Search

Your search keyword '"Kontogiorgos, Vassilis"' showing total 212 results
Start Over Author "Kontogiorgos, Vassilis"
212 results on '"Kontogiorgos, Vassilis"'

58. The effects of wheat flour, water, salt and mixing on the rheological properties and the gas phase of bread dough

Author

Ames, Nancy (Food and Human Nutritional Sciences), Sapirstein, Harry (Food and Human Nutritional Sciences), Kontogiorgos, Vassilis (University of Huddersfield), Nickerson, Michael (University of Saskatchewan), Scanlon, Martin (Food and Human Nutritional Sciences) Koksel, Filiz (Food and Human Nutritional Sciences), Sun, Xinyang, Ames, Nancy (Food and Human Nutritional Sciences), Sapirstein, Harry (Food and Human Nutritional Sciences), Kontogiorgos, Vassilis (University of Huddersfield), Nickerson, Michael (University of Saskatchewan), Scanlon, Martin (Food and Human Nutritional Sciences) Koksel, Filiz (Food and Human Nutritional Sciences), and Sun, Xinyang

Abstract

Health Canada recommends an approximately 30% reduction of sodium levels in bread products, which brings a great challenge for bakery industry due to dough handling difficulties and product quality issues induced by sodium reduction. In order to address this challenge, the effects of wheat cultivar, water content and mixing time on the response of dough’s rheological properties and gas phase to salt (NaCl) reduction were investigated to develop processing strategies for improving the breadmaking performance of reduced salt content doughs. The rheological properties of doughs with a wide range of formulations were examined using the mixograph, dynamic oscillatory rheometry and creep-recovery tests. Outcomes from these rheological studies indicated that doughs with a better tolerance to salt reduction were prepared at higher water contents, and/or optimal mixing time. The gas phase parameters, i.e., the gas volume fraction and the volumetric bubble size distribution, of doughs were examined using synchrotron X-ray microtomography. In terms of the time evolution of the bubble size distribution in unyeasted doughs, increased water content, reduced salt content, and/or increased mixing time were seen to promote disproportionation in the dough. Dough gas phase studies also confirmed a cultivar-dependent response of dough to salt reduction and suggested that the optimal-mixing condition developed the doughs to be more tolerant to salt reduction compared to under- and over-mixing conditions. In conclusion, formulation and mixing conditions play an important role in determining dough’s response to salt reduction. The type of wheat flour (associated with the cultivar’s tolerance to salt reduction), water content and optimal mixing time need to be considered when improving the breadmaking performance of reduced-salt doughs.

Published
2019

62. Mesoscopic structure of pectin in solution

Author

Alba, K., Bingham, Richard, and Kontogiorgos, Vassilis

Subjects
QD, QC
Abstract

Mesoscopic structure of pectin with different molecular characteristics was investigated by means of small angle X-ray scattering (SAXS), electrokinetic measurements and data modelling. The influence of a broad range of pH (2-7) on chain conformation in the dilute and semi-diluted regime was investigated. Scattering data and concomitant analysis revealed two length scales at all environmental conditions studied. pH showed greater influence at acidic values (pH 2.0) enhancing the globular component of the structure due to association of galacturonic acid residues. Double logarithmic scattering intensity plots revealed fractal dimensions of 1.9 ±0.2 in the low-q regime and 1.5 ±0.2 in the high q-region, irrespectively of the specific environment. Increase in branching of RG-I regions of the polysaccharide chains enhanced the compact conformation irrespectively of the pH or concentration. The present work shows that radical changes in pectin conformation can be induced only under strongly acidic conditions a finding that has important consequences in tailoring the technological performance of these biopolymers

Published
2017

63. Soluble dietary fibres from sugarcane bagasse.

Author

Dimopoulou, Maria and Kontogiorgos, Vassilis

Subjects
*BAGASSE, *SUGARCANE, *MONOSACCHARIDES, *AGRICULTURAL wastes, *FIBERS, *URONIC acids, *ARABINOXYLANS
Abstract

