Microwave broccoli seeds to create sulforaphane

Two sulforaphane topics came up in discussions with my traveling companion. Our first was an inference:

  1. 3-day-old broccoli sprouts have the optimal yields found that broccoli sprout sulforaphane content (after processing for analysis) ranged from 46% to 97% of broccoli seeds.
  2. Microwave broccoli to increase sulforaphane levels found that microwaving broccoli florets to 60°C (140°F) increased the sulforaphane amount from .22 to 2.45 µmol / g (1,114%!!).
  3. Wouldn’t broccoli seeds’ sulforaphane be more than broccoli sprouts by microwaving seeds up to 60°C in the same amount of water?

The 3-day study broccoli sprout measurements were relative to each variety’s seeds:

“To be comparable, the content of these bioactive compounds from 100 fresh sprouts was divided by the weight (gram) of 100 seeds, and then this value was compared with their content from one gram seeds.”

Broccoli compounds are similar among broccoli florets, sprouts, and seeds. A major difference is that broccoli sprouts and seeds have no initial sulforaphane content because hydrolization hasn’t occurred yet. The above graphic’s seed and sprout sulforaphane content was created by processing for analysis.

I’ll reason that sulforaphane would be created by:

  • Microwaving one tablespoon of broccoli seeds with a 1000W microwave in 100 ml of distilled water for 30 seconds to ≤ 60°C; then
  • Straining out the water; then
  • Allowing further myrosinase hydrolization of glucoraphanin and other glucosinolates into sulforaphane and other healthy compounds.

Broccoli seeds are dry, and microwaving acts directly on a material’s water content. The 3-day study methods “immersed [broccoli seeds] in distilled water and soaked at 30°C for 2 h” to start germination. I’ll stipulate two hours as a minimum broccoli seed soaking time before microwaving.

I’ve tried microwaving broccoli seeds five times so far to see if they’re palatable. Seeds soaked for at least two hours then microwaved for 30 seconds swell to almost twice their dry size. They’re easier to strain, chew thoroughly to ensure hydrolization, and swallow.

The 3-day study also found “total phenolic and flavonoid contents in sprouts were 1.12 to 3.58 times higher than seeds.” I won’t stop eating broccoli sprouts, but sometimes it may be expedient to reduce a 72-hour preparation time to 2 hours and still benefit from sulforaphane and other healthy broccoli compounds.

Let’s use Estimating daily consumption of broccoli sprout compounds runt-of-the-litter calculations and assumptions to make a worst-case estimate of sulforaphane content in one tablespoon of broccoli seeds:

  • Broccoli seed weight of one tablespoon is 10.7 grams.
  • Worst-case sulforaphane weight in one tablespoon of broccoli seeds (10.7 g x 2.43 mg sulforaphane per gram of seeds) = 26.0 mg.

I won’t calculate sulforaphane weight after microwaving because part of the 3-day study processing for analysis was:

“Broccoli seeds were comminuted by analysis grinder. Seed powder (0.5g) was immersed in distilled water at 55 °C for 5 min to inactivate the epithiospecifier protein.”

Grinding seeds into powder then heating it probably incorporates any effects of microwaving intact broccoli seeds up to 60°C.

Our second discussion topic came by gathering study data from Broccoli or Sulforaphane: Is It the Source or Dose That Matters?

Assessing these 200 μmol amount / 35 mg weight sulforaphane supplement dose studies:

  1. Peak plasma statistics ranged from 0.5 μmol in Row 2 (n = 20) to 2.15 (n = 4) μmol in Row 1. Row 4 (n = 10) statistics don’t show it, but its individual peak plasma ranges per the below graphic were 0.359 μmol to 2.032 μmol. Coincidentally, the Row 4 subject (#2) who had the lowest peak plasma amount also had the lowest urinary % of dose excreted (also termed bioavailability) of 19.5%, and the Row 4 subject (#8) who had the highest peak plasma amount also had the highest sulforaphane bioavailability of 86.9%.
  2. From the Row 4 study: “The half-life of SF in the body was 2.07 ± 0.26 h as calculated from serum area-under-the-curve determinations.” Its Subject #2 had the longest sulforaphane half-life at 2.709 hours.
  3. The peak time after dose ranged from 1 to 3 hours. Not sure why Row 4 didn’t calculate a peak time, but eyeballing the above graphic showed that all subjects peaked between 1 and 2 hours. Row 2’s time was at the study’s first of three measurement intervals (3, 6, and 12 hours). Its peak time after dose probably also took place between 1 and 2 hours.

