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The total tetramethylpyrazine (TMP) content in vinegar samples could be detected by multiple HS-SPME coupled with GC-FID (MHS-SPME-GC-FID) as a routine method. Unlike the traditional HS-SPME method, only one working curve built with different levels of standard aqueous solutions in the MHS-SPME-GC-FID method was able to calibrate the total TMP level from different matrixes (calibration standards ranging from 0.05 to 5.00 μg mL−1, R2 = 0.9986). In addition, the developed method was sensitive to the determination of TMP in vinegars (the limit of detection of 1 μg L−1, the limit of quantification of 5 μg L−1). In addition, the excellent recovery at 0.10 μg mL−1, 1.00 μg mL−1 and 5.00 μg mL−1 of TMP (ranging from 81.01% to 113.5%) and good reproducibility of the method (inter-day RSD 7.79%, intra-day RSD 3.94%) confirmed that the developed method was accurate and stable for the analysis of vinegar samples. Moreover, the detection results in real samples were consistent with the results from the traditional HS-SPME-GC-FID corrected by external standard method. In conclusion, the uniqueness of the working curve and the absence of matrix effect in MHS-SPME-GC-FID method were useful for rapidly obtaining comparable data from liquid samples with different matrix.

Abalone is one of the most valuable seafood products and the quality of ready-to-eat abalone products could be improved through tenderization treatments prior to a fully cooking process. In this study, a tenderization process (80 °C for 2 h) was applied to improve the quality properties of baked abalone muscle for the developing of ready-to-eat products. The quality properties of baked abalone (150–210 °C, 10–30 min) with and without pre-tenderization treatment prior to baking were evaluated through sensory evaluation, textural analysis and Hunter Lab colorimeter. In addition, amounts of sugars and α-dicarbonyl compounds in these products were determined via HPLC analyses. The baking condition at 180 °C for 20 min combined with pre-tenderization resulted in an optimal product. The baked abalone with pre-tenderization had better textural properties (hardness, 1031.12 ± 101.67; springiness, 0.96 ± 0.02; chewiness, 817.13 ± 113.43; shear, 2843.92 ± 35.67), sensory scores (30.1 ± 2.9) and color (25.28 ± 1.21) as compared to the baked abalone without pre-tenderization (hardness, 1990.91 ± 252.35; springiness, 0.87 ± 0.01; chewiness, 1164.43 ± 195.64; shear, 3910.79 ± 302.12; sensory score, 17.4 ± 1.0; color, 15.91 ± 0.74). The reducing sugar analysis indicated the presence of ribose and glucose in the baked abalone. In addition, the formation of α-dicarbonyl compounds (degraded from reducing sugars) including glucosone, 3-deoxyglucosone, glyoxal, methylglyoxal, and diacetyl were significantly promoted by the tenderization process in the baked abalone muscle. And the tenderization treatment led to an average of 218% increase in α-dicarbonyl compounds in the baked abalone muscle. The promotion of the formation of α-dicarbonyl compounds by the tenderization treatment contributed to the accumulation of pigments in the final baked products and led to desirable color.

Vortex-assisted liquid-liquid micro-extraction (VALLME) was applied for eliminating the matrix effect and improving the sensitivity of eugenol determination by headspace solid phase micro-extraction (HS-SPME) coupled with gas chromatography-mass spectrometer (GC-MS) in fish samples. Under the optimum condition of VALLME and HS-SPME, the good linearity of eugenol in fish samples was obtained in the range from 15.0 to 750.0 μg/kg. The limit of detection (LOD) and the limit of quantification (LOQ) for eugenol were 0.5 and 1.5 μg/kg, respectively. The recovery of eugenol was ranging from 95.4 to 119.9% and the relative standard deviation (RSD %) for eugenol was lower than 20%. The results turned out that VALLME followed HS-SPME-GC-MS was a simple, rapid, and accurate method for the determination of eugenol in fish samples. The levels of eugenol in different parts of real samples were tested by the developed method, and the results concluded that the developed method was compatible with GC-MS analysis with long-term application and had excellent repeatability, linearity, and sensitivity.

