Glucoraphanin extraction from Cardaria draba: Part 1. Optimization of batch extraction

Abstract

Glucosinolates have historically been considered an anti-nutritional component of food and feed cereal crops. Large-scale protocols have been aimed at complete glucosinolate elimination from plants, rather than maximizing the recovery of any particular glucosinolate compound. Recently, glucoraphanin, an alkenyl glucosinolate, has been found to have nutritional value in terms of anti-carcinogenic behavior and hypertension relief. In this work, we report on the efficient capture of glucoraphanin from the noxious weed Cardaria draba. The effect of temperature, ethanol content in the aqueous solvent, initial solvent pH, solids loading, and contact time on both glucoraphanin and glucosinalbin recovery were examined. The optimal extraction conditions, evaluated using 0.11 dm 3 stirred baffled vessels, were found to be 20% aqueous ethanol solvent at 70• C and an initial pH value of 3, extracted at a solid to liquid ratio of 50 g dmover 20 mins. The recovery achieved with the baffled vessels was up to three times greater than the glucoraphanin yield obtained using standard analytical procedures that involved the use of 8.0 × 10 −3 dm 3 of hot, 80% ethanol solutions in test tubes at the same solvent loading. This corresponds to 30 mg g −1 of glucoraphanin recovered from the dried C draba leaves, versus only 10 mg g −1 using the analytical method.

Optimisation of enzymatic production of sulforaphane in broccoli sprouts and their total antioxidant activity at different growth and storage days

“…1a, the solid-liquid ratio significantly influenced the content of hydrolytic products (p \ 0.05). Several reviews reported that a solid-liquid ratio between 1:10 and 1:40 is beneficial for sulforaphane formation (Powell et al 2005;Guo et al 2013;Kuang et al 2013). In the present research, a solid-liquid ratio of 1:30 was found to be optimum for sulforaphane production, which may reflect suitable conditions for myrosinase activity.…”

“…This result may be explained by the fact that both solubility and mass transfer rate increase with temperature. Temperature-induced increases in mass transfer rates promote rapid equilibrium (Powell et al 2005).…”

“…Travers-Martin et al (2008) pointed out that the optimal pH and temperature of myrosinase activity ranges from 4.0 to 9.0 and from 20 to 70°C. Solid-liquid ratios have also been reported to influence the content of hydrolytic products, with the optimal proportion ranging from 1:10 to 1:40 (Powell et al 2005;Kuang et al 2013;Guo et al 2014a). The optimal hydrolysis conditions for sulforaphane in previous report as follows: temperature, 35°C; pH, 3.0 and hydrolysis time, 4 h (Han and Row 2011).…”

Phytochemical Analysis and Antimicrobial Activity of Cardaria draba (L.) Desv. Volatiles

“…Mass spectra of a) sulforaphane (3) and b) sinalbin nitrile (5), the two main glucosinolate breakdown products of Extract II, obtained by CH 2 Cl 2 extraction subsequent to hydrolysis by myrosinase products of glucoraphanin were not identified among the volatiles obtained by hydrodistillation. It was reported previously that glucoraphanin was thermally stable up to at least 1008 and soluble in H 2 O, thus its degradation products could not be isolated by hydrodistillation [5]. Additionally, other quantitatively important glucosinolate degradation products in Extract II, such as 5 and 6, were also absent in the hydrodistillate.…”

“…Glucosinalbin and the glucosinolate salt l-prolinium 4-(methylsulfinyl)butyl glucosinolate have been isolated from the flowering heads of C. draba [3] [4]. This weed was selected as a suitable plant material for the extraction of the glucosinolate glucoraphanin, precursor of sulforaphane, known for its numerous health benefits [5]. More recently, among the volatile constituents of Iranian C. draba, glucosinolate degradation products were indicated as the main compounds.…”