Pitfalls in the desulphation of glucosinolates in a high-throughput assay

• Published in: Food chemistry Vol. 134; no. 4; pp. 2355 - 2361
• Main Authors: Hennig, K., Verkerk, R., Bonnema, G., Dekker, M.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 15.10.2012; Elsevier
• Subjects: Arylsulphatase; Biological and medical sciences; Brassica - chemistry; Brassica - enzymology; brassica-oleracea; Brassicaceae; breakdown; broccoli; Desulphation of glucosinolates; food; Food industries; Fundamental and applied biological sciences. Psychology; Glucosinolates - chemistry; High-Throughput Screening Assays - instrumentation; High-Throughput Screening Assays - methods; hplc; napus; Plant Proteins - analysis; Plant Proteins - isolation & purification; Sample preparation; Sulfatases - analysis; Sulfatases - isolation & purification; Sulphatase purification; Sulphatase side activity; vegetables; Desulphation of glucosinolates; Sample preparation; Brassicaceae; Arylsulphatase; Sulphatase side activity; Sulphatase purification; Sulfur compounds; Glucosinolate; Purification; Cruciferae; Dicotyledones; Angiospermae; Spermatophyta
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2012.04.015

► Effect of sulphatase preparation on glucosinolate analysis in microtiter plates was tested. ► High amounts of sulphatase decreased glucotropaeolin concentration. ► High amounts of sulphatase hardly affected other glucosinolates than glucotropaeolin. ► Hence, too high recoveries were calculated when glucotropaeolin is used as internal standard. ► Purified sulphatase is applicable for glucosinolate analysis in a diversity of samples. Glucosinolates are phytochemicals with health promoting properties. Determination as desulpho-glucosinolates is widely used and a desulphation in microtiter plates has been applied to reach high throughput. The use of various sulphatase concentrations and volumes throughout literature necessitates the identification of an appropriate desulphation procedure in microtiter plates. High sulphatase concentrations (⩾15mg/ml) decreased the concentration of the internal standard glucotropaeolin, whereas the other glucosinolates were less affected. Due to the calculation based on the recovery of glucotropaeolin, this leads to an overestimation of GL concentrations after desulphation with high sulphatase concentrations. A glucosidase side-activity, present in the crude sulphatase powder, is likely causing this phenomenon. At lower sulphatase concentrations (1mg/ml) glucoiberin and glucoraphanin were insufficiently desulphated. Combining these effects results in a small range of applicable sulphatase concentrations. A purified sulphatase preparation resulted in good recoveries for a diversity of samples and is hence recommended for high throughput desulphation in microtiter plates.