Tobacco leaves, after baking, have a very low moisture content—typically between 5% and 8%. This dryness makes the leaves fragile, which can significantly reduce both their yield and quality. To prevent this loss, tobacco leaves must undergo a process called "resurfacing" or "rehydration." This process gently softens the leaves, making them easier to handle during subsequent operations like tapping, removing veins, and stacking, ensuring that the final product maintains its quality and market value.
The resurfacing standards vary depending on the intended use of the tobacco. For example, if the tobacco is meant for smoking, it should be rehydrated to a moisture level of around 14–15%. If it's being sorted and sold, the moisture content should be higher—between 16% and 18%. If the moisture is too low, the leaves become brittle and prone to breaking, which reduces yield and damages quality. On the other hand, if the moisture is too high, the leaves may darken in color, lose their luster, and develop a condition known as “flushing.†Excess moisture also increases the risk of mold, further degrading the tobacco’s quality.
When properly rehydrated, the tobacco leaf feels slightly moist when held in the hand. It no longer feels dry or crisp, and the base of the veins becomes less likely to break. The leaves are supple and not easily torn. At this point, the moisture content is usually around 16–18%, which meets national purchasing standards. If the tobacco is not being sold immediately, it should be stacked carefully in a dry area. The moisture content should be kept at about 15% to prevent mold during storage. In this state, the leaves feel dry with a slight rustling sound, and the veins are more fragile. They should be handled with care and covered with plastic film to maintain optimal conditions.
If the moisture content exceeds 18%, the leaves will feel damp and wet. The main vein becomes flexible, and the leaves may stick together, forming clumps. There might even be an “oil out†phenomenon, where the leaves appear oily and wrinkled. These signs indicate that the tobacco has been over-hydrated, which not only fails to meet national standards but also increases the risk of heat generation and mold during storage.
There are several methods used for resurfacing. One common method is using a hot air circulation barn. This technique ensures even rehydration and reduces the chances of leaf breakage. After the baking process is complete, the temperature inside the barn should drop below 40°C. Then, 3 kg of water is evenly sprayed inside, and all doors, windows, and vents are closed. The fan is turned on for approximately 2.5 hours to distribute the moisture effectively.
Another method is called "borrowing the tide," also known as natural rehydration. This involves taking advantage of the higher humidity levels in the environment, typically during early evening to early morning. When the temperature in the barn drops slightly above the outside temperature, the doors and vents are opened to allow the tobacco to absorb moisture from the air. Once the leaves feel slightly softened, they are carefully removed. This method is convenient and requires minimal equipment, but it depends heavily on local weather conditions. In humid climates, the process is faster, while in dry conditions, it may take longer and could interfere with the baking process.
A third method involves using a "tide room," a specialized structure designed for rehydration. These rooms are similar to regular buildings, with sealed doors and windows to maintain humidity. The tobacco is placed on shelves or spread on the floor, allowing it to slowly regain moisture. If the indoor humidity is insufficient, water can be sprinkled on the ground to increase moisture levels. This method is not affected by external weather conditions, improves barn utilization, and results in more uniform rehydration with lower breakage rates.
No matter which method is used, constant monitoring is essential. Rehydration should not cause the veins to break, and the leaves should remain suitable for drying. Ideally, the moisture content should be around 13% after the process. Proper attention during resurfacing ensures that the final product meets quality standards and retains its value in the market.
Natural Food Colorants
what is natural food color?
Natural food coloring refers to pigments extracted or prepared from plants, animals, microorganisms or other natural sources for coloring food. These pigments are naturally produced due to biochemical reactions in living organisms and do not contain synthetic chemical components.
Natural food colors can be divided into the following categories according to their source:
1. Plant pigments: This is the most common source of natural food pigments, including pigments derived from a variety of fruits, vegetables, flowers, and plant roots. For example, red beets can provide red pigments, carrots can provide orange pigments, turmeric can provide yellow pigments, and blueberries and purple potatoes can provide purple and blue pigments.
2. Animal pigments: These pigments are rare and usually come from the tissues or excretions of certain animals. For example, cochineal is a red pigment derived from the cochineal insects that live on certain cacti.
3. Microbial pigments: Some microorganisms, such as monascus, can produce specific pigments, such as monascus red pigments.
4. Mineral pigments: Although less used, certain inorganic minerals can also be used as natural food pigments, such as titanium dioxide (white) and iron oxide (red, yellow and black). However, due to possible toxicity issues with some mineral pigments, their use is often severely restricted or banned.
Natural food colors are generally considered safer and healthier than synthetic colors due to their nature. However, their color stability, heat resistance, light resistance, and interaction with other food ingredients may not be as good as synthetic pigments, so their application in the food industry sometimes presents some challenges. At the same time, the extraction and processing of natural pigments can also affect their cost and sustainability. Nevertheless, as consumer concerns about food safety and health increase, the demand for natural food coloring is growing.
Natural Food Colorants,Natural Food Pigments, natural food color
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