What Is The Viscosity Variation Of Ice Cream Mix?

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3.3. Apparent viscosity
The apparent viscosity variations of ice cream mixes at different rotational speeds are shown in Figure 2. What is evident in all curves viscosity is generally decreased by a velocity of 10 to 100 rpm, and at higher speeds, the slope of the changes has been lowered and has become more stable. This represents the non-Newtonian behavior (pseudoplastic) of the ice cream mixes. [3] Goff and Hartel [3] consider non-Newtonian ice cream behavior as a result of dispersion of protein macromolecules and polysaccharides. Marshal and Ar-buckle (1996) argued that the accumulation of fat globules is leads to the weakness of the ice cream mix because during the rotation the fracture accumulation structure is weakened (Marshal and …show more content…

Significant differences were observed in all samples except for LFI1 and LFI3 treatments (p<0.05). CMFFI and LFI2 mixes respectively were the most viscous and CLFI mix was the least viscous (p<0.05).Results show that increasing the amount of fat alone in control treatments (CLFI, CRFI, CFFI and CMFFI), and thus increasing the TS, can cause an increase in their apparent viscosity; because the quantity of fat and type of milk used in this study are different and other factors were the same. Some researchers reported apparent viscosity of ice cream mix samples with a fat content of 5 and 10 percent which were significantly higher than the viscosity of samples with a fat content of 0.5 and 2.5 percent. According to Marshal and Arbuckle (1996), the increase in the aggregated fat globules in these ice creams was partly responsible for thinning the shear rate and hence their higher viscosity. On this basis, they the suggested the low viscosity of a nonfat sample probably due to the lack of fat globules in its formulation. (Aime et al., …show more content…

The positive effect of TSM on the viscosity of nonfat yogurt in the level of 30% due to its higher viscosity than skim milk has been reported by previous researchers (Nouri et al., 2011). Some researchers have reported changes in the volume and shape of caseins and water retention in the weak network resulting from partial accumulation as factors in increasing the viscosity of the low-fat ice cream mix containing the chymosin enzyme (Chang et al., 1995).
The viscosity of LFI2 sample is greater than that of LFI3 sample (82.8%) while both have the same fat and different TSM, so it is likely that in order to achieve higher viscosity, a certain amount of aggregate of micelles is required .Chang et al., (1995) reported that using 33% more of the chymosin enzyme gives double as much apparent viscosity of ice cream mix.
There is no significant difference between the viscosity of LFI1 and LFI3 treatments, which shows that the viscosity obtained from the higher consumption of TSM is equal to the viscosity obtained from the increase of VF

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