Table (1): Chemical properties of low fat Domiati cheeses. TREATMENTS F L LS LZ Item Months 1 2 1. 2 2 1 PH 5.8 4.9 4.4 6.0 5.2 4.5 5.5 4.5 4,0 5.1 4.2 3.8 64.2 60.6 55,3 46.1 Moisture % 62.6 58.2 46.5 58.5 55.6 52.4 7.2 16.2 17.5 66,9 63.3 59.1 19.9 16.4 7.8 F/DM % 46.9 15.7 16.9 18,4 18.6 20.5 T.N/DM% 6.1 5.8 5.5 7.7 6.8 6.2 7.9 6.6 6.1 6.5 6.0 F: Full fat cheese (control), L: Low fat cheese, LS: Low fat cheese with simplesse resemble and LZ: Low fat cheese with Z-trim resemble 3- Ripening properties Water soluble nitrogen (SN) and non protein nitrogen (NPN) of all cheese significantly increased (P < 0.05) as pickling period advanced Table (2). Similar results were found by El Abd et al (2000), Abd El Khader (2003), Kebary et al 2006, Ayat 2016 and Monira et al 2017.The increase was more pronounced after the first month than the second month low fat cheese (L) had significantly the lowest SN which might be due to low moisture content which www.wjert.org 170 Nadia. World Journal of Engineering Research and Technology in turn suppress the growth of proteolytic bacteria and also inhibit protease enzymes activity Kebary et al 2006 and Ayat 2016 .Addition of fat replacers caused significant increase in SN content(P < 0.05). Total volatile fatty acids (T.V.F.A) significantly increased (P < 0.05) after pickling storage period, Table (2). The same trend was found by Mehanna et al (2002) and Abd El Khader (2003).The first month showed higher increase in T.V.F.A than the second month. Results appeared that F cheese had higher (T .V.F.A) than L cheese. These may be due to the increase in moisture content which increase the water activity that stimulate the bacterial growth. Cheese yield Table (2) significantly decreased (P <0.05) as pickling progressed Mehanna et al (2002) and Abd El Kader (2003)the decrease during the first month was greater than the second month .L cheese recorded the lowest yield these may be due to the effect of fat of reducing whey synersis (Kebary et al 2006, Tareq al nemer 2016, Ayat 2016 and Monira et al 2017).Cheese LS had the highest yield followed by F cheese Table (2): Ripening properties of low fat Domiati cheeses made from milk containing a fat replacer during ripening at room temp. Treatment * F LS LZ Month Item 1 2 0.481 0,188 0,194 0,057 0,086 0.188 2 1 1. 2. 0.402 0.490 0.241 0.378 0.693 SN (%) NPN (%) T V.F.A Iml 0,IN NaOH Yield% 0.231 0.740 0.816 0.302 0.302 0.499 0.581 0.058. 0.159 0.263 0.068 0.219 0.268 11.8 15.6 17.6 9.8 13.8 15.4 12.3 18,6 20,8 10,8 16.2 18.4 28.2 25.4 23.7 24.9 20.7 18.6 30.4 26.3 24.5 29.8 25.6 24.8 * See table 1 for details