QUALITY OF RICOTTA CHEESE AS AFFECTED WITH THE WAY ACIDIFICATION .

Abstract

Ricotta cheese was made from skim milk by direct acidification with, lactic, phosphoric,GDL,ABT starter and yogurt starter(streptococcus thermophillus ,lactobacillus delbrukii subsp bulgaricus) at pH 5.9- 5.8 at 87 -88˚c . Cheese was made by using yogurt starter had a higher yield(17.5% ), compared with other acid coagulant . (16- 15.75-15%) Respectively , Cheese treated with phosphoric acid and yogurt starter had the highest total solids(31.59-31.33%), compared with other treatments (31.05, 30.02, 29.93%)while the cheese made with yoghurt starter and phosphoric acid had the highest total protein content(24.24, 24.20%) than that from in the other treatments(24.15, 23.15, 23.10% ), either fresh or during storage period .In addition ,cheese made by using phosphoric acid had the highest fat content(2.25%), either fresh or during storage period, compared with other treatments (2.20-1.65-1.2-1.80 % ). While cheese made using by yoghurt starter had the highest rheological properties, where hardness ,cohesiveness, springiness ,gumminess, chewiness, modules ( 5119(N)-0.74(ratio)- 11.42(mm)- 3793(N)- 4336.96(J)- 146.8(J) respectively, compared with other treatments, while cheese coagulated with phosphoric acid had the highest adhesiveness of 1067.26(J). cheese treat with ABT starter had the highest modulus (162.23) while the cheese made with phosphoric acid had the lowest highest rheological properties as hardness , springiness ,gumminess, chewiness and modules were 2145 -9.49-1381 -13107.21 -73.43 respectively. Cheese made with lactic acid had the lowest adhesiveness of 764.05(J) ,than the cheese treated with lactic acid which obtained the lowest cohesiveness of ratio ( 0.63) . Cheese made by using phosphoric acid had lower total bacteria (T.C), proteolytic bacteria count ,lipolytic bacteria counts and moulds and yeasts (M&Y). On the other hand, cheese treated with yogurt starter and phosphoric acid had higher scoring points of 86- 84.8 % either fresh or during storage, compared with the cheese treated GDL which had the lowest scoring points of 72.2 % .