Top 10 Benefits of Freeze Drying Cannabis
Freeze drying or lyophilization differs from conventional food preservation methods in which moisture is removed from the food products through sublimation using a freeze dryer machine. The direct transition of water from solid (ice) to vapor preserves the structural properties of foods, including shrinkage and density porosity.
Lyophilization is a multistep process using a cannabis freeze dryer, including freezing the product under atmospheric pressure, primary drying at reduced pressure, and secondary or desorption drying. Removing moisture from dried foods by a freeze dryer for cannabis machine does not affect their shape, texture, and flavor. Preservation of sensory qualities of food products makes freeze drying an ideal way to dehydrate foods to enhance their shelf life.
Nowadays, freeze drying has been used in the industry to conserve high-quality foods and pharmaceuticals:
- The food industry uses freeze drying to make perishable foods, such as fruits and vegetables, more convenient for processing and transport without compromising their nutritional and texture profile.
- The pharmaceutical industry benefits from this preservation process by formulating vaccines and other injectable materials with longer storage life.
- Microbiology labs use freeze drying cannabis to preserve specific strains of bacteria.
- Cannabis plants have applications in the textile industry and have been used as textile fiber for years before they were introduced as medicinal plants.
Cannabis, with tremendous medical and industrial applications, possesses thousands of bioactive molecules holding immense therapeutic potential against different chronic illnesses. However, conventional postharvest operations alter the composition of bioactive secondary metabolites (cannabinoids) of the plant and result in inconsistent product quality. Temperature, humidity, air, and light are the primary factors to control while preserving cannabis flowers.
With the legalization and licensure of medical cannabis in different regions of the world, the focus on the preservation of this medical plant has increased. Various traditional (hang-drying, hot air, and oven drying) and modern (microwave-assisted hot air drying, microwave-assisted freeze drying, or vacuum freeze drying) techniques of drying cannabis are used to conserve their phytochemistry, potency, and flavor.
Preservation of Potency
Postharvest quality of freeze drying cannabis depends on moisture content, microbial activity, room temperature, light and duration of the drying process, and freeze dryer used for cannabis. Freeze drying of cannabis not only preserves phyto cannabinoid and terpenoid content (including THC, CBD, CBN, CBG, & CBC) but also stabilizes live biomass and prevents oxidation in concentrates and flowers.
Furthermore, this controlled moisture removal technique delivers more potent food products than traditionally dried products with minimal degradation of terpenes and cannabinoids. Research studies show that freeze dryers can maintain the potency and medicinal properties of cannabis by increasing the level of cannabinoids up to 3 to 4% and delivering a premium product.
The multistep process of freeze drying prevents the nutritional loss of freeze drying cannabis. In the first step, freezing cannabis at – 400C converts all water content into ice without making water foam. After that, secondary drying removes all the residual moisture of the product without damaging its protein, lipid, and secondary metabolites.
The resulting porous and unaltered structure of cannabis hinders the degradation of the solid matrix and makes the rehydration process more convenient and damage-free. Controlled freezing and drying protocols allow the removal of maximum moisture from the cannabis buds and flowers, hence hindering the microbial degradation of the product. Otherwise, bacteria and mold growth in the frozen product destroy product integrity and alter its nutritional composition.
Retention of Terpene Profiles
Terpenes, as essential oil constituents, contribute to the sensory properties of cannabis. These fat components improve the cannabis flavor and offer value to the product by increasing the growers experience. THC, as a primary terpene compound, is present in more than 2% of the dry weight of cannabis, especially the floral part of the plant, which contains much higher terpene content. Because of the aroma characteristics of terpenes, the cannabis plant has psychoactive potential and is graded as narcotics.
Monoterpenes, sesquiterpenes, diterpenes, and triterpenes impart flavor and unique aroma to this medicinal plant. The freeze drying cannabis process could not alter terpenoid composition and preserve the frozen product's sensory attributes. Generally, taste and smell are the vital sensory systems humans perceive the world. Various products, such as cannabis buds and flowers, depend on terpenes for their character, flavor, and fragrance.
Cannabinoids and terpenes are incredibly volatile, and growers can lose a significant amount of these oil components even in the most optimal drying environment. However, freezing cannabis flowers right after harvesting can preserve most of the terpene content. At early attempts, freeze drying cannabis produces dehydrated and crushed products because the freeze dryers were not designed to dry cannabis buds.
Terpenes and other chemicals were lost in this process, resulting in a less aromatic and flavorful final product. After freeze drying of cannabis, no shrinkage or deformation is observed, and buds remain in their full form. Hence, growers can lock its original aroma, trichomes (bioactive chemicals), and potency.
Reduced Curing Time
Curing preserves many food products such as meat, fish, and vegetables. In the curing process, the moisture is removed from the product through osmosis. Moisture provides a suitable medium for various microorganisms to grow that deteriorate the food. Furthermore, perishable foods with high water content, such as fruits and vegetables, can be easily damaged through oxidation.
For decades, such techniques have been used to remove moisture from these foods and preserve them for extended periods. Dehydration was the most primitive form of curing or preserving foods. With the passage of time, smoking, spicing, and cooking were used to cure food and prolong its shelf life. Salt (such as potassium nitrite and sodium nitrite) and sugar were added to different foods to minimize the water content and lessen the microbial activities in the food.