These four studies showed that there’s wide variation among individual responses to sulforaphane supplements. Row 4 study’s Concluding Remarks ended with:

“Innate metabolic differences must not be discounted when assessing the metabolism of SF alone, delivered in supplements.”

The first of A pair of broccoli sprout studies was Row 2 (n = 20) above. Its sulforaphane supplement statistics – repeated in the below graphic’s BSE (broccoli sprout extract) column – demonstrated how humans’ sulforaphane supplement metabolic profiles were different than our fresh broccoli sprout metabolic profiles:

The divided dose was twelve hours apart at breakfast and dinner times. Also, its first measurements weren’t taken until 3 hours after ingesting, which explains its later times with lesser amounts than the above sulforaphane supplement studies’ earlier times with greater amounts.

During Week 9 of Changing to a youthful phenotype with broccoli sprouts I changed my practices to eat microwaved broccoli sprouts at breakfast and dinner times from its finding:

“In sprout consumers, plasma concentrations were 2.4-fold higher after consuming the second dose than after the first dose.”

A metabolic profile resulting from my current practices is probably between the Sprout and BSE divided-dose statistics:

  • Sulforaphane intake is greater than eating raw broccoli sprouts because microwaving 3-day-old broccoli sprouts creates sulforaphane in them before eating.
  • Sulforaphane uptake from microwaved broccoli sprouts is quicker than eating raw broccoli sprouts. It may not be as immediate as taking sulforaphane supplements, which are usually powders.
  • Sulforaphane dose from microwaved broccoli sprouts is less dependent on an individual’s metabolism than eating raw broccoli sprouts.
  • Sulforaphane release from microwaved broccoli sprouts probably continues on to the gut as does eating raw broccoli sprouts. Sulforaphane release from supplements may not per Does sulforaphane reach the colon?.

The microwaving study processed 10 grams of broccoli florets immersed in 500 ml water with a 950W microwave on full power for 108 seconds to achieve 60°C. I microwave 65.5 grams of 3-day-old broccoli sprouts immersed in 100 ml water with a 1000W microwave on full power for 35 seconds to ≤ 60°C.

After microwaving I wait five minutes to allow further myrosinase hydrolization of glucoraphanin and other glucosinolates into sulforaphane and other healthy compounds. Enhancing sulforaphane content provided evidence that myrosinase hydrolization peaks at one minute after achieving 60°C per the below graphic:

I interpret the above sulforaphane degradation from minutes 1 to 5 to be leaching caused by leaving the broccoli sample immersed in water. I strain water from broccoli sprouts after microwaving – the Time 0 mark of the above graphic – because without leaching water, further hydrolization may increase sulforaphane.

Sulforaphane supplements:

  • Are readily metabolized,
  • Blood plasma levels peak by two hours, and
  • Blood plasma levels dissipate by eight hours.

To the extent a metabolism resulting from my current practices is closer to a sulforaphane supplement profile than a raw broccoli sprouts profile, maybe that leaves the door open to a microwaved broccoli seed dose at lunch time? In any event, there are seeds in each batch that don’t germinate after soaking for 12 hours and rinsing three times a day, and I eat them after microwaving anyway.

See Caution on broccoli seed erucic acid content? if you’re concerned about that.


46 thoughts on “Microwave broccoli seeds to create sulforaphane

  1. Hi, I’m looking to get some broccoli seeds. I see your chart states that the variety named ‘MNL’ has the most glucoraphanin that produces sulforaphane so please can you let me know what MNL stands for as I am looking to get some? Thanks.

    • Good question Chris! The 3-day study only said “Broccoli seeds of six varieties were purchased from a local market (Lv Wa Wa, LWW; You Ji Qing Hua Cai, YJ; Yi Dai Lv Tan, YDLT; Ma Ni La, MNL; Xi Mei, XM; Lv Yu, LY).” Local meant Xi’an China.
      Broccoli seed vendors are missing an opportunity to market their product with evidence.

