Dairy whipping cream : effects of cream volume, temperature and fat content on foam formation and foam properties : a thesis presented in partial fulfilment of the requirements for the degree of Master of Food Technology at Massey University, Manawatū, New Zealand

Abstract

Whipping cream is a unique multiphase dairy system in which fat crystallisation, air incorporation, partial fat coalescence, protein adsorption, and continuous phase restructuring occur simultaneously under mechanical shear, directly influencing product stability, texture, and sensory quality. Despite its widespread industrial and culinary use, the dynamic physicochemical changes occurring during the whipping process remain incompletely understood, particularly with respect to the combined effects of processing parameters, temperature, fat content, and formulation. Most existing studies focus on final product characteristics such as overrun, firmness, and foam stability, while providing minimal understanding of the dynamic, real-time physicochemical changes occurring during the whipping process. In particular, the continuous evolution of mechanical resistance, fat destabilisation, and structural transitions under shear has not been sufficiently quantified using in-situ or process-based measurements. Additionally, the combined effects of processing parameters—such as cream volume, temperature, and fat content—are often investigated in isolation, leaving a lack of integrated understanding of how these variables interact to define the whipping window and the transition from optimal foam formation to overwhipping and butter formation. This thesis aims to systematically investigate the physicochemical transformations occurring during the whipping of cream, with a specific focus on torque development, microstructural evolution, aeration behaviour, and textural characteristics. In the first phase of the study, the influence of whipping volume (200 ml, 400 ml, and 600 ml) on the whipping dynamics of cream at 7°C was evaluated using a Kenwood electronics mixer. Torque vs time profiles were generated to characterise resistance development during whipping. Key parameters, including exponential time constants, whipping rates, peak torque values, time to peak torque, optimum whipping time, and the peak window, were determined. The results suggests that whipping volume significantly affected mechanical energy input and structural development, with a 400 ml volume providing the most reproducible torque behaviour and allowed for the formation of an evenly distributed air bubble matrix stabilised by a robust yet sufficiently aerated fat network. Consequently, this volume was selected as the optimal condition for subsequent experiments. In the second phase, the effect of whipping temperature (7°C, 10°C, and 13°C) on whipped cream characteristics was investigated. Temperature was found to play a critical role in fat crystallisation behaviour and partial coalescence kinetics. Lower whipping temperatures promoted greater fat solidity, enhanced partial coalescence, and improved foam stability, resulting in higher firmness and more uniform microstructures. In contrast, elevated temperatures reduced fat crystal content, leading to weaker structural networks and reduced whipping stability. The CLSM micrographs at 7°C showed fine, evenly distributed air bubbles surrounded by a cohesive fat network. The third phase examined the influence of fat content (32%, 36%, and 40%) on whipping performance. Fat standardisation was achieved through centrifugation and recombination with skim milk. Increasing fat content significantly enhanced partial coalescence, overrun, and textural strength; however, excessively high fat levels narrowed the whipping window and increased susceptibility to overwhipping. CSLM imaging confirmed denser fat networks at higher fat contents, providing direct microstructural evidence of the observed macroscopic properties. After each experiment, the whipped cream samples were characterised using a combination of visual rosette analysis, texture profile analysis, overrun measurements, and confocal scanning laser microscopy (CSLM). The results from all the experiments suggests that the optimum conditions for whipping dairy cream rely on a specific synergy of formulation and processing parameters. To achieve the ideal product profile the volume (400ml), temperature (7°C), and fat content (36%) should be maintained. The findings indicate that the consistent production of high-quality whipped cream requires strict control over processing variables to balance aeration with structural rigidity. Specifically, maintaining solid fat content through temperature regulation, utilizing an optimal fat concentration of 36%, and standardizing batch volumes are critical for stability. Furthermore, torque profiling emerged as a reliable real-time metric for predicting phase inversion, offering industrial utility in preventing over-whipping. Conversely, deviations such as excessive shear, elevated temperatures, or surplus fat were shown to accelerate structural collapse and promote premature churning. These results substantiate existing theories of foam formation while providing novel microstructural insights into the sensitivity of the whipping process to operational parameters.