Influence of thermal conditions and presence of additives on fat bloom in chocolate

Abstract

This study focused on the analysis of the effects of thermal history and presence of additives on fat bloom in chocolate. Magnetic resonance data obtained on specific chocolate samples were useful in evaluating the effect of thermal history on the appearance of fat bloom and also in understanding the underlying mechanism. Fat bloom was induced by thermal history such as storage for 3 d at 32 or 28°C. Increasing storage time at 21°C after each thermal treatment also promoted fat bloom. Differential scanning calorimetry experiments confirmed the appearance of polymorphic form VI in the bloomed samples. Also, three different components were added separately to the initial composition of dark chocolate and the appearance of fat bloom was monitored. 1,3-Dibehenoyl, 2-oleoylglycerol (BOB) did prevent fat bloom. However, magnetic resonance and differential scanning calorimetry data collected on chocolate samples did not confirm that either added sucrose or milk powder prevented fat bloom. Indeed, fat bloom occurred for these samples, but its characteristics were different from those with pure chocolate.Paper no. J9577 in JAOCS 78, 927-932 (September 2001).Fat bloom is the major issue affecting chocolate products, especially confectionery containing fatty filling (1). During storage, a dusty white layer appears on the chocolate surface, caused by the formation of fat crystals (1). This physical defect makes the chocolate undesirable for consumers who expect to buy a product with the required glossy surface and desired brown shade (2). Although the mechanism of its formation is not completely understood, the causes seem to be multiple, such as improper tempering, use of incompatible fats, and large temperature fluctuations during storage (2). Because chocolate contains more than 30% fat, its successful use depends on the proper manipulation of cocoa butter (2) and cocoa butter properties such as thermal behavior (1). Cocoa butter is a natural fat composed of a mixture of three classes of triglycerides (unsaturated, monounsaturated, and polyunsaturated) where the monounsaturated fats represent more than 80% of the total fat content (3). Moreover, only three triacylglycerols (1,3-dipalmitoyl, 2-oleoylglycerol, or POP; 1,3-palmitoylstearoyl, 2-oleoylglycerol or POSt; and 1,3-distearoyl, 2-oleoylglycerol or StOSt) account for more than 95% of this fraction (3). However, the thermal behavior of cocoa butter is complicated because of the polymorphism of these triacylglycerols (3). Cocoa butter is generally described by six different polymorphic forms, I to VI in order of increasing melting point (4). However, I, III, and VI are now considered to be a mixture or a phase separation from the other forms (5,6).It is now accepted that fat bloom is linked to the separation of the liquid fraction of cocoa butter from the chocolate matrix, followed by migration of this fat toward the surface where it recrystallizes, inducing the appearance of a white layer and loss of the glossy aspect (1,7). Moreover, the appearance of fat bloom is ge...

Comparison of quality characteristics between compound and pure milk chocolate

“…The chocolate melting profiles characterize changes and measures the relative amounts of each crystalline state using DSC. [17][18][19][20] Peak onset (T onset ) corresponds to the temperature at which a specific crystal form starts to melt whereas peak maximum (T peak ) corresponds to the greatest melting rate occurrence and end of melting (T end ) shows completion of liquefaction. All these information are related to crystal type of cocoa butter.…”

Characterization of melting properties in dark chocolates from varying particle size distribution and composition using differential scanning calorimetry

“…Differential scanning calorimetry (DSC) has been used to characterize changes in chocolate melting profiles and measures the relative amounts of each crystalline state (Tabouret, 1987;Walter & Cornillon, 2001, 2002Ziegleder & Schwingshandl, 1998); and peaks corresponding to latent heat, are observed in temperature ranges related to melting of specific polymorphs (McFarlane, 1999). Such information is relevant to sensory character and impacts on mechanical and rheological properties of chocolate and confectionery shelf life (Hartel, 2001).…”

Influence of lecithin–PGPR blends on the rheological properties of chocolate

“…Because of their special molecular structure, these surface-active ingredients lower the interfacial tension between the dispersed and the continuous phase and, besides rheology, affect a number of properties such as the sensitivity to moisture and temperature, and the tempering behaviour (Minifie, 1980;Schantz & Linke, 2001). Additionally, the emulsifiers may influence some properties of solidified chocolate such as susceptibility to fat bloom, stability to fat migration from fillings, and oxidation (Schuster, 1985;Hasenhuettl & Hartel, 1997;Walter & Cornillon, 2001).…”