RESUMO
Broccoli sprouts are a recognized source of health-promoting compounds, such as glucosinolates, glucoraphanin, and sulforaphane (SFN). Maximization of SFN content can be achieved by technological processing. We investigated the effect of blanching conditions to determine the optimal treatment that maximizes sulforaphane content in broccoli sprouts. Broccoli seeds (cv. Traditional) grown under controlled conditions were harvested after 11 days from germination and subjected to different blanching conditions based on a central composite design with temperature and time as experimental factors. Results were analyzed by ANOVA followed by a Tukey test. The optimum conditions were identified through response surface methodology. Blanching increased sulforaphane content compared with untreated sprouts, agreeing with a decrease in total glucosinolates and glucoraphanin content. Temperature significantly affected SFN content. Higher temperatures and shorter immersion times favor glucoraphanin hydrolysis, thus increasing SFN content. The optimum conditions were blanching at 61 °C for 4.8 min, resulting in 54.3 ± 0.20 µmol SFN/g dry weight, representing a 3.3-fold increase with respect to untreated sprouts. This is the highest SFN content reported for sprouts subjected to any treatment so far. The process described in this work may contribute to developing functional foods and nutraceuticals that provide sulforaphane as an active principle.
RESUMO
BACKGROUND: Broccoli sprouts are a good source of secondary metabolites, exhibiting biological activity, such as polyphenols, whose concentration is affected by the exposure to exogenous elicitors. The aim of this work was to investigate the effect of sodium selenate, chitosan and methyl jasmonate, applied directly to the seeds or through irrigation, on the content and profile of phenolic compounds in broccoli sprouts. The effect on antioxidant activity was also investigated. RESULTS: Methyl jasmonate and chitosan decreased antioxidant capacity. Methyl jasmonate significantly decreased total polyphenols content in comparison with control sprouts, while chitosan significantly increased it. Sodium selenate had no statistical effect on antioxidant capacity and total polyphenols concentration. The polyphenols profile in sprouts was composed by quercetin, morine, genisteine, luteoline and sinapic acid. Elicitor type and concentration affected the synthesis of these compounds. Chitosan stimulated the synthesis of quercetin, sinapic acid and morine, whereas methyl jasmonate stimulated the synthesis of luteoline. Sodium selenate had no effect on polyphenols synthesis. CONCLUSION: The exposure of broccoli to the elicitors produced changes in the phenolic compounds profile of broccoli sprouts. Besides, the stimulation of phenolic compounds synthesis was elicitor-specific, thus opening the possibility of managing culture conditions to increase the content of a specific phenolic compound.