Glyoxal and methylglyoxal formation in chocolate and their bioaccessibility.

The objective of this study was to assess the effects of simulated digestion on the formation of α-dicarbonyl compounds (α-DCs) in chocolates. For that purpose, the concentrations of glyoxal and methylglyoxal in chocolates were determined through High-Performance Liquid Chromatography (HPLC) analysis before and after in vitro digestion. The initial concentrations ranged from 0.0 and 228.2 µg/100 g, and 0.0 and 555.1 for glyoxal and methylglyoxal, respectively. Following digestion, there was a significant increase in both glyoxal and methylglyoxal levels, reaching up to 1804 % and 859 %, respectively. The findings indicate that digestive system conditions facilitate the formation of advanced glycation end product (AGE) precursors. Also, glyoxal and methylglyoxal levels were found to be low in chocolate samples containing dark chocolate. In contrast, they were found to be high in samples containing hazelnuts, almonds, pistache, and milk. Further studies should focus on α-DCs formation under digestive system conditions, including the colon, to determine the effects of gut microbiota.

Malondialdehyde levels and bioaccessibility in healthy diet bars: A gastrointestinal digestion model.

Malondialdehyde (MDA), which is composed when n-6 and n-3 PUFAs are peroxidized, has been utilized as an indicator of lipid peroxidation and has been considered neurotoxic, cytotoxic, and mutagenic. This study aimed to determine the bioaccessibility level of MDA in diet bars sold as healthy snacks in the market using in vitro gastrointestinal digestive model. In our study, 28 different diet bar samples were bought from markets in Istanbul. MDA contents of the products were determined by the HPLC-FLD method. The investigation showed that diet bars had an average MDA concentration of 116.25 µg/100 g before digestion, while the average MDA concentration was 90.50 µg/100 g after in vitro digestion. In line with these data, the average MDA bioaccessibility of 28 diet bar samples was calculated as 77.3%. For this reason, more studies are needed to understand the relationship between both the MDA content and the reaction and nutritional components.

Investigation of formation of well-known AGEs precursors in cookies using an in vitro simulated gastrointestinal digestive system.

The present study investigated the influence of in vitro stimulated digestion system on the content of glyoxal and methylglyoxal in commercial cookies. Glyoxal and methylglyoxal levels in different cookie samples were analyzed before and after in vitro digestion with High Performance Liquid Chromatography. Initial glyoxal and methylglyoxal values ranged between 42.9 and 126.6 µg/100 g, and between 22.9 and 507.3 µg/100 g, respectively. After in vitro digestion, formation of glyoxal and methylglyoxal values were increased up to 645% and 698%, respectively. The results revealed that in vitro stimulated digestion conditions strongly increased the amount of glyoxal and methylglyoxal in cookies. The amount of fructose was found to be more effective on the formation of both GO and MGO than those of glucose and sucrose. Further studies are needed to extensively investigate glyoxal and methylglyoxal formation under in vitro conditions in such foods.