To follow up two points of Lab analyses of broccoli sprout compounds:
3. Without knowing the broccoli sprouts’ cultivar, could a person infer from a glucoraphanin amount how much sulforaphane they would consume?
No. The 2014 Iron Man 5.2 μmol per g glucoraphanin wasn’t that different from the 2015 Sirtaki 5.4 amount. But Iron Man vs. Sirtaki differences of 0.3 vs. 0.6 μmol per g sulforaphane amounts and 5% vs. 11% hydrolyzed showed Sirtaki cultivar had double or more those of Iron Man.
4. Could a person infer from a mature broccoli glucoraphanin amount anything about its broccoli sprout glucoraphanin amount, or vice versa?
No. The Sirtaki 8.0 μmol per g sprout glucoraphanin amount was the highest cultivar, but its fully developed head was lowest at 0.27.
Studies often tailor their measurements to interests of either their sponsor or audience. This tailoring may leave gaps in what people outside of their target audience want to know.
Item 3 showed that sprout glucoraphanin amount can’t be relied upon to infer sprout sulforaphane amount because the hydrolysis process may be cultivar specific. The 3-day-old broccoli sprouts have the optimal yields study showed this result was also true using seed glucoraphanin and sulforaphane measurements.
Item 4 showed cultivar comparative measurements of glucoraphanin and sulforaphane made with broccoli florets may be the opposite of broccoli seed and sprout measurements. We should use studies that measured compounds in broccoli seeds and / or sprouts because we’re interested in eating broccoli sprouts.
A problem arises when studies compare cultivars using seed or sprout glucoraphanin but not also sulforaphane. We can’t ignore Item 3’s findings and automatically prefer a cultivar that has a higher glucoraphanin amount.
Repeating a point from Estimating daily consumption of broccoli sprout compounds, broccoli seeds and sprouts contain little or no sulforaphane. They have glucoraphanin and myrosinase enzyme which are structurally separated. Disturbing their cells mixes the two, and the enzyme hydrolyzes glucoraphanin and other glucosinolates into sulforaphane and other healthy compounds.
So if a study’s processing is what creates sulforaphane, what can we do with study findings if researchers didn’t bother to also measure that sulforaphane? I’ll guess that substantial differences in glucoraphanin seed or sprout amounts could be used as rough guides for sulforaphane amounts.
Looking at the above 2014 sprout amounts, a Iron Man 5.2 vs. Marathon 4.0 μmol per g glucoraphanin difference didn’t result in their 0.3 sulforaphane amounts being different. As a rough guide for home gardens, a 1.3 (5.2 / 4.0) ratio could be used as a threshold.
Broccoli seed glucoraphanin amounts in this 2004 table from Glucoraphanin and 4-Hydroxyglucobrassicin Contents in Seeds of 59 Cultivars of Broccoli, Raab, Kohlrabi, Radish, Cauliflower, Brussels Sprouts, Kale, and Cabbage (not freely available) are sorted by higher-to-lower glucoraphanin (GR) amounts per cultivar. Marathon can be found at 59.81 μmol per g. A threshold of 78 μmol per g (59.81 x 1.3) would roughly guide planting cultivars Premium Crop down to Monterey, depending on their availability 16 years later in 2020.
We’d like to plant broccoli cultivars that have laboratory results so we could expect comparatively higher sulforaphane from their seeds and sprouts. I’ve contacted broccoli seed suppliers for commercial growers and home gardeners, and asked them for lab evidence of their offered cultivar’s sulforaphane contents. Haven’t received responses yet. When they respond, we’ll have to clarify whether those lab results are from seeds or tailored to mature plant’s florets in order for us to reliably use them.
Broccoli seeds intended for commercial growers and home gardeners are prohibitively expensive for home sprouting. If such a supplier did sell in bulk at much lower prices, unless otherwise specified, seeds are expected to be treated with insecticides, fungicides, dyes or bulking agents.
Home sprouting has to deal with unknown cultivar, unknown glucoraphanin, and unknown sulforaphane. Even so, I’ve documented good results from eating broccoli sprouts every day for 8 weeks. A worst-case estimate of 52 mg sulforaphane with microwaving 3-day-old broccoli sprouts exceeds:
“The daily SFN [sulforaphane] dose found to achieve beneficial outcomes in most of the available clinical trials is around 20-40 mg.”
Current growing and preparation processes of microwaving to achieve 60° C, transferring broccoli sprouts to a strainer, and allowing further myrosinase hydrolization of glucoraphanin into sulforaphane compensate for some degree of these uncertainties. It would still be better, though, to know which cultivar is purchased along with lab reports of its compounds’ characteristics.
Let’s say that one day, bulk broccoli seed suppliers start advertising cultivated variety (and Calabrese isn’t a cultivar). We have Marathon in both a lab analysis and a seed glucoraphanin list to help inform our decisions.
Would I pay extra for seeds of cultivars substantially below Marathon in the glucoraphanin list like common cultivars DeCicco and Waltham 29? No, I’m doing fine changing my phenotype despite unknowns. The advertised cultivar would have to be substantially above Marathon to consider a purchase.