Summary: Soluble dietary fibres from sugarcane bagasse were extracted under alkaline conditions and characterised. Precipitated fibres were dialysed, and the fibre composition was evaluated before and after the dialysis step. Compositional analysis indicated that the fibres both before and after dialysis consisted of 39% w/w total sugars, 16% w/w protein, 10% w/w Klason lignin and 30% w/w ash. Xylose was the main neutral sugar followed by arabinose with glucose, galactose and uronic acids also present in all samples. The structural properties were also spectroscopically examined, which confirmed the presence of arabinoxylans. Macromolecular characterisation revealed that molecular weight is reduced after dialysis, indicating that a range of dietary fibres with different macromolecular characteristics may be obtained depending on the specific processing steps. The present work shows that soluble arabinoxylans may be obtained from sugarcane agricultural wastes that may be used as a source of novel dietary fibres. [ABSTRACT FROM AUTHOR]

Published
2020
Full Text
View/download PDF

64. Emulsifying properties of Ghanaian grewia gum.

Author

Kpodo, Fidelis Mawunyo, Agbenorhevi, Jacob Kwaku, Alba, Katerina, and Kontogiorgos, Vassilis

Subjects
EXTRACTION techniques, POLYSACCHARIDES, EMULSIONS
Abstract

Grewia gums were extracted with phosphate (PB) and sodium metabisulphite buffers (SMB) and their emulsification properties in acidic oil‐in‐water emulsions on ageing were studied by means of droplet size distribution, ζ‐potential measurements, interfacial composition analysis and viscometry. PB extracts showed smaller droplet sizes (~10 μm) than SMB isolates (>35 μm) and greater long‐term stability. PB‐stabilised emulsions also demonstrated the least polysaccharide (~0.6 mg m−2) and protein (~0.2 mg m−2) interfacial coverage compared with SMB counterparts (~1.5 mg m−2 for polysaccharide and ~ 1 mg m−2 for protein). ζ‐Potential measurements revealed negative interfacial charge for all emulsions confirming the presence of polysaccharide‐laden interfaces. Droplet size distribution also varied among emulsions during ageing indicating a complex relationship between interfacial composition and stability. The present work shows that different emulsifying properties may be obtained depending on the extraction technique employed that could be exploited in preparation of emulsions for flavour or bioactive‐delivery applications. [ABSTRACT FROM AUTHOR]

Published
2020
Full Text
View/download PDF

69. Editorial: Special Issue of Food Hydrocolloids: Bridging the Divide

Author

Morris, Gordon, Smith, Alan M., and Kontogiorgos, Vassilis

Subjects
QD, Q1, RS
Abstract

This special edition of Food Hydrocolloids is based on the 1st UK Hydrocolloids Symposium, held on the 10th of September, 2013, at the University of Huddersfield. The meeting was attended by nearly 80 chemists, food and pharmaceutical scientists and was organized around the theme of “Bridging the Divide between Food and Pharma” and aimed to promote the cross-fertilisation of ideas between disciplines for hydrocolloid applications.

Published
2014

70. Extrusion processing of raw food materials and by-products: A review.

Author

Offiah, Vivian, Kontogiorgos, Vassilis, and Falade, Kolawole O.

Subjects
*EXTRUSION process, *FOOD industry, *RAW foods, *WASTE products, *RAW materials, *FOOD industrial waste
Abstract

Extrusion technology has rapidly transformed the food industry with its numerous advantages over other processing methods. It offers a platform for processing different products from various food groups by modifying minor or major ingredients and processing conditions. Although cereals occupy a large portion of the extruded foods market, several other types of raw materials have been used. Extrusion processing of various food groups, including cereals and pseudo cereals, roots and tubers, pulses and oilseeds, fruits and vegetables, and animal products, as well as structural and nutritional changes in these food matrices are reviewed. Value addition by extrusion to food processing wastes and by-products from fruits and vegetables, dairy, meat and seafood, cereals and residues from starch, syrup and alcohol production, and oilseed processing are also discussed. Extrusion presents an economical technology for incorporating food processing residues and by-products back into the food stream. In contemporary scenarios, rising demand for extruded products with functional ingredients, attributed to evolving lifestyles and preferences, have led to innovations in the form, texture, color and content of extruded products. Information presented in this review would be of importance to processors and researchers as they seek to enhance nutritional quality and delivery of extruded products. [ABSTRACT FROM AUTHOR]

