Kinetic study of sulforaphane stability in blanched and un-blanched broccoli (Brassica oleracea var. italica) florets during storage at low temperatures

Abstract

Sulforaphane is a health-promoting compound found in broccoli. Given its high thermo-lability, its preservation through high-temperature processes seems inconvenient. Accordingly, storage at low temperature is an alternative. There are no studies about the evolution of sulforaphane content during storage at low temperatures. The change of sulforaphane content in blanched and unblanched broccoli florets during storage at 10,-1,-21 and-45°C for 83 days was studied. In blanched broccoli, sulforaphane content followed a first-order degradation kinetics (R 2 C 0.95). A two-consecutive irreversible reactions model described adequately the evolution of sulforaphane content in un-blanched broccoli (R 2 C 0.94). Activation energies from Arrhenius equation resulted in 19.4 kJ/mol for blanched and 30 kJ/mol (formation) and 58 kJ/mol (degradation) for un-blanched broccoli. Storage of un-blanched broccoli at-45°C for 40 days maximized sulforaphane content. These results could be useful to propose broccoli storage conditions that preserve or maximize sulforaphane content. Keywords Sulforaphane Á Broccoli Á Low temperature Á Storage Á Kinetics List of symbols C G Glucoraphanin concentration (lmol g-1 DM) C G0 Initial glucoraphanin concentration (lmol g-1 DM) C S Sulforaphane concentration (lmol g-1 DM) C S0 Initial sulforaphane concentration (lmol g-1 DM) C T Thiourea concentration (lmol g-1 DM) DM Dry matter Ea Activation energy (kJ/mol) ESP Epithiospecifier protein GFN Glucoraphanin GSL Glucosinolate k Degradation rate constant for sulforaphane in blanched broccoli (d-1) k 0 Frequency factor in the Arrhenius equation (d-1) k 1 Formation rate constant for sulforaphane in unblanched broccoli (d-1) k 2 Degradation rate constant for sulforaphane in unblanched broccoli (d-1) r Correlation coefficient R Universal gas constant (kJ mol-1 K-1) R 2 Determination coefficient SFN Sulforaphane t Time (d) T Temperature (°C)

Stable Sulforaphane Targets the Early Stages of Osteoclast Formation to Engender a Lasting Functional Blockade of Osteoclastogenesis

“…Sulforaphane (4-methylsulfinylbutyl isothiocyanate, SFN) is a phytochemical produced from a biologically inactive precursor, glucoraphanin, during the biting and chewing of certain plant sources [5][6][7][8][9]; this precursor is found in cruciferous vegetables and many nutraceuticals [10]. SFN is usually well tolerated and is known to exert potent antioxidant effects by modifying cytoplasmic KEAP1 conformation, releasing NRF2 for nuclear translocation and the transcriptional activation of genes with antioxidant response elements (ARE) in their promoters [11][12][13][14][15].…”

Stable Sulforaphane Targets Early Stages of Osteoclast Formation to Engender Lasting Functional Blockade of Osteoclastogenesis

“…Sulforaphane (4-methylsulfinylbutyl isothiocyanate, SFN) is a phytochemical produced from a biologically inactive precursor, glucoraphanin, during biting and chewing of certain plant sources [5][6][7][8][9]; this precursor is found in cruciferous vegetables and many nutraceuticals [10]. SFN is usually well tolerated and is known to exert potent antioxidant effects by modifying cytoplasmic KEAP1 conformation, releasing NRF2 for nuclear translocation and transcriptional activation of genes with antioxidant response elements (ARE) in their promoters [11][12][13][14][15].…”

Using an Agricultural Supply Chain to Train the Next Generation of STEM Professionals

“…Glucoraphanin converts into sulforaphane on a one-to-one stoichiometric mole basis. We found that a glucoraphanin concentration range between 0.88-1.10 μmol/g is common in fresh-weight broccoli microgreens [10]. Based on literature values, we assumed an average microgreens sample comprises a 0.85 μmol/g glucoraphanin concentration [11].…”

“…kd,ref represents the degradation rate constant in minutes at Tref, a reference temperature chosen to be 100°C or 373 K. The reference data was used to identify a sample degradation rate constant at 25°C or 98 K for kd,ref = 2.07×10 -2 per minute using an Arrhenius-type model. The activation energy for glucoraphanin degradation, Ea, is 159 J/mol [10].…”