Modelling the effect of storage temperature on the viscoelastic properties and quality of ice cream

Effects of Yam (Dioscorea rotundata) Mucilage on the Physical, Rheological and Stability Characteristics of Ice Cream

In the present investigation, yam mucilage was evaluated as a stabilizer and emulsifier in the formulation of vanilla flavored ice cream; physicochemical, rheological, and stability characteristics were determined. A completely randomized bifactorial design was used (yam mucilage: Carboxymethylcellulose ratio with the following levels: 100:0, 80:20, 50:50, and 20:80, and stabilizers concentration with levels of 0.4 and 0.8%). Results showed an increase in the protein content present in ice cream mixture as the amount of mucilage increases. Rheologically, it was found that ice cream has the characteristic behavior of a pseudoplastic fluid, presenting a viscoelastic structure where elastic behavior predominates. In addition, ratios with a higher content of mucilage incorporated a greater volume of air and presented the longest melting times, delaying drops falling time; in the same way mucilage gives ice cream a freezing temperature between −6.1 to −2.8 °C, indicating that the application of mucilage in food industry is possible due to its nutritional value, and it gives ice cream stability properties.

Estimation of Ice Cream Mixture Viscosity during Batch Crystallization in a Scraped Surface Heat Exchanger

Ice cream viscosity is one of the properties that most changes during crystallization in scraped surface heat exchangers (SSHE), and its online measurement is not easy. Its estimation is necessary through variables that are easy to measure. The temperature and power of the stirring motor of the SSHE turn out to be this type of variable and are closely related to the viscosity. Therefore, a mathematical model based on these variables proved to be feasible. The development of this mathematical relationship involved the rheological study of the ice cream base, as well as the application of a method for its in situ melting in the rheometer as a function of the temperature, and the application of a mathematical model correlating the SSHE stirring power and the ice cream viscosity. The result was a coupled model based on both the temperature and stirring power of the SSHE, which allowed for online viscosity estimation with errors below 10% for crystallized systems with a 30% ice fraction at the exit of the SSHE. The model obtained is a first step in the search for control strategies for crystallization in SSHE.

Characteristics of Instrumental Methods to Describe and Assess the Recrystallization Process in Ice Cream Systems

Methods of testing and describing the recrystallization process in ice cream systems were characterized. The scope of this study included a description of the recrystallization process and a description and comparison of the following methods: microscopy and image analysis, focused beam reflectance measurement (FBRM), oscillation thermo-rheometry (OTR), nuclear magnetic resonance (NMR), splat-cooling assay, and X-ray microtomography (micro-CT). All the methods presented were suitable for characterization of the recrystallization process, although they provide different types of information, and they should be individually matched to the characteristics of the tested product.

Effect of fat content on the physical properties and consumer acceptability of vanilla ice cream

Ice cream is a complex food matrix that contains multiple physical phases. Removal of 1 ingredient may affect not only its physical properties but also multiple sensory characteristics that may or may not be important to consumers. Fat not only contributes to texture, mouth feel, and flavor, but also serves as a structural element. We evaluated the effect of replacing fat with maltodextrin (MD) on select physical properties of ice cream and on consumer acceptability. Vanilla ice creams were formulated to contain 6, 8, 10, 12, and 14% fat, and the difference was made up with 8, 6, 4, 2, and 0% maltodextrin, respectively, to balance the mix. Physical characterization included measurements of overrun, apparent viscosity, fat particle size, fat destabilization, hardness, and melting rate. A series of sensory tests were conducted to measure liking and the intensity of various attributes. Tests were also conducted after 19 weeks of storage at -18°C to assess changes in acceptance due to prolonged storage at unfavorable temperatures. Then, discrimination tests were performed to determine which differences in fat content were detectable by consumers. Mix viscosity decreased with increasing fat content and decreasing maltodextrin content. Fat particle size and fat destabilization significantly increased with increasing fat content. However, acceptability did not differ significantly across the samples for fresh or stored ice cream. Following storage, ice creams with 6, 12, and 14% fat did not differ in acceptability compared with fresh ice cream. However, the 8% fat, 6% MD and 10% fat, 4% MD ice creams showed a significant drop in acceptance after storage relative to fresh ice cream at the same fat content. Consumers were unable to detect a difference of 2 percentage points in fat level between 6 and 12% fat. They were able to detect a difference of 4 percentage points for ice creams with 6% versus 10%, but not for those with 8% versus 12% fat. Removing fat and replacing it with maltodextrin caused minimal changes in physical properties in ice cream and mix and did not change consumer acceptability for either fresh or stored ice cream.