In aromatic plants' literature both these terms have been used to express the recovery of essential oil (as a percentage) from fresh or dry biomass of aromatic plants. In field experiments agronomists, soil scientists and plant breeders have expressed the essential oil yield (kg or lit per hectare or acre) by multiplying the biomass yield/ha or ac with essential oil content and density/specific gravity of the oil. Any suggestions or remarks?
In my opinion data expressed as "percent concentration" instead of "content per unit mass harvested" is a better depiction. Extrapolation of lab level biomass and oil concentration data on per ha basis is dangerous and often missguided. It is more advisable to follow such conversion on the basis of at least bench level replicated plantation in minimum of 500 m2 of plantation. This is likely to be more close to actual recovery in farmers' field during commercial cultivation. Ideally, this information must accompany the mention if geographic location, season & and soil health data of area of study to be very precise of our breeding claims or agro-technology package.
Essential oil content is the mixture of complex substances, while yield depicts oil in grams/100gm of material used for extraction. Here yield per hectare can not be enumerated exactly, but rough estimation can be made by using oil mass/biomass weight. Oil in single plant biomass X number of plants per acre of land will provide an rough estimate, because yield of essential depends on extraction device and conditions maintained.
I agree with Prof Ravi. As content is always depend on total volatile composition of the substance, where as yield always given in % of mass obtained after using particular mass.
Also, plant essential oil content can be difficult to extract (without inducing too many transformations during process) if secretory structures are located deep inside plant organs (such as woody stems). Thus, content (usable by the plant) is different than yield of extraction.
In my opinion data expressed as "percent concentration" instead of "content per unit mass harvested" is a better depiction. Extrapolation of lab level biomass and oil concentration data on per ha basis is dangerous and often missguided. It is more advisable to follow such conversion on the basis of at least bench level replicated plantation in minimum of 500 m2 of plantation. This is likely to be more close to actual recovery in farmers' field during commercial cultivation. Ideally, this information must accompany the mention if geographic location, season & and soil health data of area of study to be very precise of our breeding claims or agro-technology package.
I think there is no confusion among the members on the definition of the term ‘essential oil content’. In general, all are saying that amount of essential oil obtained from a given amount of herb is known as essential oil content (volume/weight or weight/weight). It is generally expressed in percent value (%). I also agree with this definition.
However, there are differences of opinion in defining the essential oil yield. In practice, researchers of Agriculture background are calculating essential oil yield (per unit area) by multiplying herb yield with essential oil content as also mentioned by Prof. Rao and Dr. Singh.
In my opinion, essential oil content and essential oil yield are the terms, which sounding the same meaning. Both are used to express amount of oil (extract) obtained from a given amount of herb. These values may be presented as amount (mL or g) per 100 g, per kg, per quintal, and so on. Thus, the yield is depending upon the amount of biomass processed (if other factors, like plant stage/season etc. are kept constant) not exactly on the area of field harvested.
Moreover, the term ‘essential oil yield’ used by the researchers for depicting the essential oil quantity produced per unit area (ha or acre) is not precise and in my opinion it should be replaced by ‘essential oil productivity’.
I find the discuccion somewhat hairsplitting. Yield is always what you can isolate from the material by various methods (water distillation, extraction for essentila oil compounds) and what you finally have in your hand; the yield for essential oils is normally given as mL/100 g (dry or fresh material).Because the different methods result in different yields, every information on a yield should be accompanied by the method used (e.g.: 5 mL/100 g dry material by watersteam distillation).
Content is the real content of (here) an essentuial oil of the relative plant (part). Often it is not possible to isolate all volative compounds from the plant material (for several reasons, most morphological reasons). Then you may calculate the real content on the basis of moprhological/microscopical characters such as the seize and number of glands, or excretion reservoirs. Also if you use dried plant material, a certain part of the volatiles may alredady be disappeared by evaporation. You may conclude from this information that the real content of any essential oil of a plant/plant part cannot easily be determined.
I am still confused about oil yield. Is that not the amount of seeds(kg/ha) multiplied by percentage oil content of seed and also multiplied by specific gravity of camelina sativa( specific gravity =0.935)?
I am talking about Camelina sativa. And want to know exactly how to calculate the oil yield
- Badges
- Science topic