Published
2019
Full Text
View/download PDF

71. Adding Value to Fruit Processing Waste: Innovative Ways to Incorporate Fibers from Berry Pomace in Baked and Extruded Cereal-based Foods A SUSFOOD Project

Author

Universitat Politècnica de València. Grupo de Microestructura y Química de Alimentos, Universitat Politècnica de València. Departamento de Tecnología de Alimentos - Departament de Tecnologia d'Aliments, Rohm, Harald, Brennan, Charles, Turner, Charlotta, Guenther, Edeltraud, Campbell, Grant, Hernando Hernando, Mª Isabel, Struck, Susanne, Kontogiorgos, Vassilis, Universitat Politècnica de València. Grupo de Microestructura y Química de Alimentos, Universitat Politècnica de València. Departamento de Tecnología de Alimentos - Departament de Tecnologia d'Aliments, Rohm, Harald, Brennan, Charles, Turner, Charlotta, Guenther, Edeltraud, Campbell, Grant, Hernando Hernando, Mª Isabel, Struck, Susanne, and Kontogiorgos, Vassilis

Abstract

This article communicates the set-up of BERRYPOM, a European research project established in the second call of the SUStainable FOOD Production and Consumption (SUSFOOD) network. The project deals with the by-product from berry processing, which is frequently recycled as animal feed, composted or utilized for biogas production. With BERRYPOM it is proposed to analyze the value of berry pomace, to optimize the recovery of bioactive compounds from pomace material, and to incorporate processed berry pomace in cereal-based foods to take advantage of nutritional benefits that originate from its fiber and the content of bioactive substances. Additionally, extraction methods will be evaluated to obtain products rich in phytochemicals, and the influence of OPEN ACCESS Foods 2015, 4 691 processing steps on the antioxidant capacity of pomace will be analyzed. The fiber extracts will then also be utilized in different cereal-based foods and extruded products. As project outcome we expect a substantial increase of knowledge concerning fiber and phytochemicals extraction from berry pomace, its suitability for enhancing nutritional and sensory properties of cereal-based foods, and its effects on the sustainability of the food chain.

Published
2015

75. Editorial

Author

Morris, Gordon A., primary, Smith, Alan M., additional, and Kontogiorgos, Vassilis, additional

Published
2014
Full Text
View/download PDF

85. Fundamental considerations in the effect of molecular weight on the glass transition of the gelatin/cosolute system.

Author

Jiang, Bin, Kasapis, Stefan, Kontogiorgos, Vassilis, and Bush, C. Allen

Abstract

Four molecular fractions of gelatin produced by alkaline hydrolysis of collagen were investigated in the presence of cosolute to record the mechanical properties of the glass transition in high-solid preparations. Dynamic oscillatory and stress relaxation moduli in shear were recorded from 40°C to temperatures as low as −60°C. The small-deformation behavior of these linear polymers was separated by the method of reduced variables into a basic function of time alone and a basic function of temperature alone. The former allowed the reduction of isothermal runs into a master curve covering 17 orders of magnitude in the time domain. The latter follows the passage from the rubbery plateau through the glass transition region to the glassy state seen in the variation of shift factor, aT, as a function of temperature. The mechanical glass transition temperature ( Tg) is pinpointed at the operational threshold of the free volume theory and the predictions of the reaction rate theory. Additional insights into molecular dynamics are obtained via the coupling model of cooperativity, which introduces the concept of coupling constant or interaction strength of local segmental motions that govern structural relaxation at the vicinity of Tg. The molecular weight of the four gelatin fractions appears to have a profound effect on the transition temperature or coupling constant of vitrified matrices, as does the protein chemistry in relation to that of amorphous synthetic polymers or gelling polysaccharides. © 2011 Wiley Periodicals, Inc. Biopolymers 97: 303-310, 2012. [ABSTRACT FROM AUTHOR]

