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15 February 2016, Volume 37 Issue 3
Basic Research
Effects of Proteases on Microrheological Characteristics of Soymilk Gel
LIU He, GENG Ping, WAN Jiao, ZHU Danshi, HE Yutang, MA Tao
2016, 37(3):  1-5.  doi:10.7506/spkx1002-6630-201603001
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In this research, effects of proteases (bromelain, papain and alcalase) on microrheological characteristics of
soymilk gel were explored. The results showed that all three proteases had the capacity to coagulate soybean milk, while
the curding capacity of alacase was weak. At the early stage of curding, the MVI (macro viscosity index) of bromelainsoybean
milk system was higher, while the MVI values of different systems became similar with prolonging reaction time.
Temperature in the range of 30–70 ℃ played an important role in EI (elasticity index) of soymilk gel systems containing
different proteases. The EI of gel systems induced by bormelain or papain addition showed an enhancing trend with
increasing temperature to reach the maximum level of 0.002 34 and 0.002 75 nm-2, respectively, but temperature did not
obviously affect the EI of soymilk system added with alaclase. The curding capacity of bromelain increased to the maximum
level of EI at 800 U/mL followed by a decrease with increasing protease dosage in the range of 200–1 200 U/mL. Papain
showed an increased curding capacity as its dosage increased, while alcalase showed a downward trend.

Changes in Antioxidant Properties of Red Raspberry Vinegar during Fermentation
ZHANG Qiang, XIN Xiulan, YANG Fumin, CHEN Liang, ZHANG Xue, CHI Peng
2016, 37(3):  6-11.  doi:10.7506/spkx1002-6630-201603002
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The changes in the contents of total polyphenols, total flavonoids and total anthocyanins, and radical scavenging
capacities against 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl and superoxide anion free radicals in red raspberry
vinegar produced by submerged fermentation were analyzed during the fermentation process. The results indicated that the
contents of total polyphenols, total flavonoids and total anthocyanins increased first and then decreased. The scavenging
rates of all three kinds of free radicals increased significantly with acetic acid fermentation. After acetic acid fermentation
for 10 days, 68% of the total polyphenols, 85% of the total flavonoids and 38% of the total anthocyanins were retained, and
the scavenging rates of DPPH, hydroxyl and superoxide anion free radicals were 98.63%, 78.36% and 83.82%, respectively.
Our results also showed there were had extremely significant positive correlations among the contents of total polyphenols,
total flavonoids and total anthocyanins, and each of these was highly negative correlated with principal component 1. The
scavenging rates of DPPH, hydroxyl and superoxide anion free radicals also had extremely significant positive correlation
with each other, and each showed a highly positive correlation with principal component 1. In addition, the brewing process
was divided into three clusters by cluster analysis, which represented the changing trend of antioxidant properties at different
fermentationstages.

Structure-Acivity Relationship between Peptides and Flavor in Chicken Broth
LIN Mengli, WANG Jie, LIAO Yonghong, ZHOU Xiaohong
2016, 37(3):  12-16.  doi:10.7506/spkx1002-6630-201603003
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The structure-activity relationship between peptides and flavor was studied on chicken broth made by the
traditional cooking process. The chicken broth stewed for three hours was fractionated using ultrafiltration membranes
with molecular weight cut-offs of 10, 5 and 3 kD. The peptidomics in the fraction (molecular weight < 3 kD) which had the
strongest umami taste were analyzed by high performance liquid chromatography-mass spectrometry (HPLC-MS). Totally
93 peptides with high proportion of umami and sweet amino acids and low proportion of hydrophobic amino acids were
sequenced. Peptide bonds with hydrophilic amino acids were preferentially cleaved during the heating process. The peptides
were mainly derived from muscle proteins, collagens, enzymes and antibodies.

Meat Quality Charateristics of Spotted Knifejaw (Oplegnathus punctatus) Cultured under Different Aquaculture Modes
XIONG Ming, WU Zuliang, LIN Xiangdong
2016, 37(3):  17-21.  doi:10.7506/spkx1002-6630-201603004
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In this study, growth and meat quality characteristics of Oplegnathus punctatus cultured in different aquaculture
systems were evaluated by mass/length index (K), chromatic aberration, texture properties and sensory evaluation. The
causes of eating quality difference of meat from Oplegnathus punctatus cultured under different aquaculture modes were
analyzed. The results showed that K value of Oplegnathus punctatus cultured in net cages was 19.29 g/cm, slightly higher than of
pond-cultured Oplegnathus punctatus, suggesting higher mobility in net cages and highly significant effect of mobility on K value.
The meat of pond-cultured Oplegnathus punctatus had a brighter and more saturated color, while harness, springiness, cohesiveness
and resilience of fillets of cage-cultured Oplegnathus punctatus were higher than those of the pond-cultured counterpart. Fillets of
pond-cultured Oplegnathus punctatus exhibited better chewiness (2.457 mJ). In conclusion, our findings suggest that aquaculture
mode can only influence hardness and resilience of Oplegnathus punctatus fillets.

Effect of Maillard Reaction on IgE Binding Capacity and Conformational Structure of Tropomyosin from Short-Neck Clam (Ruditapes philippinarum)
LIN Haixin, LIN Hong, WANG Xiaofei, Lü Liangtao, LI Zhenxing
2016, 37(3):  22-26.  doi:10.7506/spkx1002-6630-201603005
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The aim of the present study was to assess changes in conformational structures and potential allergenicity of
tropomyosin from short-neck clams after glycation with ribose. Changes in potential allergenicity were characterized by
immunological techniques, while circular dichroism (CD) and available lysine were determined to define conformational
changes. An unfolded structure was found as glycation proceeded. Correspondingly, the amount of available lysine was
reduced by 45.5% and surface hydrophobicity was increased by 192% when the reaction time was 12 h. Indirect enzyme
linked immunosorbent assay (ELISA) and dot-blot results of glycation showed that potential allergenicity correlated well
with structural changes. Allergenicity decreased significantly after unfolding of the protein. These results showed that
conformational changes in tropomyosin induced by glycation significantly influenced the allergenicity of tropomyosin.

Characterization and in Vitro Antioxidant Activity of Cold-Pressed Seed Oils from Four Different Grape Varieties
ZHENG Yalei, LIU Ye, SUI Yinqiang, WANG Hua,LI Hua
2016, 37(3):  27-32.  doi:10.7506/spkx1002-6630-201603006
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Objective: To evaluate the fatty acid composition and total polyphenol contents of cold-pressed seed oils from
four different grape varieties and assay their in vitro antioxidant activity. Methods: The fatty acid composition was measured
by gas chromatography with flame ionization detection (GC-FID). The content of polyphenols was determined using the
Folin-Ciocalteau method and the in vitro antioxidant activity was tested by 1,1-diphenyl-2-picryhydrazyl (DPPH)
radical scavenging, 2,2’-azinobis-3-ethylbenzthi azoline-6-sulfonic acid (ABTS) radical scavenging and Fenton
reaction methods. Results: The most abundant fatty acid in all cold-pressed grape seed oils was linoleic acid (72.77%–
77.36%) and the content of unsaturated fatty acids ranged from 88.12% to 91.06%. Total polyphenols ranged from 60.77
to 100.53 μg GAE/g and the order of total polyphenol contents in grape seed oils from different grape varieties was Ecolly >
Beibinghong > Meili > Carbernet Sauvignon. All clod-pressed grape seed oils had strong scavenging activity against
DPPH, ABTS and hydroxyl free radicals in a dose-dependent manner, with IC50 values ranging from 10.19 to
13.82 mg/mL, from 11.62 to 19.25 mg/mL, and from 13.18 to 27.08 U/mL, respectively. The IC50 value of total
antioxidant capacity ranged from 1.08 to 3.68 U/mL. The order of in vitro antioxidant activity of cold-pressed grape
seed oils was Ecolly > Beibinghong > Meili > Carbernet Sauvignon.

