Impact of Particle Size Distribution on Rheological and Textural Properties of Chocolate Models with Reduced Fat Content

Abstract

With an increasing consumption of lipids nowadays, decreasing the fat content in food products has become a trend. Chocolate is a fat-based suspension that contains about 30%wt fat. Reducing fat content causes an increase in the molten chocolate viscosity. This leads to 2 major issues: difficulties in the process and a loss of eating quality in the final product, reported to have poor in-mouth melting properties, remain hard, and difficult to swallow. Literature shows that optimizing the particle size distribution (PSD), that is, having one with an increased packing fraction, can decrease the viscosity of highly concentrated suspensions. This study focuses on the impact of the PSD and fat content on the rheological properties, melting behavior, and hardness of chocolate models (dispersions of sugar in fat). We show that optimizing the PSD while reducing the fat content to a critical amount (22%wt) can decrease the viscosity of the molten material and reduce the hardness of the crystallized chocolate models. Melting in the mouth, characterized by an in vitro collapse speed, is faster for the samples with an optimized PSD. The decrease in the viscosity by optimizing the PSD in systems with a constant fraction of medium phase is based on the decrease of interparticle contact, reducing the particle aggregates strength, and structure buildup during flow or meltdown. In its crystallized state, the particle network is less interconnected, providing less resistance to breakage and meltdown.

Rheological properties of sugarfree milk chocolate: Comparative study and optimisation

“…Addition of xylitol as a bulking agent increased the apparent viscosity of chocolate mix (data not shown). In addition, all of the chocolate samples showed shear thinning behaviour, which is in agreement with previous studies (Do et al 2007;Afoakwa et al 2008;Fernandes et al 2013). Structural decomposition and also alignment of the constituent molecules might be the reasons for shear thinning behaviour of the molten chocolate samples (Izidoro et al 2008;Fernandez et al 2013).…”

Influence of calcium fortification on physical and rheological properties of sucrose-free prebiotic milk chocolates containing inulin and maltitol

“…Grittiness is a textural defect in chocolate, but it is one of many possible defects, including difficulty in swallowing, poor melting, and hardness. In some cases, grittiness represents a minor issue (Do et al 2007). Thus, in this study we investigated the PSD of calciumfortified chocolate samples.…”

Rheological of chocolate-flavored, reduced-calories coating as a function of conching process

“…amount of fat, amount and type of emulsifiers and particle size distribution) as well as the various stages involved in chocolate processing which include mixing, refining, conching, tempering, molding and packaging (Minifie 1989;Chevalley 1999;Do et al 2007). Cocoa butter has a polymorphic structure meaning that it is made up of different types of fat, each with different melting points.…”