QUALITY OF RICOTTA CHEESE AS AFFECTED WITH THE WAY ACIDIFICATION .

Document Type : Original Article

Authors

Dairy Department, Faculty of agriculture Mansoura university ,EGYPT.

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  % .

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