Source
doi:10.1186/s42238-022-00156-7 — original publication (opens in a new tab; the file is not redistributed)
Burton et al. (2022) — Industrial hemp seed: a review
The only evidence on mechanical-press residual oil in corpus, and it is hemp-specific and non-NZ
Journal of Cannabis Research 4:45 · Australian authors, drawing on Canadian / Italian / Finnish data. Verbatim: “After expelling the oil using a screw press, the oil content in the residue obtained has 8.4–15.5% oil… while the oil content in the de-lipidated hemp meal after solvent extraction is expected to be much lower (~1% oil).” Terminology that prevents a category error, verbatim: “hemp seed cake should refer to product obtained after mechanical pressing… hemp seed meal is obtained after solvent extraction.” 🔴 This is NOT a general recovery fraction and is NOT crop-transferable. It is residual oil in hemp cake, from non-NZ data. It does not resolve the cross-cutting screw-press recovery gap (RT_391), and no recovery fraction has been derived from it here.
Summary
A review of industrial hemp seed as a food and feed resource, covering composition, processing and the products of oil extraction. The authors are Australian and the underlying data are Canadian, Italian and Finnish; there is no New Zealand content.
Its relevance to Neobiome is narrow and specific: across the entire NZ oil-crop lane, every NZ figure is oil in the seed, not oil recovered, and the general primary that would settle the recovery question (Singh & Bargale 2000, J. Food Engineering) is paywalled and has not been obtained. This paper is the only source in corpus that says anything measured about what a screw press leaves behind. It is not enough to close the gap, being hemp-specific and non-NZ, but it establishes the shape of the answer (mechanical pressing leaves a materially oil-rich cake; solvent extraction does not) and supplies the terminology that keeps cake and meal apart.
Key claims
- claim: "RESIDUAL OIL AFTER MECHANICAL PRESSING vs SOLVENT EXTRACTION, verbatim: 'After expelling the oil using a screw press, the oil content in the residue obtained has 8.4-15.5% oil… while the oil content in the de-lipidated hemp meal after solvent extraction is expected to be much lower (~1% oil).' [verified verbatim against the source]"
source_location: "Burton RA et al. (2022), Journal of Cannabis Research 4:45 — hemp seed oil extraction / by-products section."
- claim: "TERMINOLOGY THAT PREVENTS A CATEGORY ERROR, verbatim: 'hemp seed cake should refer to product obtained after mechanical pressing… hemp seed meal is obtained after solvent extraction.' [verified verbatim against the source]"
source_location: "Burton RA et al. (2022), Journal of Cannabis Research 4:45 — by-product nomenclature."
- claim: "⚠ SCOPE: NON-NZ (Australian authors; Canadian, Italian and Finnish data) and HEMP-SPECIFIC. This is not a general screw-press recovery fraction and is not crop-transferable. No recovery fraction has been derived from these figures."
source_location: "Burton RA et al. (2022), Journal of Cannabis Research 4:45 — authorship and data provenance."Neobiome Intelligence relevance
Feeds d02_smart_food_systems as the only evidence in corpus bearing on the cross-cutting recovery gap, while explicitly NOT closing it.
What it establishes:
- Mechanical pressing leaves a materially oil-rich residue. A screw-press cake retains 8.4–15.5% oil, against ~1% after solvent extraction. Whatever the true recovery fraction is for a community-scale press, it is meaningfully below 100%, and the gap is not negligible.
- The cake is a by-product with residual value. For a community, screw-press cake at 8.4–15.5% oil is a feed input, not waste — a point that matters for whole-system accounting even though it is hemp-specific.
- Cake ≠ meal. The terminology is worth holding: literature figures for “meal” describe solvent-extracted material a community would not produce.
What it does NOT establish — stated plainly because the temptation is real:
- 🔴 It is not a recovery fraction. Residual oil in the cake is not the same quantity as the fraction of seed oil recovered, and converting between them requires the seed’s own oil content and the cake’s mass fraction, neither of which is used here. No such conversion has been performed. RT_391 stays open.
- 🔴 It is hemp-specific. Oilseed rape, olive, hazelnut and walnut presses behave differently. Applying 8.4–15.5% across crops would be an unfounded transfer.
- 🔴 It is non-NZ.
topics:deliberately excludesnz_specific.
Interaction with the existing hemp evidence in corpus. NZ hemp is already covered on the oil path — measured seed oil content 30.9–32.5 g/100 g (LIT_089), measured NZ seed yields (OT_168, LIT_089) and compiled ranges (OT_112, OT_169). This source adds the processing by-product leg to that picture, from overseas data. Hemp’s existing NZ parameters are unchanged.
No engine cell is auto-changed by this ingest.
Notes
- Ingested for a negative as much as a positive. Its most important function is to be the source that people would reach for to fill RT_391 — and to carry, on its own page, the reasons it does not fill it. That is cheaper than re-litigating the question later.
topics:excludesnz_specificdeliberately. Non-NZ data on a non-NZ crop-processing question.- Vintage: 2022, current.
- Retrieval: HTML capture of the open-access article.
Research targets
Documents to retrieve
- (none new) — the screw-press recovery gap is raised as RT_391 at LIT_095 and is deliberately not duplicated here. This source is cross-referenced from that target as the only retrieved (but insufficient) evidence.
Research gaps
- Not raised as research targets (recorded here instead):
- A crop-general small-press recovery fraction. Covered by RT_391.
- The value of press cake as a community feed input. Genuinely interesting for whole-system accounting (a hemp cake at 8.4–15.5% oil is a livestock feed, closing an oil→feed loop) but not currently modelled and not NZ-quantified.
Connections
Links to
Referenced by
EDT domains (1): D02: Smart Food Systems & Agriculture
Sources (1): LIT_095