When growers hang-dry the cannabis, it will take 18 to 30 days to get rid of its green and grassy taste. This process is because enzymes that cause senescence deteriorate as they act on the chlorophyll. On the other hand, an appropriate cannabis freeze dryer cracks and opens the cell walls and makes it easy for biomass to absorb atmospheric moisture. The oxygen, humidity, and enzymes in a freeze dried cannabis, when it comes out of the freeze dryer in an oxygen-saturated environment, cause degradation of chlorophyll in just 2 – 4 hours.
Therefore, freeze drying can provide a product cured as if traditionally dehydrated and preserved for 18 – 30 days. Freeze drying is faster than traditional curing methods; however, it depends on the specific settings and freeze dryer used. Appropriate freeze dryers reduce space requirements and minimize pest infiltration and mold growth.
Prevention of Mold and Bacteria Growth
Cannabinoids and terpenes are the primary phytochemicals present in different parts of the cannabis plant. Additionally, cannabis contains an ample amount of water, which can deteriorate the product after harvesting. During storage, water content favors the growth of molds and mildew in the plant. Bacterial and mold growth reduces the shelf life, lowers the potency amount, and compromises the quality of the product. Moisture level and water activity should be carefully controlled to prevent microbial growth and ensure a satisfying and safe experience.
The global legal cannabis market was estimated at $16.7 billion in 2022 and is predicted to increase at a 25.4% annual rate until 2030. This growth potential is because of the usage of advanced preservation techniques, including freeze-drying of cannabis. It is essential to preserve the nutritional and sensory properties of marijuana to increase its consumption pattern.
Freeze drying, a three-step process, involves rapid freezing down to a temperature below -400F, heating the ice to sublimate the solid ice into vapors, and then another dose of heating is provided to eliminate the residual moisture from the product. Literature data suggest that freeze dried marijuana contains 1-4% water content. After freeze drying, frozen cannabis can be stored for a longer period with the original taste, aroma, and flavor. In addition, freeze dried cannabis has a minute microbial activity, which ensures the long-term storage of the product.
Consistency in Product Quality
Freeze drying is an extremely gentle dehydration procedure that preserves high-quality cannabis by employing a freeze drier rather than regular drying. It's a very uniform drying process that results in the cessation of shrinkage to retain the same size and shape of the flowers in the garden. Freeze dried cannabis, if stored properly, can be used for years with little to no degradation.
The cold temperature lessens the loss of volatile bioactive components such as terpenoids and cannabinoids and prevents further chemical changes in the stored product. There is a need to upgrade the regular harvest freeze dryer machines to perform the process correctly, such as harvesting the suitable large pharmaceutical freeze dryer. Apart from other benefits, the cannabis freeze dryer allows rehydration to restore cannabis's organoleptic characteristics and weight.
Increased Shelf Life
Freeze drying inhibits the growth of microorganisms by removing moisture from the cannabis. Decreased microbial activity increases the quality of the product and extends its shelf life. Moisture allows bacteria and mold to grow fast and deteriorate the food products. Furthermore, moisture favors product oxidation and destroys the foods' structural composition.
Hence, moisture removal by freeze drying can prevent oxidative and microbial damage and extend the storage life of freeze dried cannabis. Freezing the product under reduced temperature can prevent the formation of larger ice crystals, which can disturb the product's texture later on. The secondary drying step helps to evaporate the leftover moisture in the frozen product to maintain its quality over time.
Enhanced Color and Appearance
Industrial freeze dryer for cannabis can preserve its nutritional and sensory attributes, keeping the product top quality. Dehydration via sublimation does not affect cell structure; therefore, it conserves the nutritional composition and texture of frozen cannabis. When the final stored product is protected from microbial and oxidative damage, with the full potential of phyto-ingredients, it will provide maximum aesthetic benefits to its potential consumers. Freeze dried cannabis remains edible for up to 25 years if unopened.
Efficiency and Scalability
Freeze drying causes less nutrient loss of cannabis than other conventional methods of drying and preservation that use high temperatures. At high temperatures, heat-sensitive phytonutrients are removed or destroyed during processing. Microscopic pores created by ice crystals in frozen products make rehydration easy without altering its structure.
On a large scale, commercial freeze dryers are used to enhance the shelf life of pharmaceuticals and high-quality concentrates. When discussing its commercial usage, freeze drying costs about 5 times as much as conventional drying. Therefore, it can only be used for highly valued products and increased demand.
Energy Savings Compared to Traditional Drying Methods
An experiment comparing energy conservation using freeze drying and conventional methods was performed. Results indicated that freeze drying takes longer and more time than other drying methods. Moreover, lyophilization consumes more energy and power than traditional preservation methods.
Versatility in Processing Various Forms
Cannabis freeze drying keeps it fresh for longer. Lyophilization protects the nutritional ingredients of cannabis products, including flowers, edibles, and concentrates. Freeze drying reduces the time to market. Cannabis buds and blossoms are freeze dried foods commercially used for therapeutic purposes. Freezing under pressure, the primary and secondary drying process safeguards the psychoactive compounds of cannabis products and maintains their aroma, color, and texture for longer. Water removal from valuable concentrates enables them to be stored for a prolonged period of time without oxidation and microbial attack.
The Bottom Line
Freeze drying is the most appropriate method to conserve the nutritional and sensory attributes of cannabis products. It is far better than conventional preservation techniques. Cannabis's demand has increased tremendously after its removal from the narcotic list because of its medicinal properties and bioactive ingredients.
However, traditional drying methods can destroy the products' nutritional ingredients and texture. Improper process parameter selection can result in adverse changes in the material, such as shrinkage, color change, and collapsed structure. Freeze drying removes the moisture from cannabis and extends its shelf life. Additionally, it maintains the product's aroma, flavor, and texture.
