Volume 34,Issue 9,2018 Table of Contents

1 Protection of Proanthocyanidins on Kidney in Diabetic Rats

GONG Pin , ZHANG Meng-xuan , LI Xiao-fan , WANG Lan , CHEN Fu-xin

2018, 34(9):1-5. DOI: 10.13982/j.mfst.1673-9078.2018.9.001

[Abstract](702) [HTML](210) [PDF 619.43 K](788)

Abstract:
This study aims to explore the protective effect of Proanthocyanidins (PC) on diabetic rats kidney and potential mechanism. In this work, the diabetic rats model was established by feeding with a high fat and sugar diet in combination with a streptozotocin treatment. Animals were randomly divided into three groups: model group, test group (PC, 150 mg/kg) and normal group. After 4 weeks of treatment, blood glucose, total cholesterol (TC), triglyceride (TG) and kidney malondialdehyde (MDA), protein carbonyl (PCO), superoxide dismutase activities (SOD) and catalase (CAT) activities were determined. Results showed that as compared with the normal group, TC and TG in the model group were significantly increased by 4.02-fold and 6.88-fold (p < 0.01), while the SOD and CAT activities in the kidney tissue were significantly (p < 0.01) decreased by 27.88% and 17.61%, respectively. The levels of MDA and PCO increased significantly by 51.10% and 81.36% (p < 0.01). As compared with the model group, the blood glucose, TC and TG levels in the experimental group were significantly reduced by 50.84%, 55.70% and 70.52%, respectively (p < 0.01). The activities of SOD and CAT in kidney tissues were significantly increased by 26.05% and 12.97% (p < 0.01), and the contents of MDA and PCO in kidney tissues were significantly decreased to 21.54% and 11.86% l, respectively (p < 0.01). The pathologic slice revealed that PC pretreatment could reduce STZ-induced pathological damage such as glomerular atrophy. These results demonstrated that PC may exhibit a protection on diabetic rats kidney, and the underlying mechanism might be related to its anti-oxidative properties and free radical scavenging abilities.

2 The Improvement of Blood Lipid in Type Ⅱ Diabetic Rats by Pterostilbene and its Modulation of PPARγ Expression

LIU Xin-xin , SUN Hua-lei , GE Hui-na , WANG Teng , LI Wen-jie

2018, 34(9):6-11. DOI: 10.13982/j.mfst.1673-9078.2018.9.002

[Abstract](509) [HTML](232) [PDF 590.13 K](774)

Abstract:
The effects of pterostilbene (PTE) on blood lipid and PPAR γ expression of adipose tissues in type Ⅱ diabetic rats were investigated. Rats were randomly divided into five groups: normal control group, type Ⅱ diabetes mellitus (T2DM) group, PTE low dose group, PTE middle dose group and PTE high dose group. Blood lipid, the activity of SOD and the level of MDA were examined, and PPARγ mRNA and protein expression in adipose tissue were evaluated. As compared to normal rats, the levels of TG, TC, LDL-C and MDA in the T2DM group increased, while the level HDL-C and SOD decreased. The level of TG in PTE (low, middle and high) groups and TC, LDL-C and MDA in PTE (low and middle) groups were lower than those in the T2DM groups , while the activity of SOD in PTE (low and middle) groups was higher than the T2DM group (p < 0.05). As compared with normal rats, the mRNA and protein expression of PPARγ significantly decreased. Moreover, the mRNA and protein expression of PPARγ significantly increased in PTE rats as compared to the T2DM rats. Therefore, PTE can improve the the level blood lipid and mediate the state of oxidative stress, and the underlying mechanism might be associated with the regulation of PPARγ expression.

3 Immunomodulatory Effect of Polysaccharide Isolated from Cinamomum camphora Fruits on Macrophage RAW264.7

WU Jing , HU Ju-wu , XIONG Wei , GU Zhen , WANG Hui-bin , BAE Young-soo , WU Lei

2018, 34(9):12-18. DOI: 10.13982/j.mfst.1673-9078.2018.9.003

[Abstract](595) [HTML](300) [PDF 934.20 K](748)

Abstract:
Cinamomum camphora is proved to possess a lot of biological activities, including antifungal, antioxidant, antibacterial, anti-allergic, and anti-inflammatory activities. However, little research has been reported on the C. camphora fruit polysaccharides (CCFP). Therefore the objective of this study was to isolate polysaccharide from C. camphora and evaluate its immunomodulatory activities on Macrophage RAW264.7. The results indicated that CCFP significantly promoted the production of intracellular nitric oxide (NO) and cytokines such as prostaglandin E2 (PGE2) and tumor necrosis factor-α (TNF-α) in RAW 264.7 cells. When the dosage of CCFP was 100 μg/mL, the secretion of NO, TNF-α and PGE2 reached to the maximum values of 53.53 ± 4.25 mu M, 1008.32 ± 35.23 pg/mL and 434.56 ± 25.23 pg/mL, respectively. The result of RT-PCR analysis indicated that CCFP also enhanced inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and TNF-α expression. Further analyses demonstrated that CCFP rapidly activated the extracellular signal-regulated kinase (ERK) and enhanced the transcriptional activities of activator protein-1 (AP-1) and nuclear factor (NF)-κB via toll-like receptor 4 (TLR4). Taken together, these results suggest that CCFP can improve immunity, and could be explored as a potential immunomodulatory agent in functional food.

4 Hypoglycemic, Hypolipidemic and Antioxidant Activities of Doellingeria scaber Total Flavonoids in Diabetic Mice

ZHANG Li-qiu , CHEN Ling , CUI Yan-yan , SHEN Ming-hao

2018, 34(9):19-25. DOI: 10.13982/j.mfst.1673-9078.2018.9.004

[Abstract](567) [HTML](186) [PDF 600.01 K](736)

Abstract:
The effects of Doellingeria scaber total flavonoids on the hypoglycemia, blood lipid and oxidation in diabetic mice were investigated. Alloxan-iduced diabetic mice were fed with Doellingeria scaber total flavonoids, flavonoids and polysaccharide at the dose of 50 mg/kg, 100 mg/kg, 200 mg/kg, respectively, for 4 weeks. The amount of water, food intake and body weight changes were recorded. The results showed that the total flavonoids can reduce the fasting blood glucose (Glu), improve the glucose tolerance, and effectively relieve the "a little" sanduo symptoms. The total flavonoids can also effectively regulate the serum TC, TG, LDL- C, HDL-C concentrations. As compared with model group, the HDL - C value of the experimental group increased by 44.6%, while the TG, TC and LDL-C values were reduced by 18.7% , 27.4% and 24.8%, respectively. Furthermore, the total flavonoids can reduce the content of MDA in liver tissue, increase the content of gsh-px and CAT, SOD, enhance its antioxidant capacity. These effects may be associated with improved antioxidant capacity and improved lipid metabolism in diabetic mice.

5 Effects of Different 18α and 18β-glycyrrhizic acid Ratios of on P-gp Transport Function and CYP3A Enzyme Activity in Rats

HUO Xiao-wei , WANG Shi-zhong , MENG Xiang-bo , LIU Ya-fei , ZHAO Yan-yan

2018, 34(9):26-31. DOI: 10.13982/j.mfst.1673-9078.2018.9.005

[Abstract](598) [HTML](250) [PDF 656.98 K](715)

Abstract:
The present study was designed to investigate the effect of different ratios of 18α-glycyrrhizic acid (18α-GA) and 18β-glycyrrhizic acid (18β-GA) on P-gp function and CYP3A activity. A Caco-2 cell monolayers model was established. The fluorescence intensity of the rhodamine 123 solution in the receiving pool was determined to investigate the effects of different ratios of 18α-GA and 18β-GA on P-gp transport function. Microsomes were made from the liver of rats, and the effects of different concentrations and different ratios of 18α and 18β-GA on the activity of CYP3A were analyzed after incubation. The ratio of 18α-GA and 18β-GA at 6:4 exhibited the strongest inhibitory effect on P-gp, whilst the ratio at 0:10 led to the strongest induction of P-gp. The concentration of 18α-GA in the range of 50~100 μg/mL significantly inhibited the activity of CYP3A, whilst 18β-GA at 10~50 μg/mL significantly induced the activity of CYP3A. The induction of CYP3A was the strongest, when the ratio of 18α-GA and 18β-GA was at 2:8 and the total GA concentration was at 10 μg/mL. Such an induction was greater than that for 18β-GA at the same concentration. As the GA concentration and the 18α-GA to 18β-GA ratio increased, the inhibition of CYP3A enzymatic activity was enhanced. At the 18α-GA to 18β-GA ratio of 10:0 and the total GA concentration of 100 μg/mL, the inhibition of CYP3A enzyme was the strongest. Different ratios of 18α-GA and18β-GA exhibited different effects on P-gp transport function and CYP3A enzymatic activity in rats, which would provide scientific basis for guiding clinical drug therapy.

