ORCID Profile
0000-0002-8652-0220
Current Organisations
Commonwealth Scientific and Industrial Research Organisation
,
CSIRO
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Publisher: Elsevier BV
Date: 11-2016
DOI: 10.1016/J.CARBPOL.2016.06.016
Abstract: The roles that the compact structure and proteins in pasta play in retarding evolution of starch molecular structure during in vitro digestion are explored, using four types of cooked s les: whole pasta, pasta powder, semolina (with proteins) and extracted starch without proteins. These were subjected to in vitro digestion with porcine α-amylase, collecting s les at different times and characterizing the weight distribution of branched starch molecules using size-exclusion chromatography. Measurement of α-amylase activity showed that a protein (or proteins) from semolina or pasta powder interacted with α-amylase, causing reduced enzymatic activity and retarding digestion of branched starch molecules with hydrodynamic radius (Rh) 100nm.
Publisher: Elsevier BV
Date: 2017
DOI: 10.1016/J.CARBPOL.2016.08.078
Abstract: Correlations among barley protein, starch molecular structure and grain size were determined using 30 barley s les with variable protein contents. Starch molecular structure was characterized by fluorophore-assisted carbohydrate electrophoresis and by size-exclusion chromatography (SEC, also termed GPC). The chain-length distributions of amylopectin were fitted using a mathematical model reflecting the relative activities of starch branching enzymes and starch synthase enzymes. Increased protein content significantly and negatively correlated with higher amounts of amylose with longer chains (degree of polymerization, DP 1600-40000) while barley grain sizes positively associated with starch contents. Protein content also positively correlated with the proportion of longer chains of amylopectin (DP 34-100). These results showed that the enzyme activities of starch synthases change with protein content, leading to altered starch contents, structures and grain sizes. From this perspective, selecting for large grain size (or low protein content) does not necessarily relate to starch structure, although may suggest long chains of amylopectin. Measuring starch structure could give a good indication of process performance in human food, animal feed and brewing, as all these structural features contribute to significant functional properties.
Publisher: Walter de Gruyter GmbH
Date: 29-04-2014
DOI: 10.3139/217.2847
Abstract: Starch-based superabsorbent polymers (SAPs) were produced by graft copolymerization of starch-g-acrylamide using a twin-roll mixer as reactor. This work focused on the effect of starch microstructure (amylose/amylopectin contents) from the same source (corn starch) on the graft ratio (GR), graft efficiency (GE) and Add-on (AO), as well as water absorption capability (WAC) of the SAPs, which were investigated by FTIR, NMR, gravimetric and TGA. The torque variation represented all the processing in the reactor, including compress, gelatinization, graft reaction and crosslinking. Results showed that all the starches were successfully grafted with acrylamide then crosslinked by N.N′-methylene-bisacrylamide through this technology. Both AO and GR increased with increasing amylose content. But the GE decreased with increasing amylose content, which is different from the results in the solution reaction. The higher WAC of high amylose starch-based SAP corresponds with higher AO and GR, while the higher WAC of waxy-based SAP corresponds with higher GE.
Publisher: Elsevier BV
Date: 05-2019
Publisher: Elsevier BV
Date: 2012
Publisher: Elsevier BV
Date: 09-2011
Publisher: Elsevier BV
Date: 06-2016
DOI: 10.1016/J.CARBPOL.2016.02.064
Abstract: Combined analytical techniques were used to explore the effects of alkali treatment on the multi-scale structure and digestion behavior of starches with different amylose/amylopectin ratios. Alkali treatment disrupted the amorphous matrix, and partial lamellae and crystallites, which weakened starch molecular packing and eventually enhanced the susceptibility of starch to alkali. Stronger alkali treatment (0.5% w/w) made this effect more prominent and even transformed the dual-phase digestion of starch into a triple-phase pattern. Compared with high-amylose starch, regular maize starch, which possesses some unique structure characteristics typically as pores and crystallite weak points, showed evident changes of hierarchical structure and in digestion rate. Thus, alkali treatment has been demonstrated as a simple method to modulate starch hierarchical structure and thus to realize the rational development of starch-based food products with desired digestibility.
