Publications by authors named "Guantian Li"

13 Publications

  • Page 1 of 1

Solubilisation of micellar casein powders by high-power ultrasound.

Ultrason Sonochem 2020 Oct 15;67:105131. Epub 2020 Apr 15.

School of Food Science and Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, China. Electronic address:

High protein milk ingredients, such as micellar casein powder (MCP), exhibit poor solubility upon reconstitution in water, particularly after long-time storage. In this study, ultrasonication (20 kHz, power density of 0.75 W/ml) was used to improve the solubility of aged MCP powders. For all the MCP powders (concentration varying from 0.5 to 5%, and storage of MCP at 50 °C for up to 10 days) it was found that short time ultrasonication (2.5 min) reduced the size of the protein particles from >30 μm to ∼0.1 μm, as measured by light scattering. This resulted in an improvement of solubility (>95%) for all the MCP powders. Cryo-electron microscopy and small x-ray angle scattering showed that the MCP powders dissolved into particles with morphologies and internal structure similar to native casein micelles in bovine milk. SDS-PAGE and RP-HLPC showed that ultrasonication did not affect the molecular weight of the individual casein molecules. Compared to overhead stirring using a 4-blade stirrer, ultrasonication required less than 10 times the drawn electrical energy density to achieve a particle size 10 times smaller.
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http://dx.doi.org/10.1016/j.ultsonch.2020.105131DOI Listing
October 2020

Physicochemical properties of dodecenyl succinic anhydride (DDSA) modified quinoa starch.

Food Chem 2019 Dec 17;300:125201. Epub 2019 Jul 17.

School of Chemical Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand. Electronic address:

Quinoa starch granules were esterified with dodecenyl succinic anhydride (DDSA) to various degrees of substitution (DS) (0.0023-0.0095). Physicochemical properties and emulsification capacity of the modified starch were studied. Increasing DS increased the particle size, water solubility, and swelling power, while decreasing the gelatinization enthalpy change and relative crystallinity of the starch. The DDSA groups were suggested to be mostly located in the amorphous region of starch granules. With increasing DS, the viscosity and storage modulus (G') obtained from rheological analysis increased first and then decreased. The DDSA modified quinoa starch efficiently stabilized O/W Pickering emulsions and has some technical advantages compared to octenyl succinic anhydride (OSA)-modified quinoa starch. Increasing DS led to decreased droplet size of the emulsions and a higher capacity in stabilizing emulsions during storage for a period of 10 days. This study suggested the potential application of DDSA modified quinoa starch as an emulsifier in stabilizing Pickering emulsions.
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http://dx.doi.org/10.1016/j.foodchem.2019.125201DOI Listing
December 2019

Rheological properties in relation to molecular structure of quinoa starch.

Authors:
Guantian Li Fan Zhu

Int J Biol Macromol 2018 Jul 16;114:767-775. Epub 2018 Mar 16.

School of Chemical Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand. Electronic address:

Quinoa starch granules are small (~0.5 - 3μm) with potentials for some food and other applications. To better exploit it as a new starch resource, this study investigates the steady shear and dynamic oscillatory properties of 9 quinoa starches varying in composition and structure. Steady shear analysis shows that the flow curves could be well described by 4 selected mathematic models. Temperature sweep analysis reveals that the quinoa starch encounters a 4-stage process including 2 phase transitions. Structure-function relationship analysis showed that composition as well as unit and internal chain length distribution of amylopectin have significant impact on the rheological properties (e.g., G' at 90°C) of quinoa starch. The roles of some individual unit chains and super-long unit chains of amylopectin in determining the rheological properties of quinoa starch were revealed. This study may stimulate further interest in understanding the structural basis of starch rheology.
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http://dx.doi.org/10.1016/j.ijbiomac.2018.03.039DOI Listing
July 2018

Physicochemical properties of black pepper (Piper nigrum) starch.