Published
2012
Full Text
View/download PDF

86. Numerical computation of relaxation spectra from mechanical measurements in biopolymers

Author

Kontogiorgos, Vassilis, Jiang, Bin, and Kasapis, Stefan

Subjects
*PLANT proteins, *SPECTRUM analysis, *RESIDUAL stresses, *GLUTEN
Abstract

Abstract: In the present investigation, a computational methodology to treat relaxation spectra from mechanical data is developed. To calculate the spectral function that represents the relaxation process of the material, three different regularization algorithms were tested using MATLAB. Two algorithms employ Tikhonov’s regularization whereas the third investigative tool is an implementation of the CONTIN algorithm. These efforts improved the ability to look at data hence allowing utilization of the L-curve criterion in order to locate the optimum regularization parameter for accurate data inversion. Algorithms were first evaluated with hypothetical data followed by experimental datasets of hydrated gluten as a model biopolymer system. Essentially, algorithms converge on a specific relaxation spectrum that unveils the molecular features of gluten structure. The methodology described is not limited to mechanical measurements but should be used with any type of exponential decay in studies of relaxation processes. [Copyright &y& Elsevier]

Published
2009
Full Text
View/download PDF

87. Fractionation and characterisation of dietary fibre from blackcurrant pomace

Author

Alba, Katerina, Macnaughtan, William, Laws, Andrew, Foster, Tim, Campbell, Grant, Kontogiorgos, Vassilis, Alba, Katerina, Macnaughtan, William, Laws, Andrew, Foster, Tim, Campbell, Grant, and Kontogiorgos, Vassilis

Abstract

The potential of blackcurrant pomace as a raw material for the extraction of dietary fibre was evaluated using two pomaces one sourced from the UK and one from Poland. A fractionation protocol was designed to isolate and subsequently quantify the soluble and insoluble dietary fibre fractions. Blackcurrant pomace and isolated pectins, hemicelluloses and celluloses were assessed by means of sugar compositional analysis, spectroscopy, size exclusion chromatography and dilute solution viscometry. The blackcurrant pomaces presented considerable amounts of dietary fibre with soluble fibre ranging from 25-30% w/w and insoluble dietary fibre accounting for about 47% w/w for both pomaces. Blackcurrant pomaces differed in the amount of extracted pectins with an almost two times higher pectin yield obtained from blackcurrant pomace sourced from Poland. The hemicellulosic polysaccharide content was 15% w/w whereas the amount of cellulosic fraction varied from 14-17% w/w. Pectins isolated from both blackcurrant pomaces were LM pectins with a degree of esterification in the range of 11-38%. The work has identified that dietary fibres obtained from blackcurrant pomace had desirable ratio of insoluble to soluble fibre and are a potential new source of dietary fibre.

Full Text
View/download PDF

88. Fractionation and characterisation of dietary fibre from blackcurrant pomace

Author

Alba, Katerina, Macnaughtan, William, Laws, Andrew, Foster, Tim, Campbell, Grant, Kontogiorgos, Vassilis, Alba, Katerina, Macnaughtan, William, Laws, Andrew, Foster, Tim, Campbell, Grant, and Kontogiorgos, Vassilis

