@article{
author = "Fetahagić, Safet and Maćej, Ognjen and Denin-Djurdjević, Jelena D. and Jovanović, Snežana",
year = "2002",
abstract = "Reconstituted skim milk with 8.01% DM was standardized with 3% skim milk powder and with 3% demineralized whey powder (DWP), respectively. Gained milk samples are named as 8%, 11% and 8%+3%DWP. All samples were heat treated at 85ºC/10 min, 90ºC/10 min and 95ºC/10 min, respectively. Untreated milk was used as control. Milk samples were coagulated by glucono-d-lactone (GDL) at the temperature of 45ºC until pH 4.60 was reached. Milk nitrogen matter content decreased during heat treatments, but linear relationship between applied heat treatments and nitrogen matter decreasing was not found. Nitrogen matter content of sera gained from both untreated and heat treated milk increased with the increase of milk dry matter content and with the addition of DWP. The higher temperature of applied heat treatment, the smaller sera nitrogen matter content. Nitrogen matter content in sera obtained from untreated milk were 64.90 mg%, 96.80 mg% and 117.3 mg% for milk 8%, 11% and 8%+3.0% DWP, respectively. Sera samples obtained from milk 8% heat treated at 85ºC/10 min, 90ºC/10 min and 95ºC/10 min had 38.70 mg% 38.30 mg% and 37.20 mg% of nitrogen matter, respectively. Sera samples obtained from milk 11% heat treated at 85ºC/10 min, 90ºC/10 min and 95ºC/10 min had 55.90 mg%, 52.80 mg% and 51.30 mg% of nitrogen matter, respectively. Sera samples obtained from milk 8% heat treated at 85ºC/10 min, 90ºC/10 min and 95ºC/10 min had 69.50 mg%, 66.20 mg% and 66.00 mg% of nitrogen matter respectively. Distribution of nitrogen matter from untreated milk to milk sera were 12.01%, 11.14% and 17.69% for milk 8%, 11% and 8%+3.0% DWP respectively. Distribution of nitrogen matter from milk 8% heat treated at 85ºC/10 min, 90ºC/10 min and 95ºC/10 min to sera samples were 6.99%, 6.72% and 6.59%, respectively. Distribution of nitrogen matter from milk 11% heat treated at 85ºC/10 min, 90ºC/10 min and 95ºC/10 min to sera samples, were 6.02%, 5.32% and 5.21%, respectively. Distribution of nitrogen matter from milk 8%+3%DWP heat treated at 85ºC/10 min, 90ºC/10 min and 95ºC/10 min to sera samples were 9.64%, 8.66% and 8.67%, respectively. Whey protein denaturation increased with increasing of the temperature of the applied heat treatment. Denaturation was the most significant for milk sample 11%., Obrano mleko je rekonstituisano na sadržaj suve materije 8.01%. Ovako dobijeno mleko je standardizovano dodatkom 3% SM obranog mleka u prahu i 3% demineralizovane surutke u prahu, pri čemu su dobijeni uzorci 11% SM i 8+3.0% DSUP. Svi uzorci su termički tretirani na 85ºC/10 min, 90ºC/10 min i 95ºC/10 min. Kao kontrolni uzorci korišćena su termički netretirana mleka. Uzorci mleka su koagulisani pomoću glukono-d-laktona (GDL) na temperaturi od 45ºC do postizanja pH 4.60. Nakon koagulacije, serum je odvajan od koaguluma samopresovanjem u toku 10 minuta. Tokom termičkih tretmana dolazi do smanjenja sadržaja azotnih materija mleka, ali nije ustanovljena linearna korelacija sa povećanjem temperature termičkog tretmana. Sadržaj azotnih materija seruma se povećavao sa povećanjem sadržaja suve materije mleka i sa dodatkom demineralizovane surutke u prahu, kako kod netretiranih, tako i kod termički tretiranih mleka. Sa povećanjem temperature termičkog tretmana smanjenje sadržaja azotnih materija seruma je više izraženo. Kod termički netretiranih mleka sadržaj azota u serumu je u proseku iznosio 64.90 mg% 96.80 mg% i 117.3 mg% za mleka 8%, 11% i 8%+3.0% DSUP, respektivno. Kod uzoraka mlečnog seruma dobijenih od mleka 8% termički tretiranih na 85ºC/10 min, 90ºC/10 min i 95ºC/10 min, sadržaj azota je u proseku iznosio 38.70 mg%, 38.30 mg% i 37.20 mg%, respektivno. Kod uzoraka mlečnog seruma dobijenih od mleka 11% termički tretiranih na 85ºC/10 min, 90ºC/10 min i 95ºC/10 min, sadržaj azota je u proseku iznosio 55.90 mg%, 52.80 mg% i 51.30 mg%, respektivno. Kod uzoraka mlečnog seruma dobijenih od mleka 8%+3% DSUP termički tretiranih na 85ºC/10 min, 90ºC/10 min i 95ºC/10 min, sadržaj azota je u proseku iznosio 69.50 mg%, 66.20 mg% i 66.00 mg%, respektivno. Distribucija azota iz mleka u mlečni serum kod uzoraka dobijenih od termički netretiranih mleka prosečno je iznosila 12.01%, 11.14% i 17.69% za mleka 8% 11% i 8%+3.0% DSUP, respektivno. Kod uzoraka dobijenih od mleka 8% termički tretiranih na 85ºC/10 min, 90ºC/10 min i 95ºC/10 min, iznosila je 6.99% 6.72% i 6.59%, respektivno. Kod uzoraka dobijenih od mleka 11% termički tretiranih na 85ºC/10 min, 90ºC/10 min i 95ºC/10 min, iznosila je 6.02% 5.32% i 5.21%, respektivno. Kod uzoraka dobijenih od mleka 8%+3% DSUP termički tretiranih na 85ºC/10 min, 90ºC/10 min i 95ºC/10 min, iznosila je 9.64%, 8.66% i 8.67%, respektivno. Denaturacija serum proteina se kod svih uzoraka mleka povećavala sa povećanjem temperature termičkog tretmana, a denaturacija je najizraženija kod uzoraka mleka 11%.",
publisher = "Univerzitet u Beogradu - Poljoprivredni fakultet, Beograd",
journal = "Journal of Agricultural Sciences (Belgrade)",
title = "The influence of applied heat treatments on whey protein denaturation, Uticaj primenjenih termičkih tretmana na denaturaciju serum proteina",
pages = "218-205",
number = "2",
volume = "47",
doi = "10.2298/JAS0202205F"
}