Purification and Structural Analysis of Polysaccharides from Fruits of Zizyphus jujube Mill. cv. Hupingzao
ZHANG Yaolei, HUANG Lixin, ZHANG Caihong, XIE Pujun, ZHANG Qiong, DING Shasha
2016, 37(3):  33-37.  doi:10.7506/spkx1002-6630-201603007
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The polysaccharides (ZJP-2 and ZJP-5) from the fruits of Zizyphus jujube Mill. cv. Hupingzao were purified by
Sepharose CL-6B column chromatography, and the structures of the purified active polysaccharides were studied in this
investigation. The purified polysaccharides (ZJP-2b and ZJP-5a) were homogeneous, and their molecular weights were
89.21 and 61.60 kD, respectively. IR spectral analysis showed that ZJP-2b and ZJP-5a had the characteristic absorption
peaks of polysaccharide, and the main structure was β-pyranose for both polysaccharides. The polysaccharide ZJP-2b was
composed of rhamnose, arabinose, mannose, glucose and galactose with a molar ratio of 32.4:9.5:9.4:14.7:9.7, and ZJP-5a
was composed by rhamnose, arabinose, xylose, mannose and galactose with a molar ratio of 20.2:42.9:2.2:7.5:14.5. At the
concentration of 3.5 mg/mL, hydroxyl radical scavenging rates of ZJP-2b and ZJP-5a were 30.51% and 57.22%, respectively.

Establishment of Reference Scale for and Dynamic Temporal Change of Cooling Intensity
ZHANG Lulu, WANG Houyin, SHI Bolin, ZHI Ruicong, XIE Nan, ZHAO Lei, CHEN Xiuhong
2016, 37(3):  38-42.  doi:10.7506/spkx1002-6630-201603008
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Based on the cooling descriptors established by a special sensory panel and the analysis of scaling results for
reference samples with different cooling intensities, the linear scale method was adopt to establish a 15-cm labeled line scale
consistent with Fechner’s law. The concentrations of reference samples were 4.00, 7.60, 12.00, 15.00 and 20.00 g/L menthol
aqueous solutions and the labeled values in the 15-cm line scale were 2.50 cm (slight cooling), 5.00 cm (a bit cooling),
7.50 cm (moderate cooling), 11.00 cm (strong cooling) and 13.00 cm (extreme cooling), respectively. Moreover, the time
intensity method was also used to explore the dynamic sensory change of reference samples. The maximum intensity (Imax),
duration time (Ttot) and the area under the time-intensity curve (AUC) were obtained though statistical analysis of the timeintensity
curve established based on sensory panel data. The results showed that the relationship between these time-intensity
curve parameters and the concentrations of reference samples was positively correlated. Meanwhile, the effect of dynamic
sensory change on the overall intensity (Ioverall) was also studied and it was confirmed that Imax played the most important role
in scaling the overall intensity of reference samples. This paper not only has presented a powerful method for quantitative
sensory evaluation of cooling intensity, but also has provided a creative idea for multi-dimension sensory evaluation of
cooling and other trigeminal sensations.

Comparison of Structure Characteristics of Gliadin and Glutenin in Highland Barley and Wheat
WANG Hongwei, WU Jingjing, KAN Jianquan
2016, 37(3):  43-48.  doi:10.7506/spkx1002-6630-201603009
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Gliadin and glutenin were extracted from highland barley and wheat using the Osbron method, their
physicochemical properties including subunit compositions, secondary structure, surface hydrophobicity, thermal stability,
and active and total sulfydryl groups were measured. The results showed that gliadin content in highland barley protein was
16.96%, lower than that in wheat protein; glutenin content in highland barley protein was 47.83%, higher than that in wheat
protein; however, highland barley contained less high molecular weight glutenin subunit (HMW-GS) bands wheat. The total
sulfydryl and disulfide bond contents of gliadin and glutenin in highland barley were lower than those of wheat, respectively.
The hydrophobicity of gliadin and glutenin from highland barley and wheat showed a similarity. Highland barley glutenin
showed higher thermal stability compared with wheat glutenin. The secondary structure of gliadin and glutenin was studied
by circular dichroism, and β-pleated sheet was dominant in glutenin. The major secondary structures were β-pleated sheet
and β-sheet in gliadin while β-sheet content of highland barley gliadin was lower compared with wheat gliadin.

Comprehensive Evaluation of Fruit Quality Factors of Apple Trees at Different Ages in Main Growing Regions to the North of the Weihe River in Shaanxi Province
LI Peng, WANG Yiquan, LIANG Huaxue
2016, 37(3):  49-54.  doi:10.7506/spkx1002-6630-201603010
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To investigate the evolution process and stability of fruit quality of apple trees in major growing areas to the
north of the Weihe River in Shaanxi province, mature fruits of Fuji apple trees at different ages (0-10, 11–15, 16–20, 21–25,
and > 25 years old) at orchards located in two major growing counties, Luochuan and Baishui, were analyzed for single
fruit weight, volume, density, hardness, soluble solids, titratable acids and calcium content, and comprehensive quality
evaluation of apples was carried out based on these seven quality indicators. The results demonstrated that single fruit weight
and volume markedly increased with increasing tree age. When the trees entered the peak fruit period (16 years old), they
remained basically stable. Fruit density showed no significant difference with tree age. Fruit hardness slowly declined with
the increase of tree age. But the differences in the fruit hardness of apple trees of different ages did not reach the significance
level. Soluble solid contents in the fruits of trees of different ages showed fluctuation, and titratable acids first increased
and then decreased with increasing tree age. Changes in calcium content presented a V-shaped trend with the extension of
tree age. Comprehensive evaluation showed the fruit quality exhibited an ascending trend with tree age up to 16 years and
significantly declined when the tree was over 25 years old. According to the above analysis, the fruit quality of apple trees
from the best growing areas to the north of the Weihe River was unstable. The relatively stable fruiting period for the best
fruit quality was confined to trees ranging in age from 16 to 25 years old. The fruit quality was deteriorated significantly in
trees aged over 25 years old.

Comprehensive Assessment of Quality Characteristics of Introduced Table Jujube Cultivars in Southern Xinjiang
JIANG Hui, DING Huiping, BAI Hongjin
2016, 37(3):  55-59.  doi:10.7506/spkx1002-6630-201603011
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To select the table jujube cultivars suitable for cultivation in Southern Xinjiang, evaluation of 13 table jujube
cultivars introduced was carried out by comparison of fruit quality traits on the base of principal component analysis,
including single fruit weight, fruit firmness, fruit shape index, edible part ratio, soluble solid content, soluble sugar content,
titratable acidity, vitamin C content, protein content and sugar/acid ratio. The results showed significant differences in
fruit quality among the cultivars. The coefficients of variation (CV) of single fruit weight, titratable acidity, and sugar/acid
ratio were larger than those of other indices, and the CV value of edible part ratio was small. There was simple correlation
between some quality traits. In principal component analysis, 4 principal components were extracted, with a total cumulative
contribution rate of 86.224%. The cultivars with excellent comprehensive quality were Jinlingyuanzao, Zaocuiwang,
Dongzao and Lizao, and the poor cultivars were Yueguang and Tailihong. These results were similar to practical phenotype
of jujube cultivars. Principal component analysis was quite suitable for the comprehensive assessment of table jujube quality.

Anti-Ultraviolet and Anti-Microwave Radiation Effects of Five Common Wild Berry Varieties in Saccharomyces cerevisiae
YANG Hua, REN Yue, PANG Weiqiao, GUO Dejun
2016, 37(3):  60-65.  doi:10.7506/spkx1002-6630-201603012
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The anti-radiation effects of water extracts of five wild berries from the Daxinganling region of north China in
the yeast Saccharomyces cerevisiae when exposed to ultraviolet (UV) or microwave were determined through methylene
blue staining. The results showed that the anti-UV effect of berries on Saccharomyces cerevisiae became strong with
its increasing concentration, increasing radiation distance and decreasing radiation time. The order of anti-UV and antimicrowave
radiation effects of five berry varieties was blueberry > Vaccinium vitis-idaea L.> Schisandra chinensis > Aronia
melanocarpa > raspberry. The anti-microwave efficiency of all five berry varieties to 20 s microwave radiation at 120 W was
higher than 90%. When the microwave power was 380 W and the microwave treatment time was 20 s, the anti-microwave
efficiency of wild blueberry, Vaccinium vitis-idaea L. and Schisandra chinensis was approximately 90%, but the antimicrowave
efficiency of other berries was weaker. When the microwave radiation was carried out for 40 s at 780 W, the antimicrowave
capacity of blueberry was still 84%; however, the anti-microwave capacity of other berries significantly declined.
It is concluded that the five berry varieties grown in the Daxinganling region have anti-ultraviolet and anti-microwave
radiation capacity, of which blueberry provides the strongest protection from radiation.