Abstract

The potential of blackcurrant pomace as a raw material for the extraction of dietary fibre was evaluated using two pomaces one sourced from the UK and one from Poland. A fractionation protocol was designed to isolate and subsequently quantify the soluble and insoluble dietary fibre fractions. Blackcurrant pomace and isolated pectins, hemicelluloses and celluloses were assessed by means of sugar compositional analysis, spectroscopy, size exclusion chromatography and dilute solution viscometry. The blackcurrant pomaces presented considerable amounts of dietary fibre with soluble fibre ranging from 25-30% w/w and insoluble dietary fibre accounting for about 47% w/w for both pomaces. Blackcurrant pomaces differed in the amount of extracted pectins with an almost two times higher pectin yield obtained from blackcurrant pomace sourced from Poland. The hemicellulosic polysaccharide content was 15% w/w whereas the amount of cellulosic fraction varied from 14-17% w/w. Pectins isolated from both blackcurrant pomaces were LM pectins with a degree of esterification in the range of 11-38%. The work has identified that dietary fibres obtained from blackcurrant pomace had desirable ratio of insoluble to soluble fibre and are a potential new source of dietary fibre.

Full Text
View/download PDF

89. Fractionation and characterisation of dietary fibre from blackcurrant pomace

Author

Alba, Katerina, Macnaughtan, William, Laws, Andrew, Foster, Tim, Campbell, Grant, Kontogiorgos, Vassilis, Alba, Katerina, Macnaughtan, William, Laws, Andrew, Foster, Tim, Campbell, Grant, and Kontogiorgos, Vassilis

Abstract

The potential of blackcurrant pomace as a raw material for the extraction of dietary fibre was evaluated using two pomaces one sourced from the UK and one from Poland. A fractionation protocol was designed to isolate and subsequently quantify the soluble and insoluble dietary fibre fractions. Blackcurrant pomace and isolated pectins, hemicelluloses and celluloses were assessed by means of sugar compositional analysis, spectroscopy, size exclusion chromatography and dilute solution viscometry. The blackcurrant pomaces presented considerable amounts of dietary fibre with soluble fibre ranging from 25-30% w/w and insoluble dietary fibre accounting for about 47% w/w for both pomaces. Blackcurrant pomaces differed in the amount of extracted pectins with an almost two times higher pectin yield obtained from blackcurrant pomace sourced from Poland. The hemicellulosic polysaccharide content was 15% w/w whereas the amount of cellulosic fraction varied from 14-17% w/w. Pectins isolated from both blackcurrant pomaces were LM pectins with a degree of esterification in the range of 11-38%. The work has identified that dietary fibres obtained from blackcurrant pomace had desirable ratio of insoluble to soluble fibre and are a potential new source of dietary fibre.

Full Text
View/download PDF

90. Fractionation and characterisation of dietary fibre from blackcurrant pomace

Author

Alba, Katerina, Macnaughtan, William, Laws, Andrew, Foster, Tim, Campbell, Grant, Kontogiorgos, Vassilis, Alba, Katerina, Macnaughtan, William, Laws, Andrew, Foster, Tim, Campbell, Grant, and Kontogiorgos, Vassilis

Abstract

The potential of blackcurrant pomace as a raw material for the extraction of dietary fibre was evaluated using two pomaces one sourced from the UK and one from Poland. A fractionation protocol was designed to isolate and subsequently quantify the soluble and insoluble dietary fibre fractions. Blackcurrant pomace and isolated pectins, hemicelluloses and celluloses were assessed by means of sugar compositional analysis, spectroscopy, size exclusion chromatography and dilute solution viscometry. The blackcurrant pomaces presented considerable amounts of dietary fibre with soluble fibre ranging from 25-30% w/w and insoluble dietary fibre accounting for about 47% w/w for both pomaces. Blackcurrant pomaces differed in the amount of extracted pectins with an almost two times higher pectin yield obtained from blackcurrant pomace sourced from Poland. The hemicellulosic polysaccharide content was 15% w/w whereas the amount of cellulosic fraction varied from 14-17% w/w. Pectins isolated from both blackcurrant pomaces were LM pectins with a degree of esterification in the range of 11-38%. The work has identified that dietary fibres obtained from blackcurrant pomace had desirable ratio of insoluble to soluble fibre and are a potential new source of dietary fibre.

