Conching chocolate is a prototypical transition from frictionally jammed solid to flowable suspension with maximal...

Mixing powders into liquids to achieve the highest possible solid content is a widespread industrial challenge. Prior research has shown that such systems often behave as frictionally jammed solids until sufficient energy or additives are introduced. However, the precise mechanisms governing this transition remain unclear. No prior work had resolved how mechanical energy and surfactants interact to alter jamming behavior. This uncertainty drove the current investigation into a specific industrial process: chocolate conching. The gap motivating this study lies in understanding how to maximize flowability while maintaining high solid content. The process of conching involves complex interactions between particles, oil, and dispersants. Existing knowledge does not fully explain how these components influence the jamming threshold. This paper addresses that gap by examining the rheological behavior of a simplified chocolate formulation.

This study aimed to investigate how mechanical energy and surfactant addition affect the jamming behavior of a powder-liquid system. The specific problem addressed is the transition from a jammed solid to a flowable suspension in chocolate conching. The motivation stems from the need to optimize industrial mixing processes for maximum solid content. The researchers propose that conching exemplifies a broader class of powder-liquid mixing. The study focuses on a simplified chocolate formulation to isolate key variables. The goal is to determine how mechanical energy and surfactants shift the jamming volume fraction. This research may help refine industrial protocols for similar systems. The findings could inform strategies for improving flowability in high-solid dispersions.

The team used a simplified chocolate formulation containing particulates, triglyceride oil, and dispersants. They measured rheological properties to track changes in flowability. Mechanical energy was introduced through controlled mixing processes. Surfactants were added in stages to observe their impact on jamming behavior. The system's jamming volume fraction was calculated based on flowability data. The researchers monitored how these inputs altered the suspension's structure. They analyzed the role of surfactants in modifying particle interactions. The study combined experimental measurements with theoretical modeling of jamming transitions.

The study found that mechanical energy and surfactant addition significantly increased the maximum flowable solid content. The jamming volume fraction shifted from a low to a higher value as energy and surfactants were applied. The system transitioned from a frictionally jammed solid to a flowable suspension. The maximum solid content achieved was notably higher than in untreated systems. Surfactants played a key role in reducing interparticle friction. Mechanical energy input was necessary to initiate the transition. The combination of these factors caused a substantial shift in jamming behavior. These results suggest that chocolate conching is a model system for similar industrial processes.

The authors propose that conching exemplifies a broader class of powder-liquid mixing processes. The findings suggest that mechanical energy and surfactants can shift jamming thresholds. This transition from jammed to flowable states is critical for industrial applications. The study supports the idea that staged surfactant addition enhances flowability. Mechanical energy input is necessary but not sufficient on its own. The combination of these factors maximizes solid content while maintaining flowability. The results may inform strategies for optimizing similar industrial systems. The researchers suggest that this approach could be applied to other high-solid dispersions.