 

Effect of Ultrasonic Treatment on Antioxidant Activity of Polysaccharides from Mature Fruits of Schisandra chinensis
WANG Yanqun, MENG Xianjun
2016, 37(3):  66-70.  doi:10.7506/spkx1002-6630-201603013
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Ultrasonic treatment was employed to improve the antioxidant activity of polysaccharides from the mature fruits
of Schisandra chinensis. Based on hydroxyl and DPPH radical scavenging activity, the effects of ultrasonic power and
treatment time on antioxidant activity of polysaccharides were studied. The results showed that both ultrasonic power and
treatment time had significant effects on the antioxidant activity of polysaccharides. The optimal conditions of ultrasonic
treatment were 330 W of ultrasonic power, 20 min of treatment time. Under these conditions, the scavenging rates of
hydroxyl and DPPH radicals were increased from 74.34% to 87.05%, and from 84.43% to 95.05%, respectively. The IC50 of
the treated polysaccharides for scavenging of hydroxyl and DPPH radicals were 10.7 and less than 2 mg/mL, respectively.
In conclusion, appropriate ultrasonic treatment can improve the antioxidant activity of polysaccharides from Schisandra
chinensis fruits.

Effect of High-Energy Electron Beam Irradiation on Eating Quality of Rice
CHEN Xiaoping, JIN Yu, MENG Yan, XIE Jing, LIU Chao
2016, 37(3):  71-74.  doi:10.7506/spkx1002-6630-201603014
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Rice was irradiated by electronic beam at respective doses of 0, 1, 2, 3, 4, 5 and 6 kGy to examine the effect of
high-energy electron beam irradiation on cooking quality of rice. The results indicated that electron beam irradiation had
no significant impact on the moisture content or water-absorbing capacity of rice (P > 0.05). The water-absorbing capacity
and volume expansion of rice under cooking conditions dropped markedly with the increase of irradiation dose (P < 0.05).
Electron beam irradiation affected the cooking quality of rice significantly (P < 0.05). The rice subjected to electron beam
irradiation at 5 kGy exhibited noticeable browning during subsequent cooking. This study found that the dose of electron
beam irradiation should not exceed 2 kGy and that the preferable dose is 1 kGy.

Changes in Protein Gel Characteristics and Colors of Preserved Eggs (Pidan)
LONG Men, SONG Ye, DU Qingfei, ZHOU Di, CAI Huazhen, ZHAN Ge
2016, 37(3):  75-80.  doi:10.7506/spkx1002-6630-201603015
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In this study, changes in chemical composition, gel characteristics and color of preserved chicken eggs were
monitored during pickling for up to several weeks in the presence of 0.3% divalent cation (ZnCl2). The results showed that
free alkalinity, hardness, elasticity, cohesiveness and chewiness increased significantly (P < 0.05), and gelation capacity
became lower (P < 0.05) during the first 28 days of pickling, all of which tended to be stable as pickling went on (P > 0.05).
Most protein (> 86.6 kD) was degraded in the first 14 days of pickling. As the alkalinity of preserved eggs increased, smallmolecule
peptides (14.3 and 10 kD) accumulated continuously, and the total free amino acid content significantly decreased
(P < 0.05). In contrast, protein degradation did not continue to occur as the pickling period was prolonged from 21 days to
28 days. L* and b* values of preserved eggs changed in a manner opposite to a* value. Changes in the color of egg white
and yolk were significantly negatively correlated to pickling time, free alkalinity and free amino acid content, respectively.
Furthermore, a negative correlation was also seen between changes in whiteness values of egg white and yolk.

Effects of Sol Properties and Fermentation of Rennet Casein on Quality of Imitation Cheese
JIN Zelin, JIN Taihua
2016, 37(3):  81-86.  doi:10.7506/spkx1002-6630-201603016
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In order to improve the quality of imitation cheese, the effects of emulsifying salts, temperature and pH on sol
properties of rennet casein were explored, the minimum amount of emulsifying salt added before lactic acid fermentation was
determined, and the sensory quality and microstructure of the resulting cheese were analyzed. The results indicated that the
effect of five emulsifying salts on sol properties of rennet casein followed the decreasing order: sodium pentapolyphosphate >
sodium hexametaphosphate > JOHA PZ 7 > trisodium citrate dehydrate > tetrasodium pyrophosphate. In the range of
25–42 ℃, the solubility of rennet casein rapidly increased with an increase in temperature, whereas the increase was slower
as the temperature continued to increase to 85 ℃. As the pH increased from 5.5 to 11.5, the solubility significantly increased.
The minimum amount of emulsifying salt added to rennet casein was a rennet casein:sodium pentapolyphosphate:water ratio
of 1 g:25 mg:2.5 mL. The fermented imitation cheese scored much higher than the ordinary one (unfermented) in sensory
scores for both flavor and overall quality. Therefore, the imitation cheese obtained in this study not only had desirable
appearance and texture characteristics, but also overcame the intrinsic flavor defects of ordinary imitation cheese.

Molecular Docking of Benzoic Acid and Its Analogues with Tyrosinase
LI Muzi, WANG Qinghua, WANG Xiaoyi, HE Yun
2016, 37(3):  87-90.  doi:10.7506/spkx1002-6630-201603017
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Benzoic acid and its 12 analogues were docked with tyrosinase by using AutoDock 4.2 and iGEMDOCK 2.1
software, respectively. The linear correlation between docking binding free energy and experimental inhibitory activity of
benzoic acid analogues was studied. The results from AutoDock 4.2 showed that the change in Cu charge had a significant
effect on binding free energy, and the linear correlation coefficient between binding free energy and pIC50 was up to 0.803 6
when Cu charge was 2.0, but the linear correlation coefficient from iGEMDOCK 2.1 was poor. The prediction capacity of
AutoDock 4.2 was more reliable than that of iGEMDOCK 2.1.

Bioengineering
Optimization of Extraction Conditions for Cathepsin B from Takifugu obscures Muscle
LI Lin, WANG Zhengquan, ZHANG Jingjing, MIAO Xiaodan, MA Lei, WANG Xichang, LIU Yuan
2016, 37(3):  91-96.  doi:10.7506/spkx1002-6630-201603018
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In order to obtain optimal conditions for the extraction of cathepsin B from Takifugu obscures, on the basis of
results of single-factor experiments, some extraction parameters affecting cathepsin B activity were firstly evaluated by
Plackett-Burman design, and then the main variables were optimized by response surface analysis. The results showed that
the optimal extraction conditions were as follows: material/liquid ratio 1:2.1, phosphate buffer pH 7.0, and ammonium
sulfate saturation 99.2%, and these three factors had significant influence on the enzyme activity. Under these conditions,
the predicted value of cathepsin B activity was 32.65 U/g and its experimental value was 32.52 U/g, suggesting that the
established model is feasible and can provide a theoretical basis for further studies on the extraction process of cathepsin B.

