Search

Activity of ALS enzyme extracted from leaves of Xanthium strumarium L. (XS1, XS2) and Helianthus annuus L. (HA1, HA2, HA3) populations were studied in vitro in the presence of different nicosulfuron concentrations (0; 0,01; 0,1; 1; 10, 100 μM). This activity was recorded based on acumulation of acetoin per mg of protein during time interval of 1 min (nmol acetoin/min/mg protein). Nicosulfuron was reduced ALS enzyme activity in all studied populations, wherein the level of reduction depended on population and herbicide concentracion. It was confirmed that differences in susceptibility of X. strumarium populations to nicosulfuron were not consequence of altered ALS enzyme activity, while differences in susceptibility of H. annuus populations can be in relation with its altered activity. Aktivnost ALS enzima ekstrahovanog iz listova populacija Xanthium strumarium L. (XS1, XS2) i Helianthus annuus L. (HA1, HA2, HA3) je ispitivana in vitro u prisustvu različitih koncentracija (0; 0,01; 0,1; 1; 10, 100 μM) nikosulfurona. Ova aktivnost je određena na osnovu akumulacije acetoina po mg proteina u toku vremenskog perioda od 1 min (nmol acetoin/min/mg protein). Nikosulfuron je redukovao aktivnost ALS enzima u svim ispitivanim populacijama, pri čemu je nivo redukcije zavisio od populacije i koncentracije herbicida. Potvrđeno je da razlike u osetljivosti populacija X. strumarium na nikosulfuron nisu posledica izmenjene aktivnosti ALS enzima, dok se razlike u osetljivosti populacija H. annuus mogu dovesti u vezu sa njegovom izmenjenom aktivnošću.

Pšenica je jedna od najvažnijih biljnih kultura koja se koristi u ishrani ljudi kao glavni izvor energije, proteina i dijetalnih vlakana. Uprkos relativno niskom sadržaju proteina (obično 8-15%) hranljivu vrednost proteina pšenice ne bi trebalo pocenjivati. Značaj pšenice uglavnom se pripisuje njenoj sposobnosti da može biti samlevena u brašno i griz koji čine osnovne sastojke hleba, drugih pekarskih proizvoda i testenina. Kvalitet brašna, reološke i funkcionalne karakteristike testa i pekarskih proizvoda umnogome zavise od proteina pšenice. Proteini pšeničnog zrna pokazuju visoku kompleksnost i različit međusobni stepen interakcije zbog čega je njihova karakterizacija teška. Pšenica je jedinstvena među biljnim vrstama jer pšenično brašno sadrži proteinski kompleks „gluten“ koji ima svojstvo da formira testo sa reološkim svojstvima potrebnim za proizvodnju hleba i drugih pekarskih proizvoda. Formiranje viskoelastičnog testa koje ima sposobnost zadržavanja gasa tokom procesa fermentacije u potpunosti zavisi od proteina glutena. Kako je testo veoma složen sistem čije karakteristike zavise od mnogobrojnih komponenata i faktora, reološka ispitivanja testa mogu ukazati na ponašanje testa prilikom zamesa i naknadnih manipulacija u pekari. U cilju karakterizacije strukture i sastava proteina, kao i ispitivanja njihovog uticaja na tehnološka svojstva pšeničnog brašna, u ovom istraživanju korišćeno je pet hlebnih (ZP 87/1, ZP 7/1, ZP 3/1, Cimmyt 266, ZP Zemunska rosa) i pet durum (ZP 120, Cimmyt 7879, Cimmyt 7817, ZP 34/1 rana, ZP DSP/01) genotipova pšenice gajenih tokom dve godine. Elektroforetska karakterizacija albuminsko-globulinske, glijadinske i gluteninske frakcije proteina genotipova hlebne i durum pšenice u dve ispitivane godine pokazala je visoke različitosti, koje se mogu pripisati uticaju spoljnih faktora, genotipa i međusobnim delovanjem genotipa i sredine. Na sadržaj i kompoziciju glijadina i glutenina u genotipovima hlebne pšenice uticaj faktora genotipa je bio dominantan, za razliku od durum pšenica gde je faktor sredine imao veliki uticaj. Mali uticaj sredine na subjedinice glijadina i glutenina je izuzetno povoljan, jer se samim odabirom genotipa sa dobrim kvalitativnim i kvantitativnim odnosom ovih grupa proteina može uticati povoljno na tehnološka svojstva brašna... Wheat is one of the most important cereal crops worldwide and it is a major source of energy, protein, and dietary fibre in human nutrition. Despite its relatively low protein content (usually 8-15%) the nutritional importance of wheat proteins should not be underestimated. The importance of wheat is mainly attributed to the fact that its seed can be ground into flour and semolina, which form the basic ingredients of bread, other bakery products and pasta. Wheat flour quality, rheological and technological properties of dough and bakery products are largely determined by the proteins. Wheat proteins show high complexity and different interactions with each other, thus making them difficult to characterise. Wheat is unique among the edible grains because wheat flour has the protein complex called „gluten“ that can be formed into a dough with the rheological properties required for the production of bread and other bakery products. The formation of the viscoelastic dough that is capable of retaining gases during the fermentation process depends entirely on the gluten proteins. As the wheat dough is a very complex system whose characteristics depend on many components and factors, dough rheological tests