Characterization of alkali-modified soy protein concentrate

To study the influence of the preparation mode, including mild alkali modification, of soy protein concentrate on soluble protein content and composition, some of its nutritive and functional properties were investigated. Soy protein concentrate prepared by aqueous alcohol leaching was modified in mild alkaline solutions (pH 8.0) at 40, 50 and 60° C for 60 minutes and compared with two principal types of commercial soy protein concentrate. Soluble protein content, composition and properties of soy protein concentrate, as well as their potential use are essentially determined by the preparation mode. Limited mild alkali hydrolysis increased protein solubility by 40-71%, while emulsion stability was increased by 18-56%. Major storage soybean proteins exhibited different stability to alcohol denaturation and mild alkali modification. The most susceptible were acidic -A3 - and -A5- subunits of glycinin

Soy protein modification: A review

Soy protein products such as flour, concentrates and isolates are used in food formulation because of their functionality, nutritional value and low cost. To obtain their optimal nutritive and functional properties as well as desirable flavor different treatments are used. Soybean proteins can be modified by physical, chemical and enzymatic treatments. Different thermal treatments are most commonly used, while the most appropriate way of modifying soy proteins from the standpoint of safety is their limited proteolysis. These treatments cause physical and chemical changes that affect their functional properties. This review discusses three principal methods used for modification of soy protein products, their effects on dominant soy protein properties and some biologically active compounds

Primarna proteoliza kozjeg bijelog sira u salamuri praćena SDS-PAGE sistemom visokog molariteta

The aim of this work was to investigate primary proteolysis of white brined goat cheese prepared from raw milk and to correlate with the results obtained with high-molarity Tris buffer electrophoretic system. Proteolytic changes of white brined cheese were monitored by three parameters, the total protein, the water soluble proteins and the degree of proteolysis, whereas the change of major casein fractions was followed by electrophoresis in reducing conditions. Ripening caused a decrease of the total protein content, whereas in the first forty days the water soluble protein and the degree of proteolysis increased. Both casein fractions (αs- and β-casein) of goat cheese were susceptible to primary proteolysis but to the different extent. αs1- casein disappeared during processing, whereas during 60-days of ripening the content of αs2 and β-casein was reduced by 38.90 %, and 30.72 %, respectively. Such trends of major casein fractions were strongly correlated with the degree of proteolysis and the moisture content, whereas no correlation was found between them and the water soluble protein content. The results of our investigation clearly suggested that SDS-PAGE method based on high-molarity Tris-buffer system could be a very useful for purposes of monitoring the white goat cheese proteolysis.Cilj ovog rada bio je ispitati proces primarne proteolize bijelog sira u salamuri pripremljenog od sirovog kozjeg mlijeka i staviti u korelaciju s rezultatima dobivenim SDS-elektroforetskom metodom koja se bazira na primjeni Tris pufernog sistema visokog molariteta. Proteolitičke promjene bijelog sira u salamuri praćene su pomoću tri parametra: ukupnih proteina, u vodi topljivih proteina i stupnja proteolize, dok je promjena glavnih kazeinskih frakcija praćena elektroforezom u reducirajućim uvjetima. Zrenje sira uzrokuje pad sadržaja ukupnih proteina, dok sadržaj u vodi topljivih proteina i stupanj proteolize raste tijekom 40 dana zrenja. Obje kazeinske frakcije (αs- i β-kazein) podliježu procesu proteolize, ali u različitom stupnju. αs1-kazein se razgrađuje tijekom pripreme sira, dok se tijekom zrenja sira sadržaji αs2- i β-kazeina reduciraju za 38.90 % i 30.72 %. Ovakva promjena glavnih kazeinskih frakcija u jakoj je korelaciji sa stupnjem proteolize, sadržajem ukupnih proteina i sadržajem vlage, dok nije uočena korelacija između ovih parametara i u vodi topljivih proteina. Rezultati naših istraživanja jasno pokazuju da SDSelektroforetski sistem zasnovan na visoko molarnim Tris- puferima može biti vrlo korisna metoda za praćenje proteolitičkih promjena tijekom zrenja kozjeg bijelog sira u salamuri