6 Inhibitory effect of Petroleum Ether Fractions of Aged Garlic Extract on Escherichia coli

WANG Xiao-min , YANG Yu-kun , ZHANG Min

2018, 34(9):32-37. DOI: 10.13982/j.mfst.1673-9078.2018.9.006

[Abstract](477) [HTML](215) [PDF 665.93 K](639)

Abstract:
In this study, two kinds of Aged garlic extract (AGE-1 and AGE-2) were prepared and the two samples were extracted by petroleum ether to obtain the petroleum ether fractions of AGE-1 and AGE-2. The minimum inhibitory concentration (MIC) of AGE-1 and AGE-2 against Escherichia coli was determined by broth microdilution method. The MIC of AGE-1 and AGE-2 against Escherichia coli was 31 μg/mL and 62 μg/mL, respectively. The antibacterial mechanism of AGE-1 and AGE-2 against Escherichia coli was studied by growth curves, leakage of cell contents, conductivity of culture medium, confocal and scanning electron microscope. Further research found that AGE-1 and AGE-2 inhibited the growth of Escherichia coli, damaged the cell wall and cell membrane, changed the permeability of cell membrane, which led to the leakage of electrolyte and macromolecules as well as cell apoptosis. The cell surface was rough and the cell was sticky and depressed.

7 Effect of Sodium Stearoyl Lactateon on the Quality of Frozen Dough and Bread

TANG Yu-xuan , CAI Yong-jian , DENG Xin-lun , ZHAO Qiang-zhong , TANG Yu-xuan , CAI Yong-jian , DENG Xin-lun , ZHAO Qiang-zhong , TANG Yu-xuan , CAI Yong-jian , DENG Xin-lun , ZHAO Qiang-zhong , TANG Yu-xuan , CAI Yong-jian , DENG Xin-lun , ZHAO Qiang-zhong

2018, 34(9):38-44. DOI: 10.13982/j.mfst.1673-9078.2018.9.007

[Abstract](486) [HTML](302) [PDF 1.02 M](700)

Abstract:
The application of frozen dough is a challenge due to the limitations of its microstructure and baking performance. The frozen dough with good quality was investigated in this work. Sodium stearoyl lactate (SSL) was added into original frozen dough. The rheological properties of frozen dough and the specific volume, texture and sensory score of bread were anlysed to evaluate the impact of SSL on their quality. The result showed that, with the increase of the amount of SSL, the qualities of frozen dough and bread were improved. The optimal level of SSL was 0.20%. At this level, the quality of frozen dough was stable during freezing storage. The results will provide a more theoretical basis for the production of high quality frozen dough and its products.

8 Slightly Acidic Electrolyzed-Water in Combination with Different Calcium Sources Improved Storage Quality of “Jiancui” Jujube Fruit during Shelf-life Storage

ZHI Huan-huan , LIU Qi-qi , XU Juan , WANG Li-ming , ZONG Wei

2018, 34(9):45-50. DOI: 10.13982/j.mfst.1673-9078.2018.9.008

[Abstract](564) [HTML](253) [PDF 1.07 M](645)

Abstract:
This study evaluated the effects of slightly acidic electrolyzed-water (SAEW), 1% Ca(OAc)2, 1% Ca(NO3)2, 0.005% Ca(ClO)2, and SAEW in combination with 1% Ca(OAc)2 or 1% Ca(NO3)2 on quality attributes i.e. fruit firmness, soluble solids content (SSC), skin brightness, sensory quality, decay, malondialdehyde (MDA), total phenols (TP), total flavonoid (TF), DPPH• scavenging capacity, ferric reducing antioxidant power (FRAP), and total calicum (Ca2+) content of “Jiancui” jujube fruit during shelf-life storage. Results showed that, compared to the control fruit, all treated fruit maintained good storage quality and antioxidant capacity and retarded fruit senescence. Additionally, SAEW in combination with Ca(OAc)2 was the most effective treatment. It significantly inhibited the decrease of firmness and sensory scores; reduced the losses in SSC, decay and the accumulation of MDA; delayed the decrease of TP and TF; maintained strong DPPH• scavenging capacity and ferric reducing antioxidant power, and high Ca2+ content in fruit. Overall, SAEW in combination with 1% Ca(OAc)2 treatment can be used for maintaining fruit quality and prolong shelf life.

9 Effect of Fry Vacuum on the Quality and Surface Microstructure of Tofu Puffs

LI Liang , ZHOU Yan , LIU Jun , LI Shun-xiu , LOU Bin-bin , WU Chang-ling , TIAN Tian , WANG Zhong-jiang , LI Yang , JIANG Lian-zhou

2018, 34(9):51-56. DOI: 10.13982/j.mfst.1673-9078.2018.9.009

[Abstract](488) [HTML](169) [PDF 908.08 K](686)

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The effects of low- and deep-vacuum frying on the quality, protein structure and surface microstructure of tofu puffs were studied. The water holding capacity, fat content, color, protein structure, and microstructure were used as indices to evaluate the effect of vacuum degree of vacuum frying technology on the quality and microstructure of tofu puffs. As the vacuum level increased, the fat content of tofu puffs gradually increased, while the change trend of water holding capacity was opposite to the fat content. The surface color changes showed that the L* value decreased, and the b* value and a* value increased. The secondary structure of protein showed that the content of α-helix decreased, while the β-sheet structure increased first and then decreased, but the content of random coil structure seldom changed. The microstructure of tofu puffs had few wrinkles on the surface and low roughness. These results can establish a theoretical foundation for the production of tofu and related products.

10 Effect of Mixture of Safflower and Flaxseed Oil on Blood Glucose in Diabetic Mice

ZHAO Yuan-yuan , YANG Meng-juan , LI Xin-shuang , YANG Xiao-jun

2018, 34(9):57-63. DOI: 10.13982/j.mfst.1673-9078.2018.9.010

[Abstract](516) [HTML](247) [PDF 607.93 K](654)

Abstract:
The investigate the intervention of mixture of safflower and flaxseed oil on blood glucose in diabetic mice was investigated. A mouse model of diabetes was established using streptozotocin (STZ), and the mice were randomly divided into five groups (high blood glucose control group, safflower oil group, linseed oil group, linseed oil extract group, mixture of safflower and flaxseed oil group, 12 in each group, half male and half female). The mice were given the test samples in groups for 14 days. After 30 min of the last administration, mice were given 2 g/kg of glucose by gavage, the blood glucose was measured at 10 min, 30 min, 60 min, 90 min, and 120 min, respectively, and the relative value of area under blood glucose curve (AUC) in mice, pancreatic β-cell function (HOMA-β) and islet resistance index (HOMA-IR) were obtained. The results showed: There was a significant difference (p<0.05) in blood glucose concentration 30 min after meal in mice of mixture of safflower and flaxseed oil group (15.73 mmol/L) and high blood glucose control group (17.38 mmol/L). Therefore, compound oil of safflower seed and flaxseed could reduce AUC and increase insulin secretion and sensitivity of target cells to insulin in diabetic mice.

