Fat-blooming

Nucleation tempering of the stiU molten fat is necessary because the cocoa butter, if left to itself, can soHdify in a number of different physical forms, ie, into an unstable form if cooled rapidly, or into an equally unacceptable super stable form if cooled too slowly, as commonly happens when a chocolate turns gray or white after being left in the sun. The coarse white fat crystals that can form in the slowly cooled center of a very thick piece of chocolate are similarly in a super stable form known in the industry as fat bloom. 

Research on blending milk fat and its fractions with cocoa butter to reduce costs and/or to improve stability against fat bloom in chocolates has had mixed results. Milk fat hard fractions have been reported to inhibit fat bloom formation in both milk and dark chocolates (Versteeg et al., 1994 Dimick et al., 1996b Bricknell and Hartel, 1998) but to accelerate fat bloom in compound coatings based on palm kernel oil (Ransom-Painter et al., 1997). Reddy et al. (1996) showed the importance of modifying the... 

Tietz and Hartel (2000) studied the effects of removing or adding minor components naturally present in milk fat on the crystallization of milk fat-cocoa butter blends. They suggested that at low concentrations, minor lipids act as sites for nucleation and promote the rate of crystallisation and at higher concentrations inhibit crystallisation. They concluded that the presence of minor lipids, at the concentrations naturally occurring in milk fat, were sufficient to affect crystallisation rates, chocolate microstructure and fat bloom formation in chocolate. 

Bricknell, J. and Hartel, R. W. (1998). Relation of fat bloom in chocolate to polymorphic transition of cocoa butter. Journal of the American Oil Chemists Society, 75(11) 1609-1615. 

Lonchampt, P. and Hartel, R.W. (2004). Fat bloom in chocolate and compound coatings. European Journal of Lipid Science and Technology, 106(4) 241-274. 

Walter, P. and Comillon, P. (2001). Influence of thermal conditions and presence of additives on fat bloom in chocolate. Journal of the American Oil Chemists Society, 7S(9) 927-932. 

Proper control of the crystalline microstructure leads to products with the desired textural properties and physical characteristics. For example, tempering of chocolate prior to molding or enrobing is designed to control crystallization of the cocoa butter into a large number of very small crystals that are aU in the desired polymorphic form. When controlled properly, the cocoa butter crystals in chocolate contribute to the desired appearance (shine or gloss), snap, flavor release, meltdown rate upon consumption, and stability during shelf life (fat bloom). Similar... 

Bohenin (BOB) is the name given to glycerol 1,3-behenate 2-oleate, which inhibits fat bloom when added to chocolate. It is produced in Japan by enzymic interesterification of triolein and behenic (22 0) acid or ester in the presence of a 1,3 stereospecific lipase. 

Confectionery-Liquors and Liqueur. In chocolate confectionery and for pastry creams, it is the physical properties linked to the fusion and the crystallization of the fat that are essential. For milk chocolate, for coating or in bars, AMF can be used in proportions that depend on its compatibility with cocoa butter, whose properties of hardness and rapid fusion at 35°C cannot be altered. Thus it is currently accepted that AMF with high fusion levels obtained by the fractionation technique can be used. In general, milkfat has an interesting characteristic it inhibits the appearance of fat bloom (133). 

Due to the low level of milkfat in dark chocolate, fat bloom is a problem with this product. The hard fraction of milkfat (milkfat stearin) has been reported to act as an antibloom in dark chocolate, giving the chocolate an increased shelf life. However, the use of hardened milkfat is limited in several major chocolate producing countries (133). 

Adenier, H., H. Chaveron, and M. Ollivon, Mechanism of Fat Bloom Development on Chocolate, in Shelf-Life Studies of Foods and Beverages Chemical, Biological, Physical, and Nutritional Aspects, edited by G. Charalambous, Amsterdam, Elsevier Science Publishers B.V., 1993, pp. 353-389. 

Differential Scanning Calorimetry as a Means of Predicting Chocolate Fat-Blooming... 

A professional panel assessed the visual fat-bloom development after certain storage times (2, 4, 5, 7, and 9 wk after production in the first set-up and 1 wk, 1 and 3 mon after production in the second set-up). The meaning of the different values for bloom intensity is as follows 0 the product shows no difference compared to the original product 1-2 the product loses its gloss, but does not show any white spots 3 the product starts to show white spots or a gray film 4 the product clearly shows white spots or a gray film and 5 the product has turned completely white. 

Visual Fat-Bloom Assessment. Undertempering and shorter cooling lead to a faster and more pronounced fat-bloom development. The slightly overtempered chocolate (second set-up) only shows a loss of gloss when cooled during 20 min. 

FixHn both experimental set-ups, it could be concluded that chocolates with a different fat-bloom development also show differences in their melting profile. Since distinguishing all the degrees of fat-bloom development on the basis of one parameter at one storage time would be difficult, it was decided to use discriminant analysis as a statistical technique. This allows the simultaneous use of several parameters. 

In the second set-up, the visual fat-bloom after 1 wk, 1 and 3 mon is taken into account to create groups of chocolates, irrespective of the tempering and cooling... 

Fig. 3. no fat-bloom development A bloom intensity 3 after 2 wk and 5 after 5 wk group centroid O bloom intensity 5 after 2 wk. 

From this research, it can be concluded that varying the tempering conditions and/or the cooling time at 12°C influences both the visual fat-bloom development... 

Fig. 4A. O no fat-bloom development bloom intensity 0 after 1 wk and 1 after 1 and 3 mon A bloom intensity 1 after 1 wk, 1 and 3 mon bloom intensity 1 after 1 wk and 1 mon and 2 after 3 mon A bloom intensity 1 after 1 wk and 2 after 1 and 3 mon group centroid.

A method has been developed that allows for the measurement of interactions between liquid and solid lipids. This is potentially a very powerful technique that allows for the monitoring of many transformations and exchange processes. Typical processes include crystallization and solid-liquid exchange. The use of the technique on exchange processes, such as occur in fat-bloom, has been demonstrated. 

Koyano, T., I. Hachiya, and K. Sato, Fat Polymorphism and Crystal Seeding Effects on Fat-Bloom Stability of Dark Chocolate, Food Structure 9 231-240 (1990). 

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