1. Cold air fixed strip area:
Stick noodle production lines often choose to enhance air flow without heating up, using a large amount of dry air to promote noodle dehumidification, promote the initial fixation of noodle shape, and remove surface moisture from the noodles. Surface hardening, transitioning from plastic to elastic, requires early opening of the fan and dehumidification on rainy days (or rainy days). In winter, when the temperature is too low, the wet surface evaporates slowly, making it difficult to set the noodles. To avoid low temperatures, it can lead to poor wetness of the noodles, excessive evaporation of water on the surface, which affects the humidity reduction during the internal evaporation stage, excessive moisture retention, and causes excessive stretching, breakage, thinning, thickening, and adhesion of the noodles.
2. Internal evaporation zone (moisture retention and sweating):
The internal evaporation zone mainly focuses on the internal diffusion of water, strengthens ventilation, and ensures smooth air circulation. At this moment, the cross zone temperature rises, so don't worry. To form a "gradient" of temperature and maintain a certain humidity, there are two aspects. On the one hand, it transfers heat energy to the center of the noodles, reducing the temperature difference between the surface and the interior. On the other hand, it accelerates the diffusion of internal water, making the surface water vaporization speed consistent with the internal water transfer speed. The water slowly evaporates. If the temperature and humidity difference is too large at this moment, it will cause various adverse phenomena such as rapid drying of the surface, "film formation" on the surface, and cracks. The imbalance of internal and external water content will cause the noodles to dry outside and wet inside, resulting in quality problems such as sour and crispy noodles. Short storage period.
3. Full evaporation zone (heating and humidity reduction):
After the "moisture retention and sweating" stage of noodles, the internal moisture is transferred smoothly to the surface, causing water to accumulate on the surface. At this time, the noodles have a certain strength and must be further heated, with appropriate reduction of relative humidity, so that the water in the noodles can evaporate comprehensively and timely in a high temperature and low humidity state. If not heated, surface moisture will transfer again to the inner layer, achieving a balance of internal and external moisture concentrations. If the dried noodles have a thicker (>0.8mm) circular surface, this area serves as an extension of the moisture retention and sweating zone, continuing to retain moisture, so that all internal moisture is transferred to the surface without any sandwich. Then, the moisture is removed at the tail of the high-temperature zone to achieve internal and external diffusion balance, completing the entire process of the main drying stage.
4. Cooling and heat dissipation:
After the main drying stage, most of the moisture in the noodles has been removed, and the structure of the noodles has been basically fixed. At this time, only the flow of air is needed to slowly reduce the temperature of the noodles themselves, and continue to remove a small amount of moisture to meet the water content requirements of the product quality standards. The purpose of this stage is twofold. On the one hand, it adopts a softening process to adjust the extremely uneven moisture content on the surface and inside of the noodles, eliminate the internal stress caused by drying shrinkage, and increase the toughness and elasticity of the noodles.
The Dongfang Naomu low-temperature stick noodle production line can achieve highly automated control, low-temperature zone temperature control, stable and reliable drying system, high drying quality, closer to natural drying, and better taste. We are dedicated to providing comprehensive system services and professional technical support to new and old customers, from initial consultation to plan setting, equipment manufacturing, and later on-site installation and personnel training.