can indicate the behaviour of dough during dough mixing and the manipulation in the bakery. In order to characterize a structure and a composition of wheat proteins, as well as their influence on the technological properties of flour, five bread (ZP 87/1, 7/1 ZP, ZP 3/1, Cimmyt 266, ZP Zemunska rosa) and five durum (ZP 120, Cimmyt 7879, Cimmyt 7817, ZP 34/1 rana, ZP DSP/01) wheat genotypes cultivated in 2010 and 2011 growing seasons, were used. Electrophoretic patterns of albumin-globulin, gliadin and glutenin protein of bread and durum wheat genotypes showed significant differences, which can be attributed to the influence of environmental factors, genotype and the genotype x environment interaction. The content and the composition of gliadin and glutenin fractions of bread wheat genotypes were influenced by a genotype as a dominant factor, while durum wheat genotypes were highly environment dependent. A low influence of environmental factors on gliadin and glutenin subunits is favourable, because selection of genotypes with a good qualitative and quantitative composition of these protein groups could have a good effect on the technological properties of flour.

Proizvodnja i prerada kozjeg mleka je dinamična grana mlekarske industrije koja je u usponu i igra važnu ulogu u ekonomskom razvoju mnogih zemalјa. Poslednjih godina na tržištu mlečnih proizvoda širom sveta, kozji mlečni proizvodi se nalaze u žiži interesovanja. Termički tretmani su deo postupka proizvodnje velikog broja mlečnih proizvoda, a imaju za cilј pobolјšanje pojedinih karakteristika proizvoda, podizanje nivoa njihove bezbednosti, kao i produženje roka trajanja. Proteini mleka podvrgnutog termičkom tretmanu menjaju svoje funkcionalne osobine što nalazi široku primenu u prehrambenoj i farmaceutskoj industriji. Za razliku od kravljeg mleka koje nakon visokih termičkih tretmana menja svoje tehnološke karakteristike, što otežava proces proizvodnje i dovodi do stvaranja sira lošijeg kvaliteta, za kozje mleko postoje naznake u literaturi, da se nakon termičkog tretmana koagulacija neometano odvija, što ukazuje na potencijalnu mogućnost dobijanja sira sa uvećanim randmanom i nutritivnom vrednošću. Cilj ovog rada je bio da se ispita mogućnost proizvodnje kozjih belih sireva u salamuri dobijenih od mleka tretiranog režimima termičke obrade: 80°C/5 min i 90°C/5 min, bez prilagođavanja faktora proizvodnje u odnosu na kontrolnu varijantu proizvedenu od mleka tretiranog klasičnim postupkom niske pasterizacije (65°C/30 min), kao i da se ispitaju karakteristike ovako dobijenih sireva. Navedeni cilj sproveden je kroz tri faze. Ispitivan je uticaj termičkih tretmana kozjeg mleka na (1) intenzitet promena na proteinima punomasnog i obranog kozjeg mleka, kako bi se dobila jasnija slika o sirovini koja se koristi za proizvodnju sireva; (2) enzimsku koagulaciju kroz određivanje parametara koagulacije (3) tok zrenja kozjih belih sireva u salamuri, po pitanju osnovnih fizičko-hemijskih parametara, proteolitičkih promena, kao i promena teksturalnih i senzornih svojstava... Production and processing of goat’s milk is a dynamic and growing industry that is becoming an important part of economy in many countries. In receant years, the dairy products market has been showing great interest in goat’s milk products. Heat treatment has been used in dairy processing to enhance desirable properties of the products, such as texture and taste, to ensure their safety and to prolong their shelf-life. Heat-treatment modifies functional properties of milk proteins and the procedure has been widely used in the food, cosmetics and pharmacutical industries. Heat-treatment at high temperatures causes significant changes in the technological characteristics of cow’s milk; it has a negative effect on the cheese-making process and lowers the quality of cheese. However, when goat’s milk is subjected to high-heat treatment, it appears that the coagulation process is not impeded; this offers a possibility to produce cheeses from high-heat-treated milk with increased nutritional value and with a higher production yield. The object of this study was to investigate the feasibility of production of white brined goat’s cheese from milk heated at 80°C/5min and 90°C/5min, following the same production method used for cheeses made from pasteurized milk (65°C/30min); the characteristics of those cheeses were also to be analyzed and evaluated. The experiments were conducted in three phases: (1) in order to obtain a clearer picture of the raw materials used for cheese production, changes in the protein structure of whole and of skimmed goat’s milk after high-heat treatments were analyzed; (2) the coagulation parameters of high-heat-treated milk during enzymatic coagulation were measured in order to estimate the effect of high-heat treatments on enzymatic coagulation; (3) the maturing process of white brined goat’s cheeses produced from high-heat-treated milk was analyzed as a function of basic physico-chemical parameters, of the proteolytic changes and of the changes in textural and sensory properties...

