Wine phenolics: looking for a smooth mouthfeel | Author : Fernanda Cosme | Abstract | Full Text | Abstract :Each grape variety has its own phenolic profile. However, the concentration of the phenolic compounds present in wine, are mainly dependent of the winemaking process. Phenolic compounds influence wine sensorial characteristics namely taste or mouthfeel, bitterness, astringency and color. Humans can perceive six basic tastes: sweet, salty; sour; umami; fat-taste and bitter taste. This last basic taste is considered as a defense mechanism against the ingestion of potential poisons. Some of the genes, encoding G-protein-coupled receptors - TAS2Rs, which translate for these distinct bitter compounds detectors have been identified. Different phenolic compounds activate distinguished combination of TAS2Rs. Astringency in wine is primarily driven by proanthocyanidins, soluble protein-proanthocyanidins complexes diminish the protective salivary film and bind to the salivary pellicle; insoluble protein-proanthocyanidins complex and proanthocyanidins are rejected against salivary film and trigger astringency sensation via increasing friction.
Thus, the aim of this review is to expand the knowledge about the role of wine phenolic compounds in wine sensorial properties, namely in bitterness and astringency phenomenon’s. |
| Development and validation of a green HILIC-ELSD method for the determination of caffeine and taurine in energy drinks | Author : Jun Sang | Abstract | Full Text | Abstract :In the present study, a green HILIC (hydrophilic interaction liquid chromatography)-ELSD (evaporative light-scattering detection) method was developed and validated for the determination of caffeine and taurine in energy drinks using ethanol and water as mobile phases and without derivatization steps. The effects of drift tube temperature on the peak area and signal-to-noise ratio of caffeine and taurine were investigated, and the optimal parameter was determined as 55 °C. Under the optimal elution program, caffeine and taurine can be analysed within 14 min. The calibration curves of caffeine (R2 = 0.9996) and taurine (R2 = 0.9976) were calculated and revealed a good linearity. The limit of detection of caffeine and taurine were 0.0044 mg/mL and 0.0055 mg/mL, and the limit of quantification were 0.0146 mg/mL and 0.0183 mg/mL, respectively. Method validation was also performed in terms of precision, repeatability, stability and recovery. The relative standard deviation (%) of intra- and inter-day precision, repeatability and stability were 0.95, 1.81, 2.15 and 1.61 for caffeine and 0.53, 0.46, 0.65 and 0.36 for taurine, respectively. The recovery of caffeine (101.72 ± 2.08%) and taurine (100.28 ± 1.60%) were at an acceptable level. Additionally, the developed HILIC-ELSD method was applied to determine the content of caffeine and taurine in commercial energy drinks. Therefore, the developed HILIC-ELSD method was work-safe and efficient and has great potential for simultaneous analysis of caffeine and taurine in food industry. |
| Profiling of bioactive lipids of the wild edible land snails of the genus Helix | Author : valery dembitsky | Abstract | Full Text | Abstract :Pulmonate gastropod mollusks of the genus Helix are being used by human as food more than 10,000 years and they are quite important in the diet of many European countries. We investigated lipid composition of wild land snails sampled in France, Germany, Luxemburg, Norway, Switzerland, Sweden, and East Mediterranean inhabitants. Plasmalogens, glyceryl ethers, and diacyl phospholipid forms as well as their fatty aldehydes, alkyl ether glycerides, and fatty acid derivatives were studied. PE of snails, containing aldehydes C16 (variations from 17 to 40%), C18 (11-36%), C9-18:1 (22-31%), C11-20:1 (1-3%), and several minor aldehydes, were detected. The major saturated 1-O-alkyl glycerol ethers were C16:0 and C18:0. Eicosatetraenoic (ETA, 34%), ?-linolenic acid (ALA, 14%), and eicosapentaenoic acid (EPA, 7%) in PE (all forms) were dominating fatty acids. ETA (49%), EPA (13%), ALA (7%), and docosahexaenoic (DHA, 6%) were major fatty acids in PS (all forms). In PC (all forms), major fatty acids were found oleic (20%), palmitic (15%), ETA (14%), and linoleic (10%). In neutral plasmalogens, the predominant fatty acids were palmitic acid (29%), oleic acid (13%), ALA (8%), and ETA (7.8%). Predominant fatty acids in neutral plasmalogens were found to be 16:0 (29%), C18:0 (13%), ALA (8%), and ETA (7.8%). Distribution of plasmalogens, alkyl glyceryl ethers, and their fatty aldehydes and fatty alcohols in gastropod species and other mollusks is also discussed. |
| The seasonal fatty acids composition of different tissues of farmed common carp (Cyprinus carpio) | Author : Yongkang Luo | Abstract | Full Text | Abstract :The seasonal fatty acid composition of farmed common carp (Cyprinus carpio) viscera, muscle, bones, and skin were determined in spring (March), summer (June), autumn (September), and winter (December) (% of total fatty acids). Palmitic acid (C16:0) and oleic acid (C18:1n-9) were the most abundant saturated fatty acid (SFA) and monounsaturated fatty acids (MUFA), respectively. Linoleic acid (C18:2n-6), arachidonic acid (C20:4n-6), docosahexaenoic acid (DHA), and linolenic acid (C18:3n-3) were the most abundant polyunsaturated fatty acids (PUFA). All tissues had a lower percentage of MUFA but higher PUFA in the summer in comparison to the other seasons. The results of principle components analysis (PCA) and cluster analysis (CA) suggested that summer common carp could be distinguished from other seasons, but the tissue source of the oil could not be determined. |
