Guozhong Zhao

Jiangnan University, Wu-hsi, Jiangsu, China

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Publications (17)31.85 Total impact

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    ABSTRACT: Milk fat is widely accepted to be the major nutrient in human milk. Commercial infant formulas are usually based on mammalian milk such as bovine or caprine milk, but the differences in milk fat globules (MFGs) between human, bovine and caprine milk remain unclear. We showed that saturated fatty acid content was higher in bovine and caprine MFGs (>60%) than in human MFG (<40%), but that content of the unsaturated fatty acids C18:2 in human MFG was > 7 times higher than in bovine and caprine MFGs. The cholesterol content of human milk was ∼20% higher than that of bovine and caprine milk. Triacylglycerol molecular species and polar lipids also differed between bovine, caprine and human MFGs. Confocal laser scanning microscopy images of MFGs revealed that the shape of the liquid-ordered domains varied by species.
    No preview · Article · Jan 2016
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    ABSTRACT: Infant formulas are usually based on bovine milk and caprine milk. Pasteurization, homogenization and spray-drying are basic processes for the production of infant formulas. In this study, confocal Raman spectroscopy had been used to rapidly determine the differences between human, bovine and caprine milk fat globules (MFGs). The unsaturated fatty acids in human colostrum and mature MFGs were over 2 times more than in bovine and caprine MFGs. The phospholipid bands at 860 cm− 1 of human colostrum MFGs were 5 times more than human mature, bovine and caprine MFGs. The carotenoid content varied according to the species of milk, with human MFGs containing more carotenoids than bovine and caprine MFGs. And the cholesterol content was not correlated with the size of the MFGs. Human MFGs were more mobile than bovine and caprine MFGs. The lipid composition and mobility of MFGs were underwent significant changes under different processing conditions. These results laid the foundations for the improvement and development of powdered milk formulas.
    No preview · Article · Dec 2015
  • Yunping Yao · Guozhong Zhao · Xiaoqiang Zou · Lei Huang · Xingguo Wang
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    ABSTRACT: The purpose of this study was to investigate the effects of milk powder processing conditions (pasteurisation, homogenisation and spray-drying) on the microstructure and composition of fat globules in cow milk. In general, the process of pasteurisation results in fewer changes in the microstructure and lipid composition than do other processing methods. The phospholipid, sterol and the fatty acid composition of the phospholipids, with the exception of the fatty acids of total lipids, underwent significant changes under different processing conditions compared with the untreated milk fat globules. The contents and distribution of the phospholipids in pasteurised milk indicated a high level of stability, but the amounts of phosphatidylethanolamine, phosphatidylserine and sphingomyelin were significantly affected by homogenisation. A reduction in the cholesterol content was observed after pasteurisation and homogenisation. The results indicate that processing had a significant effect on the composition and structure of the membrane of the phospholipids in milk fat globules.
    No preview · Article · Jul 2015 · RSC Advances
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    ABSTRACT: Amino acids comprise the majority of the flavor compounds in soy sauce. A portion of these amino acids are formed from the biosynthesis and metabolism of the fungus Aspergillus oryzae; however, the metabolic pathways leading to the formation of these amino acids in A. oryzae remain largely unknown. We sequenced the transcriptomes of A. oryzae 100-8 and A. oryzae 3.042 under similar soy sauce fermentation conditions. 2D gel electrophoresis was also used to find some differences in protein expression. We found that many amino acid hydrolases (endopeptidases, aminopeptidases, and X-pro-dipeptidyl aminopeptidase) were expressed at much higher levels (mostly greater than double) in A. oryzae 100-8 than in A. oryzae 3.042. Our results indicated that glutamate dehydrogenase may activate the metabolism of amino acids. We also found that the expression levels of some genes changed simultaneously in the metabolic pathways of tyrosine and leucine and that these conserved genes may modulate the function of the metabolic pathway. Such variation in the metabolic pathways of amino acids is important as it can significantly alter the flavor of fermented soy sauce.
    Preview · Article · May 2015