Production and processing of goat’s milk is a dynamic and growing industry that is becoming an important part of economy in many countries. In receant years, the dairy products market has been showing great interest in goat’s milk products. Heat treatment has been used in dairy processing to enhance desirable properties of the products, such as texture and taste, to ensure their safety and to prolong their shelf-life. Heat-treatment modifies functional properties of milk proteins and the procedure has been widely used in the food, cosmetics and pharmacutical industries. Heat-treatment at high temperatures causes significant changes in the technological characteristics of cow’s milk; it has a negative effect on the cheese-making process and lowers the quality of cheese. However, when goat’s milk is subjected to high-heat treatment, it appears that the coagulation process is not impeded; this offers a possibility to produce cheeses from high-heat-treated milk with increased nutritional value and with a higher production yield. The object of this study was to investigate the feasibility of production of white brined goat’s cheese from milk heated at 80°C/5min and 90°C/5min, following the same production method used for cheeses made from pasteurized milk (65°C/30min); the characteristics of those cheeses were also to be analyzed and evaluated. The experiments were conducted in three phases: (1) in order to obtain a clearer picture of the raw materials used for cheese production, changes in the protein structure of whole and of skimmed goat’s milk after high-heat treatments were analyzed; (2) the coagulation parameters of high-heat-treated milk during enzymatic coagulation were measured in order to estimate the effect of high-heat treatments on enzymatic coagulation; (3) the maturing process of white brined goat’s cheeses produced from high-heat-treated milk was analyzed as a function of basic physico-chemical parameters, of the proteolytic changes and of the changes in textural and sensory properties... Proizvodnja i prerada kozjeg mleka je dinamična grana mlekarske industrije koja je u usponu i igra važnu ulogu u ekonomskom razvoju mnogih zemalјa. Poslednjih godina na tržištu mlečnih proizvoda širom sveta, kozji mlečni proizvodi se nalaze u žiži interesovanja. Termički tretmani su deo postupka proizvodnje velikog broja mlečnih proizvoda, a imaju za cilј pobolјšanje pojedinih karakteristika proizvoda, podizanje nivoa njihove bezbednosti, kao i produženje roka trajanja. Proteini mleka podvrgnutog termičkom tretmanu menjaju svoje funkcionalne osobine što nalazi široku primenu u prehrambenoj i farmaceutskoj industriji. Za razliku od kravljeg mleka koje nakon visokih termičkih tretmana menja svoje tehnološke karakteristike, što otežava proces proizvodnje i dovodi do stvaranja sira lošijeg kvaliteta, za kozje mleko postoje naznake u literaturi, da se nakon termičkog tretmana koagulacija neometano odvija, što ukazuje na potencijalnu mogućnost dobijanja sira sa uvećanim randmanom i nutritivnom vrednošću. Cilj ovog rada je bio da se ispita mogućnost proizvodnje kozjih belih sireva u salamuri dobijenih od mleka tretiranog režimima termičke obrade: 80°C/5 min i 90°C/5 min, bez prilagođavanja faktora proizvodnje u odnosu na kontrolnu varijantu proizvedenu od mleka tretiranog klasičnim postupkom niske pasterizacije (65°C/30 min), kao i da se ispitaju karakteristike ovako dobijenih sireva. Navedeni cilj sproveden je kroz tri faze. Ispitivan je uticaj termičkih tretmana kozjeg mleka na (1) intenzitet promena na proteinima punomasnog i obranog kozjeg mleka, kako bi se dobila jasnija slika o sirovini koja se koristi za proizvodnju sireva; (2) enzimsku koagulaciju kroz određivanje parametara koagulacije (3) tok zrenja kozjih belih sireva u salamuri, po pitanju osnovnih fizičko-hemijskih parametara, proteolitičkih promena, kao i promena teksturalnih i senzornih svojstava...