Potential of Pectins to Beneficially Modulate the Gut Microbiota Depends on Their Structural Properties

Pectins are plant cell-wall polysaccharides which can be utilized by commensal bacteria in the gut, exhibiting beneficial properties for the host. Knowledge of the impact of pectins on intestinal bacterial communities is insufficient and limited to a few types of pectins. This study characterized the relationship between the structural properties of pectins and their potential to modulate composition and activity of the gut microbiota in a beneficial way. For this purpose we performed in vitro fermentations of nine structurally diverse pectins from citrus fruits and sugar beet, and a pectic derivative, rhamnogalacturonan I (RGI), using a TIM-2 colon model. The composition of microbiota during TIM-2 fermentations was assessed by 16S rRNA gene amplicon sequencing. Both general and pectin-specific changes were observed in relative abundances of numerous bacterial taxa in a time-dependent way. Bacterial populations associated with human health, such as Faecalibacterium prausnitzii, Coprococcus, Ruminococcus, Dorea, Blautia, Oscillospira, Sutterella, Bifidobacterium, Christensenellaceae, Prevotella copri, and Bacteroides spp. were either increased or decreased depending on the substrate, suggesting that these bacteria can be controlled using structurally different pectins. The main structural features linked to the pectin-mediated shifts in microbiota included degree of esterification, composition of neutral sugars, distribution of homogalacturonan and rhamnogalacturonan fractions, degree of branching, and the presence of amide groups. Cumulative production of the total short chain fatty acids and propionate was largest in fermentations of the high methoxyl pectins. Thus, this study indicates that microbial communities in the gut can be specifically modulated by pectins and identifies the features in pectin molecules linked to microbial alterations. This knowledge can be used to define preferred dietary pectins, targeting beneficial bacteria, and favoring more balanced microbiota communities in the gut

Recovery of protein, chitin, carotenoids and glycosaminoglycans from Pacific white shrimp (Litopenaeus vannamei) processing waste

Shrimp head waste is a major byproduct of crustacean processing in North-eastern Brazil and represents an interesting source of bioactive molecules. Additionally, its use increases the sustainability of processing fishery products. the present study reports a process developed for recovering bioactive molecules from shrimp heads through autolysis. A protein hydrolysate (120 +/- 0.4 g) formed by a 9% (w/v) solution was recovered and lyophilized from I kg of shrimp heads. Approximately 195 +/- 0.5 mg of carotenoids was recovered as an ethanolic extract. the recovery of chitin and chitosan were 25 +/- 2 g kg(-1) and 17 +/- 4 g kg(-1) wet processing waste, respectively. Chitosans were characterized by C-13 NMR, and FT-IR analysis and exhibited a variable degree of deacetylation (60-80%). Sulfated glycosaminoglycans that exhibited electrophoretic migration similar to mammalian standards were also recovered (79 +/- 2 mg kg(-1) wet processing waste), and their degradation products suggested the presence of C6-sulfated heparan sulfate. These data point to the feasibility of an integrated process for isolating highly bioactive molecules, such as sulfated- and amino-polysaccharides, with a broad spectrum of applications from shrimp processing waste. (C) 2011 Elsevier B.V. All rights reserved.MPAConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)FINEPEMBRAPAUFPEFACEPEUniv Fed Pernambuco, Lab Imunopatol Keizo Asami, Dept Bioquim, Lab Enzimol LABENZ, BR-50670420 Recife, PE, BrazilUniversidade Federal de São Paulo, INFAR, Lab Biol Mol, BR-04044020 São Paulo, BrazilUniv Fed Rio Grande do Norte, Ctr Biociencias, Dept Bioquim, BR-59072000 Natal, RN, BrazilUniversidade Federal de São Paulo, INFAR, Lab Biol Mol, BR-04044020 São Paulo, BrazilWeb of Scienc