Expression and Purification of Pediocin PA-1 in Escherichia coli
CHEN Xinquan, DU Lihui, JU Xingrong, WU Xueyou, YUAN Jian, HE Rong
2016, 37(3):  97-102.  doi:10.7506/spkx1002-6630-201603019
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Pediocin PA-1 is a representative class IIa bacteriocin produced by Pediococci with the potential to serve as a
food-grade preservative for controlling Listeria contamination. To obtain its soluble expression, Pediocin PA-1 structural
and immunity gene pedAB was amplified by polymerase chain reaction (PCR) from Pediococcus acidilactici PAF, and
cloned into the vector pGEX-6p-1 to construct the pGEX/his-pedAB encoding the recombinant pediocin PA-1 with
GST-His-DDDDK in the N-terminal of pediocin PA-1. The plasmid pGEX/his-pedAB was then transformed into
Escherichia coli Rosetta (DE3). After induction with isopropyl-β-D-thiogalactopyranoside, the recombinant pediocin
PA-1 was successfully expressed in E. coli cytoplasm. The expressed fusion protein was purified by Ni-NTA metal affinity
chromatography, subsequently loaded to GST affinity column and treated with recombinant bovine enterokinase. Mature
pediocin PA-1 was liberated from the recombinant protein. The purity of pediocin PA-1 was detected by high-performance
liquid chromatography and mass spectrometry. The antibacterial activity of pediocin PA-1 was determined by agar diffusion
method using Listeria monocytogenes CMCC54004 as an indicator. The results showed that fusion pediocin PA-1 did not
have bactericidal activity against Listeria monocytogenes, but when the GST-His-DDDDK in the N-terminal was removed,
the cleaved pediocin PA-1 restored its bactericidal activity. The purified pediocin PA-1 had a purity above 90%.

Kinetics of Alcohol Fermentation by Mixed Cultures of Hanseniaspora uvarum and Saccharomyces cerevisiae
WANG Xingchen, HU Kai, TAO Yongsheng
2016, 37(3):  103-108.  doi:10.7506/spkx1002-6630-201603020
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A strain of Hanseniaspora uvarum with high activity β-glucosidase has been isolated in our previous study. In this
work we conducted a kinetic study on alcohol fermentation by mixed cultures of the isolate and Saccharomyces cerevisiae
with the aim to find out the theoretical basis and technical support for the application of the strain of Hanseniaspora uvarum
in winemaking for aroma enhancement. Ecolly grapes in Yangling, Shaanxi were used as raw materials for winemaking.
Two treatments, inoculation of the isolate 48 h earlier than S. cerevisiae and simultaneous inoculation, were designed. The
inoculation amount of the isolate was 1.0 × 106 CFU/mL. The fermentation of these two treatments with YPD liquid medium
as grape juice model system was also performed. The fermentation with S. cerevisiae alone was set as the control. During
fermentation, the amount of different yeast strains, alcohol production and residual sugar were recorded. Then the kinetic
equations were built. Results showed that, in the asynchronous inoculation treatment, the live isolate subsisted for a longer
time and its amount was higher than that in the other treatment and the control. In the logarithmic period of the isolate,
alcohol production and sugar consumption were both lower than those in the other treatment and the control. In addition, its
alcohol fermentation was normal and the final alcohol production was the same as that in two other treatments. It could be
concluded that inoculation of the isolate 48 h earlier than S. cerevisiae could show better hydrolysis of aroma precursors by
β-glucosidase during winemaking, and it will have promising applications in winemaking for aroma enhancement.

Optimal Fermentation Conditions for and Antibacterial Spectrum of Antibacterial Substance Produced by Lactobacillus pentosus S1-4
SU Rina, SHUANG Quan
2016, 37(3):  109-113.  doi:10.7506/spkx1002-6630-201603021
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Using single factor and orthogonal array designs, the optimal fermentation conditions for antibacterial substances
produced by Lactobacillus pentosus S1-4 and their antibacterial spectrum were studied. The results showed an inoculum
amount of 2.0%, an initial pH of 5.5, and 26 h cultivation at 30 ℃ proved optimal. The average diameter of inhibition zones
against Lactobacillus brevis under the optimized culture conditions was (30.08 ± 0.69) mm, and the bacteriostatic activity
was increased by 1.23 times over that before optimization. The antibacterial substances produced by Lactobacillus pentosus
S1-4 were effective against 12 strains of Gram-positive and Gram-negative bacteria, indicating a wide antibacterial spectrum.
In conclusion, S1-4 has potential applications as a bio-preservative to improve the safety of food products.

Development of Biosensor Based on Immobilized Rat Small Intestine Tissues for Detecting Resveratrol
LIU Tingting, QIAO Lixin, PANG Guangchang
2016, 37(3):  114-119.  doi:10.7506/spkx1002-6630-201603022
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Using sodium alginate-starch gel as a fixing agent, small intestine tissues of Sprague-Dawley rats were fixed
between two nuclear micro porous membranes, forming a sandwich-type membrane, and then fixed to a glassy carbon
electrode to make a biosensor electrode. By using electrochemical workstation for the detection of the response current
from receptor stimulation by different resveratrol concentrations, the results showed that the lowest limit of detection
of this biosensor for resveratrol was 1 × 10-13 mol/L and the highest rate of change in response current was found at the
concentration of 8.5 × 10-12 mol/L, indicating that the resveratrol receptor was saturated at this point. The role of resveratrol
and its receptor was fitted to a hyperbolic curve with Origin software (R2 = 0.988 7). It showed that the correlation is high.
The binding constant and dissociation constant of resveratrol and its receptor evaluated by the double-reciprocal plot method
were 1.207 × 10-11 and 1.118 × 10-12, respectively. Thus the number of receptors to every cell is estimated to be about 85.
By comparing response values of resveratrol biosensor immobilized on rat intestinal epithelial tissue to the interaction of
resveratrol with the bare electrode, the response value of the small intestine tissue to resveratrol clearly gained amplified
function of intracellular signaling system with a magnification rate of up to 100. Meanwhile, the cell receptors obviously
rendered the biosensor saturabile and the typical characteristic was similar to the enzymatic reaction kinetic equation. This
study for the first time accomplished the quantitative determination of the interactions between resveratrol and receptors
and the dynamic law of signal transmission in the body through biosensors. This will provide new methods for resveratrol
receptor analysis, separation and purification, signal transmission and biological function evaluation.

Resistance and ERIC-PCR Genotyping of Salmonella enteritidis in Broiler Production Chain
LI Nan, ZHAO Sijun, WANG Juan, ZHAO Jianmei, LI Yuqing, HUANG Xiumei, WANG Junwei, DING Yibao, LIU Huanqi, QU Zhina
2016, 37(3):  120-124.  doi:10.7506/spkx1002-6630-201603023
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Objective: To investigate the antimicrobial resistance and genetic relationship of Salmonella enteritidis in the
production chain of broiler, and to provide the basis for clinical treatment and strain traceability. Methods: The susceptibility
of 171 Salmonella enteritidis to 13 antimicrobial agents was analyzed by micro-dilution method. The molecular types of 33
strains from different production links associated with resistance were analyzed by ERIC-PCR. The data were analyzed by
SPSS 20.0 software, Gel-Pro analyzer 4.0 and NTSYS pc 2.1 software. Results: The resistance degrees of 171 Salmonella
enteritidis to 13 antimicrobial agents were different. The resistance rate of these strains to ampicillin was the highest and up
to 90.06%, and the resistance rate to ofloxacin was the most sensitive and only 5.26%. The resistance rates of different links
were significantly different (P < 0.01). The multidrug resistance rate was 95.32%, and there were 26 kinds of anti-biograms.
Totally 33 Salmonella enteritidis were divided into 4 (I–IV) different genotypes, and the genetic similarity was 66%–100%,
and type I was the dominant genotype. Anti-biograms between the same genotype were also different; conversely, the
genotypes between the same antibiogram were different. Conclusion: The Salmonella enteritidis in broiler production chain
could generate resistance to many antimicrobial agents, generating many kinds of antibiograms. The Salmonella enteritidis
could be spread horizontally along the production chain. The genotypes of broiler farm were relatively complex. There was
no significant correlation between genotype and resistant phenotype.