A new, rapid, and inexpensive method using two-step ultrasonic assisted liquid–liquid micro-extraction (UALLME) coupled with capillary electrophoresis-ultraviolet (CE-UV) was developed for 5-hydroxymethylfurfural (HMF) analysis in high ion strength samples (like vinegar and soy sauce). The factors affecting the extraction efficiency were optimized such as the extraction volume, the ultrasonic time, and the power density of ultrasonic. Under the optimum conditions, the limit of detection (LOD) and the limit of quantification (LOQ) for HMF were 0.03 and 0.10 mg/L, respectively. The relative standard deviations (RSD %) for HMF were ranging from 0.53 to 3.17%, and the recoveries of HMF were ranging from 91.24 to 109.39%. The results turned out that two-step UALLME-CE-UV was applicable to analyze HMF in vinegar and soy sauce. Eleven brands of vinegar and soy sauce were tested by two-step UALLME-CE-UV, and the results showed that the method had a potential application in analysis of foodstuffs. The two step UALLME method was effective to improve the selectivity and sensitivity of CE-UV method for HMF analysis in vinegar and soy sauce.

The flavor release mechanism related to the interaction of aroma compounds with proteins is still unclear. In this study, the interaction of protein with pyrazine homologues, such as 2-methylpyrazine (MP), 2,5-dimethylpyrazine (DP), 2,3,5-trimethylpyrazine (TRP) and 2,3,5,6-tetramethylpyrazine (TEP), was investigated to elucidate the effect of alkyl distribution in a pyrazine ring on its flavor release in bovine serum albumin (BSA) solution (pH 7.4). The results of SPME-GC-MS indicated that methyl distribution in a pyrazine ring significantly affected its release from BSA solution. The pyrazines released from BSA solution with an increasing order of MP, DP, TRP and TEP. The inhibition mechanism of alkyl-pyrazine release was further elucidated by the interaction between alkyl-pyrazines and BSA using multiple spectroscopic methods. The non-covalent interaction between alkyl-pyrazines and BSA was confirmed as the main interaction force by the value of the bimolecular quenching constant (Kq > 2 × 1010 L mol−1 s−1). A decrease in the hydrophobicity of the microenvironment between the alkyl-pyrazine and BSA was detected by synchronous fluorescence spectra, which revealed that alkyl-pyrazines were mainly bound on the sites of tyrosine and tryptophan in BSA. The UV-vis absorption spectra and circular dichromatic (CD) spectrum revealed that alkyl-pyrazines could induce polarity and conformation change of BSA. The above results indicated that the structure of the flavor homologues can affect their release in food matrices.

Vortex-assisted liquid–liquid microextraction (VALLME) is a fast and simple pretreatment method, which has been applied for the clean-up of beverages containing caramel color. Herein, a reversed-phase C18 column (50 mm × 2.5 mm, 2 μm) was used, and the MS/MS instrument was operated in the multiple reaction monitoring mode for the sensitive and selective detection of 5-hydroxymethyl-2-furaldehyde (HMF). The matrix effect and detection stability were corrected using the isotope dilution method. This method demonstrated low limit of quantification (0.3 μg L−1) and excellent linearity (R2 = 0.999). The recovery rates of HMF ranged from 87.5% to 101.0% in carbonated drinks and from 85.1% to 98.7% in soft drinks. The content of HMF was quantified in thirteen beverage samples, ranging from 0.2 to 14.8 mg L−1. In conclusion, the VALLME coupled with the HPLC-ESI-MS/MS method is a valid and rapid technique for isotope dilution quantification of HMF in beverages.

Emulsion gels with low oil contents have been continuously developed in recent decades. In this study, the use of high-intensity ultrasound for the preparation of low oil emulsion gel (oil fraction of 0.25) was investigated. Specifically, defatted Antarctic krill protein (dAKP) was used to stabilize the interface of soybean oil and water. Then, the microstructure and the stabilization mechanism of the formed emulsion gel were evaluated by cryo-SEM, CLSM, zeta potential, rheological measurements, and FTIR. Besides, the particle diameter was measured to be around 5 μm. The results of CLSM indicated that the emulsion gel was the oil-in-water type. The emulsion gel exhibited gel-like viscoelastic behavior even at a low concentration of dAKP due to the formation of a rigid particle network while the rheological behavior of the emulsion gel was significantly affected by the concentration of dAKP. The stabilization of the emulsion gel can be maintained by space steric hindrance and hydrophobic interactions between particles in the emulsion gel system.

The concentration of tetramethylpyrazine (TMP) in vinegar is an active indicator of vinegar quality. Dispersive liquid–liquid microextraction (DLLME) was first applied to vinegar as a clean-up pre-treatment for the rapid (5 min) determination of TMP by high-pressure liquid chromatography with ultraviolet detection (HPLC-UV), and may serve as an alternative to solid-phase extraction (SPE) or solid-phase microextraction (SPME). High sensitivity of HPLC for TMP determination was obtained using the DLLME pretreatment, with a limit of detection (LOD) of 0.001 mg L−1 and limit of quantification (LOQ) of 0.005 mg L−1. The developed method exhibited excellent linearity in the concentration range of 0.050–80.000 mg L−1, with a correlation coefficient R2 > 0.999. Furthermore, the percentage recovery of TMP in vinegar using the developed method was within the range 97.97–105.24%. Therefore, DLLME coupled with HPLC-UV is a sensitive and promising method for vinegar clean-up and TMP assay.

