Rheological properties of Colombian‐Caribbean‐coast sour cream from goat milk

Abstract

SummaryThe viscoelastic properties provide guidelines to help give meaning to the observations on food products, to relate them to the way in which their structures behave, and to predict or modify their properties. This study analyses the incidence of varying the initial fat content of goat milk on the rheological properties of prepared sour cream. Storage (G′) and loss modulus (G″), as well as complex viscosity (η*) and loss factor values (tan δ), were determined at different initial fat contents in goat milk (3.75%, 4.00% and 4.25%). The experimental data were adapted to Maxwell model. All the prepared samples of sour cream meet national and international microbiological standards, and the initial fat content of goat milk influenced the viscoelastic behaviour of sour cream. Structures with prevalent elastic (G′) behaviour were found, and the product that was prepared from goat milk with 4.00% fat content showed the highest elastic modules. This sour cream exhibited higher firmness and better adherence when compared to the samples that were obtained from 3.75% and 4.25% fat‐content milk. This sample also exhibited the lowest tangent of the phase angle. Sour cream that was prepared from milk with higher fat content (4.00% and 4.25%) exhibited a semi‐solid behaviour along the entire temperature range that was studied. On the contrary, rheological properties of sour cream from 3.75% fat‐content milk tend to increase at temperatures above 333.15 K. The viscoelastic behaviour of sour cream was successfully explained under Maxwell model, while data from dynamic viscosity (η′) were adapted to Arrhenius model. Microstructure analysis to the sample considered as the best (from milk with 4.00% of initial fat content) showed that the protein network presented a rough, open surface with aggregates and wide spaces.