11 Interaction between Nonionic Surfactants with Different HLB Values and Mucin

CHENG Huan , TANG Chuan-he

2018, 34(9):64-69. DOI: 10.13982/j.mfst.1673-9078.2018.9.011

[Abstract](529) [HTML](404) [PDF 632.71 K](822)

Abstract:
In this work, artificial saliva simulated human oral saliva was used to investigate the interaction between mucin and four non-ionic surfactants (Span-20, Span-40, Span-60 and Span-80 with decreasing hydrophilic-lipophilic balance (HLB) values) in the digestion in the oral cavity. The results of turbidity, particle hydration radius and atomic force microscopy (AFM) showed that interactions between Span-20, Span-40, Span-60 and mucin were inversely correlated with the HLB value; The addition of Span-80 had little effect on the particle size of mucin and tended to make it smaller, resulting in a more compact and irregular particles. Cohesion results indicated that the interaction between the non-ionic surfactants and mucin was non-covalent force, mainly relying on hydrophobic interactions and hydrogen bonds. The results of this work are helpful in developing a new type of good-taste and healthly drink in the food industry.

12 Effect of Methyl Jasmonate Treatment on Quality of Postharvest Pepper Subjected Vibration during Transportation

XU Dong-ying , LIU Jing , ZUO Jin-hua , GAO Li-pu , WANG Qing

2018, 34(9):70-76. DOI: 10.13982/j.mfst.1673-9078.2018.9.012

[Abstract](518) [HTML](186) [PDF 858.95 K](707)

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In this research, the sensory score, weight loss, respiration intensity, level of chlorophyll, soluble solids, vitamin C content, and antioxidant enzyme activities of the pepper, subjected to simulated transport vibration and treatment with 5 μmol/L methyl jasmonate (MeJA), over the storage of pepper at 20±1 ℃ were periodically measured to evaluate the preservative effect of MeJA treatment on pepper. The experimental results showed that compared with the group without vibration, the vibration-treated peppers were mechanically damaged, with accelerated there spiration and transpiration and inhibited the activities of POD, CAT and APX. MeJA treatment effectively maintained the sensory quality and antioxidant activity of pepper subjected to vibration, while reducing water and weight loss, slowing down the decline of fruit hardness, inhibiting respiratory strength, and restraining the decline of chlorophyll, soluble solids and vitamin C contents. Thus, MeJA treatment could remove active oxygen species, reduce stress-induced damage, while maintaining the storage quality and prolonging the shelf life of pepper.

13 Comparative Analysis of Chemical Constituents and Antioxidant Activities of Different Cultivars of Qingzhuan Tea

LIU Pan-pan , ZHENG Peng-cheng , GONG Zi-ming , TENG Jing , YIN Peng , GAO Shi-wei , ZHENG Lin , YE Fei , WANG Xue-ping , GUO Gui-yi

2018, 34(9):77-87. DOI: 10.13982/j.mfst.1673-9078.2018.9.013

[Abstract](743) [HTML](180) [PDF 817.76 K](752)

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In this study, the differences in sensory quality, chemical composition and antioxidant activity of tea infusions made from Chibiquntizhong, Zhongcha108, Zhu yeqi and Dangui cultivasr were investigated for the first time. The volatile components of four different varieties of Qingzhuan tea were analyzed using headspace solid-phase micro-extraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS). The result showed that significant differences were observed in the chemical compositions of Qingzhuan teas made from four different varieties. The total antioxidant activity, ability to inhibit hydroxyl free radicals, DPPH free radical scavenging activity of Qingzhuan teas made from Zhongcha108, Zhu yeqi and Dangui cultivars were higher; Correlation analysis revealed the significant correlations between the antioxidant activity of Qingzhu tea and the total amounts of tea polyphenols and catechins and total amount of caffeine, in particular, the correlations with EGCG and malic acid were the strongest; the sensory score was positively correlated with the contents of water-soluble sugars, trans-2-decenal and nonanal, while negatively correlated with the contents of gallic acid, 3-methylfuran, acetophenone and isophorone; There were significant differences in aldehydes, ketones and alcohols among the different varieties of Qingzhuan teas, and the unique aroma of Dangui cultivar was related to the abundant aromatic aldehyde and ketones. Sensory evaluation revealed that there was no significant difference in the sensory quality of Qingzhuan teas made from the four varieties. The analyses of major chemical components, antioxidant activities and sensory quality of different varieties of Qingzhuan tea would provide an important reference for breed selection and application of tea varieties.

14 The Distribution of vwb genes and Coagulation Pathogenicity to Different Animal Hosts in Porcine Staphylococcus aureus

ZHANG Yang , YAN He

2018, 34(9):88-94. DOI: 10.13982/j.mfst.1673-9078.2018.9.014

[Abstract](512) [HTML](231) [PDF 532.08 K](706)

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In this work, to investigate the coagulation pathogenicity of porcine Staphylococcus aureus to different animal hosts and whether they harbor staphylococcal coagulase genes of vwbC, vwbSbo4, vwbSov2 and vwbSeq1, 130 S. aureus were isolated from swine farm, slaughterhouse and terminal market in Xiamen. Coagulation adaptability of these isolates to rabbit, bovine and goat plasma were studied by coagulase assays. The distribution of vwbC, vwbSbo4, vwbSov2 and vwbSeq1 genes in 130 S. aureus were also investigated by PCR amplification. The results showed that positive coagulation rate of 130 S. aureus to rabbit, bovine and goat plasma were 100.00%, 28.46% and 28.46%, respectively. The staphylococcal coagulasegenes of vwbC, vwbSbo4 and vwbSov2 were identified in 100.00% (130/130), 26.92% (35/130) and 26.93% (38/130) of all isolates, respectively. None of isolates harbored vwbSeq1gene.The detection rates ofvwbSbo4 and vwbSov2 genes and the positive coagulation rates of bovine and goat plasma of S. aureus isolated from pig farms were significantly higher than those isolated from slaughterhouse and terminal marker isolates (p<0.05). This work showed that porcine S. aureus possessed coagulation pathogenicity to different animal hosts and provided a basis for studying on the coagulation pathogenicity and host adaptability of porcine S. aureus.

15 Investigation on Stress Tolerance of Saccharomyces cerevisiae of Overexpression of Transcription Factor MSN2 Gene

LI Xiao , DONG Sheng-sheng , FU Xiao-meng , WANG Peng-fei , DONG Jian

2018, 34(9):95-101. DOI: 10.13982/j.mfst.1673-9078.2018.9.015

[Abstract](545) [HTML](212) [PDF 675.17 K](721)

Abstract:
For the yeast Saccharomyces cerevisiae, the cAMP signal transduction pathway plays an important role in the control of metabolism, proliferation, differentiation and acquisition of stress resistance. During the fermentation process, stress environments such as high temperature, high osmotic pressure, nutrient starvation, high alcohol toxicity, etc. are unavoidable. There is a high requirement for yeast tolerance in industrial applications. It can increase the fermentation performance of strains and reduce the energy consumption during fermentation. The constructed mutant has great signification in industrial application. Based on the existing strain AY12a in the laboratory, the strong promoter PGK1p was added to the N-terminus of MSN2 gene to achieve overexpression of the gene by using the intracellular recombination method, using URA3 gene as the screening marker. The mutant AY12a-msn2 was successfully constructed by PCR verification. The results showed that the mutant had no temperature tolerance. The mutant and AY12a were tested for very high gravity (VHG) fermentation, and the alcohol content, residual sugar, 48 h cell survival rate, CO2 weight loss and fermentation time were determined. The results showed that the alcohol content decrease, the residual sugar content and the survival rate of 48 h cells increased. The mutant had longer fermentation time.