Full Text
View/download PDF

91. Fractionation and characterisation of dietary fibre from blackcurrant pomace

Author

Alba, Katerina, Macnaughtan, William, Laws, Andrew, Foster, Tim, Campbell, Grant, Kontogiorgos, Vassilis, Alba, Katerina, Macnaughtan, William, Laws, Andrew, Foster, Tim, Campbell, Grant, and Kontogiorgos, Vassilis

Abstract

The potential of blackcurrant pomace as a raw material for the extraction of dietary fibre was evaluated using two pomaces one sourced from the UK and one from Poland. A fractionation protocol was designed to isolate and subsequently quantify the soluble and insoluble dietary fibre fractions. Blackcurrant pomace and isolated pectins, hemicelluloses and celluloses were assessed by means of sugar compositional analysis, spectroscopy, size exclusion chromatography and dilute solution viscometry. The blackcurrant pomaces presented considerable amounts of dietary fibre with soluble fibre ranging from 25-30% w/w and insoluble dietary fibre accounting for about 47% w/w for both pomaces. Blackcurrant pomaces differed in the amount of extracted pectins with an almost two times higher pectin yield obtained from blackcurrant pomace sourced from Poland. The hemicellulosic polysaccharide content was 15% w/w whereas the amount of cellulosic fraction varied from 14-17% w/w. Pectins isolated from both blackcurrant pomaces were LM pectins with a degree of esterification in the range of 11-38%. The work has identified that dietary fibres obtained from blackcurrant pomace had desirable ratio of insoluble to soluble fibre and are a potential new source of dietary fibre.

Full Text
View/download PDF

92. Suspended manufacturing of multi-layered biopolymer hydrogels for tissue engineering

Author

Senior, Jessica Jade, Smith, Alan, and Kontogiorgos, Vassilis

Subjects
610.28, Q Science (General), QR Microbiology
Abstract

Tissue engineering is proving a promising tool as an alternative to relying on donor availability in restorative tissue therapeutics. Tissue engineering concepts entail combining cells and materials in vitro to generate 3D parts that replicate in vivo tissue environments. Much focus has been spent on researching biopolymer hydrogels as scaffolds within tissue engineering constructs as there is vast potential in their tailorability to simulate the extracellular matrices within native human tissues. Although many features within hydrogels may be finely tuned when developing tissue engineering implants, such as water content, mechanical properties, and microarchitecture, current studies in this area are seldom able to recapitulate the physicochemical and mechanical gradients that are exhibited in human tissues, within a single construct. Moreover, the hydrogel precursor solutions used in 3D bioprinting tissue engineering constructs are usually manipulated towards enhancing either print fidelity (by increasing solution viscosity) or to preserve the viability of suspended cells (by decreasing the viscosity of precursor solutions). 3D bioprinted tissue engineering constructs therefore often fail to harbour both optimal print fidelity in conjunction with viable encapsulated cells thus leaving the intended tissue engineering ECM environment poorly reproduced. The work presented in this thesis addresses these problems and demonstrates that the success of a tissue engineering construct need not be compromised by the usual trade-off between print fidelity and cell viability and can in fact possess both of these features that are crucial to the function of the part. This technology uses a supporting gel bed within which multiple cell/hydrogel printing solutions are layered to keep the construct in shape prior to solidifying. The mechanisms behind the function of the supporting gel bed as a suspending agent were first analysed, showing that its shear-thinning behaviour allows material to be deposited within it followed by rapid restructuring to uphold the construct shape. A range of contrasting hydrogels and cell types were then 3D bioprinted into multiple layers and configurations, pushing the boundaries of what can usually be achieved when conventionally 3D printing low viscosity solutions onto a planar surface. As an example of the potential of this technique in becoming commonplace in the clinic, a chronic-depth skin equivalent was 3D printed, complete with hypodermis, dual compartment dermis and epidermis. The construct contained gradients in material chemistry, mechanical properties, microarchitecture, and cell phenotype, and served as an example of the capacity that this system holds in generating highly sophisticated human tissue mimics.

