The Role of Steam Generators in Preserved Fruit Production

Candied fruits, also known as fruit preserves, were historically called honey-fried fruits. This traditional Chinese sweetened fruit confection is primarily made from fruits and vegetables, processed through methods such as pickling with sugar, honey, or salt (or without pickling). In the production of candied fruits, steam generators play an indispensable core role. Their stable steam output provides precise thermal energy support for multiple critical stages, directly impacting product quality and production efficiency.

During the raw material pretreatment stage, high-temperature steam generated by the steam generator rapidly achieves blanching of the fruit. By controlling steam temperature between 80-100°C, it simultaneously inactivates oxidase enzymes in the raw material to prevent fruit flesh browning while softening cell walls. This creates favorable conditions for sugar penetration during subsequent sugar-coating.

During the sugar-coating process, the steam generator's indirect heating system enables precise control of syrup temperature. Whether employing atmospheric sugar-curing or vacuum sugar-infusion processes, the stable steam heat source maintains syrup temperature within ±1°C. This prevents localized overheating that causes sugar caramelization, ensuring uniform sugar penetration into the fruit tissue. For candied varieties requiring multiple sugar-curing cycles—such as candied dates and winter melon candies—the continuous steam heating reduces intervals between each curing step, boosting production efficiency.During the drying process, the steam generator works in tandem with the hot-air drying system to precisely control temperature and humidity within the drying chamber. This allows candied fruits to dehydrate at a gentle 45-60°C, preserving both nutritional content and flavor compounds while preventing surface hardening. Simultaneously, the stable thermal energy supplied by steam reduces drying time by 15-20%, significantly lowering energy consumption costs.Additionally, the high-temperature steam generated by the steam generator serves as a critical safeguard in the sterilization process. During the sterilization treatment prior to packaging candied fruits, saturated steam at 121°C rapidly penetrates the packaging material, eliminating microorganisms and spores. This ensures a product shelf life of 6 to 12 months without compromising the candied fruits' texture or color.It can be said that steam generators, by providing clean, stable, and controllable thermal energy throughout the entire production process of candied fruits, serve as the core equipment that ensures consistent product quality and enhances production efficiency.