Gene Cloning and Prokaryotic Expression of Peanut Allergen Ara h 6
ZHAN Shaode, QIU Changjiang, ZHU Pan, WU Zhihua, CHEN Hongbing
2016, 37(3):  125-130.  doi:10.7506/spkx1002-6630-201603024
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Ara h 6 is one of the major peanut allergens. Ara h 6 cDNA was synthesized from total RNA using Oligo primers
by reverse transcription-polymerase chain reaction (RT-PCR) in order to provide a template for the PCR amplification of
Ara h 6 gene. The target gene was cloned into pMD19-T vector to construct a recombinant vector. Then the recombinant
vector was transferred into the bacterial expression host BL21 (DE3). IPTG was used to induce protein expression, and the
expressed product was purified by Ni affinity chromatography. DNA sequence analysis showed that the full-length gene
fragment of Ara h 6 was 438 bp and encoded 145 amino acids, which was 97% identical to the known DNA sequence.
Sodium dodecyl sulfate-polyacryl amide gel electrophoresis (SDS-PAGE) results showed that the molecular weight of the
expressed fragment was 24 kD, which matched with the theoretical value of the His-tagged fusion recombinant protein Ara h 6.
Mass spectrometric results showed that the matching degree of structure was 100% between the recombinant protein and
natural Ara h 6. Western blotting indicated that the protein could be recognized by anti-Ara h 6 polyclonal antibody, and has
strong immunogenicity.

Development of Honeysuckle Herbal Tea by Fermentation with Lactobacillus plantarum
CHEN Kang, OH Young Joo, LI Hongjun, TAE Seok Kim, HE Zhifei, IK Hyun Yeo
2016, 37(3):  131-136.  doi:10.7506/spkx1002-6630-201603025
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The purpose of this study was to explore the processing conditions for the production of honeysuckle herbal tea
fermented by Lactobacillus plantarum PMO. An orthogonal array design based on single factor experiments was employed
to examine the influence of inoculum amount, temperature, time and the concentration of sugar added to aqueous extract
of honeysuckle flowers on the fermentation process and optimize the fermentation conditions. Results showed that the
domesticated strain of Lactobacillus plantarum PMO grew well in honeysuckle tea. The content of chlorogenic acid in
honeysuckle tea was little affected by the fermentation process, where it always remained at approximately 29.20 mg/g. The
optimal fermentation conditions were determined as fermentation of honeysuckle extract containing 7% sugar added at 37 ℃
for 14 h with an inoculum amount of 3%.

Growth Simulation and Discrimination of Botrytis cinerea, Rhizopus stolonifer and Colletotrichum acutatum by Using Hyperspectral Reflectance Imaging Technique
SUN Ye, GU Xinzhe, WANG Zhenjie, HU Pengcheng, TU Kang, PAN Leiqing
2016, 37(3):  137-144.  doi:10.7506/spkx1002-6630-201603026
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This study used a hyperspectral imaging system (HIS) to measure the spectral response of fungi inoculated
on potato dextrose agar plates. In this work, three methods for calculating HIS parameters, including the mean of whole
spectral response values covering the range of 400–1 000 nm, the spectral response value of the wave peak at 716 nm, and
the score of the first principal component in the whole spectral range of 400–1 000 nm using principal component analysis
(PCA), were used to simulate the growth of fungi. The results showed that the coefficients of determination (R2) of the
simulation models for test datasets of three fungi, Botrytis cinerea, Rhizopus stolonifer and Colletotrichum acutatum, were
0.722 3–0.991 4, and the sum square error (SSE) and root mean square error (RMSE) were in a range of 2.03 × 10-4–5.34 × 10-3
and 0.011–0.756, respectively, based on the three methods. The correlation coefficients between HIS parameters and colony
forming units of fungi were high ranging from 0.887 to 0.957. In addition, fungal species can be discriminated by PCA and
partial least squares-discrimination analysis (PLS-DA) based on the spectral information in the full wavelength range. The
classification accuracy of the test dataset by PLS-DA models for fungi cultured for 36 h was 97.5% among Botrytis cinerea,
Rhizopus stolonifer, Colletotrichum acutatum, and the control. This paper offers a new technique and useful information for
further study into modeling the growth of fungi and detecting fruit spoilage caused by fungi based on HIS.

Strain Improvement by Protoplast Fusion for Enhanced Transglutaminase Production
HOU Xiaolun, LIU Yaqing, GUO Weiting, GAO Hongliang, CHANG Zhongyi, BU Guojian, LU Wei, XIE Xiujuan, JIN Mingfei
2016, 37(3):  145-150.  doi:10.7506/spkx1002-6630-201603027
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Objective: To obtain a high-yield transglutaminase (TGase)-producing strain through protoplast fusion between
mutant strains of Streptomyces mobaraensis. Methods: Protoplasts were obtained by lysozyme digestion, and after protoplast
fusion, the selected fusants were screened for TGase production by primary high-throughput screening in 96-well plates and
fermentation in test tubes and shake flasks, respectively. Results: The colonies regenerated from protoplasts had a smaller
diameter, and the diameter of colonies formed by mycelia was larger. The two different colonies had a significant difference
in TGase activity during fermentation in 96-well microplates. Different mutant strains of Streptomyces mobaraensis were
very different with respect to TGase activity, protoplast purity and protoplast regeneration rate. The maximum protoplast
regeneration rate was 1 804.25%, and the minimum was only 12.76%. After genome shuffling, we selected the top 3% of
fusant strains with high TGase activity through high-throughput screening in 96-well plates to carry out fermentation in test
tubes. Of these strains, 32.2% were high-yield strains having a 22.4% higher TGase activity than the parental strain. The
production was increased by 16.28% in shake flask fermentation. Conclusion: Genome shuffling can be used to improve
Streptomyces mobaraensis for enhanced TGase production.

Strain Improvement of Bacillus subtilis for Enhanced Production of Nattokinase and Optimization of Solid-State Fermentation Conditions
ZHANG Jie, GE Wupeng, CHEN Ying, ZHANG Yue, LIU Liting
2016, 37(3):  151-156.  doi:10.7506/spkx1002-6630-201603028
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In this study, the nattokinase-producing capacity of Bacillus subtilis subsp. subtilis BS21076 was improved by
sequential mutagenization with ultrasonic followed by UV light at the appropriate doses determined according to death
and mutation rates. The optimal mutation conditions of strain BS21076 were established as 60 min ultrasonic treatment at
45 kHz and 280 W followed by 120 s UV irradiation at a distance of 30 cm. A high nattokinase-producing mutant strain
named BSCZ-4, producing 1.96 times higher nattokinase than BS21076, was obtained after several rounds of primary and
secondary screening. After 20 consecutive passages, the diameter of the zone of dissolution produced by BSCZ-4 remained
stable in the range of 18–19 mm, suggesting good genetic stability. Using Box-Behnken response surface methodology,
the optimal culture conditions for the enhanced production of nattokinase by BSCZ-4 in solid-state fermentation were
determined as addition of 5% konjac power to the culture medium, an inoculum size of 8%, and 24 h culture at 34 ℃,
resulting in a nattokinase activity of (4 087.83 ± 93.75) U/g.

Preparation and Application of Monoclonal Antibody against Furazolidone
CHEN Yinnan, CHEN Hua, SHI Xianai, YE Xiaojun, FAN Haiping
2016, 37(3):  151-157.  doi:10.7506/spkx1002-6630-201603029
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Based on the hapten of furazolidone (FZD), a monoclonal (mAb)-based enzyme-linked immunosorbent assay
(ELISA) method for the detection of FZD was established after the preparation of mAb against FZD-bovine serum albumin
(BSA). The linear range for furazolidone detection was 10–500 ng/mL, and the IC50 was 0.06 μg/mL with a lowest detection
limit of 6.92 ng/mL. Meanwhile, the mAb showed almost no cross reactivity with other nitrofurans or their metabolites. This
method had good reproducibility, with an average error of 6.54%. In tested samples, the recovery for furazolidone addition
was 76.84%–88.31%.

