Variations in the composition of milk in dairy industry "Zdenka" - the influence on yield and quality of Emmenthal cheese

Proučavajući kolebanja količina bjelančevina i masti te stupnja kiselosti u uzorcima sirovog mlijeka s otkupnog područja Mljekarske industrije »Zdenka«, koje dostavlja oko 12.000 proizvođača, te kolebanja suhe tvari, masti u suhoj tvari i bjelančevina uzoraka sira ementalca proizvedenog od sabranog mlijeka, nastojalo se pridonijeti poznavanju utjecaja sastava mlijeka na randman i proizvodnju sira. Istraživanja su provedena od početka 1980. do kraja 1982. godine. Analizirano je 1.096 uzoraka sirovog zbirnog mlijeka, 1.096 uzoraka sirutke i 1.096 uzoraka svježeg sira ementalca. Zbirni uzorci mlijeka sadržavali su 2,75% do 3,28% bjelančevina, 3,55%) do 3,69%) masti poslije standardizacije, a kiselost uzoraka kolebala je od 6,80° SH do 8,07° SH. Razlike između srednjih vrijednosti utvrđenih bjelančevina i masti pojedinih mjeseci većinom su bile signifikantne, a razlike srednjih vrijednosti stupnjeva kiselosti (°SH) pojedinih mjeseci većinom nisu bile signifikantne. Sirutka je sadržavala suhe tvari 6,10% do 7,50%, masti 0,40% do 0,80%) i sirnog zrna 0,20% do 0,80%. Uzorci sira sadržavali su 65,49% do 66,49% suhe tvari, 26,65% do 28,63%) bjelančevina i 45,35% do 47,52% masti u suhoj tvari. Za jedan kilogram svježeg sira utrošeno je prosječno mjesečno 11,80 do 12,18 litara mlijeka, a prosječni je mjesečni randman kolebao od 8,21% do 8,47%. Razlike randmana pojedinih mjeseci većinom nisu bile signifikantne.This study was carried out in order to observe the variations in protein contents, milk fat contents and titratable acidity (in degrees S. H.) of raw milk from commercial collection region of Dairy industry "Zdenka" and in order to contribute to the knowledge of their influence on yield and quality of produced Emmenthal cheese. Raw milk was delivered by about 12000 producers. Investigation was conducted from the beginning of 1980 to the end of 1982. A total of 1026 samples of raw collected milk, 1096 samples of whey and 1096 samples of Emmenthal cheese fresh from the brine bath was analysed. Collected samples of raw milk contained 2.75% to 3.28% of total protein, 3.55% to 3.69% of milk fat in standardized milk prepared for cheese production. Degrees of titratable acidity (S. H.) varied from 6.80 °SH to 8.07 °SH. Differences between average monthly contents of total protein and milk fat were mainly significant and the differences between average monthly values of degrees S. H. were mainly not significant. Whey samples contained 6.10% to 7.50% of total solids, 0.40% to 0.80% of milk fat and 0.20% to 0.80% of curd grains. Emmenthal cheese samples contained 65.49% to 66.49% of total solids, 26.65% to 28.65% of total protein and 45.35% to 47.52% of fat in total solids. To produce 1 kg of cheese fresh from the brine bath 11.80 to 12.18 litres of milk was used and average monthly cheese yield varied from 8.21% to 8.47%. The differences between monthly average yield were mainly not significant