Enzymatic Production of Xylo-oligosaccharides from Destarched Wheat Bran and the Impact of Their Degree of Polymerization and Substituents on Their Utilization as a Carbon Source by Probiotic Bacteria.

The enzymatic production of xylo-oligosaccharides (XOs) from destarched wheat bran with a GH11 xylanase was studied. Xylo-oligosaccharides (XOs) produced were separated into different fractions according to their degree of polymerization (DP) and the nature of their substituents: arabinoxylo-oligosaccharides (AXOs) with a DP from 2 to 3 and DP from 2 to 6 and feruloylated arabinoxylo-oligosaccharides (FAXOs) esterified by ferulic and p-coumaric acids with a DP from 3 to 6. Both AXOs (short and long DP) and FAXOs stimulated the growth of Bifidobacterium adolescentis, Faecalibacterium prausnitzii, and Prevotella copri similarly but not Lactobacillus rhamnosus. The utilization of AXOs and FAXOs as a carbon source resulted in the increase in turbidity, decrease in pH, and production of short-chain fatty acids (SCFAs) in the culture broth. The highest amount of SCFAs was produced by F. prausnitzii using FAXOs. Results suggest that FAXOs and AXOs have the potential to be considered as prebiotics.

2-Furoylmethyl amino acids as indicators of Maillard reaction during the elaboration of black garlic.

This study reports the formation of 2-furomethyl-amino acids (2-FM-AA) as indicators of Maillard reaction (MR) in black garlic elaboration, followed by the determination of furosine by ion-pair RP-HPLC-UV. The method was assessed for accuracy, repeatability and detection and quantitation limits indicating its adequacy. Traditional procedure of black garlic obtainment and the inclusion of convective drying (CDP) and ohmic heating (OHP) were assayed. For comparison purposes, three commercial black garlic samples were used. Together with furosine (2-FM-lysine), 2-furoylmethyl-γ-aminobutyric acid and 2-FM-arginine were detected. Levels of furosine were higher in CDP (46.6-110.1mg/100g protein) than in OHP (13.7-42.0mg/100g protein) samples, probably due to the most severe processing conditions used in the former. These results highlight the suitability of 2-FM-AA as chemical indicators to monitor the process of black garlic elaboration in order to obtain high quality products.