Ali Üren

A method for benzoyl chloride derivatization of biogenic amines for high performance liquid chromatography

A new benzoylation procedure was developed which was more reliable than the most common benzoylation procedures in terms of reaction time, peak resolution, detector response and repeatability. Methylamine, putrescine, cadaverine, tryptamine, beta-phenylethylamine, spermidine, spermine, histamine, tyramine and agmatine were studied. Linearity for each biogenic amine was observed with a good regression coefficient. Limits of detection were found between 0.2mg/l and 2.5mg/l. Recovery rates varied from 72.8% to 103.4%. Temperature and pH of mobile phase were studied and found that 20 degrees C of column temperature with a pH of 8 was preferable. It was established that polyvinylpyrrolidone adsorbed biogenic amines and caused interference in HPLC determination of biogenic amines that had been used by some authors to eliminate interfering phenolic compounds in wine samples.

Inhibitory effects of pomegranate seed extract on the formation of heterocyclic aromatic amines in beef and chicken meatballs after cooking by four different methods.

Beef and chicken meatballs with a 0.5% (w/w) pomegranate seed extract were cooked using four different cooking methods (oven roasting, pan cooking, charcoal-barbecue, and deep-fat frying) and six heterocyclic aromatic amines; IQ, MeIQx, 4,8-DiMeIQx, PhIP, norharman, and harman were observed. In the beef meatballs, the highest inhibitory effects of pomegranate seed extract on heterocyclic aromatic amines formation were 68% for PhIP, 24% for norharman, 18% for harman, 45% for IQ, and 57% for MeIQx. Total heterocyclic aromatic amine formation was reduced by 39% and 46% in beef meatballs cooked by charcoal-barbecue and deep-fat frying, respectively. In the chicken meatballs, the highest inhibitory effects were 75% for PhIP, 57% for norharman, 28% for harman, 46% for IQ, and 49% for MeIQx. When the pomegranate seed extract was added to the chicken meatballs cooked by deep-fat frying, the total heterocyclic aromatic amine formation was inhibited by 49%, in contrast the total heterocyclic aromatic amine contents after oven roasting increased by 70%.

Colour parameters of Turkish-type fermented sausage during fermentation and ripening

Colour parameters of Turkish-type fermented sausage during fermentation and ripening were evaluated. CIE x y, L(∗) a(∗) b(∗), C(∗) h°, pigment nitrosation (NI) and pigment discoloration (RSI) were measured. Sausage processing had four stages consisting of first and second fermentation steps and then two consecutive ripening steps. Variations of colour parameters with processing indicated that Turkish-type fermented sausage processing might be divided into two well defined phases from the colour point of view. Optimum colour was obtained at the end of the first ripening step.

Effect of steam baking on acrylamide formation and browning kinetics of cookies.

UNLABELLED Effects of baking method and temperature on surface browning and acrylamide concentration of cookies were investigated. Cookies were baked in natural and forced convection and steam-assisted hybrid ovens at 165, 180, and 195 °C and at different times. For all oven types, the acrlyamide concentration and surface color of cookies increased with increasing baking temperature. Significant correlation was observed between acrylamide formation and browning index, BI, which was calculated from Hunter L, a, and b color values, and it showed that the BI may be considered as a reliable indicator of acrylamide concentration in cookies. Acrylamide formation and browning index in cookies were considered as the first-order reaction kinetics and the reaction rate constants, k, were in the range of 0.023 to 0.077 (min(-1) ) and 0.019 to 0.063 (min(-1) ), respectively. The effect of baking temperature on surface color and acrylamide concentration followed the Arrhenius type of equation, with activation energies for acrylamide concentration as 6.87 to 27.84 kJ/mol; for BI value as 19.54 to 35.36 kJ/mol, for all oven types. Steam-assisted baking resulted in lower acrylamide concentration at 165 °C baking temperature and lower surface color for all temperatures. Steam-assisted baking is recommended as a healthy way of cooking providing the reduction of harmful compounds such as acrylamide for bakery goods, at a minimal level, while keeping the physical quality. PRACTICAL APPLICATION The kinetics of acrylamide formation and browning of cookies will possibly allow definition of optimum baking temperatures and times at convectional and steam-assisted baking ovens. The kinetic model can be used by developing baking programs that can automatically control especially a new home-scale steam-assisted hybrid oven producing healthy products, for the use of domestic consumers.

Biogenic Amine Content of Shalgam (Şalgam): A Traditional Lactic Acid Fermented Turkish Beverage

Shalgam is a traditional Turkish fermented beverage. The biogenic amine contents of 20 shalgam samples from different manufacturers in Turkey were analyzed for the first time, using HPLC after derivatization with benzoyl chloride. Of the 10 biogenic amines under study, putrescine, cadaverine, histamine, and tyramine were detected in all shalgam samples. Putrescine was the prevailing biogenic amine. Putrescine concentrations were between 5.0 and 42.3 mg/L. Total biogenic amine contents were between 26.7 and 134.3 mg/L. Concentrations of biogenic amines were below the maximum permissible limits. pH values of shalgam samples were in the range from 3.15 to 4.25; acidities of shalgam samples were from 0.530% to 1.028% (w/v); total dry matter values were from 2.33% to 3.67% (w/w); total free amino acid contents were from 0.0074% to 0.0318% (w/v). Significant correlations were detected between biogenic amine concentrations and pH values, acidities, total dry matter contents, and total free amino acid contents.