Publisher: Wiley
Date: 25-06-2012
Publisher: Elsevier BV
Date: 04-2018
Publisher: Wiley
Date: 07-09-2010
Publisher: Springer Science and Business Media LLC
Date: 25-09-2017
DOI: 10.1007/S00216-017-0639-5
Abstract: Amylose, one of the components of starch, is a glucose polymer consisting largely of long, linear chains with a few long-chain branch points. The chain-length (molecular weight) distribution (CLD) of the component chains of amylose can provide information on amylose biosynthesis-structure-property relations, as has been done previously by fitting amylopectin CLDs to a model with physically meaningful parameters. Due to the presence of long chains, the CLD of amylose can currently best be obtained by size-exclusion chromatography, a technique that suffers from band-broadening effects which alter the observed distribution. The features of the multiple regions present in amylose chain-length distributions are also difficult to resolve, an issue that combines with band broadening to compound the difficulty of analysis and subsequent parameterization of the structural characteristics of amylose. A new method is presented to fit these distributions with biologically meaningful parameters in a way that accounts for band broadening. This is achieved by assuming that band broadening takes the form of a simple Gaussian over a relatively small region and that chain stoppage is a random process independent of the length of the substrate chain over the same region these assumptions are relatively weak and expected to be frequently applicable. The method provides inbuilt consistency tests for its applicability to a given data set and, in cases where it is applicable, allows for the first nonempirical parameterization of amylose biosynthesis-structure-property relations from CLDs by using parameters directly linked to the activities of the enzymes responsible for chain growth and chain stoppage. Graphical abstract Model calculation illustrating the method described and showing the ision between the three characteristic regions of a typical amylose chain-length distribution.
Publisher: Springer Science and Business Media LLC
Date: 07-06-2012
Publisher: Elsevier BV
Date: 09-2017
DOI: 10.1016/J.CARBPOL.2017.05.046
Abstract: Australian wild rices have significant genetic differences from domesticated rices, which might provide rices with different starch molecular structure and thus different functional properties. Molecular structure, gelatinization properties, and pasting behaviours of starch of three Australian wild rices (Oryza australiensis, taxa A (O. rufipogon like) and taxa B (O. meridionalis like)) were determined and compared to domesticated indica and japonica rice. These had higher amylose content, more shorter amylose chains and fewer short amylopectin chains, resulted in a high gelatinization temperature in these wild rices. Compared to domesticated japonica rice, taxa A had a lower pasting viscosity taxa B had a similar pasting viscosity but lower final viscosity. The significantly different starch molecular structure from that of normal domesticated rices, and concomitantly different properties, suggest advantageous uses in products such as rice crackers or rice pudding, and a source of nutritionally-desirable slowly digestible starch.
Publisher: American Chemical Society (ACS)
Date: 27-03-2017
Abstract: The efficiency of gluten extraction is of critical importance to the results derived from any analytical method for gluten detection and quantitation, whether it employs reagent-based technology (antibodies) or analytical instrumentation (mass spectrometry). If the target proteins are not efficiently extracted, the end result will be an under-estimation in the gluten content posing a health risk to people affected by conditions such as celiac disease (CD) and nonceliac gluten sensitivity (NCGS). Five different extraction protocols were investigated using LC-MRM-MS for their ability to efficiently and reproducibly extract gluten. The rapid and simple "IPA/DTT" protocol and related "two-step" protocol were enriched for gluten proteins, 55/86% (trypsin/chymotrypsin) and 41/68% of all protein identifications, respectively, with both methods showing high reproducibility (CV < 15%). When using multistep protocols, it was critical to examine all fractions, as coextraction of proteins occurred across fractions, with significant levels of proteins existing in unexpected fractions and not all proteins within a particular gluten class behaving the same.