16 Preliminary Identification and Application of Main Microorganisms Involved in Natural Fermentation of Vaccinium uliginosum L. at a Constant Temperature

SUI Shuang , ZHOU Sai-nan , WANG Ping

2018, 34(9):102-110. DOI: 10.13982/j.mfst.1673-9078.2018.9.016

[Abstract](472) [HTML](238) [PDF 1.44 M](629)

Abstract:
The broth derived from the natural fermentation of Vaccinium uliginosum L. at a constant temperature was used as the research object, and the microbial composition was analyzed using the plate separation technique. The isolated strains were analyzed via morphological identification and physiological and biochemical identification. The results were as follows: The microorganisms in the natural fermentation broth of Vaccinium uliginosum L. were mainly lactic acid bacteria, acetic acid bacteria, yeast and molds; the strains A1 and A2 were lactic acid bacteria, with the strain A1 being Lactobacillus and the strain A2 being Streptococcus; the strain B1 was a yeast, and the strain B1 was Kluyveromyces. The broth derived from the constant temperature natural fermentation of Vaccinium uliginosum L. was inoculated as the starting fermentation seed into the sterilized artificial fermentation substrate for fermentation. The total phenolic content and total flavonoid content were increased by 38.10% and 5.69%, respectively, and the anthocyanin and procyanidin contents were reduced by 30.22% and 31.26%, respectively, and the •OH scavenging capacity and the total antioxidant capacity were increased by 3.74% and 39.22%, respectively, compared with those before fermentation. The antioxidant capacity of the seed broth was significantly higher than that of the positive control group (p < 0.01). The ethanol content in the final product of seed fermentation was 0.98%, indicating a low alcohol fermentation product. This experiment provided a new approach for processing Vaccinium uliginosum L.

17 Effect of 1-MCP Treatment on Sugar Metabolism in Aksu Fuji Apples Harvested at Different Stages and Stored for Different Periods

XIE Ji-yun , ZHAO Xiao-min , WANG Yong-qin , MA Shao-shuai , BAI You-qiang , DU Lin-xiao , MA Nan , LI Dan , LI Xue-wen

2018, 34(9):111-121. DOI: 10.13982/j.mfst.1673-9078.2018.9.017

[Abstract](582) [HTML](195) [PDF 1.32 M](618)

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Through using Aksu Fuji apple as the test material, and analyzing the sucrose, glucose, fructose and sorbitol contents as along with sucrose phosphate synthase (SPS), sucrose synthase (SS-S, SS-C), acid invertase (AI), neutral invertase (NI) and sorbitol dehydrogenase (SDH) activity, this study examined the changes of sugar metabolism and related enzyme activities of these apples harvested at different stages. The effects of 1-MCP treatment on them were analyzed during storage (0~150 days). The obtained results showed that 1-MCP treatment during postharvest storage inhibited the increase of sucrose, glucose, fructose and sorbitol contents in Fuji apple fruit during storage, and exerted different effects on the enzymatic activities in the apples harvested at different stages. The sucrose and sorbitol contents and SDH activity in fruit decreased, whilst the contents of fructose and glucose and activities of SPS and SS-S decreased first and then increased. AI and NI showed significant peak values during storage, and 1-MCP treatment significantly increased these peaks.

18 In Vitro Antioxidant Activities of Nervilia Fordii Methanol Extracts

ZHOU Yan-yuan , LIU Qing-hua , YAN Huo-lian , CHANG Hui-min , CHEN Si-rong , SONG Jia-le

2018, 34(9):122-128. DOI: 10.13982/j.mfst.1673-9078.2018.9.018

[Abstract](603) [HTML](237) [PDF 598.39 K](641)

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The in vitro antioxidant activities of Nervilia fordii mthanol extracts (NFME) were investigated. Total polyphenols and flavonoids in NFME were determined by ultraviolet spectrophotometry. The antioxidant capability of NFME was evaluated according to the 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydroxyl radicals(•OH) scavenging assay, respectively. Protective effect of NFME was investigated using a model of hydrogen peroxide (H2O2, 150 μmol/L) induced oxidative stress in intestinal epithelial Caco-2 cells. Cell viability was determined by MTT assay. The cellular levels of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) were determined by commercial assay kits according the manuscripts. The cellular levels of malondiadehycle (MDA) and reactive oxygen species (ROS) were determined by thiobarbituric acid reactive substance (TBARS) and dichloro-dihydro-fluorescein diacetate (DCFH-DA) assay, respectively. The levels of interlukin-8 (IL-8) and IL-10 were determined used an enzyme linked immunosorbent assay (ELISA). The NFME were enriched in total flavonoids (4.72 ± 0.13 mg Rutin/g) and poly phenols (4.25 ± 0.46 mg GAE/g). NFME also exhibited a great DPPH and ?OH radical scavenging activity. NFME was able to increase the cell viability, and significantly increased the activity of SOD, CAT and GSH-Px in oxidative damaged Caco-2 cells. In addition, NFME treatment was also effectively decreased the generation of ROS, MDA and IL-8 secretion in H2O2 treated Caco-2 cells. In contrast, NFME increased the IL-10 secretion in damaged Caco-2 cells. These results suggested that the NFME exhibits a great in vitro antioxidant activity and can effectively attenuate the H2O2-induced oxidative stress in Caco-2 cells.

19 Lipase-catalyzed Synthesis of Cinnamate Sucrose Ester and Its Antibacterial Activity

HE Shi-jun , ZHAO Guang-lei , HE Bei-hai

2018, 34(9):129-135. DOI: 10.13982/j.mfst.1673-9078.2018.9.019

[Abstract](561) [HTML](216) [PDF 901.61 K](668)

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A feasible route for lipase-catalyzed synthesis of sucrose ester with excellent antibacterial properties was developed in this paper. Binaryorganic solvent of DMAc and tert-amyl alcohol was used as the reaction medium to well dissolve the polar sugar substrate and maintain the enzyme activity of immobilized lipase. And the effect of solvent volume ratio and reaction temperature on the synthesis method was explored. The FTIR of ester product showed that the lipase promoted the acylation of sucrose with cinnamic acid. The structure of ester product was further identified by 13C-NMR spectrum and it confirmed that esterification occurred on the C-6 cite of sucrose. TGA analysis showed a high thermal stability of cinnamate sucrose ester. And the antimicrobial activity of cinnamate sucrose ester was determined, the inhibitory rates of the ester product to Escherichia coli and Geotrichum candidum were 97.83% and 96.04%, respectively. Furthermore, the cinnamate sucrose ester showed great water retention property and the water retention rate was 76%. The findings are of importance for the application of sucrose ester in food and cosmetics industry.

20 Fermentation Transformed Ginsenoside by Lactic acid bacteria

XIA Wan-xia , ZHANG Shang-wei , GE Ya-zhong , REN Jie , YU Qing-tao , YANG Ji-guo , NING Zheng-xiang

2018, 34(9):136-142. DOI: 10.13982/j.mfst.1673-9078.2018.9.020

[Abstract](837) [HTML](434) [PDF 853.62 K](1078)

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Lactic acid bacteria suitable for ginsenosides bioconversion were screened and the fermentation conditions were optimized. The bioconversion pathway of the ginsenosides during the fermentation was discussed. The results showed that Lactobacillus plantarum exhibited the strongest ability to produce rare ginsenosides. Optimal fermentation conditions were 35 ℃, pH 7.0, incubation time of 16 days, 7% inoculum size and 10% substrate concentration. The contents of 3 rare ginsenosides were 106.52 μg/mL(F2), 74.62 μg/mL(Rg3) and 100.56 μg/mL(CK), which were enhanced 188.13%, 203.21% and 395.86%, respectively. The changes in major ginsenosides content were consistent with the possible transformation pathway of ginsenosides. The results indicated that the ginsenosides were converted to rare ginsenosides through Lactic acid bacteria fermentation and the reasonable fermentation process was constructed to improve the content of rareginsenosides. This work has important significance for microbial transformation of ginsenoside, and the fermentation broth have an advantage in deep-processing ginseng products.

21 Preparation of Antioxidant Peptides from Eggshell Membrane by Sodium Sulfite-assisted Enzymatic Hydrolysis

ZHAO Jie-yuan , LI Xiao-yun , HUANG Xi

2018, 34(9):143-149. DOI: 10.13982/j.mfst.1673-9078.2018.9.021

[Abstract](542) [HTML](219) [PDF 756.84 K](791)

Abstract:
The eggshell membrane has abundant protein, which acounts for about 90% of the dry weight of the eggshell membrane. However, eggshell membranes are often discarded as waste in food industry, resulting in waste of resources and environmental pollution, thus, the efficient use of eggshell membranes is extremely necessary. In this study, the antioxidant peptides were prepared by sodium sulfite-assisted enzymatic hydrolysis. Effect of protease species, enzyme dosage, Sodium sulfite concentration and hydrolysis time on antioxidant activity and hydrolysis degree of eggshell membrane peptides was researched. The results showed that alkaline protease assisted by sodium sulfite was better than the other four proteases. At 12 U/mg alkaline protease, sodium sulfite concentration 40 mM, hydrolysis time 4 h, the degree of hydrolysis and total antioxidant activity of the hydrolysates were 8.58% and 245.88 μg/mL, respectively, indicating that the hydrolysates have good antioxidant activity in vitro. The results of SDS-PAGE and Tricine-SDS-PAGE showed that the molecular weight of the eggshell membrane polypeptide was mainly in the range of 3.3~14.4 ku.

