Sprouting oats

Three 2020 studies investigated properties of sprouted oats. This first study compared one oat cultivar’s seed and sprout contents for phenolic compounds, and evaluated oat sprouts’ protection against developing colon cancer:

“The purpose of this investigation was to evaluate whether sprouted oats (SO) of the Turquesa variety still possessed effective physiologically bioactive compounds, i.e., phenolics, flavonoids, AVAs [avenanthramides], and phytosterols, and whether it exerted antioxidant and anti-inflammatory effects, as well as the capacity to improve relevant intestinal parameters, in an AOM [azoxymethane] / DSS [dextran sulfate sodium]-induced CRC [colorectal cancer] mouse model.

Suboptimal intake of whole grains (38 g/d) was associated with CRC burden across 16 European countries. An optimal intake of 50–100 g/d was considered in our study to establish the dose administered in the AOM/DSS-induced CRC mouse model (75 g/d).

Seeds (100 g) were soaked in distilled water for 12 h then watered daily. Temperature and relative humidity were set at 25 °C and 60%. Germination was performed in darkness for five days. Germination percentage was determined based on total number of fully emerged seedlings.

We reached 100% of germination and a radicle length of 6.47 ± 0.22 cm. Sprouts were dried at 50 °C for 12 h, milled to a particle size of 0.5 mm, and stored at 4 °C until analyses.

Protein and lipid contents were higher in SO, whereas carbohydrate and ash contents were lower. A more than four-fold increase [0.64 mg/g to 2.79 mg/g] in TPC [total phenolic compounds] was obtained after five days.

We identified AVA-D as the most abundant AVA, followed by AVA-L, which had not been reported as one of the three most abundant AVAs in other oat varieties. Of the three most abundant AVAs previously reported, only AVA-B had a higher abundance in germination.

Phytic acid, an antinutritional compound present in oats, was 10 times lower in oat sprouts. Phytic acid has its content decreased by 15%–35% during even a short three-day germination due to activation of phytase activity. Although high doses of phytic acid inhibit absorption of metals and minerals in humans, it has been observed that, in small doses, it can function as a protective factor in several chronic degenerative diseases.

Mice in groups 3 and 4 were gavaged every morning with phenolic-AVA extract (0.084 mg GAE) and 30 mg of SO, respectively. We observed a mild anti-inflammatory effect of SO and AVA treatments, and a reduced adenocarcinoma incidence of 52.5% and 21.3%, respectively.

SO was more efficient in activating the Keap1-Nrf2 signaling pathway compared to treatment with AVA. Oat phenolic compounds together with β-glucans may be acting synergistically, thus offering greater protection for cancer prevention and treatment.”

https://www.mdpi.com/2304-8158/9/2/169/htm “Chemopreventive Effect of the Germinated Oat and Its Phenolic-AVA Extract in Azoxymethane/Dextran Sulfate Sodium (AOM/DSS) Model of Colon Carcinogenesis in Mice”

The supplementary material developed this oat cultivar’s seed and sprout profiles for 138 phenolic compounds. It measured C-type AVAs, but not A-type AVAs.

This was my model study for Sprouting whole oats.

A second study was reviewed in Eat oats today! and repeated here:

“The first evaluation of anti-inflammation effects of A-type AVAs was published from our own group. Fifteen A-type AVAs from commercial sprouted oat products interacted with lipopolysaccharide-induced nitric oxide production and iNOS expression.”

https://pubs.acs.org/doi/full/10.1021/acs.jafc.9b06812 “Quantitative Analysis and Anti-inflammatory Activity Evaluation of the A-Type Avenanthramides in Commercial Sprouted Oat Products” (not freely available)

Oat variety and sprout age weren’t available for the six sprouted oat products tested, so oat seed-to-sprout comparisons weren’t possible. A-type AVA comparisons among products were performed, but weren’t meaningful due to unknown varieties, ages, product processing, and storage.

A third study compared four grains’ sprouted and unsprouted contents:

“Seeds were soaked at 25°C in 1 L of distilled water for 20 (brown rice), 12 (sorghum and millet) and 8 h (oat), respectively. Hydrated grains were allowed to germinate with layering over wet cellulose pads in a humid chamber for 60 h at 25°C (oat seeds) or 30°C (brown rice, sorghum, and millet seeds) with 95% relative humidity.

All seeds derived from brown rice and oat were germinated after 48 h in the humid chamber. Germinated grains were dried at 50°C until reaching a moisture content of 10%. Sample seeds were milled to fine flour, screened through a 100-mesh sieve and stored at 4°C for further analysis.

After 60 h of germination, sprout length in sorghum and millet ranged from 8 to 24 mm, while sprouts obtained from brown rice and oat ranged from 3 to 6 mm.

Compared to raw flours, germinated flours derived from brown rice, sorghum, and millet had lower gelatinization enthalpy, whereas germinated oat flour showed higher gelatinization enthalpy.

During germination, enzymes are activated, catalyzing starch degradation, which may disrupt the double helical structure of starch. Consequently, less energy is required to unravel and melt double helices of starch in germinated flours. The increase in gelatinization enthalpy of germinated oat flour may be due to dissolution of hydrolyzed starch granules during germination.”

https://link.springer.com/article/10.1007%2Fs10068-020-00770-2 “Influence of germination on physicochemical properties of flours from brown rice, oat, sorghum, and millet” (not freely available)

The first study sprouted oats for five days to full germination and a minimum radicle length of 6.25 cm. The third study sprouted oats to full germination in 60 hours and a 3 mm minimum total length.

At the same 25°C, with 60% relative humidity and daily watering, it took 120 hours to achieve full germination. With 95% relative humidity, it took half that time.

Was humidity a relevant difference in oat sprout growth? Would Choyang variety oat sprouts increase their minimum 3 mm total length more than 20 times between Hours 60 and 120 to match the minimum Turquesa radicle length?

This is a count of PubMed “oat sprout” search results, 20 results total: