Experimental investigations of pseudo-diffusion coefficient of salt in cheese moisture by penetration theory

Abstract

The main purpose of this research is to investigate salt diffusion in brine-salted cheeses. The experimental results were discussed in terms of penetration theory of mass transfer. The pseudo-diffusion coefficients D' of salt in cheese moisture were determined from the curve of mA/A1, vs.t/0.5 plots. For the cheese types investigated in this work, D' ranged between 0.111 and 0.188 cm2/d, which is within the range of 0.1-0.3 cm2/d reported in the literature (4,5). The lowest D' value of 0.113 ± 0.002 cm2/d was obtained for Edam cheese, and the highest D' value of 0.181 ± 0.007 cm2/d was obtained for Emmental cheese. It was found that the penetration theory holds over a salting period of 24 h the mean salt concentration in low-calcium cheese reaches 84 and 74 percent of its equilibrium value, for the cheese thickness of 5 and 10 mm, respectively. In the region of penetration theory the mean salt flux through the interfacial area was independent on the cheese thickness, and after that it was higher for the cheeses of 10 mm thickness. .

U ovom radu je ispitana kinetika difuzije soli pri soljenju različitih vrsta sireva u salamuri. Eksperimenti su vršeni na četiri vrste sira, koje se bitno razlikuju po karakteristikama sirnog testa i to sa sirom edamskog tipa, sirom dobijenim od mleka koje je podvrgnuto visokom termičkom tretmanu, sirom ementalskog tipa i sirom kod koga je smanjen sadržaj kalcijuma u sirnom testu. Za sve vrste sireva određen je koeficijent stešnjene difuzije soli u vodenoj fazi primenom penetracione teorije. Proučen je uticaj vremena soljenja i debljine sira na masu primljene soli, srednju koncentraciju soli u siru i srednji fluks soli kroz međufaznu površinu. Takođe je određen vremenski period u kome važi penetraciona teorija za sve vrste sireva i korišćenje debljine uzoraka. Izvedene su formule za izračunavanje zapreminskog udela vodene faze i gustine sira u funkciji od sastava sira i gustine surutke. Ustanovljeno je da su dobijeni koeficijenti stešnjene difuzije soli u vodenoj fazi sira u dobroj saglasnosti sa podacima iz literature.