22 Crude Protein Extraction from Spirulina Platensis by Ultrasound Coupling Subcritical Water and Its Anti-oxidant Activity

HU Shuang-fei , ZHANG Xue-wu , FAN Xiao-dan

2018, 34(9):150-157. DOI: 10.13982/j.mfst.1673-9078.2018.9.022

[Abstract](628) [HTML](235) [PDF 993.99 K](951)

Abstract:
In this work, ultrasound coupling subcritical water extraction of crude protein from Spirulina platensis was investigated. The extractive reactor was redesigned to increase the contact area of the raw material and subcritical water, and the extraction rate of crude protein was improved significantly from 10.30% to 40.20% (p<0.01); The factors affected on the extraction rate, including temperature, ultrasonic power, pressure and time were systematically discussed using single factor level analysis, and the order was temperature>ultrasonic power>extraction time>pressure; The optimal extraction conditions were obtained by orthogonal design and verification, and the best extraction rate of 74.32% was achieved under the following extraction conditions: temperature of 150 ℃, ultrasonic power of 200 W, extraction time of 80 min and pressure of 10 MPa. The antioxidant activity of crude protein extracted with different temperatures was determined by measuring its reducing power and clearance ability on DPPH and ABST+ and OH- radicals in vitro, and the results showed that crude protein extraction exhibited an excellent antioxidant activity in a dose-dependent manner at concentrations of 0.15~10.00 mg/mL. Therefore, ultrasound coupling subcritical water extraction of protein from marine algae can be used as a new technology with high efficiency, low energy consumption and environmental protection.

23 Comparative Analysis of the Quality of Litopenaeus vannamei Subjected to Different Heat Treatments

SUN Lu-hao , MAO Wei-jie , ZHANG Wei-hong , JI Hong-wu , LIU Shu-cheng , GAO Jing

2018, 34(9):165-170. DOI: 10.13982/j.mfst.1673-9078.2018.9.024

[Abstract](615) [HTML](313) [PDF 617.96 K](794)

Abstract:
This research examined the effects of boiling, steaming, baking, frying, and microwave heating on the weight reduction rate, color, elasticity, protein solubility and comprehensive sensory quality of shrimp, as well as the changing patterns of these indices The obtained results showed that baking method led to the maximum weight reduction whilst boiling in water caused the opposite effect; The reduction of water could affect the color of shrimp surface to a certain extent. Steam heating and boiling heating could increase the brightness of shrimps, with steam heating making shrimps reddish. Frying could make the shrimp turn yellow; Deep frying and baking could maintain the elasticity and hardness of the shrimp, thereby improving its chewiness; Protein solubility reflects the degree of denaturation of the shrimp protein to some extent under different heating conditions. Boiling in water could maximally stablized the ionic bond, whilst steam heating enhancing the hydrophobic effect and microwaving increasing hydrogen bonds. The sensory evaluation on factors such as color, aroma, taste and texture revealed that the microwaved shrimp product had the highest sensory score.

24 Process Optimization for Hot-air Drying of Daqu

ZHANG Yun-zhao , LUO Hui-bo , ZHOU Ping , HUANG Dan

2018, 34(9):171-181. DOI: 10.13982/j.mfst.1673-9078.2018.9.025

[Abstract](508) [HTML](213) [PDF 1.59 M](803)

Abstract:
In this project, the uniform optimization experiment design method was used to optimize the staged temperature-variable drying process of Daqu, and the influence of process parameters on the energy consumption, quality, volatile flavor and microbial indices of Daqu was explored. Results showed that the interaction of the first stage temperature and the second stage temperature had the greatest impact on the energy consumption of Daqu, the interaction between the first stage wind speed and the second stage wind speed exerted the greatest impact on the Daqu quality indices, the interaction between the first stage temperature and the second stage wind speed had the greatest impact on Daqu’s volatile flavor index, and the microbial index was easily affected by drying process parameters; Through function evaluation, the evaluation indices of Daqu were comprehensively standardized, and it was found that the interaction between the first stage wind speed and the second stage wind speed had the greatest influence on the comprehensive evaluation indices of the Daqu. The highest comprehensive index function score of Daqu was 1.367, where the optimal Daqu drying process parameters are: The first stage temperature was 47.8 ℃, the first stage wind speed was 1.3 m/s, the water content conversion point was 15.5%, the second stage temperature was 45.0 ℃, and the second stage wind speed was 0.3 m/s. The finished Daqu product was pure and rich in flavor with a neat section and well-grown mycelium, thus, met the requirements of high quality Daqu.

25 Drying Characteristics and Quality Attributes of Chinese Chives by Catalyzed Infrared Drying

ZHAO Xing , WU Ben-gang , MA Hai-le , LIU Xiao

2018, 34(9):182-189. DOI: 10.13982/j.mfst.1673-9078.2018.9.026

[Abstract](503) [HTML](164) [PDF 1022.25 K](667)

Abstract:
In this work, the drying characteristics and product quality of Chinese chives were investigated under different temperatures (60, 70, 80, 90 ℃) by using catalytic infrared drying technology. The drying rate increased with the increase of temperature. The trends in drying rate of Chinese chives under different drying temperatures were different during the drying process. According to the statistical results, the catalytic infrared drying of Chinese chives was properly described by Page among three mathematical models that were used to fit the experimental data. The relationship between the color and the moisture content of Chinese chives was studied under different drying temperatures. The result showed that, when the moisture content was less than 70%, the color (a*) increased with the decrease of the moisture content. In addition, the Vc content and rehydration ratio of dried Chinese chives under different drying temperatures were studied. The result demonstrated that no significan difference in color, the highest values in Vc content and rehydration ratio were found at 70 ℃. Considering the combination of drying time and quality, 70 ℃ is the optimum drying temperature for the catalytic infrared drying of chives.

26 Preservative Effects of Low-dose 60Coγ-ray Irradiation Treatment on the Freshness of Fresh Lentinus edodes in Storage

ZHOU Ran-ran , GAO Hong , FAN Xiu-zhi , YIN Chao-min , CHEN Zhe-ya , YAO Fen , SHI De-fang

2018, 34(9):190-197. DOI: 10.13982/j.mfst.1673-9078.2018.9.027

[Abstract](478) [HTML](159) [PDF 776.16 K](927)

Abstract:
This study examined the freshness-preserving effect of low-dose 60Co γ-ray irradiation treatment on the freshness of fresh mushrooms. Fresh Lentinus edodes were irradiated with 0, 1, 1.5 or 2 kGy dose, respectively, before being stored at 4±1 ℃ and humidity of 80±5%. Then, the microbial content, tissue firmness, color, and activities of enzymes (superoxide dismutase (SOD), glutathione reductase (GR), phenylalanine ammonia lyase (PAL), cellulase, and chitinase) were measured. Obtained results showed that the exposure to irradiation at a dose of 1 kGy significantly delayed (4~8 days) fruit softening and browning. During storage, the irradiation dose of 1 KGy can control the reduction of enzyme activity in the antioxidant systems, reduce the accumulation of cellulose and chitin, and inhibition the aging of the mushroom. Therefore, the 60Co γ-ray irradiation dose of 1 KGy can help preserve the characteristic quality of fresh mushrooms, but an irradiation doses above 1.5 kGy could accelerate the quality deterioration of fresh mushrooms.

