Possibility of the ultrafiltered sweet whey protein incorporation into fresh cheese

Cilj ovoga rada bio je iskoristiti veću količinu proteina od UF-slatke sirutke primjenom toplinske denaturacije a) pri 90 °C; b) pri 90 °C/10 minuta i c) pri 90 °C/20 minuta. Proizvedeni su kontrolni svježi sir od mlijeka (1,8% mliječne masti); kontrolni albuminski sirevi od UF-sirutke (a, b i c) te eksperimentalni sirevi od mješavine mlijeka i UF-sirutke (a, b i c). Uklapanjem proteina od UF-sirutke, denaturirane pri 90 °C (a), u mješavinu s mlijekom (2:1) proizveden je eksperimentalni sir (a) izvrsnih senzorskih osobina, a postignut je veći prinos (za 19,9%) od prinosa kontrolnog sira (25,0%). Eksperimentalni sir (a) bio je nešto vlažniji, a sadržavao je manje masti (za 41,1 %) i malo više mineralnih tvari te proteina, ali je imao znatno veći udjel proteina sirutke nego kontrolni sir (masa eksperimentalnog sira veća za 74%). Produženo trajanje toplinske obrade UF-sirutke (b i c) rezultiralo je povećanjem prinosa eksperimentalnog sira i do 36,6%, a albuminskog sira do 44,8%. Tada proizvedeni eksperimentalni sirevi (b i c) su, međutim, bili grizaste konzistencije, što je izbjegnuto intenzivnim miješanjem. Stoga su ti sirevi pogodni za pripravu simih namaza (osobito uz neke aromatične dodatke), kao i albuminski sirevi koji su slatkastog okusa i neprihvatljivi za potrošača, ali nutritivno najvrjedniji.The aim of this work was to achieve higher whey protein quantity from UF-sweet whey with applied different heat denaturation procedures a) at 90 °C; b) at 90 °C/10 minutes and c) at 90 °C/20 minutes. Control fresh cheese from milk (1.8% fat), control albumin cheese from UF-whey (a, b and c) as well as experimental cheeses from mixture of milk and UF-whey (a, b and c denaturation procedures) (2:1), were produced. The experimental cheese samples obtained by whey protein incorporation (procedure a) showed excellent sensory properties and higher yield (for about 19.9%D) compared to control fresh cheese (25.0%) sample. The obtained experimental cheese (a) had slightly higher moisture, mineral matter and total protein content, but significantly higher whey protein content (experimental cheese mass was 74%) higher) and for 41.1%D lower fat content. Extended heat treatment of UF-whey (b and c procedures) had an influence on increased yield of experimental cheeses up to 36.5% (c), and up to 44.8% for the control albumin cheeses (c). However, those experimental cheeses (b and c) had grainy consistency, which after intense agitation was eliminated. Therefore those cheese samples were very suitable for preparation of cheese spread (especially with some aroma addition) as well as albumin cheese samples which, from the consumers point of view, have unacceptable sweet taste and more perceptible side-effects (flavour of cooked whey proteins), but the highest nutritive value