Microwave cooking increases sulforaphane level in broccoli

Abstract

Sulforaphane (SFR), an anticarcinogenic compound, forms from the hydrolysis of glucoraphanin (GLR) in broccoli. Cooking methods have been shown to affect broccoli GLR and SFR levels, but little is known about the effect of lightly cooking processes on them. In this study, the effects of microwave and low-temperature cooking on GLR and SFR contents in broccoli were investigated. Both microwaving and mild heating increased the GLR and SFR levels in broccoli compared to the raw samples (without any treatment). In particular, SFR level was significantly low under 40°C and dramatically increased from 40 to 60°C, but nothing was detected at 70°C. Compared with conventional heating, microwave heating increased the GLR and SFR yield by about 80% at 50 and 60°C. Microwave power level also influenced the SFR contents. At the same temperatures (50 and 60°C), high-power microwave (950 W) with a short time produced over 40% more SFR than low-power microwave treatment (475 W). Hence, mild heating by microwave could increase the GLR and SFR levels in broccoli, and high-power microwave heating with temperature control at 60°C could retain higher bioavailability of these bioactive compounds in broccoli. K E Y W O R D Sbroccoli, glucoraphanin, low-temperature cooking, microwave cooking, sulforaphane

Effects of cooking methods on total isothiocyanate yield from cruciferous vegetables

“…To note, there were no detectable ITCs in the cooking water from boiling, stewing, and steaming in our study (results not shown). Interestingly, microwaving and steaming were reported to increase the level of glucosinolates (Gliszczyńska-Świgło et al, 2006;Lu, Pang, & Yang, 2020), which was assumed that mild-heating causes disintegration of plant tissues, thus leads to more release of glucosinolates (Nugrahedi, Verkerk, Widianarko, & Dekker, 2015). However, the potential contribution (Jiao et al, 1994;Navarro, Li, & Lampe, 2011;Singh & Singh, 2012;Wang et al, 2011).…”

Enhancement of ultrasound-assisted extraction of sulforaphane from broccoli seeds via the application of microwave pretreatment

“…Proper heating treatment can reduce ESP activity and the production of sulforaphane nitrile as well as allow for more production of sulforaphane [19] . It has been reported that ESP was inactivated after heating for 5–10 min at 60–70 ℃, while myrosinase was inactivated after heating for 5–15 min at 100℃ [20] .…”

Is Bitterness Only a Taste? The Expanding Area of Health Benefits of Brassica Vegetables and Potential for Bitter Taste Receptors to Support Health Benefits

“…Epithionitriles are formed from GSLs containing an unsaturated terminal side chain [ 17 ]. Different cooking conditions and food matrices (such as heating time and temperature, microwaving time and power level, volume of water added, and cutting size) impact the chemical composition of the food ingested, the conversion of GSLs to ITCs, and thus the extent of bioactivity [ 15 , 19 , 20 ]. For example, sulforaphane (SF, the ITC metabolite of GRP) production from broccoli sprouts is significantly increased by preheating the sprouts to 60 °C for 10 min, destroying the very heat-sensitive ESP (the plant protein that favors the formation of nitriles over ITCs during hydrolysis).…”