| Dissipation of 8 pesticides on bok choy (Brassica chinensis) with once and multiple times application under field condition | Author : Xiang-Yang Yu | Abstract | Full Text | Abstract :For better understanding the impact of multiple applications on the possible residue risk of pesticides on vegetables, a field trial was performed to evaluate eight pesticides (Phoxim, dichlorvos, cyhalothrin, ?-cypermethrin, deltamethrin, fenvalerate, dimethoate and chlorothalonil) on bok choy. The dissipation of the selected pesticides was monitored after once application (OA) or multiple applications (MA). The suitability of multiple applications strategy of the selected pesticides for pest management on bok choy was also evaluated. The deposition ratio for all the pesticides ranged from 0.77‰ to 9.7‰. Dissipation of all the pesticides followed a typical first-order pattern. The estimated degradation half-lives of all the pesticides ranged from 0.6 to 11.95 days and from 0.68 to 11.87 days for OA and MA, respectively. However, the practical concentrations of all the pesticides measured at 2 h after the last application raged from 1.43 to 14.61 mg kg-1 and from 2.34 to 21.29 mg kg-1 for OA and MA, respectively. It is acceptable for the recommend doses for phoxim, dichlorvos, cyhalothrin, and ?-cypermethrinon on bok choy for OA or MA in the present study. For the sake of food safety and sustainable use of pesticides, however, special attention needs to be paid to the MA of deltamethrin and fenvalerate. The MA of dimethoate and chlorothalonil on bok choy was not recommended. |
| Effects of Stresses on the Growth and Cytotoxicity of Shiga-Toxin Producing Escherichia coli in Ground Beef and Spinach | Author : Cheng-An Hwang | Abstract | Full Text | Abstract : The objectives of this study were to examine the effect of stresses on the growth and cytotoxicity of pathogenic Escherichia coli in beef and spinach. A mixture of three strains of Shiga toxin-producing E. coli (STEC) O157:H7 or 4 strains of non-O157 STEC, O26:H11, O103:H1, O104:H4, and O145:NM, was subjected to stress of 2 ppm chlorine, aw 0.97, pH 5, or 15-day starvation. Stressed or non-stressed STEC was inoculated into 5 g of irradiated ground beef or spinach. The cell populations during storage at 8, 12, or 16?C for 4 weeks were compared to evaluate the growth variation between O157 and non-O157 STEC. Supernatant from each sample after 24-h incubation at 22?C was used to determine Vero-cytotoxicity using [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, MTS] or lactate dehydrogenase (LDH) assay to evaluate the effects of stresses on the cytotoxicity exhibited by STEC. After one week at 8?C, the population of non-stressed non-O157 (3.1 log CFU/g) was significantly (p<0.05) higher than O157 (1.9 log CFU/g) in ground beef, and the difference in populations (3.9 vs. 1.7 log CFU/g, p0.05) different in beef and spinach. MTS assay showed that stressed O157 and non-O157 STEC exhibited significantly (p<0.05) higher cytotoxicity than the non-stressed controls. The numbers of surviving Vero cells were 47-52% (stressed) vs. 65% (control) in beef and 20-30% (stressed) vs. 52-53% (non-stressed) in spinach. Similarly, LDH assay also indicated an increased cytotoxicity (p<0.05) in stressed O157 and non-O157 STEC than non-stressed controls in spinach. There was no significant difference among the four stresses in inducing the levels of cytotoxicity in O157 or non-O157 STEC. Results showed that STEC cells exposed to sub-lethal stresses might have increased cytotoxicity during subsequent growth in ground beef or spinach. The findings illustrate the importance of applying suitable control measures to eliminate the presence of stressed STEC in beef and spinach processing environment or their subsequent contamination in the products. |
| Evaluation of hygiene practices and microbial analysis of street food vendors in Rawalpindi and Islamabad | Author : hizb ullah | Abstract | Full Text | Abstract :Introduction Street foods are prone to many hazards which consequently bear a high number of medical issues around the globe. Street food is generally sold in all urban communities of Pakistan even in the capital of the state which is consumed by many people from kids to grown-ups. Methods The present study was conducted to assess the microbiological status of road distributed organic products which were sold in the chosen regions of Rawalpindi and Islamabad. For the collection of data, a total of 14 sites were examined of street foods during the period of October-2016 to March-2017. Results The merchants were entirely male. Out of 200 of them 15-25 age were 76/200 (38%), 26-35 age 102/200 (51%) and 36-50 age 22/200 (11%), while the educational status was reported as 8th 95/200 (47.5%), SSC 38/200 (28.5%) and F. A/ F. Sc 10/200 (5%) but no one was aware about the foods safety.64 % of vendor did not have portable water facilities whereas only 36% of the stalls had this facility. 78.80% of the vendor did not keep the cooked and uncooked food separately, 51.50% of the operator used dirty water for cleaning. Samosa posed a high risk for consumer since it showed higher number of bacterial load on aerobic plate count i.e. (9×104 ±0.10, 9.20×104 ±0.10), while there were no TBC, positive sample found at I-10 Markaz.The highest count was observed for Salmonella spp on samosa was (5.60×102 (±0.20) CFU/g, while in cholay bacterial count was 0.45×102 (±0.20) CFU/g. Maximum number of Staphylococcus was reported in I-9 Markaz which was 4×104±1.00 CFU/mg). The highest number of E. coli was reported at Saddar Bazar and Faizabad and lowest number was examined in Goldra Sharif. Conclusions Samosa stood a high risk for the customer and found a lot of bacteria, while, Salmonella and Staphylococcus were found the maximum in Markaz I-10 and I-9. There was no fungal count observed at the selected area during the study.
Keywords: male, street foods, Salmonella, Staphylococcus |
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