol (STI_G2) u oba kultivara, dok je otopina Na2CO3 nakon 4. dana uzrokovala najveću redukciju rasta korijena za 94% (Futura 83) , odnosno 95% (Santhica 70). Stres izazvan otopinom NaCl imao je najmanje štetne posljedice na klijavost i rast korijena iz čega slijedi da odgovor na solni stres ovisi o vrsti biljnog tkiva. Nakon 4. dana klijavost Future 83 bila je 7,6% (NaCl) i 13,8% (NaHCO3) veća od klijavosti Santhice 70. Nadalje, Futura 83 na otopini NaCl imala je veće vrijednosti STI_G2 i STI_G4 te 15% dulji korijen nego Santhica 70, iz čega proizlazi da tolerantnost saliniteta i alkaliteta ovisi o genotipskim obilježjima.Salinity and alkalinity are important abiotic stress factors that restrict the plant’s availability of water, cause ionic stress, and contribute to the disruption of cellular homeostasis. Both stress factors negatively impact all stages of plant development, with an emphasis on germination, which is the most sensitive due to direct contact of the embryo with saline solution in the soil. Industrial hemp (Cannabis sativa L.) has a high tolerance to NaCl stress but knowledge of the effects of different salt types is limited. Seeds of two hemp genotypes (Santhica 70 i Futura 83) were exposed to salinity (NaCl i Na2SO4) and alkalinity (NaHCO3 i Na2CO3) stress for 4 days. The germination percentage and root growth under all treatments were reduced in both genotypes compared to the control. After 2nd day of growth, Na2SO4 had the strongest inhibitory effect on germination and germination salt tolerance index (STI_G2) in both genotypes while the most detrimental effect on root growth was observed under 4-day exposure to Na2CO3 treatment. The least negative effect of salt stress on germination and root growth was observed under NaCl treatment, suggesting that the salt response is tissue-dependent. Futura 83 showed a higher germination percentage, higher values of STI_G2 and STI_G4, and longer roots than Santhica 70 in both NaCl and NaHCO3 treatments. Our results suggest that tolerance to salinity and alkalinity depends on genotype properties