Chun-Feng Guo

Harbin Institute of Technology, Charbin, Heilongjiang Sheng, China

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Publications (6)19.31 Total impact

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    ABSTRACT: Guaiacol, a potent volatile compound, has proven to be responsible for the distinct medicinal off-flavor in spoiled apple juice produced by Alicyclobacillus acidoterrestris. In this study, the artificial sensing system electronic nose (e-nose) was employed to detect this off-flavor compound in apple juice, using GC–MS and test panel evaluation as reference, as well as water as a comparative medium. Principle component analysis and linear discriminant analysis were employed to evaluate the capacity of e-nose for guaiacol detection in both media. A loadings analysis was used to examine the sensors' chemometric discrimination. Multiple regression analysis was applied to investigate the potential relationship between the concentration of guaiacol and the e-nose response. The detection limit based on e-nose for guaiacol in apple juice was 0.25–0.5 mg/L. For comparison, a 12-member test panel evaluation found an aroma detection threshold of 1.50 mg/L in apple juice, and the GC–MS detection limit for guaiacol in apple juice was determined to be 0.4 μg/L. In summary, the e-nose was capable of detecting guaiacol in apple juice, with significantly higher sensitivity than the test panel evaluation. This information should be useful for developing instrumental sensory detection techniques for rapid scanning of potential medicinal off-flavor in Alicyclobacillus-spoiled apple juice prior to consumer perception.
    Food Control 05/2015; 51. DOI:10.1016/j.foodcont.2014.11.037 · 2.82 Impact Factor
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    ABSTRACT: Suan-tsai and koumiss are traditional Chinese fermented foods. This study compared the dominant lactobacilli in suan-tsai and koumiss for their probiotic properties, cholesterol-lowering potentials and antioxidant activities. Thirty Lactobacillus strains were isolated from eight homemade suan-tsai samples (8 Lactobacillus plantarum and 6 Lactobacillus brevis) and seven homemade koumiss samples (7 Lactobacillus helveticus, 5 Lactobacillus acidophilus, 2 L. plantarum and 2 Lactobacillus casei), and they were subsequently analyzed for the above parameters. No significant differences were found between the mean antioxidant activities of the lactobacilli isolated from koumiss and suan-tsai, whereas the lactobacilli isolated from koumiss exhibited higher mean bile tolerance, adhesion to HT-29 cells, cholesterol removal and percentage of bile salt hydrolase-positive strains than did those isolated from the suan-tsai samples. Thus, koumiss could be considered a better source of potential probiotics, especially cholesterol-lowering probiotics, than suan-tsai.
    Journal of Functional Foods 01/2015; 12. DOI:10.1016/j.jff.2014.11.029 · 4.48 Impact Factor
  • Chun-Feng Guo, Jing-Yan Li
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    ABSTRACT: The effects of a Tween 80 and CaCl2 mixture on the hypocholesterolemic activity of bile salt hydrolase (BSH)-active Lactobacillus casei F0422 were investigated in rats fed a cholesterol-rich diet for 3 weeks. This mixture significantly enhanced the hypocholesterolemic activity of strain F0422 in rats. The group administered drinking water supplemented with both strain F0422 and the Tween 80 and CaCl2 mixture had significantly lower levels of total serum cholesterol, low-density lipoprotein cholesterol and total liver cholesterol than did the group administered drinking water supplemented only with strain F0422 or the Tween 80 and CaCl2 mixture. The hypocholesterolemic activity of the combined strain F0422 and Tween 80 and CaCl2 mixture was attributed to the increase in fecal bile acid excretion through enhancement of bile salt tolerance and BSH catalytic activity of strain F0422 by Tween 80 and up-regulation of the adhesion of strain F0422 to intestinal epithelial cells by CaCl2.
    Journal of Functional Foods 07/2014; 9:131–140. DOI:10.1016/j.jff.2014.04.014 · 4.48 Impact Factor
