Madhav P. Yadav

Glycan complexity dictates microbial resource allocation in the large intestine

The structure of the human gut microbiota is controlled primarily through the degradation of complex dietary carbohydrates, but the extent to which carbohydrate breakdown products are shared between members of the microbiota is unclear. We show here, using xylan as a model, that sharing the breakdown products of complex carbohydrates by key members of the microbiota, such as Bacteroides ovatus, is dependent on the complexity of the target glycan. Characterization of the extensive xylan degrading apparatus expressed by B. ovatus reveals that the breakdown of the polysaccharide by the human gut microbiota is significantly more complex than previous models suggested, which were based on the deconstruction of xylans containing limited monosaccharide side chains. Our report presents a highly complex and dynamic xylan degrading apparatus that is fine-tuned to recognize the different forms of the polysaccharide presented to the human gut microbiota.

Fractionation, characterization, and study of the emulsifying properties of corn fiber gum.

Corn fiber gum (CFG) has been fractionated by hydrophobic interaction chromatography on Amberlite XAD-1180 resin using ionic, acidic, basic, and hydrophobic solvents of different polarities. Characterization, including determination of total carbohydrate, acidic sugar, and protein content, has been done for each fraction together with measurements of molar mass, polydispersity, radius of gyration, Mark-Houwink exponent, and intrinsic viscosity using multiangle laser light scattering and online viscosity measurements. Emulsification properties of all fractions in an oil-in-water emulsion system with 20:1 oil to gum ratio were studied by measuring turbidity over 14 days. The results indicate that CFG consists of different components differing in their molecular weights and carbohydrate and protein contents. The main fraction eluted with NaCl, although low in protein content, has the highest average molecular weight and was determined to be a better emulsifier than the other fractions. The unfractionated CFG, which contains different molecular species, is the best emulsifier.

Molecular Characteristics of Corn Fiber Gum and Their Influence on CFG Emulsifying Properties

ABSTRACT The molecular characteristics of two purified arabinoxylan fractions derived from corn kernels, corn fiber gum-1 and -2 (CFG-1 and -2), have been studied and correlated with emulsifying properties. CFG-1 and -2 fractions were isolated from different corn fiber sources by 1) a sequential alkaline extraction and H2O2 bleaching to produce CFG-1; and 2) additional H2O2 treatment of the alkali-extracted residue at pH 11.5, yielding CFG-2. Multiangle laser light-scattering and online viscosity were used to measure the molar mass, polydispersity, structure compactness, and intrinsic viscosity of the generated CFG fractions. Emulsification properties in an oil-in-water emulsion system with 10:1 oil-to-gum ratio was investigated by measuring turbidity of an aliquot from the bottom of the diluted emulsion over 10 days. The isolated CFG-2 from each fiber source was higher in weight-average molar mass (Mw) polydispersity) (Mw/Mn) and structure compactness, and also lower in solution weight-average intrinsic ...

Importance of Protein-Rich Components in Emulsifying Properties of Corn Fiber Gum

ABSTRACT Purified corn fiber gum (CFG-F) isolated from fine (kernel endosperm-derived) corn fiber that contained ≈2% residual protein was extracted with 70% aqueous ethanol. The aqueous ethanol extract (AEE), which contained 19.5% of the total CFG, contained a high percentage of the proteinaceous material present in the original gum sample. The AEE gum contained 6.81% protein by weight. The residue (R), which constituted 66% of the total CFG-F, contained only 0.55% of protein. The emulsifying properties of R and AEE in a model oil-in-water emulsification system were studied by measuring turbidity after 1, 2, and 3 weeks, particle size after 4 weeks, and by confocal laser scanning microscopy after three months of storage at room temperature. These gums were compared with the standard well-known emulsifiers native acacia gum (NAG) and modified acacia gum (MAG). The results indicate that although AEE contains protein-rich components, it is not as good an emulsifier as the residue which contains only 0.55% of...

Physico-chemical characterization of protein-associated polysaccharides extracted from sugar beet pulp

We have solubilized and separated polysaccharides from sugar beet pulp (SBP) into three fractions with steam assisted flash extraction (SAFE). For pectin, recovery ranged from 8 to 14%, degree of methy-esterification 66-73%, crude protein 1.3-1.7%, M(w) 262-318 kDa, η(w) 0.22-0.23 dL/g, Rg(z) 36-39 nm and Rh(z) 41-42 nm. For alkaline soluble polysaccharides, (ASP I) recovery ranged from 4.0 to 6.5%, crude protein 1.2-4.8%, weight average molar mass (M(w)) 66-68 kDa, weight average intrinsic viscosity (η(w)) 0.27-0.30 dL/g, z-average radius of gyration (Rg(z)) 25-29 nm and z-average hydrated radius (Rh(z)) 10-11 nm. ASP II recovery ranged from 2.0 to 8.6%, crude protein 1.2-4.8%, M(w) 299-339 kDa, η(w) 0.22-0.33 dL/g, Rg(z) 33-34 nm and Rh(z) 30-34 nm. Recovery of the residue mainly cellulose, ranged from 20.3 to 22.3%. The cellulose in this fraction was converted to carboxymethyl cellulose (CMC). The CMC fraction contained 0.33-0.43 crude protein and had an M(w) ranging from 127 to 263 kDa, η(w) 3.6-8.0 dL/g, Rg(z) 35-45 nm and Rh(z) 27-40 nm.

