了解食品工业中的喷雾干燥
食品行业的喷雾干燥
食品经过各种流程以确保符合高质量的消费标准. 在长途运输过程中保持可用性, 有些食物通过改变其特性来保存, 例如从液体转变为固体. 用于此目的的一种重要方法是喷雾干燥, 确保产品质量一致.
喷雾干燥技术: 关键工艺及参数
喷雾干燥包括三个主要步骤: 雾化, 烘干, 和恢复. 该技术将液体转化为, 半液体, 或使用称为喷雾干燥器的专用设备将软产品制成粉末. 该系统包括带喷嘴的液体注射机构, 喷雾干燥室, 鼓式或旋风收集器, 以及使用压缩气体的加热空气系统.
雾化过程
雾化开始于液体通过喷射系统和喷嘴进入腔室. 喷嘴将液体分解成以下范围的液滴 10 到 500 千分尺, 平均尺寸介于 100 和 200 千分尺. 常用的喷嘴有高压单流体喷嘴和双流体喷嘴, 其中还可能包括旋转盘或高涡流设计.
单流体喷嘴直接喷射液体, 而双流体喷嘴利用额外的压缩气体流来协助干燥. 目标是产生尽可能最小的液滴, 减少将液体转变为固体所需的热量.
干燥工艺
干燥阶段取决于喷雾干燥系统的类型, 腔室设计, 和喷嘴. 它通常涉及单效或多效干燥过程, 两者都去除水分以形成细小的灰尘颗粒.
In single-effect drying, a heat source at the top of the chamber flows in the same direction as the sprayed liquid. Multiple-effect drying incorporates additional heating elements, such as a static bed at the bottom, which helps to form powder particles between 100 到 300 千分尺. Compressed gas warms the air, targeting the liquid injection and promoting rapid, even drying without excessive heat that could damage the product.
Recovery Process
Once the liquid is transformed into a solid, the fine powder is collected using drums, cyclones, or bag filters. The particles are then inspected for quality control before packaging and transportation.
Applications of Spray Drying in the 食品工业
Spray drying is widely used to convert liquids into solids, which can later be reconstituted with liquids like water, milk, or oil. Foods that often use this method include powdered gravy, cheese sauces, instant pudding, soup mixes, 牛奶, drink mixes, flavorings, and powdered eggs.
Many products, such as gravies and sauces, return to a liquid state to complete a dish. Other powdered items, like drink mixes and cheese powders, are used as flavorings or coatings. Some are complete meals requiring only a liquid to transform them, such as instant puddings needing milk or dry soups that rehydrate with water.
Principles of Spray Drying for Food Preservation
Spray drying preserves food during transport, preventing spoilage from mold or mildew by removing moisture and ensuring a stable product quality. This method also extends the shelf life of food by making it stable at room temperature, which is crucial when transporting products over long distances.
By transforming food into a powder form, spray drying eliminates the need for refrigeration, thereby extending the storage time. When the powdered food reaches the consumer, it can be reconstituted back to its original liquid form.
Spray drying remains a critical process for food preservation and transport, allowing for longer shelf life and maintaining product integrity across various food items.