27 Effects of CO2 Maceration on the Kinetics and Quality of Hot Air Coupled with Intermittent Microwave Drying of Ginger

WEI Lai , TANG Dao-bang , FU Man-qin , ZOU Bo , WU Ji-jun , AN Ke-jing

2018, 34(9):198-207. DOI: 10.13982/j.mfst.1673-9078.2018.9.028

[Abstract](504) [HTML](364) [PDF 974.73 K](735)

Abstract:
In this paper, carbonic maceration was used as a pretreatment coupled with hot air-intermittent microwave drying (AD&MW)for ginger. The effect of pressure, temperature, and treatment time were explored on the drying kinetics and quality attributes of ginger. The mathematical model of thin layer drying was also studied. The results indicated that when the ginger was treated under 0.2 MPa, 40 ℃, and 10 h, the drying rate of ginger was the fastest, and the drying time was shortened by up to 45% compared with the direct drying samples. The fitting results of five thin layer drying models showed that the R2 of Modified Page model was the largest, the χ2, 2and the RMSE were relatively small. So the Modified Page model was proved to be in the best agreement with the experimental results. When the ginger was treated under the CO2 maceration condition of 0.2 MPa, 30 ℃, 10 h, the contents of 6,8,10-gingerol and 6-shogaol were 2.49, 1.45, 1.45, and 1.36 times compared with the directly dried sample, respectively. Furthermore, carbonic maceration can retain the color of ginger preferably. The SEM showed that carbonic maceration can also increase the porous structure of ginger and enhance the permeability of cell membrane.

28 Determination of Hydroxymethyl Furfural Derivatives in Soy Sauce by Headspace Solid-phase Microextraction Coupled with Gas Chromatography-mass Spectrometry

WAN Bo-kai , LI Dan-dan , NI Hui , YANG Yuan-fan , HUANG Gao-ling

2018, 34(9):208-214. DOI: 10.13982/j.mfst.1673-9078.2018.9.029

[Abstract](562) [HTML](259) [PDF 555.99 K](619)

Abstract:
In order to assay the content of hydroxymethylfurfural derivatives and evaluate the safety of soy sauces, five soy sauces that were collected in the local market were analyzed for the hydroxymethyl furfural derivatives by headspace solid-phase microextraction (SPME) combined with gas chromatography-tandem mass spectrometry (GC-MS). As a result, three kinds of hydroxymethyl furfural derivatives, i.e., furfural, 5- methyl furfural and 2- ethyl -1- hexanol were identified. The linear regressive calibration curve was plotted within the concentration of 3.33~666.67 μg/mL with the LOD of 3.33×10-1 μg/L and the LOQ of 3.33 g/L. The original soy sauce showed that the spiked recovery range was out of the national standard, and whereas the soy sauce after 5-fold dilution with distilled water had the recovery range between 82.23%~115.04%, with the inter-day recovery range between 93.31~111.50%. The inter-day recovery rate was ranged from 93.02% to 115.91%. The inter-day and intra-day precisions were 4.36% and 8.02%, respectively. The furfural content in the five soy sauces was between 70.14~98.75 μg/L, the 2-ethyl-1-hexanol content was between 66.61~79.20 μg/L, and the 5-methyl furfural content was between 221.87~527.40 μg/L. The above results indicated that the content of hydroxymethylfurfural derivatives were significantly different in different soy sauces. However, the daily consumption of soy sauce is safe because the intake of hydroxymethyl furfural derivatives is far below the bottom level to cause safety problems.

29 Comparison on Two Pre-column Derivatization Methods for RP-HPLC Determination of Biogenic Amines in Pickled Vegetable

GUO Xiao-li , LI Er-hu , SONG Ya-dong , ZHONG Wu , WANG Mei-yu , GUO Xiao , PAN Si-yi

2018, 34(9):215-221. DOI: 10.13982/j.mfst.1673-9078.2018.9.030

[Abstract](548) [HTML](205) [PDF 708.12 K](580)

Abstract:
This study used the 4-fluoro-3-nitrobenzotrifluoride (FNBT) pre-column derivatization RP-HPLC analysis method with UV detector (abbreviated as FNBT method) and the dansyl chloride pre-column RP-HPLC analysis method with UV detector (abbreviated as DNS-Cl method) to determine biogenic amines in pickled vegetable, and compared the differences between the two methods in 8 types of biogenic amines in pickled vegetable (histamine, tryptamine, guanidine-phenylethylamine, putrescine, tyramine, cadaverine, spermidine and spermine). Results showed that in the concentration range of 1~100 mg/L, the two methods showed a good linear with the detection of the eight biogenic amines with the correlation coefficient R2 greater than 0.999 and detection limit of the FNBT derivatization method (0.016~0.071 mg/L) lower than that of DNS-Cl derivatization method (0.066~0.191 mg/L). The accuracy test of the methods showed that the average recovery of the FNBT derivatization method (92.87%~100.18%) were slightly better than that of DNS-Cl derivatization method (83.52%~102.33%), with the precision (RSD%) of the two different methods less than 5%. DNS-Cl derivatization method requires a large amount of expensive reagents and cumbersome operation with low sensitivity to biogenic amines analysed, whilst the FNBT derivatization method allows simple, rapid and accurate analyses of eight biogenic amines with low consumption of derivatization reagents and higher sensitivity for biogenic amines. FNBT derivatization method is more suitable for rapid and accurate analysis of trace biogenic amines in large quantities of food. There were significant differences in the levels of eight biogenic amines in pickled vegetables analyzed by two methods (p<0.05).

30 Determination of Allergens of Antarctic Krill by Ultra-high Performance Liquid Chromatography Coupled with High Resolution Quadrupole Time of Flight Mass Spectrometer

LI Zi-wei , ZHANG Xiao-mei , HU Ling-ping , LI Zhao-jie , ZHANG Hong-wei , XUE Chang-hu

2018, 34(9):222-227. DOI: 10.13982/j.mfst.1673-9078.2018.9.031

[Abstract](581) [HTML](336) [PDF 729.92 K](741)

Abstract:
A method was established in this study to determine allergen of Antarctic krill based on high resolution mass spectrometry. The protein of Euphausia superba is determined by Foline-Phenol and digested by sequence-grade trypsin. The allergens are identified by NCBI protein database and computer retrieval, and validated by using Skyline software combined with triple quadrupole mass spectrometry. Two main kinds of allergens were detected from trpsin digested peptides of Euphausia superba, from which tropomyosin and arginine kinase could be identified. And the corresponding codes of identified peptides of protein allergens were 74 and 44 respectively. As compared with ELISA and PCR, the method is more sensitive, accurate and easy to operate, which may provide a strategy to reduce allergens in foods.

31 Effects of Tea Green Leafhoppers Empoasca vitis Gothe Hazards on Volatiles of Jin Xuan Black Tea

QIAO Xiao-yan , CAO Jun-xi , HUANG Hua-lin , LI Bo , CHEN Dong

2018, 34(9):228-234. DOI: 10.13982/j.mfst.1673-9078.2018.9.032

[Abstract](758) [HTML](249) [PDF 729.96 K](776)

Abstract:
The volatiles from healthy intact tea shoots, tea shoots damaged by the tea green leafhopper (Empoasca vitis Gothe) and their black teas were analyzed by gas chromatography and mass spectrometry (GC-MS), extracted by headspace solid phase microextraction (HS-SPME). Jin xuan was selected as masteries. The results showed that alcohols were the main volatiles, of which terpene alcohols accounting for above ninety-two percentage in tea shoots and black teas. For tea shoots damaged by tea green leafhopper, terpene alcohols decreased, while these volatiles (fatty alcohols, aromatic alcohols, terpene ketones, aliphatic ketones, esters and hydrocarbons) increased. Terpene alcohols, fatty alcohols, terpene ketones and aliphatic ketones decreased in black teas made by damaged shoots. But esters increased in black teas made by damaged shoots. Based on principal component analysis (PCA) and cluster analysis, the volatiles of tea shoots and black teas could be divided into two distinct classes, terpene alcohols and esters could distinguish from the damaged tea shoots and its black teas. PCA results for main volatiles showed that terpene alcohols (including β-linalool, neroli, linalool-oxide ii, linalool-oxide I, geraniol), were the unique volatiles in intact tea shoots. For the damaged tea shoots, terpene alcohols decreased and aldehydes (β-cyclocitral, 3,7-dimethyl-2,6-octadienal, benzaldehyde) increased. Three kinds of black teas implied distinctive esters and terpene alcohols.