  2. So if i just consume a table spoon of brocoli seeds i will get approx 26 mg of sulforaphane? Most supplement contain 400 micrograms lol 😀 Are they easy to chew after soaking? I have a hand blender i don;t know if i could blend them with it

    • Hi John! Thanks for commenting.
      Yes, using the worst case from the 3-day study. Soak a few hours then microwave them to not more than 60C. The times I’ve sampled haven’t had unpleasant tastes.
      Don’t know about a blender. Chewing thoroughly to mix the enzyme and glucoraphanin used to be required of study subjects before researchers moved to extracts and supplements.

    • Sure, Kareem! Just be careful about the temperature.
      Further down in this blog post is a chart showing myrosinase robustly hydrolyzes glucoraphanin into sulforaphane at 60°C. There’s clearly a myrosinase deactivation cliff between 60°C and 65°C.
      I use a 1000W microwave because of Microwave broccoli to increase sulforaphane levels findings. That blog post has a chart that shows at 60°C, a 950W microwave produces more sulforaphane than does a 475W microwave. Cell disruption caused by a higher power microwave adds to the 60°C sulforaphane results by releasing more myrosinase and glucoraphanin.

    • Thanks for commenting Mr. Tonne!
      I noticed that Beneforté is grown and distributed by a division of Monsanto / Bayer. I’d expect them to be treated with insecticides, fungicides, dyes or bulking agents for planting rather than home sprouting.
      My latest purchase was a 5 lb can of “Organic Broccoli Sprouting Seeds by Handy Pantry” (True Leaf) for $90. The company is clueless about their own product, but I’ve benefited from it.

      • I’m sorry. I seemed to have missed something. Is there something special about the Handy Pantry seeds or is it just that their organic seeds are a bargain relative to supplements?

        Thanks for all the info!

  3. Hey there, amazing stuff! Can we say whether deciding not to chew the seeds would make us miss out on much of the benefits? Not exactly loving the taste 🙂

      • Hey, one more question: Do you have an estimation on the importance of the temperature of the water we soak the seeds in? Thanks in advance.

        • Good question, Ulf! I’ve asked that about oat sprouts but not broccoli sprouts.
          The 3-day-old broccoli sprouts have the optimal yields study soaked at 30°C but only for two hours. Then sprouts grew in an incubator at 25°C and unspecified relative humidity, maybe 90+%?
          I’ve noticed that broccoli sprout and oat sprout batches grow well and more consistently now that it’s summer, and my kitchen is around 26°C and 70% relative humidity. In winter when the kitchen was closer to 21°C and 30% relative humidity, sometimes a 3-day-old batch ended up being not much different than seeds.

  4. Have you reviewed the recent work of Albert Wright PhD that adds ground mustard seed to heated ground broccoli seeds for creating a tincture/or tea? What are your thoughts?

    • Hi Ms. Lindberg! Thanks for commenting.
      Dr. Wright knows what he’s doing, and has a big stake in his research outcomes.
      I don’t have any diseases other than aging. I tried adding 2% ground mustard seed per Does sulforaphane reach the colon? with a much larger dose of sulforaphane in microwaved broccoli sprouts than what Dr. Wright uses. My gut said that wasn’t for me.

      • Ah yes, It’s a weird feeling for the GI system-but for ppl like me w Parkinson’s that’s ok! Doesn’t It cross the Blood Brain barrier? As to Colon,I do not know. I feel energetic when I take it as a tea- if it’s placebo or real, it’s got added value to my regimen. Less medicine, more plants 🌱

        • Hi Ms. Lindberg! I read but didn’t curate the 2021 https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0248777 “Sulforaphane (SFA) protects neuronal cells from oxygen & glucose deprivation (OGD)” study.
          In that they assert “SFA can cross the blood-brain and placental barrier.” Not sure they provided sufficient evidence, though.
          I also feel energized by sulforaphane intake now that I don’t eat anything an hour before or an hour after eating microwaved broccoli sprouts. Switching to that practice helped isolate Nrf2 and other pathways’ activation effects. Prefer it to coffee when waking up.

