Navel oranges are not only delicious and juicy, but their skin is also a valuable spice resource, rich in essential oils with unique aroma and biological activity. However, the initial oil extracted from the fruit peel usually contains impurities such as pigments and wax, which affect its purity and quality.The citrus essential oil molecular distillation equipment, as an efficient separation method, can finely purify the essential oil of navel orange peel, effectively concentrate active ingredients and remove impurities, and obtain essential oil products with better color, aroma, and purity.

　　1、 Principles of Molecular Distillation Technology

It is a liquid-liquid separation technology performed under high vacuum conditions. The core principle is to use the difference in mean free path between molecules of different substances for separation.

In a high-temperature vacuum environment, material molecules escape from the liquid surface. Light molecules have a longer free path of motion and can reach the condensation surface to be collected; Heavy molecules have a short free path and are difficult to reach the condensation surface, thus remaining in the residue. This makes molecular distillation particularly suitable for separating high boiling point and thermosensitive materials, which can greatly reduce separation costs and better protect the quality of thermosensitive substances.

　　2、 The refining process of navel orange peel essential oil

The refinement of navel orange peel essential oil using molecular distillation technology typically involves the following key steps:

1. Raw material preparation and initial oil extraction: After crushing the navel orange peel, crude navel orange peel essential oil can be obtained through microwave ultrasonic synergistic extraction and other processes. Taking Chu Orange as an example, the initial oil obtained from pressing still needs to undergo freeze-drying and ultrafiltration membrane filtration to remove some pigments and wax.

2. Multi stage molecular distillation refining: The initial oil enters the equipment for multi-stage separation. The refining process often uses three-stage molecular distillation:

① First stage distillation: removes moisture, some volatile small molecules, and possible residual extraction solvents at relatively high vacuum levels (such as 80Pa) and low temperatures.

② Secondary distillation: Adjust parameters and focus on removing heavy phase pigment molecules, wax, and some large molecule terpene compounds.

③ Third stage distillation: Under more optimized conditions, collect light components rich in aroma components to obtain refined navel orange essential oil with light color and pure aroma.

The entire process is carried out under high vacuum and relatively low temperature, and the material is formed into a very thin liquid film through a scraping system, greatly improving mass and heat transfer efficiency, shortening heating time, and effectively ensuring the retention of thermosensitive aroma components.

　　3、 Advantages of equipment refinement

1. Efficient separation and purification: It can effectively enhance the aroma components, while selectively removing impurities such as pigments and wax that affect the appearance and stability of the product, significantly improving the color and quality of essential oils.

2. Protecting thermosensitive components: Low operating temperatures and short heating times can minimize the damage to thermosensitive aroma substances in essential oils, preserving their natural aroma characteristics and biological activity.

3. Enhance product safety: The process involves physical separation and does not introduce external chemical solvents, avoiding the risk of solvent residue and making the product safer and more natural.

4. Improve product yield and efficiency: Studies have shown that after optimizing the process, the retention rate of target components or the removal rate of impurities can reach a high level.

　　4、 Application of refined navel orange essential oil

The quality of navel orange peel essential oil refined by equipment has been improved, and its application is more extensive

1. High grade essence and perfume: used in perfume, cosmetics, shampoo, soap, detergent and other daily chemical products to provide fresh and natural citrus aroma.

2. Food and beverage industry: used as a natural spice in candies, beverages, baked goods, etc. to enhance flavor.

3. Tobacco industry: Used for adding fragrance to cigarettes, research shows that it can increase the delicacy of aroma, sweetness, and oral comfort.

4. Pharmaceuticals and health products: Thanks to their antibacterial, anti-inflammatory, antioxidant and other properties, they can be used for the development of related products.

　　V. Conclusion

Molecular distillation technology, based on the principle of molecular mean free path differential separation under high vacuum, provides an efficient, low-temperature, and environmentally friendly path for the refinement of navel orange peel essential oil. It can not only effectively remove pigments and impurities, concentrate active ingredients, but also protect the thermosensitive aroma substances of essential oils, significantly improving the quality and added value of products. With the increasing demand for natural products, equipment will play an increasingly important role in the deep processing of citrus essential oils.