32 Determination of Sulfonamides and Quinolones in Eggs by QuEChERS EMR-Lipid and High Performance Liquid Chromatography-Tandem Mass Spectrometry

LIU Hong , ZENG Jian-yong , LIANG Xue-qi , DENG Xiao-hua , LI Zhen-yuan

2018, 34(9):235-243. DOI: 10.13982/j.mfst.1673-9078.2018.9.033

[Abstract](674) [HTML](225) [PDF 768.58 K](1037)

Abstract:
A sensitive liquid chromatography-tandem mass spectrometry(LC-MS/MS) method has been developed for assaying fourteen sulfonamides and sixteen quinolone antibiotics in egg samples. The egg samples were extracted with 8 mL 2% formic acid acetonitrile, shaked in 0.5 mL 0.1 mol/L EDTA buffer (pH 7). The extract was purified with QuEChERS EMR-Lipid-based rapid sample treatment method, and gradiently eluted with 0.2% formic acid (A) and acetonitrile (B) as the mobile phase. The electrospray ion source was applied with multiple reaction monitoring (MRM) for qualitative and quantitative analysis of 30 sulfonamides and quinolones. The results showed that the recoveries were 50.09%~102.11% for the 30 antibiotics at spiked levels of 8~32 μg/kg, and the relative standard deviation(RSD) was less than 15.66%. The limit of detection (LOD) for the 30 antibiotics was 0.00131~0.09717 μg/kg. The method of determinating sulfonamides and quinolones is simple, easy, and reliable, which can meet the rapid and accurate detection requirements of sulfonamides and quinolones in eggs.

33 Analysis of Aroma Compounds in Xiangyu Pumpkin using Electronic Nose and Head Space-Solid phase Microextraction/Gas Chromatography-Mass Spectrometry

LI Jun-xing , ZHONG Yu-juan , LUO Jian-ning , WANG Wen-wen , HUANG Wen-jie , SHI Jing-fang , HUANG He-xun

2018, 34(9):244-250. DOI: 10.13982/j.mfst.1673-9078.2018.9.034

[Abstract](1149) [HTML](175) [PDF 710.65 K](849)

Abstract:
To understand the volatile aroma compounds in Xiangyu pumpkin fruit, and the characteristics of the main aroma contributors at different development stages of fruit, this study used electronic nose and head space solid-phase micro-extraction (HS-SPME) combined with gas chromatography (GC)-mass spectrometry (MS) to analyze the volatile compositions in both Xiangyu pumpkin and non-Xiangyu pumpkin resources. Significant differences in aroma trait were found by electronic nose between Xiangyu pumpkin and non-Xiangyu pumpkin. A total of 31 volatile aroma compounds were identified in mature fruit of Xiangyu pumpkin using HS-SPME/GC-MS. Subsequently, GC-MS and mass profiler professional were used to analyse the differences in volatile compounds between Xiangyu pumpkin and two kinds of mature non-Xiangyu pumpkin, and the obtained results revealed significant differences in volatile compounds (which was consistent with those obtained by electronic nose analysis). And 2-acetyl-1-pyrroline (2-AP) was the unique volatile compound in Xiangyu pumpkin as compared with the two sets of control samples (non-Xiangyu pumkins). Finally, the changing trends of 2-AP at different fruit development stages of unpollinated fruit, fruits collected at the 25th day and 55th day, respectively, after pollination. And unpollinated fruit and fruit obtained at the 25th day after pollination had a similar amount of 2-AP, while the 2-AP content deceased significantly in fruit at late maturity stag. This study has laid the foundation for future studies on aroma trait in Xiangyu pumpkin.

34 TRFES Combined with Chemometrics for Geographical Identification of Camellia Oils

CHEN Hui , LU Dao-li , CHEN Bin

2018, 34(9):251-255. DOI: 10.13982/j.mfst.1673-9078.2018.9.035

[Abstract](433) [HTML](181) [PDF 549.39 K](613)

Abstract:
An accurate and rapid method for geographical identification of camellia oil was established based on the combination of time-resolved fluorescence emission spectrum (TRFES) and chemometrics. Totally 180 samples from Zhejiang, Jiangxi and Hunan were collected and their TRFES were compared from the dimensions of steady-state fluorescence emission and fluorescence decay; Parallel factor analysis (PARAFAC) was performed for the dimensional reduction and the optimization of characteristics based on training set; two factors were selected and then their factor scores were utilized as the input of artificial neural network (ANN), and finally the geographical identification model of camellia oil was established. The result showed that fluorescence decay was less influenced by the concentration of fluorophores than steady-state fluorescence emission. Hence, TRFES displayed stronger fingerprint characteristics and could be good for the geographical identification of camellia oil. The cross-validation coefficient was 98.7% and prediction coefficient was 96.1% for the geographical identification model of camellia oil, indicating the strong robustness and high accuracy of the model, which is considered to be suitable for the geographical identification of camellia oil. This study proved that geographical identification of camellia oil could be completed by the combination of TRFES and chemometrics.

35 Simultaneous Determination of Vitamins A, D and E in Oil-rich Foods using Gel Permeation Chromatography Coupled with MS

LI Min , ZHANG Li , YU Ting-ting , FAN Zhi-yong

2018, 34(9):256-262. DOI: 10.13982/j.mfst.1673-9078.2018.9.036

[Abstract](673) [HTML](242) [PDF 671.01 K](672)

Abstract:
The vitamins A, D and E in oil-rich foods were simultaneously determined using high performance liquid chromatography coupled with mass spectrometry (HPLC-MS/MS), after purified with a gel permeation chromatography (GPC). The optimal extraction conditions were achieved on the PT785 Bio-BeadsS-X3 column, with a cyclohexane - ethyl acetate mixture at ratio of 5:5 (V/V) as the mobile phase. The optimal MS condition was positive electrospray ionization (ESI+)-MS method under multiple reaction monitoring (MRM) mode. The results indicate that retinol, retinol acetate, vitamin D2, vitamin D3, vitamin E were all in good linear relationship with correlation coefficient above 0.999 in the concentration range of 5-200 μg/L; the limit of detection of this method were 2 μg/kg, 1 μg/kg, 5 μg/kg, 2 μg/kg and 10 μg/kg respectively; the recovery rate at four spiked levels range from 93.1 to l06.6% with relative standard deviations (RSD, n = 6)above 1.09% and lower than 4.77%. The method is accurate, sensitive, rapid and easy, and can be applied to determine vitamins A, D and E in oil-rich foods.

36 Study on the Flavonoids in the Leaves of Prunus cerasifera Grown in Xinjiang

LIU Wei , LI Zi-wei , WANG Hang , YANG Feng-ling , LI Ming-xi , LIU Xiao , WAN Chun-peng

2018, 34(9):263-267. DOI: 10.13982/j.mfst.1673-9078.2018.9.037

[Abstract](612) [HTML](282) [PDF 488.91 K](662)

Abstract:
This study analyzed the chemical constituents of flavonoids in the active fraction of ethyl acetate in the leaves of Prunus cerasifera. The leaves were firstly soaked in methanol and the alcoholic extract was extracted sequentially using cyclohexane, ethyl acetate and n-butanol. The active fraction of ethyl acetate was roughly separated by MCI (Middle Chromatogram Isolated Gel) macroporous resin column, followed by further purification by chromatography using silica gel column, Sephadex LH-20 gel column, ODS (Octadecyl silane) reverse silica gel column and preparative HPLC. The isolated flavonol constituents were identified by 1H-NMR and 13C-NMR analyses. Identification of compounds based on their physicochemical properties and nuclear magnetic resonance spectroscopy (NMR) data and through comparison with related references. Eleven flavonol flavonoids were isolated and identified: quercetin-3-O-α-L-arabinoside (1), quercetin-3-O-β-D-xyloside (2), quercetin-3-O-β-D-galactoside (3), quercetin-3-O-α-L-rhamnoside (4), kaempferol-3-O-α-L-arabinoside (5), kaempferol-3-O-β-D-xyloside (6), kaempferol-3-O-β-D-glucoside (7), kaempferol-3-O-α-L-rhamnoside (8), trans-dihydrokaempferol-3-O-α-L-rhamnoside (9), cis-dihydrokaemp-ferol-3-O-α-L-rhamnoside (10), cis-dihydrokaempferol-3-O-β-D-glucoside (11). All flavonoids were isolated and identified from the leaves of P. cerasifera for the first time, with quercetin and kaempferol glycosides being the major flavonoids.

