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Guan Y.-G.,South China University of Technology | Yu P.,South China University of Technology | Yu S.-J.,South China University of Technology | Yu S.-J.,Guangdong Province Key Laboratory for Green Processing of Natural Products and Product Safety | And 2 more authors.
Journal of Dairy Science | Year: 2012

A simultaneous analysis of reducing sugars and 5-hydroxymethyl-2-furaldehyde of the Maillard reaction products was detailed. It was based on a high performance anion exchange chromatography with electrochemical detector system and an HPLC with refractive index detector. Results showed that high performance anion exchange chromatography with electrochemical detector using a CarboPac PA-1 column (Dionex Corp., Sunnyvale, CA) was more suitable for reducing sugars and 5-hydroxymethyl-2-furaldehyde determination, especially for trace analysis. The lowest detectable limit of reducing sugars and 5-hydroxymethyl-2-furaldehyde was 0.00005. mol/L in this experiment. However, HPLC with a refractive index detector always produces a tailing peak for 5-hydroxymethyl-2-furaldehyde, and mannose and fructose cannot be absolutely separated. The results of the present study could provide a more sensitive means for 5-hydroxymethyl-2-furaldehyde and reducing sugar detection. © 2012 American Dairy Science Association.


Yu D.,South China University of Technology | Yu S.-J.,South China University of Technology | Yu S.-J.,Guangdong Province Key Laboratory for Green Processing of Natural Products and Product Safety
Food and Function | Year: 2016

Starch is a glucose polymer of vast importance to mankind. It forms the major component of all our staple foods. Starch is often used as an important material in cooking meat. In this study, the effects of waxy rice starch and short chain amylose (SCA) from debranched waxy rice starch on the formation of PhIP in a model system were investigated and compared. The results showed that the addition of waxy rice starch and SCA significantly decreased PhIP, and the effect of SCA was more pronounced than that of waxy rice starch. This decrease may be attributed to the fact that the glucose residues of starch condense with the amino group of the creatinine formed N-glycosyl conjugate. This reaction path could disturb the reaction of creatinine with phenylacetaldehyde, subsequently influence the aldol condensation product formation, and finally suppress the formation of PhIP. Furthermore, the complex spatial structure of waxy rice starch disturbs the reaction of the glucosyl hydroxyl groups of glucose with the amino group of creatinine in the model reaction. So the effect of SCA was more pronounced than that of waxy rice starch on suppressing PhIP formation. A possible mechanism of waxy rice starch and SCA for inhibiting PhIP formation in the model system is also proposed. © The Royal Society of Chemistry 2016.


Yu D.,South China University of Technology | Yu S.-J.,South China University of Technology | Yu S.-J.,Guangdong Province Key Laboratory for Green Processing of Natural Products and Product Safety
Food Chemistry | Year: 2016

The present study aimed to investigate in detail the changes to 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) and its precursors in the presence of some cations (i.e., K+, Na+, Ca2+, Mg2+, Fe2+ and Fe3+) in a creatinine/phenylacetaldehyde model system. Results showed that PhIP yields decreased when Fe2+and Fe3+ were added to a mixture of phenylacetaldehyde and creatinine. This decrease may be attributed to the fact that Fe3+ can form complexes with various properties with creatinine and accelerate creatinine degradation. This pathway can disturb the reaction with phenylacetaldehyde, influence aldol condensation product formation, and suppress PhIP formation. Furthermore, Ca2+and Mg2+ enhanced PhIP content. Such enhancement may be attributed to the fact that CaCl2 and MgCl2 promote aldol and aldol condensation product reactions with ammonia and formaldehyde. A possible mechanism for the action of cations during PhIP formation in a model system is also proposed. © 2016 Elsevier Ltd. All rights reserved.