Carbohydr Polym 2018 Feb 15;181:986-993. Epub 2017 Nov 15.

School of Chemical Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.

Black pepper (Piper nigrum) is among the most popular spices around the world. Starch is the major component of black pepper. However, little is known about functional properties of this starch. In this study, swelling, solubility, thermal properties, rheology, and enzyme susceptibility of 2 black pepper starches were studied and compared with those of maize starch. Pepper starch had lower water solubility and swelling power than maize starch. It had higher viscosity during pasting event. In dynamic oscillatory analysis, pepper starch had lower storage modulus. Thermal analysis showed that pepper starch had much higher gelatinization temperatures (e.g., conclusion temperature of 94°C) than maize starch. The susceptibility to α-amylolysis of pepper starch was not very different from that of maize starch. Overall, the differences in the physicochemical properties of the 2 pepper starches are non-significant. The relationships between structure (especially amylopectin internal molecular structure) and properties of starch components are highlighted.
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http://dx.doi.org/10.1016/j.carbpol.2017.11.051DOI Listing
February 2018

Quinoa starch: Structure, properties, and applications.

Authors:
Guantian Li Fan Zhu

Carbohydr Polym 2018 Feb 23;181:851-861. Epub 2017 Nov 23.

School of Chemical Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand. Electronic address:

Quinoa (Chenopodium quinoa Willd.) has gained popularity worldwide largely due to the attractive nutritional profile. It also has much potential for food security due to the great genetic diversity. Starch is the main component of quinoa grain and makes up to 70% of the dry matter. The starch plays a crucial role in functional properties of quinoa and related food products. The starch granules are rather small (∼1-3μm) with relatively low amylose contents as compared with most of the other starches. Quinoa amylopectin has significant amounts of short chains and super-long chains. These unique features have generated research interest in using the starch for food and other applications such as creating Pickering emulsions. This review summarizes the present knowledge of the isolation, composition, granular and molecular structures, physicochemical properties, modifications, and applications of quinoa starch. It becomes obvious that this starch has great potential for food and nonfood applications.
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http://dx.doi.org/10.1016/j.carbpol.2017.11.067DOI Listing
February 2018

Unit and internal chain profiles of maca amylopectin.

Food Chem 2018 Mar 7;242:106-112. Epub 2017 Sep 7.

School of Chemical Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand. Electronic address:

Unit chain length distributions of amylopectin and its φ, β-limit dextrins, which reflect amylopectin internal structure from three maca starches, were determined by high-performance anion-exchange chromatography with pulsed amperometric detection after debranching, and the samples were compared with maize starch. The amylopectins exhibited average chain lengths ranging from 16.72 to 17.16, with ranges of total internal chain length, external chain length, and internal chain length of the maca amylopectins at 12.49 to 13.68, 11.24 to 11.89, and 4.27 to 4.48. The average chain length, external chain length, internal chain length, and total internal chain length were comparable in three maca amylopectins. Amylopectins of the three maca genotypes studied here presented no significant differences in their unit chain length profiles, but did show significant differences in their internal chain profiles. Additional genetic variations between different maca genotypes need to be studied to provide unit- and internal chain profiles of maca amylopectin.
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http://dx.doi.org/10.1016/j.foodchem.2017.09.024DOI Listing
March 2018

Effect of high pressure on rheological and thermal properties of quinoa and maize starches.

Authors:
Guantian Li Fan Zhu

Food Chem 2018 Feb 30;241:380-386. Epub 2017 Aug 30.