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    ABSTRACT: Aspergillus oryzae 100-8 and the parental strain A. oryzae 3.042 are used in soy sauce fermentation in China. The growth rate of A. oryzae 100-8 is faster than A. oryzae 3.042, and the soy sauce flavors obtained with A. oryzae 100-8 fermentation are better than those obtained with A. oryzae 3.042. In this study, comparisons were made through biomass, reactive oxygen species (ROS) and gas chromatography–mass spectrometry (GC-MS) measurements, and the reasons for these differences were investigated through transcriptome and qRT-PCR analysis. The analysis indicated that several unique genes are closely associated with hyphal growth and flavor formation, as demonstrated by changes in the expression levels of these genes. These unique genes regulated hyphal growth and flavor formation in soy sauce koji fermentation.
    Preview · Article · Feb 2015 · RSC Advances
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    ABSTRACT: Freeze drying and spray drying are conventional methods for converting milk into powder in the dairy industry. The purpose of this study was to investigate the effects of these drying methods on the physical, chemical and structural features of milk fat globules (MFGs). The globule sizes increased after freeze drying and spray drying, but the integrity of their microstructures was still maintained. Compared with that in untreated MFGs, the composition of the fatty acids underwent fewer changes under the two different drying conditions. The main phospholipids showed some differences between the freeze-dried milk and spray-dried milk, and the saturation of the fatty acids of phospholipids was increased after the drying treatments. A reduction in the cholesterol content was observed after the freeze-drying and spray-drying processes. The level of unsaturation decreased as the diameter of the globules increased. The results indicated that freeze drying had a significant effect on the liquid-ordered domains in the MFG membrane, which was formed by sphingolipids and cholesterol. However, spray drying influenced the liquid-disordered domains, which were formed by glycerophospholipids. Thus, the drying method appears to affect the physical, chemical and microstructure characteristics of MFGs, which may affect the stability of the globules in milk and the way the milk is digested.
    No preview · Article · Jan 2015 · RSC Advances
  • Guozhong Zhao · Yunping Yao · Lihua Hou · Chunling Wang · Xiaohong Cao
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    ABSTRACT: Aspergillus oryzae is used to produce traditional fermented foods and beverages. A. oryzae 3.042 produces a neutral protease and an alkaline protease but rarely an acid protease, which is unfavourable to soy-sauce fermentation. A. oryzae 100-8 was obtained by N(+) ion implantation mutagenesis of A. oryzae 3.042, and the protease secretions of these two strains are different. Sequencing the genome of A. oryzae 100-8 and comparing it to the genomes of A. oryzae 100-8 and 3.042 revealed some differences, such as single nucleotide polymorphisms, nucleotide deletion or insertion. Some of these differences may reflect the ability of A. oryzae to secrete proteases. Transcriptional sequencing and analysis of the two strains during the same growth processes provided further insights into the genes and pathways involved in protease secretion.
    No preview · Article · Jul 2014 · Biotechnology Letters
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    Guozhong Zhao · Yunping Yao · Lihua Hou · Chunling Wang · Xiaohong Cao
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    ABSTRACT: Aspergillus oryzae is a common fungus for traditional fermentation in Asia, such as spirit, soybean paste, and soy sauce fermentation. We report the 36.7-Mbp draft genome sequence of A. oryzae 100-8 and compared it to the published genome sequence of A. oryzae 3.042.
    Preview · Article · May 2014 · Genome Announcements
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    Wei Qi · Cong Wang · Xiaohong Cao · Guozhong Zhao · Chunling Wang · Lihua Hou
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    ABSTRACT: Chinese cereal vinega represented the east vinegar, is well known to the world. In order to understand the Chinese cereal vinegar further, its characteristic flavour should be researched. The purpose of the work is to find out the characteristic flavour compounds and analyze the dynamic variation trend in the process of Chinese cereal vinegar fermentation. HS- SPME fibered with polyacrylate (PA) was used in detecting aromatic compounds. It was found that in the ethanol fermentation, ethanol increased rapidly, and other aromatic compounds accumulated slowly; in the acetic acid fermentation, acetic acid and esters increased fast with reduction of alcohol, while phenols, aldehyde, ketones, hydrocarbons and heterocyclic were still slowly accumulated. The characteristic aromatic compounds were ethyl acetate, isoamyl acetate, phenylethyl acetate, β-phenylethyl alcohol and 4-Vinylguaiacol. The contents of organic acids reached 6.79±0.11 g/100 g sample finally, and acetic acid, succinic acid, malic acid and lactic acid were the main organic acids. The variation trend of the characteristic flavour compounds had been found out preliminarily, which could be the symbol of Chinese cereal vinegar and the basis of further study. Here, the foundation for improving flavour and quality of Chinese cereal vinegar was established.
