Today barley is considered to be a minor cereal and is largely used as fodder. However, it is still important for human nutrition. In germinated form, it is the main ingredient in beer brewing. In recent years, due to its high content in beta-glucans, tocols, and polyphenols, it has been used in the preparation of functional foods. Furthermore, the secular custom in China of drinking barley or malt coffee instead of traditional coffee as a tasty beverage has greatly spread in Western regions, because the children and adults alike are highly susceptible to the negative effects of caffeine. Such beverages use roasted barley. During roasting treatment, caramelization and the Maillard reaction occur and dicarbonyl compounds are formed as reactive intermediates. The most extensively studied alfa-dicarbonyl compounds are methylglyoxal and glyoxal, which have attracted considerable attention as lipid peroxidation product. Glyoxal can also derive from sugar fragmentation and has been isolated in many foodstuffs such as roasted coffee and cocoa. The toxicological profile of these compounds is not completely clear. In recent years, the interest has focused on the implications of the glycation process and the role of dietary glycation products is debated. Various methods have been developed to determine alfa-dicarbonyl compounds. The best current assays involve derivatization of these substances with 1,2-diaminobenzene followed by quantification of the resulting quinoxaline by GC or by HPLC. The aim of this study was to devise a method allowing simultaneous and accurate determination of alfa-dicarbonyl compounds by RP-HPLC-DAD-ESI/MS. Eight different beverages prepared using commercial roasted conventional and organic barley samples, were tested. The applied method involved the elimination of interfering compounds by solid phase extraction (SPE), the derivatization of alfa-dicarbonyl compounds with 1,2-diaminobenzene to give quinoxaline derivatives, the purification and concentration of quinoxaline fractions by SPE, and finally RP-HPLC-DAD-ESI/MS analysis. The obtained results indicated the presence in different amounts of glyoxal, methylglyoxal, and diacetyl in all the tested samples.

Isolation and identification of alfa-dicarbonyl compounds by RP-HPLC-ESI/MS in roasted barley

PAPETTI, ADELE;DAGLIA, MARIA;MASCHERPA, DORA;GAZZANI, GABRIELLA
2009-01-01

Abstract

Today barley is considered to be a minor cereal and is largely used as fodder. However, it is still important for human nutrition. In germinated form, it is the main ingredient in beer brewing. In recent years, due to its high content in beta-glucans, tocols, and polyphenols, it has been used in the preparation of functional foods. Furthermore, the secular custom in China of drinking barley or malt coffee instead of traditional coffee as a tasty beverage has greatly spread in Western regions, because the children and adults alike are highly susceptible to the negative effects of caffeine. Such beverages use roasted barley. During roasting treatment, caramelization and the Maillard reaction occur and dicarbonyl compounds are formed as reactive intermediates. The most extensively studied alfa-dicarbonyl compounds are methylglyoxal and glyoxal, which have attracted considerable attention as lipid peroxidation product. Glyoxal can also derive from sugar fragmentation and has been isolated in many foodstuffs such as roasted coffee and cocoa. The toxicological profile of these compounds is not completely clear. In recent years, the interest has focused on the implications of the glycation process and the role of dietary glycation products is debated. Various methods have been developed to determine alfa-dicarbonyl compounds. The best current assays involve derivatization of these substances with 1,2-diaminobenzene followed by quantification of the resulting quinoxaline by GC or by HPLC. The aim of this study was to devise a method allowing simultaneous and accurate determination of alfa-dicarbonyl compounds by RP-HPLC-DAD-ESI/MS. Eight different beverages prepared using commercial roasted conventional and organic barley samples, were tested. The applied method involved the elimination of interfering compounds by solid phase extraction (SPE), the derivatization of alfa-dicarbonyl compounds with 1,2-diaminobenzene to give quinoxaline derivatives, the purification and concentration of quinoxaline fractions by SPE, and finally RP-HPLC-DAD-ESI/MS analysis. The obtained results indicated the presence in different amounts of glyoxal, methylglyoxal, and diacetyl in all the tested samples.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11571/225192
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