37 Analysis of Volatile Flavor Compounds Changes during Traditional Processing of Salted Spanish Mackerel

WANG Yu , WANG Rui-di , XUE Yong , ZHAO Yan-ning , XUE Chang-hu

2018, 34(9):268-276. DOI: 10.13982/j.mfst.1673-9078.2018.9.038

[Abstract](633) [HTML](170) [PDF 1.10 M](646)

Abstract:
The study was focus on the mechanism of flavor formation during traditional processing of salted spanish mackerel. Solid phase micro-extraction (SPME) coupled with gas chromatography-mass spectrometry (GC-MS) and electronic nose were used to identify the flavor changes from fresh fish through salting and three stages drying, then the main volatile flavor compounds were assayed. The results of electronic nose showed that the response values of sensor to sample were different during the five processing stages, and the response value of the sensor No.2 (sensitive to nitrogen oxides) was the highest. So the results confirmed that electronic nose was capable to discriminate flavor of salted fish in different processing stages. Moreover, GC-MS analysis showed that the total volatile flavor compounds of L sample in 5 stages were 22, 17, 26, 23 and 33, respectively. Meanwhile, the total volatile flavor compounds of J sample were 32, 29, 25, 36 and 33, respectively. Therefore the characteristic compounds of salted spanish mackerel were formed during salting and drying. And the major volatile compounds of salted spanish mackerel were aldehydes and alcohols, including nonanal, hexanal, heptanal, (Z)-4-heptenal, octanal, 1-Penten-3-ol, 1-Pentanol, (Z)-2-Penten-1-ol, 1-Hexanol, 1-Octen-3-ol and 2-ethyl- Furan. Controlling the conditions of salting and drying could provide theoretical guidance for the process production of salty spanish mackerel.

38 Microbial Risk Assessment for the Production of Bottled Drinking Water

CHEN Ling , YANG Xiao-juan , LU Yong-cheng , SHANG Jian-gang , LUO Zhi-gang , GUO Wei-peng , WU Qing-ping , ZHANG Ju-mei

2018, 34(9):277-282. DOI: 10.13982/j.mfst.1673-9078.2018.9.039

[Abstract](719) [HTML](201) [PDF 504.02 K](678)

Abstract:
Microorganisms from the production process of bottled drinking water plants distributed in A, B, C, D four cities were investigated, to obtain basic microbial contamination data, and evaluate the effectiveness of the microbial contamination control system for the production process of the plants. Microbial analyses of raw water, process water and finished water from the production process of four factories were carried out, and the dominant strains were identified by traditional and molecular identification techniques. The obtained results revealed that the number of molds and yeasts or coliforms of 33 samples was less than 1 CFU/mL. The number of total bacterial colonies in sand-filtering water and carbon-filtering water was detected and the detection values were high. Fecal streptococcus was detected in the process water through a carbon filter, and Pseudomonas aeruginosa was detected in the Reverses Osmosis (RO) water, although Clostridium perfringens was not detected in either water. A total of 34 strains of bacteria were isolated, and dominant bacteria included Acidovorax sp., Pseudomonas sp., Mycobacterium sp., and Bacillus sp.. Microbial monitoring in the production process of bottled drinking water is reasonably effective and the microbial risk is low. It is suggested that the bottled drinking water plants should establish the in-process microbial identification system in the production, strengthen microbial supervision, monitor the microbial risk in the production process, and provide scientific basis for the rational and effective control of microbial risk in the production process.

39 Evaluation of Flavor Quality Stability of Peppermint Essential Oils using Gas Chromatography-Mass Spectrometry Fingerprints in Combination with Cluster Analysis

LU Zhi

2018, 34(9):283-290. DOI: 10.13982/j.mfst.1673-9078.2018.9.040

[Abstract](691) [HTML](232) [PDF 653.86 K](769)

Abstract:
In order to evaluate the flavor quality stability of peppermint essential oils, a quantitative analysis method based on an optimized gas chromatography-mass spectrometry (GC-MS) technique was developed using the 2-methoxy-3-methylpyrazine as internal standard. To analyze the stability of the 5 peppermint flavor samples, similarity degree and relative standard deviation were calculated and cluster analysis (CA) was conducted. One hundred and twenty three flavor components were determined. The main volatile components were menthol, anethol, carvone, menthone, and the others. The similarity degrees of 2-pinene and the other 40 components were higher than 0.99. These 40 components could be used as fingerprints of the peppermint flavors. The results of relative standard deviation and CA showed that there existed differences between the 5 peppermint flavor samples. The results indicated that GC-MS with CA could be used for the analysis of flavor quality stability of peppermint flavors.

40 Chemical Structure and Analysis Methods of Soybean Saponins: A Review

XUE Peng , ZHAO Lei , ZHENG Xing , ZHANG Feng-xiang , REN Gui-xing

2018, 34(9):291-297. DOI: 10.13982/j.mfst.1673-9078.2018.9.041

[Abstract](780) [HTML](167) [PDF 559.28 K](1401)

Abstract:
Soya saponins are one of the main classes of bioactive ingredients in plants of Leguminosae, especially soybean, and have been applied in various fields of food, cosmetics and pharmaceuticals. At present, according to the structural type of aglycone, and different functional groups of C-21, C-22 and C-29, soy saponins could be grouped into three categories, namely, type A, type B and type Sg-6. To facilitate the analysis andgeneralization, saponins are further divided into saponins A, B, DDMP, E, H, I, and J subclasses. Due to the wide application of soy saponins, more and more methods become available for separation and detection. Based on the principles for quantitative or qualitative analysis of soybean saponin, the analysis methods can be divided into two kinds: one type is for quantitative analysis based on separation, including TLC (Thin Layer Chromatography), HPLC (High Performance Liquid Chromatography), UHPLC (Ultra High Performance Liquid Chromatography), and GC (Gas Chromatography); The other is for qualitative analysis without separationincluding NMR (Nuclear Magnetic Resonance), HSCC (High-speed Countercurrent Chromatography), MS (Mass Spectrometry), metabolic fingerprint analysis and immunological analysis methods. It is worth noting that mass spectrometry-coupled analyses are important qualitative means and commonly used quantitative techniques. In this review, the recent studies on the chemical structure and analysis methods of soya saponins are reviewed, and their future applications are also explored.

41 Current Development in Analytical Methods for Organic Acids, Monosaccharides and Oligosaccharides in Fruits: A Review

CHEN Shan-qiao , CHEN Hui-yun , SUN Zhi-dong , SHI Ting-ting , YANG Meng , ZHANG Hong-qin

2018, 34(9):298-309. DOI: 10.13982/j.mfst.1673-9078.2018.9.042

[Abstract](704) [HTML](602) [PDF 690.48 K](967)

Abstract:
As the major flavor substances in fruit products, the contents of organic acids, monosaccharides and oligosaccharides are critical indexes in postharvest preservation. The physiological features of fruits in postharvest can be presented by contents of organic acids and small-molecular sugars. These substances had been emphatically concentrated in postharvest investigation. Due to the high efficiency and accessibility to automatic analysis, high performance liquid chromatography (HPLC) has occupied the mainstream of analytical methods for organic acids and small-molecular sugars. This review article summarized the features including: the introducing of organic solvent and solid phase extraction (SPE) in pretreatment; universal and specialized packing materials as stationary phase; selecting of detector according to spectrometry properties of analytes, of HPLC based analytical methods for organic acids and small-molecular sugars in the investigations about postharvest preservation of fruits.

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Volume 34,Issue 9,2018 Table of Contents