Expression and Enzymatic Properties of β-Amylase
ZHANG Xiaoxiao, NIU Dandan, SHEN Wei, LI Yu, LU Fuping
2016, 37(3):  164-169.  doi:10.7506/spkx1002-6630-201603030
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In this research, a recombinant Pichia pastoris strain GS-BBA overexpressing barley β-amylase was developed
using the recombinant expression plasmid pPIC-BBA. Strain GS-BBA could produce approximately 180 U/mL β-amylase in
shaking flask culture. The biochemical properties of the recombinant β-amylase were examined. The maximum activity was
achieved under the conditions of pH 5.0 and 55 ℃. Meanwhile, its excellent thermostability and pH stability was observed at
a temperature not exceeding 55 ℃ and in the pH range of 3.0–10.0. The recombinant enzyme could hydrolyze starch to form
maltose as the major product. With the aid of pullulanase, it hydrolyzed starch to form maltose with a conversion efficiency
up to 78.28%.

Isolation and Identification of Specific Spoilage Organisms in Chilled Sea Bass
TANG Wenjing, WANG Chuwen, LIU Yunlong, NING Xibin
2016, 37(3):  170-174.  doi:10.7506/spkx1002-6630-201603031
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The specific spoilage organisms (SSOs) were isolated and identified from chilled sea bass under 4 ℃ refrigerated
condition. These SSOs were individually isolated using selective medium and their spoilage ability was analyzed. These
isolates were identified based on morphological, physiological and biochemical characteristics and 16S rDNA sequence
analyses. The results showed there were 4 SSOs present in chilled sea bass, including one Pseudomonas fragi, one
Shewanella putrefaciens, and two Pseudomonas sp.. In refrigerated condition at 4 ℃, the spoilage ability of Pseudomonas
fragi was the highest, followed by Shewanella putrefaciens and Pseudomonas sp.

Performance Evaluation of Three Media for Alicyclobacillus Isolation
HE Tianwen, LU Mianfei, CAI Zhihe, ZHOU Meilian, WU Qingping
2016, 37(3):  175-179.  doi:10.7506/spkx1002-6630-201603032
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Objective: To evaluate the efficacy of three media, K agar, yeast extract starch glucose (YSG) medium and Bacillus
acidoterrestris (BAT) agar medium each from three manufacturers (Guangdong huankai, manufacturer II and manufacturer
I), in detecting Alicyclobacillus. Methods: The colony growth of standard strains and the separation of Alicyclobacillus
isolates from real samples were evaluated using the three media. Results: The number of colonies of Alicyclobacillus
acidoterrestris reference culture and Alicyclobacillus isolate 4-2 in K medium, YSG medium and BAT medium did not
significantly differ (P > 0.05). Similarly, there was no significant difference in the number of colonies of A. acidoterrestris
reference culture and Alicyclobacillus isolate 5-3 in YSG medium and BAT medium (P > 0.05), but neither could grow in
K medium. The separation and consistency rates of three media from three manufacturers for isolating A. acidoterrestris
in samples were similar. The separation and consistency rates of YSG medium for isolating A. acidocaldarius in samples
were similar to those of BAT medium from HK and manufacturer II, which were better than those from manufacturer I.
Conclusion: K medium was more effective for isolating A. acidoterrestris, but it was not suitable for isolating all
Alicyclobacillus isolates. YSG medium and BAT medium were suitable for isolating all Alicyclobacillus isolates. The media
from HK and manufacturer II had superior performance than those from manufacturer I.

Optimization of Electroporation Conditions for Lactobacillus plantarum G63
FAN Jing, XI Xuedong, HUANG Yan, CUI Zhongli
2016, 37(3):  180-185.  doi:10.7506/spkx1002-6630-201603033
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The objective of this work was to explore an efficient method for Lactobacillus plantarum G63
electrotransformation. We evaluated the effects of the growth phase, weakening cells, washing buffer, plasmid
DNA concentration and electrical parameters on electroporation efficiency. The results showed that after culture in
MRS medium containing 1 g/100 mL glycine to mid-logarithmic phase, the cells were harvested and washed with
1 mmol/L MgCl2 and 30 g/100 mL PEG1000. The optimal electroporation conditions could be achieved by using 30 g/100 mL
PEG1000 as the electroporation buffer with 20 μg of plasmid DNA added in 80 μL of the cell suspension, and pulsing under
specific conditions (field strength, 1.5 kV; resistance, 400 Ω). The transformation efficiency was 1.18 × 103 CFU/μg DNA
under the optimal conditions, which could meet the requirements for subsequent genetic experiments.

Optimization of Fermentation Conditions for Cholesterol Reduction in Egg Yolk by Mixed Lactobacillus Culture
ZHANG Gensheng, DING Xiaojun, YU Min, CHENG Jianbo, DING Jian
2016, 37(3):  186-190.  doi:10.7506/spkx1002-6630-201603034
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Egg yolk was inoculated with a mixed culture of three strains with high cholesterol-reducing capacity and kept
in a thermostatic oven in order to maximize cholesterol reduction. Direct saponification-colorimetry method was used to
measure the reduction rate of cholesterol. The fermentation conditions were optimized using an orthogonal array design as
follows: fermentation temperature, 40 ℃; fermentation time, 24 h; inoculum amount, 3%; bile salt concentration, 3 g/L; and
the proportion of mixed strains, 1:2:1 (Streptococcus thermophilus:Lactobacillus acidophilus:Bifidobacterium). Under these
conditions, the cholesterol in egg yolk was reduced by 31.5%.

Nutrition & Hygiene
Effect of Tributyrin on Liver Antioxidant Capacity and Mitochondrial Function of Piglets with Intrauterine Growth Retardation during Sucking Period
HE Jintian, DONG Li, BAI Kaiwen, XU Wen, NIU Yu, HUANG Qiang, ZHANG Lili, WANG Tian
2016, 37(3):  191-196.  doi:10.7506/spkx1002-6630-201603035
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Objective: The effect of tributyrin on liver antioxidant capacity and mitochondrial function of sucking piglets
with intrauterine growth retardation (IUGR) was observed in the present study. Methods: Totally 8 piglets with normal birth
weight and 16 IUGR piglets were selected. The IUGR piglets were randomly divided into 2 groups (IUGR group fed basic
artificial milk; IT group (IUGR + 0.1% tributyrin) fed basic artificial milk supplemented with 0.1% tributyrin). The piglets
with normal birth weight were provided with basic artificial milk (NBW group). The experiment started at the age from
7 to 21 days. Totally 6 piglets (similar body weight) were selected from each group and slaughtered, and liver histological
sections, antioxidant enzyme activities and mRNA expression were measured. Results: 1) Compared with NBW group,
liver histological sections from IUGR group revealed central venous congestion, but IT group had no significant change.
2) Compared with NBW group, IUGR group had lower glutathione peroxidase (GSH-Px) activity (P < 0.05) and increased
malondialdehyde (MDA) content (P < 0.01) in liver, and lower malate dehydrogenase (MDH) and Mn-superoxide (Mn-SOD)
activities in mitochondria (P < 0.05). IT group had higher SOD and GSH-Px activities, glutathione (GSH) content and
total antioxidant capacity (T-AOC) (P < 0.05), and lower MDA content (P < 0.01) in liver, as well as higher activities of
MDH and Mn-SOD in mitochondria when compared to IUGR group. Compared with NBW group, the activities of GSH
and T-AOC were significantly increased (P < 0.05), and the MDA content was significantly decreased (P < 0.01) in IT
group. 3) Compare with NBW group, the mRNA expression levels of the SOD and CAT genes in liver of IUGR group were
significantly increased (P < 0.05), and the mRNA expression levels of SOD and PRDX3 in liver of IT group were also
significantly increased (P < 0.05). Compared to IUGR group, the mRNA expression of CAT was significantly decreased
(P < 0.05) and the mRNA expression of PRDX3 was significantly increased (P < 0.05) in liver of IT group. Conclusion:
Piglets with IUGR exhibited decreased antioxidant capacity in liver and impaired mitochondrial function. Diets
supplemented with tributyrin could improve antioxidant capacity and protect mitochondria from damage in liver of IUGR
piglets. Tributyrin may be an efficient antioxidant.

