Broccoli sprouts pack far more glucoraphanin and folate than mature heads, study finds

Broccoli sprouts, the tiny seedlings usually eaten within days of germination, contain dramatically more glucoraphanin and folic acid than the mature vegetable heads sold in stores, according to a detailed metabolite analysis of two broccoli breeding lines grown at the Institute of Vegetables and Flowers of the Chinese Academy of Agricultural Sciences in Pinggu. The study, published in Food Chemistry: X, compared the sprouting and heading stages of two high-quality broccoli lines, B195 and B245, using high-performance liquid chromatography, ultraperformance liquid chromatography coupled with tandem mass spectrometry, and gas chromatography-mass spectrometry to quantify glucosinolates, water-soluble vitamins, and short-chain fatty acids in the edible tissues.

The researchers transplanted seedlings with four true leaves into an open experimental field, with three biological replicates per group and twenty plants per replicate, and harvested heads at a uniform growth stage. For the sprout samples, seeds were washed, germinated on moist gauze at room temperature, and collected once the sprouts reached roughly three centimeters. All samples were flash-frozen in liquid nitrogen, stored at minus eighty degrees Celsius, freeze-dried, ground, and sieved before extraction and analysis. Every assay was run in triplicate, and differences were tested by one-way analysis of variance followed by Tukey’s multiple comparison test, with metabolomic differences screened using fold change, p-values, and variable importance in projection scores.

The headline result concerns glucoraphanin, a methionine-derived glucosinolate that is hydrolyzed by the plant enzyme myrosinase into sulforaphane, the bioactive compound that has drawn the most scientific attention in cruciferous vegetables. In the B195 line, glucoraphanin measured 3.35 micromoles per kilogram dry weight at the sprouting stage but only 0.593 micromoles per kilogram dry weight at heading. The B245 line showed the same directional pattern at far higher absolute levels, falling from 12.24 micromoles per kilogram dry weight at sprouting to 1.95 micromoles per kilogram dry weight at heading. Expressed as relative differences, the sprouting stage carried 465 percent more glucoraphanin than the heading stage in B195 and 530 percent more in B245.

Genotype mattered as much as growth stage. Across both stages, B245 consistently outperformed B195, with 265 percent higher glucoraphanin content during sprouting and 227 percent higher content at heading. The authors note that this is consistent with earlier reports that glucoraphanin accumulation peaks in young plants, with published concentrations in sprouts ranging from 67.4 to 174.6 milligrams per 100 grams fresh weight, and that final yields vary considerably across cultivars and genetic lineages. Within this study, the identification and quantification of glucosinolates relied on HPLC with mass spectrometric support, using software tools to deduce fragment ions and confirm molecular structures.

The vitamin analysis painted a more stage-dependent picture. Seventeen water-soluble vitamins and related metabolites were targeted, and sixteen were detected in both sprouts and heads; vitamin B12, as cyanocobalamin, was not detected in either stage. Nicotinamide, one form of vitamin B3, was essentially unchanged between stages in B195, at 8.16 micrograms per gram dry weight during sprouting and 8.59 micrograms per gram dry weight at heading. In B245, however, nicotinamide rose from 5.94 micrograms per gram dry weight at heading to 17.78 micrograms per gram dry weight at sprouting, a 199 percent increase. Nicotinic acid, the other measured form of vitamin B3, rose sharply at sprouting in both lines, from 0.49 to 29.91 micrograms per gram dry weight in B195 and from 2.14 to 14.14 micrograms per gram dry weight in B245.

Folic acid, vitamin B9, followed the same sprout-favoring pattern as glucoraphanin. Folic acid content was 452.84 percent higher at the sprouting stage than at heading in B195 and 476.38 percent higher in B245. Line B195 also carried more folate than B245 at both stages, exceeding the B245 heading value by 88.10 percent and the B245 sprouting value by 80.41 percent. The paper situates this against dietary reference figures attributed to the FAO, citing a recommended daily intake of 400 micrograms of vitamin B9 for healthy adults and 400 to 800 micrograms per day during pregnancy, and noting that folate compounds participate in one-carbon metabolism underlying purine and pyrimidine synthesis, amino acid interconversion, and methylation.