Supplementary data for the article: Uzelac, T. N.; Nikolić-Kokić, A. L.; Spasić, S. D.; Mačvanin, M. T.; Nikolić, M. R.; Mandić, L. M.; Jovanović, V. B. Opposite Clozapine and Ziprasidone Effects on the Reactivity of Plasma Albumin SH-Group Are the Consequence of Their Different Binding Properties Dependent on Protein Fatty Acids Content. Chemico-Biological Interactions 2019, 311. https://doi.org/10.1016/j.cbi.2019.108787

Supplementary material for: [https://www.sciencedirect.com/science/article/pii/S0009279719310257?via%3Dihub]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/3333]Related to accepted version: [http://cherry.chem.bg.ac.rs/handle/123456789/3865

Studija projekta 'Optimizacija i standardizacija autohtone tehnologije sjeničkog sira sa zaštitom oznake porekla'

Investigations are based on use of natural potentials on the wide region of Sjenica-Pešter highlands. Certain parameters on selected locations are recorded (soil, vegetation, livestock production, technology of milk and cheese production). On selected locations, farms and processing capacities detail researches are carried out relating to soil, artificial and natural grasslands, reproductive and production potential of cattle and sheep, determination of genetic and non-genetic factors affecting milk traits, quantity and quality of milk, proteins, milk fat, lactose, etc., technological and microbiological traits of milk and cheese. Main objectives of this research and development project is to realize scientific -technological solutions in primary livestock production using our own scientific potentials in order to provide increased productivity, increased number of market farmers capable for competitive economy and production on domestic and foreign market with recognized final product with protected geographical origin, in other words - optimization and standardization of native technology of white cheese from Sjenica with protected brand and origin.Istraživanja su zasnovana na korišćenju prirodnih potencijala šireg regiona Sjeničko-pešterske visoravni. U okviru ovih istraživanja obavlja se snimanje i proučavanje određenih parametara na odabranim lokalitetima ( zemljište, vegetacija, stočarstvo, tehnologija mleka i sira). Na odabranim lokalitetima, farmama i preradjivačkim kapacitetima obavljaju se detaljna istraživanja, zemljišta, prirodnih i veštačkih travnjaka i livada, reproduktivnih i proizvodnih potencijala goveda i ovaca, determinacija genetskih i negenetskih faktora na svojstva mlečnosti, kvantitet i kvalitet mleka, proteini, mlečna mast, laktoza i dr.,tehnološka i mikrobiološka svojstva mleka i sira. Osnovni ciljevi ovog istraživačko-razvojnog projekta je da se korišćenjem sopstvenih naučnih potencijala dođe do naučno-tehnoloških rešenja u primarnoj stočarskoj proizvodnji, koja će obezbediti porast produktivnosti, povećanje robnih proizvođača osposobljenih za konkurentnu proizvodnju na domaćem i stranom tržištu sa prepoznatljivim finalnim proizvodom zaštićenog geografskog porekla, odnosno optimizaciju i standardizaciju autohtone tehnologije Sjeničkog sira sa zaštitom oznake porekla

Influence of various coagulation factors on chemical composition of sera gained by centrifugation from casein gel

Technological operations applied during curd processing influence syneresis and total solids content of cheese. Syneresis is not a simple physical process representing whey segregation due to curd contractions. Numerous factors can influence the process of syneresis. The aim of this work was to investigate the influence of various parameters (pH, quantity of CaCl2 added, temperature of coagulation and heat treatment) on induced syneresis. Reconstituted instant skim milk (control samples) and reconstituted instant skim milk heated at 87ºC for 10 min (experimental samples) were coagulated at 30ºC and 35ºC, and pH of 5.8 and 6.2 with 100, 200 and 400 mg/l of CaCl2 added. According to our results, these parameters had significant influence on nitrogen content of serum as well as on the distribution of nitrogen matter from gel into sera. Due to the formation of coaggregates the best rheological properties of gel were obtained for experimental samples coagulated with 400 mg/l of CaCl2 added at pH 5.8 and temperature of 35ºC