    Full-text · Article · Dec 2013
  • Guozhong Zhao · Xiaohong Cao
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    ABSTRACT: A. oryzae 3.042 (China) and A. oryzae RIB40 (Japan) used for soy sauce fermentation show some regional differences. We sequenced the genome of A. oryzae 3.042, and compared it with A. oryzae RIB40 in an attempt to understand why different features are shown by these two A. oryzae strains. We predict 11,399 protein-coding genes in A. oryzae 3.042. The genomes of these two A. oryzae strains are collinear revealed by MUMmer analysis indicating that the differences are not obvious between them. Several strain-specific genes of two strains are identified by genome sequences' comparison, and they are classified into some groups which have the relationship with cell growth, cellular response and regulation, resistance, energy metabolism, salt tolerance and flavor formation. A. oryzae 3.042 showed stronger potential for mycelial growth and environmental stress resistance, such as the genes of chitinase and quinone reductase. Some genes unique to A. oryzae RIB40 were related to energy metabolism and salt tolerance, especially genes for Na+ and K+ transport, while others were associated with signal transduction and flavor formation. The genome sequence of A. oryzae 3.042 will facilitate the identification of the genetic basis of traits in A. oryzae 3.042, and accelerate our understanding of the different genetic traits of the two A. oryzae strains.
    No preview · Article · Jul 2013 · Journal of Agricultural and Food Chemistry
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    ABSTRACT: Soy sauce is considered the most important food condiment in China for its distinct fragrance and salty taste. Highly valued for its unique tastes and flavours, soy sauce exhibits many beneficial functions, such as 4‐hydroxy‐2(or 5)‐ethyl‐5(or 2)‐methyl‐3(2H)‐furanone and 4‐ethylguaiacol. Soy sauce has been widely used in Asian countries for cooking. With the rapidly growing popularity of these unique tastes and flavours, it is important to have a comprehensive reference of its functional benefits. Meanwhile, the genes encoding the major enzymes of metabolism exhibit specialised roles. This review provides a valuable source for the abundant metabolism genes of strains and current knowledge on antioxidant activity, antihypertensive effect, anticarcinogenic activity, fortification and their relationships with soy sauce tastes and flavours.
    No preview · Article · May 2013 · International Journal of Food Science & Technology
  • Guozhong Zhao · Yunping Yao · Chunling Wang · Lihua Hou · Xiaohong Cao
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    ABSTRACT: The filamentous fungus Aspergillus oryzae 3.042 (Chinese strain) is a close relative of A. oryzae RIB40 (Japanese strain), which is the important agent used for soy sauce fermentation. The genome of A. oryzae 3.042 was sequenced and compared with A. oryzae RIB40 in an attempt to understand why different soy sauce flavors are produced by these strains. The A. oryzae 3.042 chromosome is 36,547,279bp and contains 11,399 protein-encoding genes. MUMmer analysis revealed that the genomes of A. oryzae 3.042 and RIB40 are mostly collinear. Genome sequence data and comparative analysis of the two strains identified several strain-specific genes that encode putative proteins involved in cell growth, salt tolerance, environmental resistance and flavor formation. A. oryzae 3.042 showed stronger potential for mycelial growth. Some genes unique to A. oryzae RIB40 were related to salt tolerance, especially genes for K(+) transport, while others were associated with ester formation and amino acid metabolism, which likely contribute to flavor formation. In conclusion, comparative genome analysis provided insights into the different genetic traits of the two A. oryzae strains. The unique genes that we found in A. oryzae would make sense to the soy sauce fermentation.
    No preview · Article · Apr 2013 · International journal of food microbiology
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    Bin Zeng · Guozhong Zhao · Xiaohong Cao · Zhen Yang · Chunling Wang · Lihua Hou
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    ABSTRACT: Salmonella typhi is a pathogen that causes the human disease of typhoid fever. The aim of this study was to investigate the viable but nonculturable (VBNC) state of S. typhi. Some samples were stimulated at 4°C or -20°C, while others were induced by different concentrations of CuSO4. Total cell counts remained constant throughout several days by acridine orange direct counting; however, plate counts declined to undetectable levels within 48 hours by plate counting at -20°C. The direct viable counts remained fairly constant at this level by direct viable counting. Carbon and nitrogen materials slowly decreased which indicated that a large population of cells existed in the VBNC state and entered the VBNC state in response to exposure to 0.01 or 0.015 mmol/L CuSO4 for more than 14 or 12 days, respectively. Adding 3% Tween 20 or 1% catalase enabled cells to become culturable again, with resuscitation times of 48 h and 24 h, respectively. The atomic force microscope results showed that cells gradually changed in shape from short rods to coccoids, and decreased in size when they entered the VBNC state. Further animal experiments suggested that resuscitated cells might regain pathogenicity.