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    ABSTRACT: Elevated serum cholesterol in humans is generally a risk factor correlated with the development of coronary heart disease (CHD). Reducing deoxycholic acid (DCA) content in the intestine can reduce serum cholesterol levels, which reduce the incidence of CHD. A total of 150 strains of lactic acid bacteria and bifidobacteria were isolated from human fecal samples. The DCA removal ability of these strains was evaluated. Results showed that 9 strains displayed above 10% DCA removal rate. The probiotic potentials of the 9 strains were evaluated. The strain Lactobacillus casei F0822 was screened out due to the stronger adhesion to HT-29 cells and tolerance to bile and acid. DCA removal for this strain resulted from that the S-layer protein locating the cell surface bound DCA. The FTIR spectra showed that the carboxyl group in DCA was the principal group by which DCA was bound to the S-layer protein of L. casei F0822. These findings suggested that L. casei F0822 is a better candidate probiotic strain, which has the potential to reduce human serum cholesterol levels.
    Anaerobe 08/2012; 18(5):516-22. DOI:10.1016/j.anaerobe.2012.08.003 · 2.36 Impact Factor
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    ABSTRACT: Cis-9, trans-11 conjugated linoleic acid (c9, t11 CLA) producing bacteria have attracted much attention as novel probiotics which have shown beneficial effects on host health. However, bile salts are able to inhibit bacterial growth and c9, t11 CLA production. For recovering growth and c9, t11 CLA production of Lactobacillus acidophilus F0221 in the presence of bile salts, Tween series (Tween 20, Tween 40, Tween 60 and Tween 80) were added in growth culture containing 0.3% oxgall. Results showed that the viable counts were significantly (P < 0.05) recovered to 8.58-8.75 log CFU/mL in the presence of all Tween treatments. However, recovery of c9, t11 CLA production was only demonstrated in the presence of Tween 80 (72.89 μg/mL). Stepwise increasing oxgall in a concentrations range from 0.1% to 0.9% according to human intestinal physiological environments, Tween 80 still showed significant (P < 0.05) recovery ability on growth (8.91-8.04 log CFU/mL) and c9, t11 CLA (69.22-34.27 μg/mL) production. The effect of Tween 80 on growth and production was also investigated in the presence of different types of bile salts (sodium salts of cholic acid (CA), deoxycholic acid (DCA), chendeoxycholic acid (CDCA), glycocholic acid (GCA) and taurocholic acid (TCA)). Results showed that Tween 80 could significantly (P < 0.05) recover c9, t11 CLA production in the presence of all types of bile salts, but the Tween 80 could only significantly (P < 0.05) recover viable counts of the strain in the presence of CA, DCA and CDCA. This recovery ability could be attributed to the protection of leakage of intracellular material. Additionally, although bile salts inhibited growth and c9, t11 CLA production by the growing cell, it promoted the c9, t11 CLA production by the resting cell.
    International Journal of Molecular Sciences 12/2011; 12(12):9138-54. DOI:10.3390/ijms12129138 · 2.34 Impact Factor
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    ABSTRACT: In this study, seven lactobacilli with a high degree of antagonistic activity against three pathogens and good adherence to HT-29 cells were selected. The ability of these seven lactobacilli to inhibit adhesion of Shigella sonnei to intestinal mucosa was studied on cultured HT-29 cells. Lactobacilli were added simultaneously with, before or after S. sonnei to test for their effectiveness in exclusion, competition and displacement assays, respectively. Lactobacillus paracasei subp. paracasei M5-L, Lactobacillus rhamnosus J10-L and Lactobacillus casei Q8-L all exhibited significant inhibitory activity. In order to elucidate the inhibitory functions of S-layer proteins, the S-layer proteins were removed with 5 M LiCl from the M5-L, J10-L and Q8-L strains. Under such conditions, inhibition activity was decreased in all three strains, as revealed in exclusion, competition and displacement assays. SDS-PAGE analysis confirmed the presence of S-layer proteins with dominant bands of approximately 45 kDa. Further analysis of S-layer proteins revealed that the hydrophobic amino acids accounted for 40.5%, 41.5% and 43.8% of the total amino acid for the M5-L, J10-L and Q8-L strains, respectively. These findings suggest that the M5-L, J10-L and Q8-L strains possess the ability to inhibit S. sonnei adherence to HT-29 cells, and S-layer proteins are involved in this adhesion inhibition.
    Research in Microbiology 10/2010; 161(8):667-72. DOI:10.1016/j.resmic.2010.06.005 · 2.83 Impact Factor