Publisher: Society for Neuroscience
Date: 28-01-2009
DOI: 10.1523/JNEUROSCI.4341-08.2009
Abstract: Functional neuroimaging studies of probabilistic category learning in healthy adults report activation of cortical-striatal circuitry. Based on previous findings of normal learning rate concurrent with an overall performance deficit in patients with schizophrenia, we hypothesized that relative to healthy adults, patients with schizophrenia would display preserved caudate nucleus and abnormal prefrontal cortex activation during probabilistic category learning. Forty patients with schizophrenia receiving antipsychotic medication and 25 healthy participants were assessed on interleaved blocks of probabilistic category learning and control tasks while undergoing blood oxygenation level-dependent functional magnetic resonance imaging. In addition to the whole s le of patients with schizophrenia and healthy adults, a subset of patients and healthy adults matched for good learning was also compared. In the whole s le analysis, patients with schizophrenia displayed impaired performance in conjunction with normal learning rate relative to healthy adults. The matched comparison of patients and healthy adults classified as good learners revealed greater caudate and dorsolateral prefrontal cortex activity in the healthy adults and greater activation in a more rostral region of the dorsolateral prefrontal, cingulate, parahippoc al and parietal cortex in patients. These results demonstrate that successful probabilistic category learning can occur in the absence of normal frontal-striatal function. Based on analyses of the patients and healthy adults matched on learning and performance, a minority of patients with schizophrenia achieve successful probabilistic category learning and performance levels through differential activation of a circumscribed neural network which suggests a compensatory mechanism in patients showing successful learning.
Publisher: Elsevier BV
Date: 12-2015
DOI: 10.1016/J.FOODCHEM.2015.05.032
Abstract: The aim of the present study is to characterise the influence of gluten structure on the kinetics of starch hydrolysis in pasta. Spaghetti and powdered pasta were prepared from three different cultivars of durum semolina, and starch was also purified from each cultivar. Digestion kinetic parameters were obtained through logarithm-of-slope analysis, allowing identification of sequential digestion steps. Purified starch and semolina were digested following a single first-order rate constant, while pasta and powdered pasta followed two sequential first-order rate constants. Rate coefficients were altered by pepsin hydrolysis. Confocal microscopy revealed that, following cooking, starch granules were completely swollen for starch, semolina and pasta powder s les. In pasta, they were completely swollen in the external regions, partially swollen in the intermediate region and almost intact in the pasta strand centre. Gluten entrapment accounts for sequential kinetic steps in starch digestion of pasta the compact microstructure of pasta also reduces digestion rates.
Publisher: Elsevier BV
Date: 11-2020
Publisher: Walter de Gruyter GmbH
Date: 29-04-2014
DOI: 10.3139/217.2847
Abstract: Starch-based superabsorbent polymers (SAPs) were produced by graft copolymerization of starch-g-acrylamide using a twin-roll mixer as reactor. This work focused on the effect of starch microstructure (amylose/amylopectin contents) from the same source (corn starch) on the graft ratio (GR), graft efficiency (GE) and Add-on (AO), as well as water absorption capability (WAC) of the SAPs, which were investigated by FTIR, NMR, gravimetric and TGA. The torque variation represented all the processing in the reactor, including compress, gelatinization, graft reaction and crosslinking. Results showed that all the starches were successfully grafted with acrylamide then crosslinked by N.N′-methylene-bisacrylamide through this technology. Both AO and GR increased with increasing amylose content. But the GE decreased with increasing amylose content, which is different from the results in the solution reaction. The higher WAC of high amylose starch-based SAP corresponds with higher AO and GR, while the higher WAC of waxy-based SAP corresponds with higher GE.
Publisher: Elsevier BV
Date: 02-2018
DOI: 10.1016/J.FOODCHEM.2017.09.021
Abstract: The conversion of barley starch to sugars is a complex enzymic process. Most previous work concerned the biotechnical aspect of in situ barley enzymes. However, the interactions among the macromolecular substrates and their effects on enzymic catalysis has been little examined. Here, we explore the mechanisms whereby interactions of protein and starch in barley flour affect the kinetics of enzymatic hydrolysis of starch in an in vitro system, using digestion rate data and structural analysis by confocal microscopy. The degradation kinetics of both uncooked barley flour and of purified starches are found to be two-step sequential processes. Barley proteins, especially the water-soluble component, are found to retard the digestion of starch degraded by α-amylase: the enzyme binds with water-insoluble protein and with starch granules, leading to reduced starch hydrolysis. These findings are of potential industrial value in both the brewing and food industries.
Location: Australia
No related grants have been discovered for Wei Zou.