Commercial cultivation of cannabis
Betty Wedman-St. Louis in Cannabis, 2018
Drying cannabis is an important control measure to be taken to ensure the cannabis is ready for human use. There are two different technique utilized in industry, air drying and freeze drying. When harvesting cannabis, a separate area for drying is recommended with ventilation and a consistent temperature of around 21°C. Drying helps promote a high potency in cannabinoids for certain strains of cannabis. The most common method of air drying is to suspend the plant upside down and allow air to circulate throughout the area. The flower should be checked daily to ensure that mold and mildew does not start to grow in the humid environment. Once the cannabis flower has reached a moisture content range of 45%–55%, it can be cured to promote the preservation of terpenes and cannabinoids. Curing is the last step to enhance the flavor of the cannabis before reaching the consumer. The best method for curing is to store the flower in an airtight, light-resistant container at room temperature, from seven days to months [5]. Freeze drying works by utilizing dry ice to uptake the moisture from the plant and disperse the moisture as humidity in the environment. This technique requires the plant material to be fresh, and it dries the material within a couple of days. Cannabis should have moisture content of 45%–55% before removing from packaging in light-resistant, airtight containers.
Postharvest Care of Medicinal and Aromatic Plants: A Reservoir of Many Health Benefiting Constituents
Amit Baran Sharangi, K. V. Peter in Medicinal Plants, 2023
The moisture content of the fresh produce is lowered to the safe acceptable limit it results in a reduction in the activity of the microorganism as well as the material and biological changes taking place at the internal tissues which helps in refining the steadiness of the herbs (Hatamipour et al., 2007; Das and Sharangi, 2018). To get a better status of the final output, it is thus required that the orthodox systems used for moisture removal must be changed to modern or innovative ways of dehydration. Vacuum, osmotic, and freeze-drying can be brought into use. For example, by the application of freeze-drying method very high rated dehydrated products can be expected (Muthukumaran et al., 2008). However high capital required for undertaking these types of drying innovations into implementation, often restricts their utilizations (Shishehgarha et al., 2002).
Towards the Importance of Fenugreek Proteins
Dilip Ghosh, Prasad Thakurdesai in Fenugreek, 2022
Drying using spray, freeze, and vacuum oven methods, etc., as a tool for preservation, is the common step of protein isolates’ processing. Although accompanied with more limited changes in proteins’ attributes, freeze drying is less used on an industrial scale owing to the time and energy required. Spray drying, in contrast, is more favored in the industry because of its speed and some characteristics in its final products, including smaller and more uniform particles. Feyzi et al. (2018b) found that while vacuum oven drying resulted in less Lys, Met, and total amino acids content in fenugreek protein isolate, no considerable difference would occur between freeze and spray dried samples. Such phenomena occur as a result of Maillard and oxidation during prolonged vacuum oven procedure. Moreover, results of FTIR proved that freeze and spray drying methods resulted in more retention of α-helix structures compared with vacuum oven procedure. However, bands related to β-sheet structures were more profound in spray dried samples than freeze dried ones, probably due to conversion of α-helix structures to β-sheet ones during the cooling step after heating. Finally, no protein aggregation was detected for three dried fenugreek protein samples based on SDS-PAGE and FTIR results. These findings coincided with those reported about various grass pea protein isolates dried using vacuum oven and freeze drying methods (Feyzi et al., 2018b).
Nanocrystals based pulmonary inhalation delivery system: advance and challenge
Published in Drug Delivery, 2022
Pengfei Yue, Weicheng Zhou, Guiting Huang, Fangfang Lei, Yingchong Chen, Zhilin Ma, Liru Chen, Ming Yang
The process of freeze-drying is to first freeze the liquid solution or suspension under atmospheric pressure and then heat it under vacuum in order to remove ice crystals by sublimation. Finally, the high-porosity powder with low moisture content was obtained. The freeze-drying process consists of three steps: freezing, primary drying, and secondary drying (Siow et al., 2016). Freeze-drying and spray-drying are most commonly used techniques for solidification of nanosuspension as they are easily applied in practice, their scale up production and high industrial acceptability. In order to form inhalable microparticles (NP-agglomerates), El-Gendy et al. (2009) used freeze-drying to solidify the nanosuspension, which was obtained through a controlled flocculation process (protocol under the name NanoClustersΤΜ, owned by Savara Pharmaceuticals, Austin, TX). Budesonide nanocrystals-agglomerates prepared by this method showed enhanced dissolution rate when compared with the raw drug, with an MMAD of 2.1 ± 1.8 µm (mean standard deviation) in terms of aerosolization, which is aided by the penetration of the particles deeper into the lungs.
An expert opinion on respiratory delivery of high dose powders for lung infections
Published in Expert Opinion on Drug Delivery, 2022
Bishal Raj Adhikari, Jack Dummer, Keith C. Gordon, Shyamal C. Das
The spray freeze drying process involves two distinct steps. The first step is the spray freezing in which a solution is atomized into liquid nitrogen, and the second step is the freeze drying of the frozen droplets [68]. Freeze drying involves removal of solvent in low temperature and pressure; hence the solvent from the frozen droplets is sublimed leaving behind porous solid particles. Such porous particles would be expected to reach deeper into the lungs due to their low density, which can decrease chances of inertial impaction (equations 3–5). For example, preparation of voriconazole dry powder (80% w/w) with mannitol has been reported using spray freeze drying [69]. Here, the FPF was ~40%. As inhalation of voriconazole (in dose of ~40 mg 2–3 times a day) was reported to be effective in treating pulmonary aspergillosis, inhalation of ~125 mg of voriconazole/mannitol formulation would be required for the treatment.
Cryoprotectant choice and analyses of freeze-drying drug suspension of nanoparticles with functional stabilisers
Published in Journal of Microencapsulation, 2018
Lulu Wang, Yingying Ma, Yu Gu, Yangyang Liu, Juan Zhao, Beibei Yan, Yancai Wang
Freeze-drying method has been the highlight to stabilise and handle colloidal systems (Hirsjärvi et al.2006). One of the purpose of freeze-drying is to prong the storage time of product and keep its stability (Bildstein et al.2009). Hence, a solid state product is easily to get by freeze-drying method and it would be readily re-dispersable when needed. Freeze-drying is a dehydration process through sublimation. That corresponds to three processes, freezing, primary drying, and secondary drying (Chung et al.2012). The water is removed from ice by sublimation and then desorbed of unfrozen water under vacuum (Bozdag et al.2005). During this process, freezing and desiccation stresses are generated, and there would be likely increasing the aggregation of nanoparticles and instability (Fonte et al.2016). Besides the system of nanoparticles, the freezing-drying conditions should be mainly considered.
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