Influence of curd particles drying temperature on the composition of curd made of milk in which co aggregates were formed

The influence of different drying temperatures of curd particles in order to obtain curd particles with chemical composition characteristic for Dutch-type semi-hard cheeses was investigated. The experiments were performed with heat-treated milk at 87ºC for 10 minutes to induce chemical interaction between casein and serum proteins and to form the co-called co aggregates. The curd particles were dried at 42ºC and 45ºC for 60 minutes and two types of curd, named curd A and curd B were formed afterwards. The results of the experiments showed that the used temperatures had no significant influence on chemical composition of the curd. The average total solids of curd A was 49.09%, moisture in fat free basis (MFFB) 68.78% protein content 22.23%, lactose content 1.55%, ash 1.98%, titratable acidity 71.700T and pH 6.22. On the other side, the average values for curd B were 49.40%, 68.58%, 22.74%, 1.47%, 1.94%, 75.920T and 6.07, respectively. The use of different drying temperatures, as well as the other treatments (pressing, salting and ripening) provide conditions for semihard cheese producing, with the chemical composition similar to the Dutch-type semihard cheese prepared according to the traditional method

Influence of curd particles washing on the composition of curd made of milk in which co aggregates were formed

The composition of curd A and curd B was investigated as influenced by the technological process known as curd washing after removing 1/3 or 1/2 of whey and replacing by the same volume of water at the drying temperatures of 42ºC and 45ºC, respectively. Milk used for experiments was heat-treated at 87ºC/10 min, during which the chemical complex between casein and whey proteins (milk protein co aggregates) was formed. It is shown that the applied drying temperatures of 42ºC (curd A) and 45ºC (curd B) do not have significant influence on the curd composition. The curd A and B gained without washing of the curd had 50.91% and 50.60% of moisture, respectively. If the curd washing process is applied after removing 1/3 of whey, the resulting curd has higher moisture content, 52.27% and 52.63%, respectively for the curd A and B. The highest moisture content in the curd is noted in the curd gained when 1/2 of whey is replaced by water during washing treatment. The same tendency is noted for the moisture in fat- free basis (MFFB), the parameter used for cheese classification. Also, it is observed that fat, protein and ash content are lower in the curd A and B when the curd washing process is applied than in the curd produced without the curd washing process. However, regardless of the increased moisture content of the curd gained by washing process, it is possible (even from heat-treated milk in which coaggreagates are formed) to achieve the average MFFB typical for semi-hard cheeses of Dutch type, by further technological processes such as molding, pressing, salting and ripening

The influence of investigated factors on viscosity of stirred yogurt

Skim milk was reconstituted to obtain milk with 8.44% DM, which was standardized with demineralized whey powder (DWP) to obtain milk sample A (9.71% DM) and milk sample B (10.75% DM). Milk samples were heat treated at 85ºC/20 min and 90ºC/10 min, respectively. Untreated milk was used as control. Milk samples were inoculated with 2.5% of commercial yogurt culture (containing Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus in the ratio 1:1) at 43ºC. Samples were incubated until pH 4.6 was reached. Samples were immediately cooled to 4ºC and held at that temperature until analyses. Samples of acid casein gels were stirred after 1, 7 and 14 days of storage. Measurements of viscosity were done with Brookfield DV-E Viscometer. Spindle No 3 at 30 rpm was used for all samples. Duration of fermentation decreased when DWP was used for standardization of milk dry matter content. Yogurt samples produced from milk heat treated at 85ºC/20 min, obtained by stirring of gel 1 day after production had a higher viscosity than sample produced from milk heat treated at 90ºC/10 min. On the other hand, samples produced from milk heat treated at 90ºC/10 min had a greater viscosity after 7 and 14 days of storage, which indicates a greater hydrophilic properties and a more pronounced swelling of casein micelles