Zhao L.,South China University of Technology | Li L.,South China University of Technology | Li L.,Guangdong Province Key Laboratory for Green Processing of Natural Products and Product Safety | Liu G.-Q.,South China University of Technology | And 3 more authors.
Molecules | Year: 2012

In this study, the effects of frozen (-18°C) storage time on molecular weight, size distribution, conformation, free amino groups and free sulfhydryl groups of gluten were studied by small-angle X-ray scattering (SAXS), multi-angle laser light scattering (MALLS) in conjunction with a size exclusion chromatography (SEC) and spectrophotometrically. The results showed that the gluten dissolved in 50 mM acetic acid appeared to be similar to quasi-spherical of the chain conformation and the slope of the conformation plot decreased during the storage. Both the molecular weight and radius of gyration of the frozen gluten decreased with the storage time showing a depolymerization in the high molecular weight fraction of gluten (10 5 Da ∼ 10 9 Da). Therefore, at constant molecular weight the change of the chain conformation did not show a clear correlation with the storage time. The free amino groups content changed little and the free sulfhydryl groups content of the gluten increased from 9.8 μmol/g for the control to 12.87 μmol/g for 120-day-stored gluten, indicating that the water redistribution and ice recrystallization lead to the breakage of the disulphide bonds and may be one of the reasons for the depolymerization of gluten polymer. © 2012 by the authors.


Guo X.-M.,South China University of Technology | Zhu S.-M.,South China University of Technology | Tang Q.,South China University of Technology | Yu S.-J.,South China University of Technology | And 2 more authors.
Food Chemistry | Year: 2014

This paper was aimed at characterising the insoluble substances (IS) responsible for the turbidity of the extract and impurity of the resulting pectins. Results showed that the IS caused a significant increase in the turbidity of the extract. The IS had bi-pyramidal shapes under the SEM observation. The observed XRD peaks for the IS were similar to those of calcium oxalate dihydrate (COD). Moreover, the IS consisted of mainly oxalate and calcium. Results from the present study indicate the IS is COD. The influence of the IS on the purity of pectin was also studied. The presence of the IS in the pectins indicated the IS can precipitate with pectins during the alcohol precipitation, thereby contaminating the resulting pectins. © 2014 Elsevier Ltd. All rights reserved.


Lian X.,Tianjin University of Commerce | Lian X.,South China University of Technology | Lian X.,Guangdong Province Key Laboratory for Green Processing of Natural Products and Product Safety | Wang C.,Tianjin University of Commerce | And 3 more authors.
International Journal of Biological Macromolecules | Year: 2014

The experiment was conducted to study the retrogradation properties of glutinous rice and buckwheat starch with wavelengths of maximum absorbance, FT-IR, 13C NMR, and DSC. The results show that the starches in retrograded glutinous rice starch and glutinous rice amylopectin could not form double helix. The IR results show that protein inhabits in glutinous rice and maize starches in a different way and appearance of C-H symmetric stretching vibration at 2852cm-1 in starch might be appearance of protein. Retrogradation untied the protein in glutinous amylopectin. Enthalpies of sweet potato and maize granules are higher than those of their retrograded starches. The 13C NMR results show that retrogradation of those two starches leads to presence of β-anomers and retrogradation might decompose lipids in glutinous rice amylopectin into small molecules. Glutinous rice starch was more inclined to retrogradation than buckwheat starch. The DSC results show that the second peak temperatures for retrograded glutinous rice and buckwheat starches should be assigned to protein. The SEM results show that an obvious layer structure exists in retrograded glutinous rice amylopectin. © 2013 Elsevier B.V.


Lian X.,Tianjin University of Commerce | Lian X.,South China University of Technology | Lian X.,Guangdong Province Key Laboratory for Green Processing of Natural Products and Product Safety | Zhu W.,Tianjin University of Commerce | And 4 more authors.
International Journal of Biological Macromolecules | Year: 2013

Starch retrogradation is the main cause of quality deterioration of starch-containing foods during storage. The purpose of this study is to find out whether certain soy protein polypeptide in hydrolysates will retard maize starch retrogradation. The results show that all soy protein hydrolysates retard maize starch retrogradation to a certain extent. The IR spectra of hydrolysates and the blends of hydrolysates and maize starch show that the polypeptides might act with reducing end of maize starch during retrogradation. The results of electrospray ionization-mass spectrometry [ESI-MS] show that the polypeptide (m/ z 863) is present in all three hydrolysates remarkedly retarding maize starch retrogradation and its relative abundence is also the highest. So the polypeptide containing seven amino acids probably is the key component to significantly inhibit maize starch retrogradation. © 2013 Elsevier B.V.


