Enhancing heat stability and bloom resistance in low-fat chocolates using bigels

To improve the heat stability and bloom resistance of low-fat chocolate, three types of bigels stabilized by glycerol monostearate and citrus fiber-O/W, bicontinuous, and W/O-were used as fat substitutes to replace 25 % or 50 % of cocoa butter (CB) in chocolate. Among all schemes, chocolate with 25 % CB replaced by W/O-type bigel (BG3-C25) showed the greatest potential for application. Compared with the control, BG3-C25 exhibited twice the hardness at 32 °C and a higher shape retention index at 40 °C (0 % vs. 73.32 %), attributed to the reinforcement of the chocolate fat network by bigels. After 45 days of temperature cycling, BG3-C25 displayed only slight grayish-white specks on the surface, whereas the control showed extensive bloom. This is because bigels delayed the β_V-to-β_VI polymorphic transition and promoted the formation of a dense fat crystal network through smaller, uniformly distributed crystals. Additionally, BG3-C25 demonstrated acceptable sensory properties without a waxy mouthfeel.