In this study, a rapid and reliable pretreatment method called dispersive liquid-liquid microextraction (DLLME) was developed for the determination of 4(5)-methylimidazole (4-MeI) in beverages. The clean-up samples were analyzed by a high performance liquid chromatography coupled with triple quadrupole mass spectrometer (HPLC–MS/MS) using a reversed-phase C18 column (250 mm × 4.6 mm, 5 μm). The matrix effects and the fault of DLLME operation were corrected by the isotope dilution technique. The developed method exhibited the limit of quantification (0.3 μg L−1) and excellent linearity (R2 = 0.999). In addition, the recovery values of 4-MeI in carbonated beverage were ranging from 102.60% to 113.22%, in soft drinks were ranging from 103.24% to 108.85%. The content 4-MeI was detected in thirteen beverage samples treated with DLLME and solid phase extraction method (SPE) (ranging from 6.4 to 165.5 μg L−1). The consistent result of 4-MeI content detected by DLLME and SPE method concluded that the established method on the basis of DLLME was rapid, robust and accurate for the trace 4-MeI determination in beverages.

C-X-C motif chemokine receptor type 2 (CXCR2), a key regulatory protein, has been associated with multiple roles in the progression of numerous tumors, including gastric adenocarcinoma (GA). However, the mechanism of CXCR2 in the development of tumors remains controversial and unclear. In a previous study, the expression of CXCR2 and interleukin-22 receptor 2 (IL-22BP) was observed in GA. This promoted the present study, which aimed to explore the association between the two proteins, and to further analyze their roles in GA. CXCR2 and IL-22BP protein expression was analyzed by immunohistochemistry and reverse transcription-quantitative polymerase chain reaction assays in gastric cancer (GC) tissue, additionally confirmed via western blotting and immunocytochemical analysis in the MKN-45, BGC-823 and SGC-7901 cell lines. The association between expression levels and clinicopathological characteristics was evaluated by the Mann-Whitney U and Kruskal-Wallis tests. Using Kaplan-Meier plots and Cox proportional hazard models, overall survival (OS) was analyzed. Compared with non-cancerous tissue, CXCR2 and IL-22BP were over expressed (P

Cancer cells produce a substantial amount of energy through aerobic glycolysis even in the presence of adequate oxygen. Lactate dehydrogenase (LDH), a key regulator of glycolysis, reversibly catalyzes the conversion of pyruvate to lactate. Recently, oxamate, an inhibitor of LDH, has been shown to be a promising anticancer agent. However, the detailed mechanism remains largely unclear. In this study, we demonstrate that oxamate inhibits the viability of human gastric cancer cells in a dose- and time-dependent manner. In addition, treatment with oxamate induces protective autophagy in gastric cancer cells. Moreover, autophagy inhibited by chloroquine or Beclin 1 small interfering RNA (siRNA) enhances oxamate-induced apoptosis and proliferation inhibition. Further study has shown that oxamate treatment significantly augments reactive oxygen species (ROS) production. Furthermore, cells pretreated with N-acetyl cysteine (NAC), a ROS inhibitor, display significantly reduced ROS production and attenuated oxamate-induced autophagy. Finally, functional studies reveal that the Akt-mTOR signaling pathway, a major negative regulator of autophagy, is inhibited by oxamate. Together, our results provide new insights regarding the biological and anti-proliferative activities of oxamate against gastric cancer, and may offer a promising therapeutic strategy for gastric cancer.

Objectives To explore metabolic symbiosis in gastric cancer and its relationship with cancer prognosis. Patients and methods Immunohistochemistry was used to detect MCT4 and TOMM20 expression in 113 gastric cancer patient specimens. The correlations of MCT4 and TOMM20 expression with gastric cancer clinicopathological features and survival were studied. Results Stromal MCT4 expression was closely associated with the pathological (p) TNM stage and TOMM20 expression. We also assessed the predictive value of epithelial MCT4 expression. However, no correlation with patient clinical outcome was evident. TOMM20 expression was closely associated with tumor size and stromal MCT4 expression. Further, stromal MCT4 and mitochondrial TOMM20 were positively correlated, and Kaplan–Meier analysis showed that high stromal MCT4 expression and high mitochondrial TOMM20 expression were associated with reduced overall survival and disease-free survival. Both univariate and multivariate analyses revealed that stromal MCT4 expression and mitochondrial TOMM20 expression were independent prognostic factors in gastric cancer patients. Conclusions Our findings directly support the existence of metabolic symbiosis in gastric cancer. Stromal MCT4 and mitochondrial TOMM20 could be promising biomarkers for predicting the prognosis of patients with gastric cancer. These proteins might also serve as novel therapeutic targets in gastric cancer treatment.

