Rainy day thought for the 13th week of lockdown: What are methods of estimating the minimum contents of broccoli sprouts for those of us who aren’t willing to turn their kitchen into a laboratory?
With the 3-day-old broccoli sprouts have the optimal yields study as a reference, minimum values of the six broccoli cultivated varieties studied were:
- Lowest weight of 100 seeds: .33 grams.
- 100 of that cultivar’s 3-day-old sprouts weighed 1.55 grams.
- A different cultivar had the lowest total phenolics (gallic acid equivalents): 0.94 mg per gram of 3-day-old sprouts.
- That second cultivar also had the lowest total flavonoids (rutin equivalents): 1.02 mg per gram of 3-day-old sprouts.
- A third cultivar had the lowest weight of sulforaphane in its seeds: 2.43 mg per gram of seeds.
- Reduction of sulforaphane content during germination from seeds to 3-day-old sprouts is evident from the below chart. The only 3-day-old sprout chart number the study provided was the best case, though. I requested the study data, but in the meantime..I enlarged the chart, measured the worst cultivar as a 8.5 cm bar where the seed bar was 16 cm. Its 3-day-old sprout sulforaphane yield was ~53% of its seed yield.
Another caveat for contents: Researchers had to process broccoli seeds and 3-day-old broccoli sprouts in order to make measurements. Total phenolics and total flavonoids may not have been affected by processing. However, processing generated sulforaphane.
Broccoli seeds and 3-day-old broccoli 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 into sulforaphane.
I start out each daily batch with two tablespoons of broccoli seeds of an unknown cultivar. I counted 812 broccoli seeds in a teaspoon (yes, I did), and multiplied by 6 for 4,872 total seeds.
Runt-of-the-litter calculations for the six broccoli cultivars studied are:
- (4,872 / 100) x .33 g = 16.08 g broccoli seeds
- (4,872 / 100) x 1.55 g =75.52 g 3-day-old broccoli sprouts
- 75.52 x 0.94 mg per gram of 3-day-old sprouts = 70.99 mg total phenolics
- 75.52 x 1.02 mg per gram of 3-day-old sprouts = 77.03 mg total flavonoids
- 16.08 g broccoli seeds x 2.43 mg per gram of seeds = 39.07 mg sulforaphane
- 39.07 mg x 53% = 20.71 mg sulforaphane in 3-day-old broccoli sprouts
I’ll use the Microwave broccoli to increase sulforaphane levels study as a reference for an alternate sulforaphane calculation. The cultivar wasn’t mentioned, only that it was ordinary broccoli purchased in Silver Spring, Maryland, grocery stores.
- Week 6 of changing an inflammatory phenotype with broccoli sprouts discussions with a study author clarified that microwaving broccoli florets to 60°C (140°F) increased the sulforaphane amount from .22 to 2.45 µmol / g!!
- https://pubchem.ncbi.nlm.nih.gov/compound/sulforaphane lists sulforaphane’s molecular weight as 177.3 g / mol. A 5.64 μmol sulforaphane amount (.001 / 177.3) equals a 1 mg weight of sulforaphane.
- I currently microwave 3-day-old broccoli sprouts immersed in 175 ml of distilled water for 70 seconds in a 1000W microwave to achieve a 58°C temperature.
One assumption is that microwaving broccoli sprouts will have the same effects as microwaving broccoli florets to increase sulforaphane content. Are the similarities between broccoli floret and broccoli sprout characteristics enough to say whether or not that’s a valid assumption?
Another assumption is that there’s no beginning amount of sulforaphane in 3-day-old broccoli sprouts. Microwaving them on full power to 60°C produces all of the sulforaphane.
A third assumption is that the sulforaphane increase from .22 to 2.45 µmol / g of the tested cultivar fairly represents other broccoli cultivars.
Combining this with the worst-case calculated weight of 3-day-old broccoli sprouts in the first study:
((2.45 – .22 µmol / g)
x 75.52 g 3-day-old broccoli sprouts)
/ 5.64 μmol conversion of amount to weight
= 29.86 mg sulforaphane
“The daily SFN [sulforaphane] dose found to achieve beneficial outcomes in most of the available clinical trials is around 20-40 mg.”
I’ll guess that my daily consumption of broccoli sprout compounds is at least in this clinical trial range with worst-case calculations of 20.71 and 29.86 mg sulforaphane in 3-day-old broccoli sprouts. I’ll include this estimate in Week 8 of changing to a youthful phenotype with broccoli sprouts.
Broccoli seed suppliers are missing a marketing opportunity by not specifying their cultivars. They could be advertising specific benefits, etc.
The first study showed that sulforaphane contents vary widely among broccoli cultivars, from the 2.43 mg used above to 12.07 mg per gram of seeds. If your product was almost 5 times better than a competitor’s, why wouldn’t you advertise it?