    Preview · Article · Mar 2013
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    ABSTRACT: Aspergillus oryzae is the most important fungus for the traditional fermentation in China and is particularly important in soy sauce fermentation. We report the 36,547,279-bp draft genome sequence of A. oryzae 3.042 and compared it to the published genome sequence of A. oryzae RIB40.
    Full-text · Article · Sep 2012 · Eukaryotic Cell
  • Guozhong Zhao · Lihua Hou · Yunping Yao · Chunling Wang · Xiaohong Cao
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    ABSTRACT: Aspergillus oryzae plays a central role in soybean fermentation, particularly in its contribution to the flavor of soy sauce. We present a comparative assessment of the intracellular differences between wild-type strain 3.042 and mutant strain A100-8, at the proteome level. 522 different protein spots were identified by MALDI-TOF MS, with 134 spots being confirmed by MALDI-TOF MS/MS. Of these, 451 were differentially expressed proteins (DEPs). There was at least a two-fold increase for 288 spots, and at least a two-fold decrease for 163 spots, in strain A100-8 when compared to 3.042. Further analysis showed that 63 of the more abundant proteins were involved in glycolysis and the citrate cycle; 43 more abundant proteins and 10 less abundant proteins were related to amino acid biosynthesis and metabolism; two of the more abundant proteins were involved in vitamin biosynthesis; and five of the more abundant proteins and four of the less abundant proteins were related to secondary metabolites. Moreover, quantitative real time PCR showed that the mRNA expression levels of six typical genes we selected were consistent with changes in protein expression. We postulate that there may be a relationship between DEPs and the flavor formation mechanism in A. oryzae.
    No preview · Article · May 2012 · Journal of proteomics
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    ABSTRACT: Because of secreting large amounts of enzymes, Aspergillus oryzae was widely used in the fermentation of soy sauce in many Asian countries. Here, N+ ion implantation mutagenesis was applied to improve the ability of A. oryzae to secrete acid protease. Several mutants were screened using three kinds of plates (Casein medium, Czapek’s medium and carboxymethyl cellulose medium agar plates). Compared with the other mutants, the mutant A100‐8 could secrete the most protease. Acid protease activity of A100‐8 was enhanced about 44.1% at 36 h by koji fermentation test. In addition, A100‐8 was stable by periodically subculturing and maintaining on the agar slant. The mRNA expression levels of two kinds of acid protease (serine carboxypeptidase and aspartyl protease) were measured by RT‐PCR at different periods. Serine carboxypeptidase and some kinds of aspartyl protease of A100‐8 were significantly (P 0.01) expressed higher than the control at all times.
    No preview · Article · Mar 2012 · International Journal of Food Science & Technology
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    ABSTRACT: The similarities and differences of eight vegetable oils produced in China were investigated in terms of their fatty acid, sterol, and tocopherol compositions and subsequent data processing by hierarchical clustering analysis and principal component analysis. The lipid profiles, acquired by analytical techniques tailored to each lipid class, revealed great similarities among the fatty acid profiles of corn and sesame oil as well as few differences in their sterol profiles. It turns out that not only was there great similarity between the fatty acid profiles of corn oil and sesame oil but also there were not too many differences for the sterol profiles. Sunflower and tea-seed oil showed similar sterol compositions, while the tea-seed oil tocopherol was very similar to palm oil. The results demonstrated that the use of only one of these profiles was unreliable for indentifying oil origin and authenticity. In contrast, the use of the sterol or tocopherol profile together with the fatty acid profile more accurately discriminates these oils.
    No preview · Article · Nov 2011 · Journal of Agricultural and Food Chemistry

Publication Stats

59 Citations
31.85 Total Impact Points

Institutions

  • 2013-2015
    • Jiangnan University
      • School of Food Science and Technology
      Wu-hsi, Jiangsu, China
  • 2011-2013
    • Tianjin University of Science and Technology
      T’ien-ching-shih, Tianjin Shi, China