Vitamin C moved in the opposite direction. Ascorbic acid measured 1.50 micrograms per gram dry weight in B195 heads and 0.80 micrograms per gram dry weight in B245 heads, but only 0.27 and 0.42 micrograms per gram dry weight in the corresponding sprouts. In other words, the mature heads of both lines were the richer source of vitamin C, while the sprouts dominated in glucoraphanin, folate, and the nicotinic acid form of vitamin B3. The full vitamin panel, including pantothenic acid, biotin, riboflavin, thiamine, the various vitamin B6 forms, aminobenzoic acid, 5,10-methenyltetrahydrofolic acid, and methylmalonic acid, was quantified for each line and stage, with pantothenic acid and methylmalonic acid among the most abundant measured compounds.

To test whether these compositional differences reflected systematic pathway-level shifts, the team applied differential abundance scoring, circular plot enrichment, and Sankey flow analysis to the vitamin metabolite data. In the B245 line relative to B195, 4-pyridoxic acid, methylmalonic acid, ascorbic acid, pyridoxine, biotin, riboflavin, pyridoxal, 5,10-methenyltetrahydrofolic acid, and pyridoxamine were upregulated, while nicotinamide, nicotinic acid, aminobenzoic acid, folic acid, pyridoxal 5′-phosphate, and pantothenic acid were downregulated, and thiamine showed no response. Pathway mapping against Brassica oleracea reference databases ranked vitamin B6 metabolism as the most enriched pathway in B245, followed by biotin metabolism, riboflavin metabolism, and ABC transporters, with the one-carbon folate pool, thiamine metabolism, nicotinate and nicotinamide metabolism, folate biosynthesis, the sulfur relay system, and pantothenate and CoA biosynthesis also enriched.

The short-chain fatty acid analysis, performed by gas chromatography-mass spectrometry, added a further stage-specific dimension. Nine fatty acids were profiled, including acetic, propionic, butyric, valeric, hexanoic, heptanoic, octanoic, nonanoic, and decanoic acid. Hexanoic acid was strongly enriched at heading in both lines: it increased by 1128.63 percent in B195 at heading relative to B195 sprouting and by 3314.58 percent in B245 at heading relative to B245 sprouting. Heptanoic acid showed the same heading-stage preference, rising 362.31 percent in B195 at heading versus B195 sprouting and 1020.83 percent in B245 at heading versus B245 sprouting. Propionic acid and butyric acid were also most enriched at heading, with the maximum butyric acid content in B195 heads and the minimum in B245 sprouts, whereas acetic acid peaked in B195 sprouts and B245 heads, and nonanoic acid was higher in B245 sprouts than in B245 heads.

The authors frame these stage- and genotype-specific patterns as baseline data for tailoring broccoli consumption and breeding. Their conclusion is that sprouting broccoli is a markedly richer dietary source of glucoraphanin and folate, that the B245 line is the stronger glucoraphanin genotype at both stages, and that mature heads concentrate hexanoic and heptanoic acid. The study is a compositional analysis of two experimental lines under a single field protocol, not a dietary intervention trial, so the reported human health associations of sulforaphane, folate, and short-chain fatty acids, which the authors draw from prior literature on antioxidant, anti-inflammatory, and gut-related effects, remain context rather than demonstrated outcomes of eating these particular broccoli lines. What the data do establish is measurable: in these two genotypes, the choice between a three-centimeter sprout and a mature head changes the balance of glucosinolates, B vitamins, and fatty acids by several-fold, and the direction of that change depends on which compound the consumer is seeking.

Subject of Research: Metabolite profiling of glucoraphanin, water-soluble vitamins, and short-chain fatty acids in two broccoli lines at sprouting and heading stages

Article Title: Distribution characteristics of glucoraphanin, folic acid, and short-chain fatty acids in broccoli heads and sprouts

Article References: Anwar, A., Gao, W., Liu, Q., Liu, G., Liu, Y., He, H., Ke, X., Xu, D., & Li, Z. (2026). Distribution characteristics of glucoraphanin, folic acid, and short-chain fatty acids in broccoli heads and sprouts. Food Chemistry: X, 40, Article 104690. https://doi.org/10.1016/j.fochx.2026.104690

Image Credits: AI Generated

DOI: 10.1016/j.fochx.2026.104690

Keywords: broccoli, glucoraphanin, sulforaphane, folic acid, broccoli sprouts, short-chain fatty acids, water-soluble vitamins, UPLC-MS/MS, HPLC, GC-MS, glucosinolates, plant metabolomics