Acute and Accumulative Toxicity and Detection of Residual Sodium 4-Chlorophenoxyacetate in Mice
LIU Hong, ZENG Zhijie, LI Chuanyong, ZHANG Shuihua, SUN Lechang, CHEN Qiong, CAO Minjie, LIU Guangming
2016, 37(3):  197-204.  doi:10.7506/spkx1002-6630-201603036
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Objective: To investigate acute and accumulative toxicity and residual patterns of sodium 4-chlorophenoxyacetate
(4-CPANa), a plant growth regulator usually abused in poisonous bean sprouts, in mice. Methods: The oral acute toxicity
of 4-CPANa in mice was determined by a modified Korbor method, and oral accumulative toxicity was assayed by
an incremental exposure accumulative coefficient method with an initial dose of 107.4 mg/kg. Physiological indices
of mice were recorded during the experimental period. Serum biochemical and organ indices and morphological
examination of mice were carried out, and the 4-CPANa residues in mouse body were analyzed by ultrahigh-performance
liquid chromatography at the end of the experiment. Results: The half-lethal dose (LD50) of 4-CPANa to mice was
1 074.1 mg/kg and the accumulative coefficient K was larger than 8. Compared with the control group, 4-CPANa showed
different influence on physiological and serum biochemical indices in mice. Furthermore, 4-CPANa also resulted in visible
lesions and significant histopathological changes in the liver and kidney of mice. The 4-CPANa residue in mice was
observed in the following decreasing order: urine > kidney > liver > blood > heart > brain > muscle. Conclusion: 4-CPANa
was classified as the 4th level of toxicity and belonged to the low-accumulation family. The toxic effect of 4-CPANa toward
mice was mainly exhibited as lesions in liver and kidney.

Cytotoxicological Test of Photoactivated Curcumin
WU Juan, LIU Yiming, LI Xia, WANG Jingfeng
2016, 37(3):  205-210.  doi:10.7506/spkx1002-6630-201603037
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The main purpose of this research was to explore the cytotoxicity of photoactivated curcumin based on fibroblast
cell line L929. The cell morphology was examined by an inverted microscope, relative growth rate (RGR, %) was
detected by methyl thiazolyl tetrazolium (MTT) method, cytotoxicity was evaluated according to the general standard,
and cell apoptosis was detected by DNA ladder analysis and Hoechst nuclear staining, respectively. Results showed that
photoactivated curcumin did not affect cell morphology, which was fusiform or irregular in shape and had no significant
difference when compared with the control group. It had no cytotoxicity with the toxicity grade “0” or “1”, and did not
cause apoptosis according to DNA ladder analysis and Hoechst nuclear staining. This study confirmed that photoactivated
curcumin had no toxicity to L929 cells at the concentrations of 5, 10 and 20 μmol/L. These results will lay a foundation
for exploring the safety of consumption of photoactivated curcumin and provide the theory basis for the popularization and
application of curcumin-mediated photodynamic non-thermal sterilization technology in daily life.

Inhibitory Effect of Conjugated Linoleic Acid on Obesity of Mice
WANG Wu, LI Qiling, PAN Jian
2016, 37(3):  211-216.  doi:10.7506/spkx1002-6630-201603038
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Conjugated linoleic acid (CLA), a mixture of positional and geometric isomers of linoleic acid with conjugated
double bonds, has attracted considerable attention since cis-9, trans-11-CLA (c9, t11-CLA) and trans-10, cis-12-CLA
(t10, c12-CLA) have a great application potential in medicines, foods and health products based on anticancer, immune
regulatory, anti-atherosclerosis, anti-obesity and antioxidant activities. In this study, Kunming mice were used as
experimental subjects to evaluate the inhibitory effect of CLA (80% purity, containing 36.40% c9, t11-CLA, 36.26%
t10, c12-CLA and 7.14% other CLA isomers) on the obesity of mice. The tested mice were divided into obesity model
control group, normal control group and CLA treatment group, and the mice in the CLA treatment group were administered
with CLA by gavage for six weeks, and then obesity indexes, such as body weight, Lee’s index, total weight of fat, fatty
coefficient, and total cholesterol (TC), triglyceride (TG), low density lipoprotein cholesterol (LDL-C), high density
lipoprotein cholesterol (HDL-C) in serum, fatty acid synthase (FAS) in liver and viscera of the mice, were measured. The
results showed that the obesity indexes, including Lee’s index, fatty coefficient, TC, TG and LDL-C, in the CLA treatment
groups at various dosages were significantly lower than the obesity model control group (P < 0.05 or P < 0.01), and HDL-C
was significantly higher than the obesity model control group (P < 0.01). Lee’s index, fatty coefficient, TC, TG, and LDL-C
decreased with increasing CLA dose, while HDL-C increased. High-dose CLA (0.15 mL/10 g) could control the obesity
indexes of obesity model control group to the level of the normal control group, and CLA treatment at each dose had no
significant effect on the viscera of the mice; therefore, CLA could inhibit obesity and had no toxic side effect on the growth
of mice. The Lee’s index, fatty coefficient, TC, TG, and LDL-C had high positive correlation with FAS, while HDL-C
had a highly negative correlation. An obvious correlation between FAS and obesity index was observed and it was further
confirmed that FAS is the potential target of obesity. CLA treatment can significantly reduce FAS (P < 0.01), and this could
be the mechanism of its antiobesity effect.

Reviews
Odorant and Taste Receptors and Their Potential Applications in Evaluation of Functional Foods
PANG Guangchang, CHEN Qingsen, HU Zhihe, XIE Junbo
2016, 37(3):  217-228.  doi:10.7506/spkx1002-6630-201603039
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The mammalian gustatory system is classified into five primary tastes: umami, sweet, salty, sour and bitter,
which enable us to evaluate food constituents. The tastes have been identified as the major members of the G protein-coupled
receptor (GPCR) family, the largest family of receptor proteins in mammals (referred to as taste receptor type 1 (T1R) and
type 2 (T2R)). Another taste quality related to lipid sensing is mediated by free fatty acid (FFA) GPCR family. An increasing
number of reports on the expression of odorant and taste receptors in tissues beyond the nose and mouth started to appear in the
literature. But most literatures have been relied on reverse transcription PCR (RT-PCR) and microarray data without demonstrating
either protein expression or function. Recently, some publications are appearing on the function of odorant and taste receptors in
the gastrointestinal tract. These studies reinforce the broader potential and even more important roles beyond the odorant and taste
receptors. In this review, the prevailing evidence for the expression of odorant and taste GPCRs in cells and tissues beyond the
nose and mouth is summarized, and then the putative function for these receptors in diverse physiological functions, ranging from
nutrient sensing, regulation of nutrient uptake, metabolic balance, energy control and metabolic disorder is highlighted. Finally,
the future trends and potential applications of detection technologies for these GPCRs are expected for the evaluation of functional
ingredients such as resveratrol, polyphenols, flavonoids and other phytochemicals.

A Review on the Structure and Immune Regulation Function of Lactobacillus S-Layer Protein
ZHANG Yingchun, XIANG Xinling, ZHANG Lanwei, MA Fang, LI Shaohui
2016, 37(3):  229-234.  doi:10.7506/spkx1002-6630-201603040
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The structure and function of Lactobacillus S-layer protein are reviewed in this paper with special focus on its
tolerance to digestive enzymes and bile salts, involvement in host cell adhesion of Lactobacillus and role in inhibiting host
cell adhesion and intrusion by pathogens. Meanwhile, the regulatory effect of Lactobacillus S-layer protein on cell signaling
pathways is expounded. In conclusion, this review suggests that Lactobacillus S-layer protein plays an important role in the
immunoregulatory effect of Lactobacillus.

Progress in Research on the Antitumor Mechanisms of Plant Polyphenols Based on Proteomics
LI Yao, LIAO Xia, XIAO Xingning, ZHANG Xiaoli, LU Keke, WU Surui, MING Jian
2016, 37(3):  235-240.  doi:10.7506/spkx1002-6630-201603041
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Proteomics, an important method for the large-scale study of cellular proteins, has been widely used for exploring
the molecular mechanisms of cancer, searching for biomarkers, and screening for new anticancer drugs. The antitumor
potential of plant polyphenols, as natural active substances, has been confirmed. This paper provides an overview of
proteomics and reviews recent progress in proteomic studies of the antitumor mechanisms of plant polyphenols, aiming to
provide a scientific basis for the application of plant polyphenols in health food and drugs.