School of Chemical Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand. Electronic address:

Quinoa starch has small granules with relatively low gelatinization temperatures and amylose content. High hydrostatic pressure (HHP) is a non-thermal technique for food processing. In this study, effects of HHP up to 600MPa on physical properties of quinoa starch were studied and compared with those of a normal maize starch. Both starches gelatinized at 500 and 600MPa. The pressure of 600MPa completely gelatinized quinoa starch as revealed by thermal analysis. Dynamic rheological analysis showed that HHP improved the gel stability of both starches during cooling. HHP had little effects on amylopectin recrystallization and gel textural properties of starch. Overall, quinoa starch was more susceptible to HHP than maize starch. The effects of HHP on some rheological properties such as frequency dependence were different between these two types of starches. The differences could be attributed to the different composition, granular and chemical structures of starch, and the presence of granule remnants.
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http://dx.doi.org/10.1016/j.foodchem.2017.08.088DOI Listing
February 2018

Amylopectin molecular structure in relation to physicochemical properties of quinoa starch.

Authors:
Guantian Li Fan Zhu

Carbohydr Polym 2017 May 5;164:396-402. Epub 2017 Feb 5.

School of Chemical Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand. Electronic address:

Structure-function relationships of starch components remain a subject of research interest. Quinoa starch has very small granules (∼2μm) with unique properties. In this study, nine quinoa starches varied greatly in composition, structure, and physicochemical properties were selected for the analysis of structure-function relationships. Pearson correlation analysis revealed that the properties related to gelatinization such as swelling power, water solubility index, crystallinity, pasting, and thermal properties are much affected by the amylopectin chain profile and amylose content. The parameters of gel texture and amylose leaching are much related to amylopectin internal structure. Other properties such as enzyme susceptibility and particle size distribution are also strongly correlated with starch composition and amylopectin structure. Interesting findings indicate the importance of amylopectin internal structure and individual unit chain profile in determining the physicochemical properties of starch. This work highlights some relationships among composition, amylopectin structure and physicochemical properties of quinoa starch.
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http://dx.doi.org/10.1016/j.carbpol.2017.02.014DOI Listing
May 2017

Molecular structure of quinoa starch.

Authors:
Guantian Li Fan Zhu

Carbohydr Polym 2017 Feb 2;158:124-132. Epub 2016 Dec 2.

School of Chemical Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand. Electronic address:

Quinoa starch has very small granules with unique properties. However, the molecular structure of quinoa starch remains largely unknown. In this study, composition and amylopectin molecular structure of 9 quinoa starch samples were characterised by chromatographic techniques. In particular, the amylopectin internal molecular structure, represented by φ, β-limit dextrins (LDs), was explored. Great variations in the composition and molecular structures were recorded among samples. Compared with other amylopectins, quinoa amylopectin showed a high ratio of short chain to long chains (mean:14.6) and a high percentage of fingerprint A-chains (A) (mean:10.4%). The average chain length, external chain length, and internal chain length of quinoa amylopectin were 16.6, 10.6, and 5.00 glucosyl residues, respectively. Pearson correlation and principal component analysis revealed some inherent correlations among structural parameters and a similarity of different samples. Overall, quinoa amylopectins are structurally similar to that from starches with A-type polymorph such as oat and amaranth starches.
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http://dx.doi.org/10.1016/j.carbpol.2016.12.001DOI Listing
February 2017

Physicochemical properties of quinoa flour as affected by starch interactions.

Authors:
Guantian Li Fan Zhu

Food Chem 2017 Apr 31;221:1560-1568. Epub 2016 Oct 31.

School of Chemical Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand. Electronic address:

There has been growing interest in whole grain quinoa flour for new product development due to the unique nutritional benefits. The quality of quinoa flour is much determined by the properties of its major component starch as well as non-starch components. In this study, composition and physicochemical properties of whole grain flour from 7 quinoa samples have been analyzed. Flour properties have been correlated to the flour composition and the properties of isolated quinoa starches through chemometrics. Great variations in chemical composition, swelling power, water soluble index, enzyme susceptibility, pasting, gel texture, and thermal properties of the flour have been observed. Correlation analysis showed that thermal properties and enzyme susceptibility of quinoa flour are highly influenced by the starch. Interactions of starch with non-starch components, including lipids, protein, dietary fibre, phenolics, and minerals, greatly impacted the flour properties. For example, peak gelatinization temperature of the flour is positively correlated to that of the starch (r=0.948, p<0.01) and negatively correlated to the lipid content (r=-0.951, p<0.01). Understanding the roles of starch and other components in physicochemical properties of quinoa flour provides a basis for better utilization of this specialty crop.
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http://dx.doi.org/10.1016/j.foodchem.2016.10.137DOI Listing
April 2017

Physicochemical properties of maca starch.