Protein/Arabinoxylans Gels: Effect of Mass Ratio on the Rheological, Microstructural and Diffusional Characteristics

Wheat bran arabinoxylan (WBAX) gels entrapping standard model proteins at different mass ratios were formed. The entrapment of protein affected the gel elasticity and viscosity values, which decreased from 177 to 138 Pa. The presence of protein did not modify the covalent cross-links content of the gel. The distribution of protein through the network was investigated by confocal laser scanning microscopy. In mixed gels, protein aggregates forming clusters were detected at protein/polysaccharide ratios higher than 0.25. These clusters were not homogeneously distributed, suggesting that WBAX and protein are located in two different phases. The apparent diffusion coefficient (Dm) of proteins during release from mixed gels was investigated for mass ratios of 0.06 and 0.12. For insulin, Dm increased significantly from 2.64 × 10−7 to 3.20 × 10−7 cm2/s as the mass ratio augmented from 0.06 to 0.12. No significant difference was found for Dm values of ovalbumin and bovine serum albumin released from the mixed gels. The results indicate that homogeneous protein/WBAX gels can be formed at low mass ratios, allowing the estimation of Dm by using an analytical solution of the second Fick’s law.

Antimicrobial edible coatings and films from micro-emulsions and their food applications

This study focused on the use of antimicrobial edible coatings and films from micro-emulsions to reduce populations of foodborne pathogens in foods. Corn-Bio-fiber gum (C-BFG) was used as an emulsifier with chitosan. Allyl isothiocyanate (AIT) and lauric arginate ester (LAE) served as antimicrobials. Micro-emulsions were obtained from a solution consisting of 1% chitosan, 0.5% C-BFG, and 1-4% AIT or LAE which was subject to high pressure homogenization (HPH) processing at 138MPa for 3cycles. Coatings and films produced from the micro-emulsions had micro-pores with sizes ranging from 100 to 300nm and micro-channels that hold antimicrobials effectively and facilitate the release of antimicrobials from the center to the surface of the films or coatings, thus enhancing their antimicrobial efficacy. The coatings and films with 1% AIT reduced populations of Listeria innocua by over 5, 2, and 3 log CFU in culture medium (Tryptic soy broth, TSB), ready-to-eat meat, and strawberries, respectively. The coatings and films with 1% LAE reduced populations of Escherichia coli O157:H7 and Salmonella spp. by over 5 and 2 log CFU in TSB and strawberries, respectively. This study provides an innovative approach for the development of effective antimicrobial materials to reduce food borne pathogenic contaminants on ready-to-eat meat, strawberries, or other food.

Corrigendum: Glycan complexity dictates microbial resource allocation in the large intestine

Nature Communications 6 Article number: 748110.1038/ncomms8481 (2015); Published June262015; Updated February052016 The financial support for the work described in this Article was not fully acknowledged. The Acknowledgements should have included the following:This work was supported in part by a grant to H.J.G., B.H. and N.T. (European Unions Seventh Framework Program (FP/2007/2013)/European Research Council (ERC) Grant Agreement 322820).

Production and applications of bio-based fiber gum and Z Trim from agricultural biomass

