Yingtai: Applications of Vacuum Freeze-Drying Technology in Plant Extract Preparation

Yingtai: Applications of Vacuum Freeze-Drying Technology in Plant Extract Preparation

1. Comparison of Freeze-Drying for Plant Extracts

Using the example of the Plumeria sap, the study compared the effects of freeze-drying and non-freeze-drying treatments on the quality of chloroform extracts to reveal the significance of freeze-drying technology in preserving extract quality. The experimental design included two groups: one group used freeze-drying to reduce the moisture content of Plumeria sap, while the other group did not undergo freeze-drying. Both groups then underwent extraction using the immersion method with chloroform as the solvent. The extracts were assessed for physical properties and plant chemical components, with particular focus on flavonoids, anthraquinones, polyphenols, alkaloids, terpenes, and triterpenes analyzed by thin-layer chromatography. The color intensity was evaluated, and statistical tests were applied to validate result differences.

The study found that samples without freeze-drying treatment exhibited fungal contamination during storage, whereas the freeze-dried group did not show such issues, highlighting the positive impact of freeze-drying technology on extending the shelf life of extracts. Although neither group of extracts contained flavonoids, anthraquinones, or polyphenols, both contained alkaloids, terpenes, and triterpenes. Notably, the freeze-dried group showed significantly higher color intensity for these active components compared to the non-freeze-dried group, suggesting that freeze-drying treatment is beneficial for increasing the concentration or stability of specific active components in the extract. The chloroform extract of Plumeria sap treated with freeze-drying exhibited superior physical properties and active component content, avoiding microbial contamination and enhancing the detection signal for target components. However, to fully understand the effects of freeze-drying and its specific quantitative contribution to extract components, future research should delve into compound quantification and explore the applicability of this technique to a broader range of natural plants to optimize the entire extraction process and advance technology in the natural plant field.

2. Advantages of Freeze-Drying for Natural Plant Extracts

With the increasing global interest in natural therapies and traditional medicine, natural plants are highly regarded for their unique therapeutic effects and minimal side effects. However, effectively and stably extracting and preserving the active components of these herbs remains a key challenge to their widespread application. Freeze-drying technology, as a modern method for maintaining the activity of biological materials, demonstrates significant advantages in handling natural plant extracts.

(1). Increased Stability of Active Components: Natural plants often contain heat-sensitive or easily oxidized active components such as alkaloids, flavonoids, and saponins. Traditional heat-drying methods can lead to the degradation or denaturation of these components. In contrast, freeze-drying operates at low temperatures, effectively reducing thermal effects and preserving the stability of active components in herbal extracts.

(2). Enhanced Bioavailability: Freeze-dried herbal extracts have a loose, porous, sponge-like structure, which facilitates rapid dissolution and absorption, thus improving bioavailability. For oral administration, freeze-dried products can accelerate release in the body and enhance therapeutic effects.

(3). Convenient Storage and Transport: Due to their extremely low moisture content, freeze-dried products are less prone to microbial spoilage, extending the shelf life of herbal extracts. Additionally, they are smaller in volume and lighter in weight, making them suitable for long-distance transport and long-term storage.

(4). Comparison with Traditional Drying Methods: Compared to traditional methods such as air-drying and oven-drying, freeze-drying technology, although initially more costly in terms of equipment and energy, offers significant advantages in product quality, preservation of active components, and extended shelf life. Especially for high-value natural plants, the long-term economic benefits of freeze-drying technology are more pronounced.