Food Chem 2017 Mar 31;218:56-63. Epub 2016 Aug 31.

School of Chemical Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand. Electronic address:

Maca (Lepidium meyenii Walpers) is gaining research attention due to its unique bioactive properties. Starch is a major component of maca roots, thus representing a novel starch source. In this study, the properties of three maca starches (yellow, purple and black) were compared with commercially maize, cassava, and potato starches. The starch granule sizes ranged from 9.0 to 9.6μm, and the granules were irregularly oval. All the maca starches presented B-type X-ray diffraction patterns, with the relative degree of crystallinity ranging from 22.2 to 24.3%. The apparent amylose contents ranged from 21.0 to 21.3%. The onset gelatinization temperatures ranged from 47.1 to 47.5°C as indicated by differential scanning calorimetry. Significant differences were observed in the pasting properties and textural parameters among all of the studied starches. These characteristics suggest the utility of native maca starch in products subjected to low temperatures during food processing and other industrial applications.
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http://dx.doi.org/10.1016/j.foodchem.2016.08.123DOI Listing
March 2017

Morphological, Thermal, and Rheological Properties of Starches from Maize Mutants Deficient in Starch Synthase III.

J Agric Food Chem 2016 Aug 19;64(34):6539-45. Epub 2016 Aug 19.

School of Chemical Sciences, University of Auckland , Private Bag 92019, Auckland 1142, New Zealand.

Morphological, thermal, and rheological properties of starches from maize mutants deficient in starch synthase III (SSIII) with a common genetic background (W64A) were studied and compared with the wild type. SSIII deficiency reduced granule size of the starches from 16.7 to ∼11 μm (volume-weighted mean). Thermal analysis showed that SSIII deficiency decreased the enthalpy change of starch during gelatinization. Steady shear analysis showed that SSIII deficiency decreased the consistency coefficient and yield stress during steady shearing, whereas additional deficiency in granule-bound starch synthase (GBSS) increased these values. Dynamic oscillatory analysis showed that SSIII deficiency decreased G' at 90 °C during heating and increased it when the paste was cooled to 25 °C at 40 Hz during a frequency sweep. Additional GBSS deficiency further decreased the G'. Structural and compositional bases responsible for these changes in physical properties of the starches are discussed. This study highlighted the relationship between SSIII and some physicochemical properties of maize starch.
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http://dx.doi.org/10.1021/acs.jafc.6b01265DOI Listing
August 2016

Physicochemical properties of quinoa starch.

Carbohydr Polym 2016 Feb 17;137:328-338. Epub 2015 Oct 17.

School of Chemical Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand. Electronic address:

Physicochemical properties of quinoa starches isolated from 26 commercial samples from a wide range of collection were studied. Swelling power (SP), water solubility index (WSI), amylose leaching (AML), enzyme susceptibility, pasting, thermal and textural properties were analyzed. Apparent amylose contents (AAM) ranged from 7.7 to 25.7%. Great variations in the diverse physicochemical properties were observed. Correlation analysis showed that AAM was the most significant factor related to AML, WSI, and pasting parameters. Correlations among diverse physicochemical parameters were analyzed. Principal component analysis using twenty three variables were used to visualize the difference among samples. Six principal components were extracted which could explain 88.8% of the total difference. The wide variations in physicochemical properties could contribute to innovative utilization of quinoa starch for food and non-food applications.
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http://dx.doi.org/10.1016/j.carbpol.2015.10.064DOI Listing
February 2016
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