Development of a cost-effective method for nitrate and nitrite determination in leafy plants and nitrate and nitrite contents of some green leafy vegetables grown in the Aegean region of Turkey.

An accurate, fast, easily applicable, and cost-effective method for the determination of nitrate and nitrite was developed. This method was much more reliable than the cadmium column reduction method, which is a tedious and time-consuming procedure and not easily applicable. The principle of the method was reduction of nitrate to nitrite with cadmium acetate solution and zinc powder and then treatment with Griess reagent. Recovery of the method changed from 92.9 to 102.8%, and detection limit was found as 31.4 mg/kg. Coefficient of variation was 3.16% for intraday precision. Nitrate and nitrite contents of 10 types of leafy vegetables native to the Aegean region of Turkey were determined. Wild radish, chicory, fennel, blessed thistle, blue mallow, and chard were analyzed for the first time. Nitrate contents were found between 354.8 mg/kg for iceberg lettuce and 4653 mg/kg for wild radish. Tested vegetables contained <26.33 mg/kg nitrite.

Plasma copper, zinc and magnesium levels in patients with premenstrual tension syndrome

We measured plasma Cu, Zn and Mg levels in 40 women suffering from premenstrual tension syndrome (PMTS) and in 20 control subjects by atomic absorption spectrophotometer. Mean plasma Cu. Zn and Mg levels, the Zn/Cu ratio were 80.2±6.00 μg/dl, 112.6 ±8.35 μg/dl, 0.70±0.18mmol/1, and 1.40± 0.10 in the PMTS group; and 77.0±4.50 μg/dl. 117.4 ±9.50 μg/dl. 0.87±0.10 mmol/l, and 1.51 ±0.05 in the control group respectively. The mean Mg level and the Zn/Cu ratio were significantly lower in PMTS patients than in the control group. Plasma Mg and Zn levels were diminished significantly during the luteal phase compared to the follicular phase in PMTS group. Mg deficiency may play a role in the etiology of PMTS.

Determination of Turkish-type fermented sausage colour by a reflectance method

An objective method is described for the determination of Turkish-type fermented sausage colour. The method is based on reflectance measurements and specified as (R570−R525)(R650−R525). This ratio was simply termed as the TSC value (Turkish sausage characteristics) and was compared with 14 other objective values. The correlation coefficient of the TSC value with panel scores was higher than those of the other objective values except the CIE y value. The other 13 objective values were CIE xz, L∗a∗b∗, L∗C∗H ° Hunter Lab, RSI, NI and percentage nitrosomyoglobin (NOMb) pigment. Correlation coefficients of CIE y and TSC values are -0.901 and -0.875, respectively. TSC value is a measure of both pigment nitrosation and pigment discoloration and more useful than the RSI value. A regression equation was estimated for calculating scores from TSC values. This regression equation was converted to a table to determine the grade for colour of fermented sausages.

Biogenic Amine Content of Tarhana: A Traditional Fermented Food

Tarhana is a traditional fermented cereal food consumed in nearly all regions of Turkey as a soup having a delicious and desired taste. There are some other products similar to tarhana in Syria, Jordan, Egypt, Iraq, Hungary, Finland, Greece, and Scotland. Fifteen homemade and 5 commercially produced tarhana samples were analyzed for the first time to determine biogenic amine contents. Tyramine was the prevailing biogenic amine. Average tyramine concentrations of homemade and commercially produced tarhana samples were 92.8 and 55.0 mg/kg of tarhana, respectively. Concentrations of biogenic amines were below the permissible limits except for two homemade samples. The pH values of tarhana samples were in the range from 3.43 to 5.03; acidities were from 0.60 to 3.89 g/100 g tarhana (as lactic acid); total dry matters were from 86.42 to 92.32 g/100 g tarhana; and total free amino acid contents were from 0.035 to 1.427 g/100 g tarhana (as leucine).

Monitoring of Biogenic Amines in Kumru: A Traditional Fermented Cereal Food

Kumru is a traditional fermented cereal food made with flour and chickpea yeast. Ten samples of kumru supplied from different manufacturers in Turkey were analysed for the first time to determine biogenic amine contents using HPLC with benzoyl derivatization. Of the 10 amines under study, putrescine, cadaverine, spermidine, spermine, and histamine were detected in all samples. Spermine was the prevailing biogenic amine. Spermine concentrations of kumru samples changed from 2.4 to 17.9 mg/kg of kumru. Total amine contents of kumru samples were between 23.9 and 42.2 mg/kg of kumru. Concentrations of biogenic amines were far below the allowable limits. The pH values of kumru samples were in the range from 5.28 to 6.40; acidities were in the range from 0.12 to 0.28 g/100 g kumru (as lactic acid); total dry matters were from 63.36 to 69.71 g/100 g kumru; and total free amino acid contents were from 0.101 to 0.251 g/100 g kumru (as leucine). Significant correlations were detected between biogenic amine concentrations and pHs, acidities, and total free amino acid contents. No significant correlations were detected between biogenic amine concentrations and total dry matter contents of kumru samples.