Wu X.-L.,South China University of Technology | Yu S.-J.,South China University of Technology | Yu S.-J.,Guangdong Province Key Laboratory for Green Processing of Natural Products and Product Safety | Kang K.-R.,Guangzhou Wondfo Biotech Co.
Food Chemistry | Year: 2014

In this study, an indirect competitive enzyme-linked immunoassay (ic-ELISA) based on monoclonal antibody for 4(5)-Methylimidazole (4-MI) detection was described. The artificial antigens were prepared by conjugating bovine serum albumin (BSA) or ovalbumin (OVA) with the hapten of 4-MI. And monoclonal antibody, evaluated by ic-ELISA, was obtained by immunizing BABL/c mice. After optimizing, a standard curve for ic-ELISA detection on 4-MI was obtained with the linear detection range of 0.64-20.48 mg/L. The cross-reactivity (CR) of all the structural analogues of 4-MI was less than 5.62%. The recoveries of 4-MI in caramels detection were ranged from 88.69% to 114.09%, with relative standard deviation (n = 3) below 8.07%. The results suggested that the established ic-ELISA is promising for 4-MI commercial detection in caramels. © 2014 Elsevier Ltd. All rights reserved.


Xu X.-B.,South China University of Technology | Liu D.-B.,South China University of Technology | Yu S.-J.,South China University of Technology | Yu S.-J.,Guangdong Province Key Laboratory for Green Processing of Natural Products and Product Safety | And 3 more authors.
Food Chemistry | Year: 2015

A method for simultaneous determination of 4-methylimidazole (4-MeI), 2-methylimidazole (2-MeI) and 5-hydroxymethylfurfural (HMF) in beverages was developed using solid-phase extraction (SPE) and amino trap column coupled with pulsed amperometric detection (AMTC-PAD). A single amino trap column (P/N: 046122) was first applied to separate the targeted analytes in samples after SPE pretreatment. This method demonstrated low limit of quantification (0.030 mg/L for methylimidazoles and 0.300 mg/L for HMF) and excellent linearity with correlation of determination (R2 = 0.999 for 2-MeI, 0.997 for 4-MeI and 0.998 for HMF). Nearly no 2-MeI was found in all soft drinks. However, 4-MeI could be detected in cola drinks and soft drinks containing caramel colour (ranging from 0.13 to 0.34 mg/L), whereas HMF were only found in cola drinks (ranging from 1.07 to 4.47 mg/L). Thus, AMTC-PAD technique would be a valid and inexpensive alternative to analysis of 4-MeI, 2-MeI and HMF. © 2014 Elsevier Ltd. All rights reserved.


Yu D.,South China University of Technology | Chen M.-S.,South China University of Technology | Yu S.-J.,South China University of Technology | Yu S.-J.,Guangdong Province Key Laboratory for Green Processing of Natural Products and Product Safety
Food Chemistry | Year: 2016

Molasses, the main by-product of sugar production, is a well-known source of antioxidants. In this study, sugarcane molasses extract was investigated for its total phenolic content and in vitro antioxidant capacity. The experimental total phenolic content was 101.3 mg of gallic acid equivalent (GAE) in 1 g of extract, IC50 of Trolox and sugarcane molasses extract were 125.33 μg/ml and 126.0 μg/ml, respectively. A chemical model system showed that the sugarcane molasses extract effectively reduced the formation of phenylacetaldehyde and the aldol condensation product, meanwhile, the amount of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) also decreased. This could be due to the reaction between the phenolic compounds of sugarcane molasses extract and the carbonyl group of phenylacetaldehyde inhibiting the aldol condensation product formation, and this would suppress the formation of PhIP. A pathway that phenolic compounds inhibited the formation of PhIP is proposed. This pathway also suggested a mechanism for how the sugarcane affects the formation of PHIP. © 2015 Elsevier Ltd.

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