          • For expediency, can you distill the method and measures for simply heating and eating the seeds for best health benefit-I trust your science, I just want to bypass the sprouting and get right to the seed. Eating is preferred to pulverizing them to drink as a tea extract (more steps involved).

            • Hi Ms. Lindberg! The third study in Microwaving broccoli sprouts may not affect phenolic levels had good results with another glucosinolate hydrolysis product, indole-3-carbinol. They blended 100 grams broccoli in 200 ml water, halved the purée, then microwaved half on 700W power for 30 seconds. No disclosure of what temperature was achieved, but it was probably < 60°C (140°F). They found:
              “I3C in broccoli was increased by 3.1, 9.1 and 1.9 folds respectively using blenders 1, 2 and 5 with microwaving.”
              I haven't tried it, but it makes sense that blending and microwaving broccoli seeds would similarly increase other glucosinolate hydrolysis products like sulforaphane.

                • Hi Ms. Lindberg! I still don’t blend sprouts because of proximity to neighbors. How about you?
                  I switched in Week 87 to a mix of broccoli / red cabbage / mustard 3-day-old microwaved sprouts started with 3.6 g / 3.6 g / 3.5 g of seeds. Also eat them just once a day, usually right after coming home from walking the beach at sunrise.
                  Currently in Week 124 of eating a clinically relevant dose of sulforaphane every day. Had an annual physical three weeks ago with very good lab tests. Kind of boring, but I don’t see a reason to stop.

  5. Just two questions.
    1. Instead of using microwave, can we just put them in a warm water (+/- 60°C)? – with a thermomeyrt it is alot more accurate

    2. The 26 mg sulforaphane….., is that your daily take? Isn’t too much. I thought it wad 400 mcg.

  6. Just two questions.
    1. Instead of using microwave, can we just put them in a warm water (+/- 60°C)? – with a thermometer it is alot more accurate

    2. The 26 mg sulforaphane….., is that your daily take? Isn’t too much. I thought it was 400 mcg.


  7. So, wondering if i got this right

    Leave 10 grams of broccoli sprout seeds in water for 2 hours

    Microwave to <= 60 degrees celsius

    Leave it in the water for 5 minutes

    Use a sieve for the water

    Eat and chew thoughroughly

    • Yep. 🙂
      For disclosure, I microwave seeds as a backup plan in case sprouting encounters a problem. There are always plenty of unsprouted seeds after three days of coaxing.

      • Thank you for replying!!

        Got a couple more questions 😅

        Is 26 mg of sulforaphane alot for 10 grams of broccoli sprout seeds? or did i read the study wrong? Is 26 mg sfn before or after microwaving? Because i see that 100 grams of broccoli sprouts can have more than 200 mg? Even eating 100 gram of fresh broccoli can have way more than 26mg? Or is google wrong?

        Is eating 10 grams of seeds a day healthy? I see some comments on reddit about erucic acid that may be a problem?

  8. Thanks for the great work. I’ve been consuming a similar amount of sprouts for years except every other day. I microwave for 45 seconds and add ice water to cool, followed by blending. Taste is fairly horrible. Never any GI issues. I use 2 mason jars with strainer lid for my sprouting, rinse twice a day and leave tilted in a bowl to drain.

  9. Tribest PB-150. It’s a great little blender, don’t know if it’s even made anymore.
    I noticed if I microwave too long I don’t get that spicy taste, probably means myro getting destroyed by the heat?
    I microwave the sprouts inside the blender cup (16 oz) without water, then add cold water and blend.

    • Thanks, Joe! I looked it over and saw some attractive features like being able to use Mason jars.
      My son keeps on me to use a blender. If I used one this morning, though, I’d wake people up at 5:00 a.m.

  10. Can you clarify the broccoli seed method

    How do you know what settings to microwave them on to keep it under 60 degrees

    • Hi Tim! Thanks for commenting.
      I use a $5 candy thermometer to check. Start with 100 ml water to get a temperature range, then check with seeds.
      One thing I didn’t put into this post was that a large number of seeds don’t sprout. So even when I’m microwaving sprouts, I’m microwaving seeds that were given their chance to germinate.

        • Yes, sprouting to 3 days adds phenolic and flavonoid compounds, but reduces sulforaphane compared to seeds. Whatever people can do to keep up a consistent daily broccoli intake would be beneficial.

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