Pre-Crystallization of Nougat by Seeding with Cocoa Butter Crystals Enhances the Bloom Stability of Nougat Pralines

Fat bloom is an outstanding quality defect especially in filled chocolate, which usually comprises oils of different origins and with different physical properties. Dark chocolate pralines filled with nougat contain a significant amount of hazelnut oil in their center and have been reported as being notably susceptible to oil migration. The current study was designed to test the assumption that a targeted crystallization of nougat with cocoa butter seed crystals is an appropriate technological tool to reduce filling oil transfer to the outside of the praline and, hence, to counteract chocolate shell weakening and the development of fat bloom. For this purpose, the hardness of nougat/chocolate layer models and the thermal properties of chocolate on top of nougat were analyzed during storage at 23 °C for up to 84 days. Pronounced differences between layer models with seeded nougat and with control nougat that was traditionally tempered were observed. The facts that chocolate hardness increased rather than decreased during storage, that the cocoa butter melting peak was shifted towards a lower temperature, and that the hazelnut oil content in the chocolate was reduced can be taken as explicit indicators for the contribution of seeded nougat to the fat bloom stability of filled chocolate.

Spontaneous Pattern Growth on Chocolate Surface: Simulations and Experiments

The natural variation of temperature at ambient conditions produces spontaneous patterns on the surface of chocolate, which result from fat bloom. These metastable patterns are peculiar because of their shape and cannot be obtained by controlled temperature conditions. The formation of these spontaneous grains on the surface of chocolate is studied on experimental and theoretical grounds.Three different kinds of experiments were conducted: observation of formed patterns in time, atomic force microscopy of the initial events on the grain formation and rheology of the melted chocolate. The patterns observed in our experiments follow the trends described by the Avrami model, which considers a constant value at all spatial scales of the rate of linear growth α that governs the formation of isolated grains, starting from molecular clusters. Through NVT-ensemble computer simulations, using a Mie-segmented coarse-grained model of triacylglycerides molecules, we studied the process of nucleation that starts the pattern growth. From simulation and experiment results it is possible to derive a realistic value of α.

Stability of Chocolates Enriched with Cocoa Shell during Storage

The stability of chocolate is mainly influenced by cocoa butter re-crystallization during storage, shown through fat bloom (appearance of white layers of cocoa butter on

Binary Phase Behavior of 1,3-Distearoyl-2-oleoyl-sn-glycerol (SOS) and Trilaurin (LLL)

This paper reports the precise analysis of the eutectic mixing behavior of 1,3-distearoyl-2-oleoyl-sn-glycerol (SOS) and trilaurin (LLL), as a typical model case of the mixture of cocoa butter (CB) and cocoa butter substitute (CBS). SOS was mixed with LLL at several mass fractions of LLL (wLLL); the mixtures obtained were analyzed for polymorphic phase behavior using differential scanning calorimetry (DSC) and synchrotron radiation X-ray diffractometry (SR-XRD). In melt crystallization with constant-rate cooling, SOS and LLL formed eutectics in their metastable polymorphs, allowing the occurrence of a compatible solid solution at wLLL ≥ 0.925. With subsequent heating, the resultant crystals transformed toward more stable polymorphs, then melted in a eutectic manner. For mixtures aged at 25 °C after melt crystallization, eutectics were found in the extended wLLL region, even at wLLL = 0.975. These results indicate that phase separation between SOS and LLL progressed in their solid solution under stabilization. The crystal growth of the separated SOS fraction may cause fat-bloom formation in compound chocolate containing CB and CBS. To solve this problem, the development of retardation techniques against phase separation is expected.

INFLUENCE OF INTENSIVE SUGAR SUBSTITUTES ON CHOCOLATE STORAGE

Исследовано влияние комбинации интенсивных сахарозаменителей стевиозида (Ст) и сукралозы (Су) на тепловые свойства, содержание влаги, текстуру и поседение шоколада, не содержащего сахарозу, при различных температурах хранения. В ходе исследования отмечена тесная связь между микроструктурой и наибольшим процентом поседения шоколада. Образцы со 100% Су и 50% Ст + 50% Су имели микроструктуру с каналами, через которые твердые вещества и жир могли легче мигрировать к поверхности, увеличивая образование жира и сахара в поверхностных слоях. Однако образцы с 50% Ст + 50% Су и 75% Ст + 25% Су показали минимальное образование жирового поседения. Исследования показали, что образцы 100% Ст и 75% Ст + 25% Су имели наименьшее снижение энтальпии плавления при повышении температуры хранения. Кроме того, была изучена неизотермическая кинетика кристаллизации путем применения модели Аврами. У образца 75% Ст + 25% Су отмечены самые высокие значения энергии активации и наибольшая стабильность в интервале температур от 7 до 30°C. The effect of the combination of the stevia (St) and sucralose (Su) sweeteners on the thermal properties, moisture content, texture and graying of chocolate that does not contain sucrose at different storage temperatures was studied. The study noted a close relationship between the microstructure and the highest percentage of chocolate graying. Samples with 100% Su and 50% St + 50% Su had a microstructure with channels through which solids and fat could more easily migrate to the surface, increasing the formation of fat and sugar in the surface layers. However, samples with 50% St + 50% Su and 75% St + 25% Su showed minimal fat bloom. Studies have shown that for samples containing 100% St and 75% St + 25% Su, the melting enthalpy had the smallest decrease with increasing storage temperature. In addition, the nonisothermal kinetics of crystallization was studied by applying the Avrami model. A sample of 75% St + 25% Su showed the highest values of activation energy, demonstrating the greatest stability in the studied temperature range from 7 to 30°C.