Progress in Staphylococcal Enterotoxins and the Mobile Genetic Elements Encoding Them
WANG Qiong, TANG Junni
2016, 37(3):  241-246.  doi:10.7506/spkx1002-6630-20160342
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Staphylococcal enterotoxins (SEs) belong to the family of pyrogenic toxin superantigens. The consumption
of foods containing SEs could cause food poisoning with the symptoms of nausea, vomiting, abdominal cramping, and
diarrhea. This review summarizes the classification and physicochemical properties of different SEs, especially focusing
on the mobile genetic elements encoding SEs, which would have a theoretical and practical significance to epidemiological
investigation and understanding of the virulence mechanism of Staphylococcus aureus enterotoxins.

Advances in Koumiss and Viili
WANG Hao, LIU Zhenmin, ZHANG Hui
2016, 37(3):  247-252.  doi:10.7506/spkx1002-6630-201603043
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The sensory profiles, physicochemical properties, microflora, health benefits and manufacturing processes of
koumiss and viili, as distinctive representatives of traditional fermented milk, have been summarized in this article. The
introduction and large-scale production of koumiss and viili improved to meet the increasing requirements of Chinese
consumers is beneficial for developing the emerging niche market in the field of fermented milk and further catering to
changing consumer demands.

Management of Food Allergens in Japan and Its Revelation for China
ZHENG Ying, CHEN Shuguang, YE Yu, FANG Qingying, CHEN Hongbing, GAO Jinyan
2016, 37(3):  253-257.  doi:10.7506/spkx1002-6630-201603044
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The influence of food allergy on consumers and the food industry has become more and more serious in China. It
is very urgent for China to solve this problem. Japan is the first country in the world to enact laws for the mandatory labelling
of allergen information on food containers and has already had a whole allergen labelling system. The law-making process,
the scope of the restraint, the lablelling strategies for food allergens, the punishment measures for false labelling, and the
detection methods for food allergens in Japan can offer enlightenments for China to enact laws and establish detection
methods for solving the problem of food allergens.

Application Architecture of Food Safety Testing Laboratory Information Management System
CHEN Ting, LIU Qingjun, ZHANG Xu, SUN Chang
2016, 37(3):  258-265.  doi:10.7506/spkx1002-6630-201603045
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To address the problems encountered in food safety testing in laboratories such as difficulty in aligning detection
requirements, low management informatization level and insufficient data analysis, this paper has analyzed the role of
laboratory information management system in food safety technology system, and proposed application architecture
protocols of food safety testing laboratory information management system with rapid acquisition of information/data
required for laboratory management, and secondary utilization of the data and secure data access as the core based on
informatization construction of the laboratory testing process. The informatization of the whole laboratory testing process
enables the availability of services such as inquiry online, whole-process tracing, automatic data acquisition, real-time
monitoring of the quality system, data analysis and evaluation, quantitative assessment of laboratory personnel performance,
which helps achieve the goals of enhancing the operational efficiency of laboratory testing services by process information
management, of improving the alignment of detection requirements by data collection and extraction, and of creating a new
testing service mode by data mining and analysis.

Advances in Biosynthesis of Abscisic Acid and Its Roles in Regulation of Fruit Ripening
YANG Fangwei, DUAN Yifei, FENG Xuqiao
2016, 37(3):  266-272.  doi:10.7506/spkx1002-6630-201603046
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As an important plant hormone, abscisic acid (ABA) plays a series of significant physiological roles
in higher plants including but not limited to bud dormancy, leaf fall, stoma closure, growth inhibition and plant
resistance. Recently, it has been revealed that ABA also has an important regulatory role in the growth, development
and ripening of fruits. In higher plants, the sesquiterpenoid ABA is produced via an indirect pathway from the cleavage
products of C40 carotenoids. The accumulation of endogenous ABA levels in plants is a dynamic balance controlled by
the processes of biosynthesis and catabolism, through transcriptional regulation of key ABA biosynthetic genes and
enzymes activities. Levels of endogenous ABA gradually increase during the late stage of fruit development, and fruit
ripening and softening are promoted by ABA accumulation. It has been hypothesized that the ABA level could be part
of the signal that triggers fruit ripening, and that ABA biosynthesis and accumulation may play an important role in the
regulation of ripening and senescence of both non-climacteric and climacteric fruits. These findings have demonstrated
that ABA has varieties of important roles in the regulation of growth and development, quality formation, coloring
and softening, ripening and senescence of fruits, which has great realistic significance in food science and postharvest
biology of horticultural products. In this review, we summarize recent progress in the study of the role of ABA in fruit
ripening and transcriptional regulation. In addition, we prospecte possible commercial applications of ABA signal
regulation to improve fruit quality and shelf life.

Advances in Research on Milk-Clotting Enzymes
HANG Feng, HONG Qing, WANG Qinbo, LIU Peiyi, LIU Zhenmin, CHEN Wei
2016, 37(3):  273-279.  doi:10.7506/spkx1002-6630-201603047
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Calf rennet is conventionally used as milk coagulant for the production of cheese. However, the supply of
calf rennet is not equivalent to the demand in cheese industry, which merely meets 20%–30% of the global demand for
cheese production. Due to the scarcity and high price of calf rennet, it is necessary and urgent to find potential substitutes.
This review gives an overview of the current discoveries of calf rennet, the characteristics of different types of milkclotting
enzymes including animal rennet, recombinant chymosin, plant- and microbial-derived coagulants, and specifies
the application of coagulants in cheese production. The objective of this review is to provide the fundamental theory and
inspiring ideas for the researchers and manufacturers to find calf rennet substitutes.

Progress and Prospects for Methionine Bioproduction
WANG Longyang, MIN Weihong
2016, 37(3):  280-285.  doi:10.7506/spkx1002-6630-201603048
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Methionine is widely used in many fields such as feed, food, pharmaceutical and biotechnology, and has an
increasing market demand. Compared with chemical synthesis, the biological production of methionine has many advantages
especially in sustainable production and environmental protection. The biological methods used for methionine production
include microbial fermentation and enzymatic treatment. Researchers have been trying to describe the biosynthetic pathway
of methionine and breed high methionine-producing strains. However, no bacteria are now used in industrial production of
methionine because of the complex biosynthesis pathway of this amino acid and the affinity with other intracellular reaction
systems. In-depth study of methionine biosynthesis pathway, expansion of methionine exporting system and optimization
of fermentation conditions are effective to increase the yield of methionine produced by the existing strains. The stateof-
the-art technology of enzymatic hydrolysis for the production of methionine, combining genetic engineering with
enzyme immobilization, has great application potential. This article summarizes the latest advances in the biotechnologies
for methionine production in China and abroad with emphasis on microbial fermentation, enzymatic treatment and their
combination. According to the characteristics of methionine production by microbial fermentation, existing problems and
corresponding suggestions with respect to the removal of allosteric inhibition, the application of composite sulfur source
and the stability of key enzymes are put forward. The combination of enzymatic treatment and microbial fermentation
is recommended to be used for the production of methionine from preferably hydrolyzed plant proteins, achieving the
advantages of low cost, low pollution, high yield and high purity.

Progress in the Mechanism and Application of Guanosine-Binding Protein Coupled Receptor (GPCR) Family Taste Receptor Signal Transduction
GAO Qian, ZHU Zhouhai, ZENG Wanli, HUANG Haitao, ZHOU Lan, LI Xuemei, YAO Jianhua
2016, 37(3):  286-291.  doi:10.7506/spkx1002-6630-201603049
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Taste is the sensation produced when a substance in the mouth reacts chemically with taste receptor cells. When
flavor substances stimulate taste receptors, the signal is transmitted to the brain via the nervous sensory system, resulting in
the sense of taste after the analysis in the central nervous system. In recent years, taste receptors, taste signal transduction
and application caused great concern of the public, and a lot of cell research results showed that different tastes are
produced by different taste receptors. This paper reviews the signal transduction process and corresponding application of
guanosine-binding protein coupled receptor (GPCR) family taste receptors.