A study has found microwave pre-treatment of hemp seed makes several improvements in subsequent oil extraction.
Hemp seed oil is extracted by high temperature pressing or cold pressing hemp seed, which is then filtered to remove sediment. Cold-pressed oils have a grassy and fresh flavor, while hot-pressed oils have a smoky, nutty, and roasted taste.
Light to dark green, hemp seed oil may be refined further, becoming a lighter, golden colour. In food applications, it’s often used in recipes where olive oil is called for. Nutritionally speaking, hemp seed oil is rich in essential fatty acids, and contains a wide range of other nutrients.
In ongoing efforts to improve yields, quality and taste from oilseed pressing, an approach that has seen significant research interest is the use of microwave technology in conjunction with or prior to processing.
Looking to fill a gap in knowledge of the impacts of the process on hemp seed, researchers at the School of Food Science and Technology, Shenyang Normal University in China tinkered with microwave pre-treatment of seed prior to pressing. This involved heating seed at various temperatures, timeframes and microwave power ratings, and the use of a digital mechanical stirring system.
The results:
- Oil yields of microwave-treated hemp seeds (79.06% to 85.25%) were significantly higher than those of non-microwave-treated hemp seeds (57.88%).
- Highest yield was reached when the microwave power was 850 W over 2 minutes.
- The microwave pre-treatment improved oxidative stability of hemp seed oil.
- Pre-treatment enriches hemp seed oil flavour.
“The results showed that microwave pre-treatment improved the quality characteristics of hemp seed oil and affected the flavour of hemp seed oil, while metabolomics approaches have great potential for the authentication of hemp seed oil,” state the authors.
The study has been published in the journal Industrial Crops and Products.
High quality food grade oil is just one of the many uses of industrial hemp. Hemp seed oil shouldn’t be confused with hemp oil, which is extracted from the flowering heads of the plant and can be high in cannabinoids such as cannabidiol (CBD). The seed contains only traces of CBD, so lacks the therapeutic potential attributed to this cannabinoid.