B fiber gums (BFGs) and Z Trim are water soluble arabinoxylan (Hemicellulose B) and water insoluble fibrous cellulose rich arabinoxylan respectively, isolated from various low value agricultural residues (corn stover, wheat straw, etc.), agricultural processing by-products (corn fiber, wheat bran, rice fiber, sorghum bran, sugar cane bagasse, etc.) and energy crops (switch grass and miscanthus) by alkaline treatment. The BFGs, isolated from different agricultural materials are purified, characterized and their functionalities are studied. They appear to have useful properties as emulsifiers, antioxidants, dietary fibers and other food ingredients. Like corn fiber gum (CFG), these polysaccharides are unique in making low viscosity solutions, even at high concentrations. Z Trims, prepared from the residues left over after BFG isolation, are also characterized and their water holding capacity, rheological behavior and ORAC values are determined. The rheological studies of these gels show that they make very viscous gels at low concentrations in water. They are completely non-digestible to humans and therefore make an excellent non-caloric food bulking agent and become helpful in replacing fat with healthy fiber and water without changing taste but improving mouth feel. Due to their high water absorbance, fiber addition, oil emulsification, and the reduction of calories, cholesterol, trans-fat and saturated fat, they become very useful ingredient in bakery products, dairy products, meats, dressing, mac and cheese etc. Understanding the functional properties of BFG and Z Trim will be beneficial from their commercialization point of view for their use in food industries.C is the one of birthplace of tea culture and the processing of tea or the drinking method of tea are both tea’s native habitats. Tea is featured by their health beneficial, refreshing and thirst quenching effects. However, people’s tea-drinking habits changed as the times. Drinking tea with a scientific way is a worthy and usefule problem to us from the past to the present. This study seeks to explore the different antioxidant activity of five kinds of tea by pouring hot water into tea many times which is based on people’s teadrinking habits. The result showed that antioxidant substance of green tea is significantly higher than in white tea, oolong tea, black tea and dark tea by online ABTS+ test, on the other hand, the antioxidant activity of the tea extracts was decreased with the increasing times of making tea. In the end, the main antioxidant substances of tea were quantitatively determinate by LCMS. The major findings suggested that: Both tea had powerful antioxidant capacity; green tea showed the higher antioxidant capacity than others and; four times of pouring hot water into tea was enough to drink by evaluation of antioxidant capacity of tea extracts. This study is usefule for drinking tea in a scientific way.Statement of the Problem: In recent years several disease outbreaks were linked to unpasteurized juices contaminated with human enteric pathogens such as Salmonella enterica and Escherichia coli O157:H7 (CDC 2011; EFSA 2015). While heat pasteurization and canning can inactivate vegetative pathogens, such processes can destroy heat labile nutrients and negatively alter sensory characteristics of juices. Also growing consumer demands for foods which are nutritious, fresh-like, and devoid of synthetic preservatives, have forced juice manufacturers to explore non-thermal processes and natural antimicrobials for pathogen control in juices. The present study investigated the effect of low concentrations of cinnamaldehyde combined with high pressure processing (HPP) for killing S. enterica in carrot juice (CRJ) and a mixed berry juice (MBJ) at 4oC. Methodology & Theoretical Orientation: CRJ (pH 6.25) and MBJ (pH 3.59) with added cinnamaldehyde (0.10, 0.15 and 0.25 μl/ml) were inoculated with S. enterica (5-strain; final concentration ~107 CFU/ml). Inoculated juices without added cinnamaldehyde served as control. Juices (4oC) were packaged in polyester pouches and pressurized (400 or 300 MPa) for 60, 90 and 120 seconds. The time between inoculation and HPP was approximately 1.5 hours. Salmonella survived for 42 days or more in control CRJ following HPP (400 MPa) for 30, 60, or 120 s. Addition of cinnamaldehyde to juices increased the sensitivity of S. enterica to HPP. Cinnamaldehyde (0.25 μl/ml) combined with 400 MPa (60 s) inactivated S. enterica by more than 5.5-log in CRJ. In MBJ, cinnamaldehyde (0.15 μl/ml) with a lower pressure (300 MPa for 120 s) resulted in complete inactivation (negative enrichment) and greater than a 5-log10 CFU/ ml reduction of S. enterica. Conclusion & Significance: The use of CA in conjunction with HPP has good potential to serve as an alternative process for heat pasteurization of juices and meet the 5-log reduction performance standard as stipulated in the juice HACCP regulations. Disciplines Food Science | Human and Clinical Nutrition | Meat Science | Molecular, Genetic, and Biochemical Nutrition Comments This abstract is published as Daraba[SLL[1] , A., Mendonca, A., Manu, D., Dickson, J., Sebranek, J., Shaw, A., and A. Dispirito. 2016. Enhanced destruction of Salmonella enterica in carrot and berry juices by a combination of cinnamaldehyde and high pressure processing. Journal of Experimental Food Chemistry: 2:4 (supplement). DOI: 10.4172/2472-0542.C1.006. Creative Commons License Creative Commons AttributionShare Alike 4.0 License This work is licensed under a Creative Commons Attribution-Share Alike 4.0 License. Authors Aura Daraba, Aubrey F. Mendonca, David Manu, James S. Dickson, Joseph G. Sebranek, Angela M. Shaw, and Alan A. DiSpirito This abstract is available at Iowa State University Digital Repository: https://lib.dr.iastate.edu/fshn_ag_pubs/166

Suppression of Psyllium Husk Suspension Viscosity by Addition of Water Soluble Polysaccharides

Psyllium seed husk is an insoluble dietary fiber with many health benefits. It can absorb many times its weight in water, forming very viscous suspensions, which have low palatability and consumer acceptance. We report here a novel approach for decreasing its viscosity, involving inclusion of a soluble polysaccharide in the suspension. This leads to a drastic decrease (up to 87%) in viscosity of suspensions, while maintaining the same dosage level of psyllium and also delivering a significant amount of soluble dietary fiber such as corn bio-fiber gum in a single serving. Four soluble polysaccharides with a range of molecular weights and solution viscosities have been studied for their viscosity suppression effect. Besides improving palatability, another advantage of this approach is that it makes it possible to deliver 2 different dietary fibers in significant quantities, thus offering even greater health benefits.