Published
2020

93. Aeration and rheology of high fibre bread doughs

Author

Aigbe, Mariam, Campbell, Grant M., and Kontogiorgos, Vassilis

Subjects
664, QD Chemistry
Abstract

Although there is continuous advice to increase consumption of dietary fibre, the intake of dietary fibre by individuals remains inadequate. Bread is potentially a major source of dietary fibre in the population; however, a factor mitigating against adequate consumption of high fibre bread is the damage caused by the fibre to the aerated structures of bread, which is key to its palatability and appeal. Wheat bran is a rich source of dietary fibre but its presence in wholemeal bread damages the aerated structures and lessens its appeal. Addition of wheat bran and other sources of dietary fibre to bread tends to give decreased dough strength and loaf volume, impaired crumb structure and reduced crumb softness. Potential mechanisms reported in the literature by which bran exerts its deleterious effects include dilution of the gluten protein, mechanical disruption of gluten films, and starch gelatinisation at a lower temperature during baking (as a consequence of the increased water availability) giving less oven spring and lower loaf volumes. The particle size of the wheat bran mediates its detrimental effect, with smaller particles generally giving finer crumb textures, although not necessarily producing larger loaf volumes or the most appealing or healthy bread. However, the full complexity of the effects of bran within the range of dough formulations and breadmaking processes is not yet understood, making it hard to find ways to produce acceptable high-fibre breads. Meanwhile, another potential new class of fibre-based bakery ingredient are Arabinoxylans (AX) which can be extracted from biorefinery by-products such as wheat bran, oat bran and sugarcane bagasse. AX can have either beneficial or detrimental effects on the dough depending on the type or level of AX used. This thesis therefore presents work to understand effects of bran and AX on dough aeration and rheology in order to better understand their effects in bread. The effects of ethanol and retardation time (over 18 hours at 4°C) were investigated with the use of the Dynamic Dough Density (DDD) system, to investigate the hypothesis that retardation affected dough expansion through the production of ethanol by the yeast during the retardation period, and to demonstrate the sensitivity and usefulness of the DDD system prior to its use to investigate fibre effects in doughs. The addition of ethanol even at small levels decreased the maximum expansion of dough, while retardation showed the reverse, giving an increase in maximum dough expansion over time. It was therefore concluded that the effects of retardation did not arise as a result of ethanol. The DDD system proved a sensitive discriminator of these effects. The Solvent Retention Capacity (SRC) test was used to determine the effect of fibre addition on water absorption. The SRC test uses four solvents to distinguish effects related to protein, starch damage and pentosans. The test was sensitive to addition of bran and AX, but its interpretation was ambiguous as it is conventionally used for characterising white flours. Rheological studies were carried out using creep-recovery measurements and the expansion capabilities of dough formulations were investigated using the DDD system. Bread doughs were found to be less compliant with an increase in the level of fibre added; AX also inhibited the expansion capacity of bread doughs. Bread aeration and dough rheology were investigated simultaneously by varying processing and ingredient factors during mixing. Dough aeration was quantified using dough density measurements, while dough rheology was characterised under dynamic oscillatory deformations using a Kinexus rheometer. Doughs were prepared using a bench top Minorpin mixer and a high-speed laboratory scale Tweedy 1 mixer. The high-speed Tweedy 1 mixer developed the gluten network better, leading to greater DDD expansion than the doughs produced from the Minorpin mixer. Dough formulations containing wheat bran gave less expansion in the DDD system. Dough formulations containing AX from wheat bran and from sugarcane bagasse also decreased DDD expansion, more so for AX from bagasse that wheat bran. Bread loaf volume decreased in all formulations with added fibre. The current work has expanded understanding of the effects of fibre on aspects of dough and bread quality: aeration and rheology of doughs, water absorption, expansion of doughs, and baked loaf volume.

Published
2019

Catalog

Books, media, physical & digital resources
See catalog results