Effect of Manufacturing Methods Stages on Composition and Properties of Frozen Dairy Products (Ice cream)

Abstract

Forty samples (40) representing group (A) were produced using the following stages: High Temperature Short Time H.T.S.T pasteurization, two-stage homogenization, continuous freezing and flooded refrigeration and cooling system . The other 40 samples representing group (B) were processed by applying batch pasteurization, single – stage homogenization, batch freezing and brine cooling. All samples were then subjected to laboratory tests on value of fat % Total solids % Acidity % and the pH Value . The laboratory tests were carried out after finishing every single stage of the manufacturing method on 10 samples of each group. The values obtained for fat and total solids % , when using H.T,S,T-pasteurization were 7.95±1.29% and 37.48±9.53% respectively , while by batch pasteurization 7.53±4.11%and 32.34 ± 5.89 % obtained respectively . The statistical analysis revealed significant difference p-value > 0.05 in the values of the fat and total solids % produced by the two methods of pasteurization . The acidity , when applying H.T.S.T and batch pasteurization were found as 0.20± 0.41 and 0.20± 0.21% respectively and the pH – value as 5.77± 0.41 & 5.77± 1.00 respectively . No signification difference were recorded for Acidity and the pH- value. By performing the two – stage and single stage of homogenization the values obtained for fat % were 7.6±4.43 and 7.6±3.79 % respectively. Also no difference was recorded.

The total solids % recorded was 35.33±5.98 and 33.97±7.03% respectively. A significant difference was recorded hereby p-value > 0.05. The acidity % and pH value obtained were (0.21±0.04 and 0.20±0.02%) and (5.81±1.42 and 6.03±0.90) respectively. Also no variation p-value < 0.05 is found for these values. Applying continuous and batch freezing processes the fat % was 7.76± 3.85% and 5.85± 4.45% respectively . A significant p-value > 0.05 differences was detectable in this case. Total solids % values obtained were (35.28± 3.55 and 30.23 ± 7.34%)respectively . Also significant variation was noticed hereby p-value > 0.05. Value of acidity % recorded were ( 0.19±0.02 and 0.23±0.07% ) and for the pH value ( 6.05±1.27 and 5.28±1.76) respectively . A significant difference were noticed for the value of acidity and pH . Using the two processes. The application of flooded and brine cooling systems resulted in a fat % of 7.77±3.19 and 7.64±4.78% respectively , and a significant difference was recorded p-value > 0.05 . The total solids % value were equal for both methods ( 36.15±6.32 and 36.15± 6.72%) and no significant difference was noticed p-value < 0.05. The acidity % obtained for flooded system 0.20±0.01% and for brine cooling , 0.21±0.03% and no difference was detectable p-value < 0.05. The pH- value obtained was 5.87±1.33 and 5.73± 1.22 for flooded and brine cooling respectively and a variation is recorded . It is noticed that the better values of components and properties subject of this research were reached , when applying the manufacturing process involving H.T.S.T pasteurization two-stage homogenization , continuous freezing and flooded cooling stages . Finally certain recommendation were given.