Seed to Table: Hemp Seed Production and Processing
Learn about the cultivation, harvesting, and further processing that transforms industrial hemp seeds into hemp protein powder.
Prducers across the globe cultivate hemp as a crop for its manifold applications—fibre and hurds are extracted from the stalks to produce textiles and paper; oil, hemp cake, and hemp nuts derived from the seeds are used in dietary supplements, flours, animal feed, and protein powders; the plant's roots are utilised for medicine and compost; its leaves and flowers provide bedding for animals, mulch for land, and medicine for people. In this article, we take a brief look at the steps that go into the production and processing of hemp seeds.
Today, Europe accounts for around 25% of hemp crops around the world. Approximately 40% of Europe’s hemp is cultivated in France alone. High volumes are also cultivated in Estonia, The Netherlands, Romania, Lithuania, and Italy. Hemp is an annual crop valued across by farmers and industry players alike for its durable plants and notably high yields. Generally, industrial hemp is divided into two cultivar types: so-called ‘fibre cultivars’, which have long stalks and minimal branching, and ‘seed cultivars’ which are characterised by their short stalks, large seed heads, and higher branch density. Depending on the species and growing conditions, hemp plants can grow up to 1.3 - 5 metres in height. Hemp crops thrive in nitrogen-rich, non-acidic, well-drained soil with a minimum pH of 6.
On some farms, workers still hand-cut hemp plants using special cutters or tobacco knives to ensure the plants can be harvested with the utmost precision and care. Because of the labour-intensive and time-consuming nature of this approach, many large-scale hemp seed farmers opt for specially modified harvesting equipment, called combine harvesters. These machines are equipped with rows of teeth and choppers which can remove the heads for flower and seed processing and cut the stalks for fibre processing. This process is called ‘threshing’. Generally, seed cultivars are deemed ready for harvesting when the seeds start to shatter.
Cleaning, Screening, Grading, Milling & Dehulling
Once the plants have been harvested, they are transported off the fields and stored indoors to be cleaned carefully and dried under optimal conditions. Processors utilise a range of techniques for cleaning, including mechanical screening (sieving), grading, and gravity separation. In one example, the seeds pass through two different sized sieves before being sent through a fanning mill. In a further example, a hemp seed grader separates the seeds according to their size, thereby allowing processors to allocate batches of sorted seeds to further processing according to their applications. When hemp seeds are cultivated for food processing, they also undergo a process called ‘dehulling’ which encompasses the manual or mechanical removal of the seeds’ outer shells. Producers work carefully to minimise the damage inflicted on the inner seeds, thereby maintaining their quality and integrity. Next, the hemp oil is extracted, resulting in a by-product known as hemp cake or hemp meal, which is the base substance used for the production of hemp protein powder. Hemp protein powder is usually milled before being screened to separate the fine powder substance forms its coarser fibre counterparts.
Drying storage and mechanisms differ vastly between operations and include everything from barns and dehumidifiers, sheds and fans to racks and mechanical dryers. Once the seeds have reached an adequately dry state, they are transported to food processors for further production and packaging. In the cosmetics industry, hemp sometimes undergoes further refining and deodorising processes.
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Imagery: (1, 3) unsplash.com; (2) medium.com; (4) source unknown