To investigate whether transanal natural orifice specimen extraction (NOSE) is a better technique for rectal cancer resection.A prospectively designed database of a consecutive series of patients undergoing laparoscopic low anterior resection for rectal cancer with various tumor-node-metastasis classifications from March 2011 to February 2012 at the First Affiliated Hospital of Sun Yat-Sen University was analyzed. Patient selection for transanal specimen extraction and intracorporeal anastomosis was made on the basis of tumor size and distance of rectal lesions from the anal verge. Demographic data, operative parameters, and postoperative outcomes were assessed.None of the patients was converted to laparotomy. Respectively, there were 16 cases in the low anastomosis and five in the ultralow anastomosis groups. Mean age of the patients was 45.4 years, and mean body mass index was 23.1 kg/m². Mean distance of the lower edge of the lesion from the anal verge was 8.3 cm. Mean operating time was 132 min, and mean intraoperative blood loss was 84 mL. According to the principle of rectal cancer surgery, we performed D2 lymph node dissection in 13 cases and D3 in eight. Mean lymph nodes harvest was 17.8, and the number of positive lymph nodes was 3.4. Median hospital stay was 6.7 d. No serious postoperative complication occurred except for one anastomotic leakage. All patients remained disease free. Mean Wexner score was 3.7 at 11 mo after the operation.Transanal NOSE for total laparoscopic low/ultralow anterior resection is feasible, safe and oncologically sound. Further studies with long-term outcomes are needed to explore its potential advantages.

To summarize the experience and short-term clinical outcomes of hand-assisted laparoscopic surgery (HALS) in sphincter-preserving surgery for low and ultralow rectal cancer.Data of 49 patients with rectal cancer who underwent HALS for low or ultralow anterior resection between January 2010 and January 2011 were analyzed retrospectively.The proximal resection margin was (14.3±6.9) cm and the distal margin was(4.3±1.9) cm. The mean operative time was(128.3±70.9) min. On postoperative macroscopic evaluation, the mesorectum was intact in 42 cases, nearly intact in 7 cases. The circumferential resection margin was more than 2 mm in 42 cases, and less than 2 mm in 7 cases. Forty-six patients underwent R0 resection, and 3 cases underwent R1 resection. The median retrieved lymph node (LN) was 16.20±9.23, and the median positive LN was 1.12±2.19. Postoperative pathological examination showed TNM stage was I( in 12 patients, II(A in 18, II(B in 1, III(A in 2, III(B in 8, III(C in 5, IIII( in 3. The median postoperative hospital stay was (6.25±3.87) d. There were no anastomotic leakage, ileus, intra-abdominal or anastomotic bleeding. There were two wound infections.Low and ultralow anterior resection for rectal cancer using HALS approach is safe and feasible with favorable short-term outcome.

AIM: To investigate the clinicopathological significance and prognostic value of caveolin-1 (CAV-1) in both tumor and stromal cells in colorectal cancer (CRC). METHODS: A total of 178 patients with CRC were included in this study. The correlation between CAV-1 expression and clinicopathologic features and survival was studied. RESULTS: CAV-1 expression was detected in tumor and stromal cells. The expression of stromal CAV-1 was closely associated with histological type (P = 0.022), pathologic tumor-node-metastasis stage (P = 0.047), pathologic N stage (P = 0.035) and recurrence (P = 0.000). However, tumor cell CAV-1 did not show any correlation with clinical parameters. Additionally, the loss of stromal CAV-1 expression was associated with shorter disease-free survival (P = 0.000) and overall survival (P = 0.000). Multivariate analysis revealed that the loss of stromal CAV-1 expression was an independent prognostic factor for both overall survival (P = 0.014) and disease-free survival (P = 0.006). CONCLUSION: The loss of stromal CAV-1 expression in CRC was associated with poor prognosis and could be a prognostic factor for CRC patients.

In this paper a model in which the flashing colored noise induces the directed motion of Brownian motors is proposed. The problems of the directed motion and the current reversal of the Brownian particle can be discussed in a unified theoretical framework. For the specified potential, the current of the directed motion and the current reversal depend on the factors such as the noise intensity and the flip frequency are calculated. The changing of correlation time can also lead to current reversal.